专注于blackberry » browser

每周一技：HyperLinkField

Taigoo — Tue, 14 Jul 2009 11:35:11 +0000

这是每周一技的第二篇了。

前一篇介绍了从BES读取contacts的技术以及遇到相关问题的解决方案（via 每周一技:从BES服务器上lookup联系人）。

本篇将介绍如何编写自定义的超级链接控件。

背景

在很多情况下，我们都会遇见超级连接的显示，遗憾的是在Blackberry没有提供类似于HyperLinkField的组件，这给我们增加了很多麻烦，如果能够解决该问题，将会是一个不错的选择。

分析

既然Blackberry API没有，我们自己可以写一个该Field，在这里，我们将之命名为HyperLinkField，以符合Blackberry API命名的规则。

实现

先看几张效果图：

图1，当focus在其他field时HyperLinkField的样式.

图2 当光标移到该field上时，颜色会变蓝，当然你也可以更改颜色。

图3，当点击该Field时，

图4，其菜单如下

该Get Page就会打开连接。

在编写代码需要注意一下几个地方：

参数的设置
Layout的处理
如何paint
菜单的处理
点击该field如何处理

下面给出部分重要的代码。

package com.taigoo.blackberry.weekskills.hyperlink;

import net.rim.device.api.ui.Color;
import net.rim.device.api.ui.DrawStyle;
import net.rim.device.api.ui.Field;
import net.rim.device.api.ui.MenuItem;
import net.rim.device.api.ui.ContextMenu;
import net.rim.device.api.ui.Font;
import net.rim.device.api.ui.Graphics;
import net.rim.device.api.ui.XYRect;
import net.rim.device.api.system.Display;
import net.rim.blackberry.api.browser.*;

public class HyperLinkField extends Field {

    private String _displayName ;
    private String _url;
    private Font _font;
    private MenuItem _openMenuItem;

    /**
     * Create a field for the hyperlink to implement the behaviour.
     * @param text  The text to display
     * @param url  The url to navigation
     */
    public HyperLinkField(String text, String url) {
        super();
        this._displayName = text;
        this._url = url;
        this._font = Font.getDefault().
                  derive(Font.DOTTED_UNDERLINED).
                  derive(Font.UNDERLINED);

        //create the menu item
        this._openMenuItem = new MenuItem("Get Page",100000,10) {
            public void run() {
                openUrl();
                }
               };
        }

        /**
         * set the display name
         * @param name
         */
        public void setDisplayName(String name) {
                this._displayName = name;
        }

        /**
         * Get the url
         * @return returns the url
         */
        public String getURL() {
                return this._url;
        }

        /**
         * @see net.rim.device.api.ui.Field#paint(Graphics)
         */
        protected void paint(Graphics g) {

                //draw text
                g.setColor(Color.BLUE);
                g.setFont(_font);
                g.drawText(this._displayName, 0, 0,(int)(
                        getStyle() & DrawStyle.ELLIPSIS |
                        DrawStyle.HALIGN_MASK ),
                        this.getPreferredWidth() );

                this.invalidate();
        }

        /**
         * @see net.rim.device.api.ui.Field#layout(int, int)
         */
        protected  void layout(int width , int height) {
                width = Math.min(this.getPreferredWidth(), width) ;
                height = getPreferredHeight() ;
                 // set dimensions
        setExtent( width, height );
        }

     protected void drawFocus(Graphics graphics,boolean on){
         XYRect rect = new XYRect();
         getFocusRect(rect);
         graphics.setColor(Color.RED);
         graphics.setDrawingStyle(Graphics.DRAWSTYLE_FOCUS, true);
         drawHighlightRegion(graphics, Field.HIGHLIGHT_FOCUS, on,
          rect.x, rect.y, rect.width, rect.height);
         this.invalidate();

     }

     protected  boolean navigationClick(int status, int time){
            openUrl();
             return true;

        }

     private void openUrl() {
         BrowserSession visitSession = Browser.getDefaultSession();
         visitSession.displayPage(_url);
         }

     protected  void  makeContextMenu(ContextMenu contextMenu){
          contextMenu.addItem(_openMenuItem);
          contextMenu.setDefaultItem(_openMenuItem);
     }
}

上面的代码已经很能说明问题了，我就不多解释了。

Field写好之后就是调用。调用也非常简单，和普通的代码一样，代码如下

 HyperLinkField _hyperlinkField = new HyperLinkField(
                      "Click here to visit Inbalckberry",
                      "http://www.inblackberry.com/blog/wap");
        this.add(_hyperlinkField);

每周一技术系列

每周一技:从BES服务器上lookup联系人

BlackBerry 应用程序开发者指南第二卷：高级–第5章 BlackBerry浏览器

Taigoo — Mon, 28 Apr 2008 04:28:57 +0000

第5章 BlackBerry浏览器

浏览器API

在浏览器显示Web内容

在一个浏览器域里显示Web内容

支持附加的MIME类型

注册一个HTTP过滤器

浏览器API

API名和包	描述
浏览器应用程序API(net.rim.blackberry.api.browser)	通过调用Blackberry浏览器,API允许应用程序显示web内容,包括支持的图片格式,HTML以及WML页面.也允许应用程序提供HTTP请求的一个Referrer,HTTP头,以及提交的内容.为获得更多信息,参看51页的”在浏览器显示Web内容”.
浏览器域API (net.rim.blackberry.api.browser.field)	此API允许一个应用程序获取web内容在一个浏览器域里的显示,此域包含在应用程序UI里.也允许应用程序配置浏览器域的表现形式,例如去除滚动条,或者指定仅显示屏幕一部分的浏览器域.
浏览器页面API(net.rim.blackberry.api.browser.plugin)	此API允许应用程序支持附加的MIME类型.当BlackBerry启动时,注册一个提交提供者,所有后发的浏览器对话将支持附加的MIME类型.为获取更多信息,参看66页的”支持附加的MIME类型”.
HTTP过滤器API (net.rim.device.api.io.http)	API允许应用程序向浏览器注册一个或多个URL的提供者.为获取更多信息,参看71页的”注册一个HTTP过滤器”.

在浏览器里显示Web内容

为了在浏览器里显示web内容,使用浏览器应用程序API(net.rim.blackberry.api.browser).

获取一个浏览器对话(Session)

为了获取一个缺省的BrowserSession对象,调用静态方法Browser.getDefaultSession().本对象允许你访问正在BlackBerry设备上运行的浏览器.

为了新增一个约会,调用EventList.importEvent().
注:获取缺省的对话会覆写任何BlackBerry设备上已经打开的对话.

为获取一个不同的对话,调用getSession().此方法根据它的唯一ID(UID)获取一个浏览器配置服务记录.为获得更多信息,参见113页的”服务定制API”.

请求一个Web页面

为请求一个Web页面,调用BrowserSession.displayPage()方法.下面的实例使用了仅接受一个URL的displayPage()方法.为指定一个referrer,HTTP头,以及提交的数据,使用接受这些附加信息的方法.

代码实例

下面来自Restaurants.java实例的引用创建了一个菜单,此菜单会在浏览器中显示一个Web页面.

private MenuItem browserItem = new MenuItem(

_resources.getString(MENUITEM_BROWSER), 110, 12) {

public void run() {

synchronized(store) {

String websiteUrl = websitefield.getText();

if (websiteUrl.length == 0) {

Dialog.alert(_resources.getString(ALERT_NO_WEBSITE));

}

else {

BrowserSession visit = Browser.getDefaultSession();

visit.displayPage(websiteUrl);

}

};

在浏览器域显示Web内容

为了在应用程序UI里包含一个浏览器域,使用浏览器域API (net.rim.device.api.browser.field).浏览器呈现(rendering)库为域处理web内容的描绘,然后返回一个BrowserField-在此域URL内容得到描绘-到你的应用程序显示.
注:用来打开一个浏览器域的浏览器对话独立于BlackBerry设备上缺省的浏览器对话. 任何打开的浏览器对话则不受影响.

RenderingApplication接口定义了一个描绘对话所需要的回调功能来帮助处理URL资源, RenderingApplication接口的实现在一个浏览器域里显示web内容.

为呈现创建一个独立的线程

当应用程序获取和显示浏览器域时,为阻止应用程序挂起,在一个独立线程上完成这些操作.

class CreationThread extends Thread {

BrowserFieldHandlerApplication _callBackApplication;

BasicRenderingApplication _renderingApplication;

public CreationThread(BrowserFieldHandlerApplication callBackApplication) {

_callBackApplication = callBackApplication;

}

public void run() {

_renderingApplication = new BasicRenderingApplication(_callBackApplication);

BrowserField field = _renderingApplication.getBrowserField("www.blackberry.com");

_callBackApplication.displayBrowserField(field);

}

设置呈现选项

覆写getRenderingOptions().如果你没有覆写此方法, 将使用缺省的呈现选项.为获得更多信息,参看API参考的RenderingOptions.

处理事件

eventOccurred()的实现处理事件,例如一个URL请求.

public Object eventOccurred(Event event) {

int eventId = event.getUID();

switch (eventId) {

case Event.EVENT_URL_REQUESTED : {

UrlRequestedEvent e = (UrlRequestedEvent) event;

// This is a regular request.

String absoluteUrl = e.getURL();

HttpConnection conn = null;

OutputStream out = null;

try {

conn = (HttpConnection) Connector.open(absoluteUrl);

FormData postData = e.getPostData();

if (postData == null) {

conn.setRequestMethod(HttpConnection.GET);

}

else {

conn.setRequestMethod(HttpConnection.POST);

byte[] postBytes = postData.getBytes();

conn.setRequestProperty(HttpProtocolConstants.HEADER_CONTENT_LENGTH,

String.valueOf(postBytes.length));

if (conn.getRequestProperty(

HttpProtocolConstants.HEADER_CONTENT_TYPE) == null) {

conn.setRequestProperty(

HttpProtocolConstants.HEADER_CONTENT_TYPE,

postData.getContentType());

}

out = conn.openOutputStream();

out.write(postBytes);

}

HttpHeaders requestHeaders = e.getHeaders();

if (requestHeaders != null) {

/* From http://www.w3.org/Protocols/rfc2616/rfc2616-sec15.html#sec15.1.3

* Clients SHOULD NOT include a Referer header field in a

* (non-secure) HTTP request if the referring page was

* transferred with a secure protocol.*/

String referer =

requestHeaders.getPropertyValue("referer");

boolean sendReferrer = true;

if (referer != null && referer.startsWith("https:") &&

!absoluteUrl.startsWith("https:")) {

sendReferrer = false;

}

int size = requestHeaders.size();

for (int i = 0; i < size; i++) {

String header = requestHeaders.getPropertyKey(i);

// Remove refer header if needed.

if ( !sendReferrer && header.equals("referer")) {

requestHeaders.removeProperty(i);

continue;

}

conn.setRequestProperty( header,

requestHeaders.getPropertyValue( i ) );

}

catch (IOException e1) {

}

finally {

if (out != null) {

try {

out.close();

}

catch (IOException e2) {

}

BrowserField browserField = getBrowserField(conn, e);

_callbackApplication.displayBrowserField(browserField);

break;

}

case Event.EVENT_BROWSER_FIELD_CHANGED : {

// Browser field title might have changed. Update title.

break;

}

case Event.EVENT_REDIRECT : {

RedirectEvent e = (RedirectEvent) event;

switch (e.getType()) {

case RedirectEvent.TYPE_SINGLE_FRAME_REDIRECT :

// Show redirect message.

Application.getApplication().invokeAndWait(new Runnable() {

public void run() {

Status.show("");

}

});

break;

case RedirectEvent.TYPE_JAVASCRIPT :

case RedirectEvent.TYPE_META :

case RedirectEvent.TYPE_300_REDIRECT :

}

String absoluteUrl = e.getLocation();

HttpConnection conn = null;

try {

conn = (HttpConnection) Connector.open(absoluteUrl);

}

catch (IOException e1) {

}

BrowserField browserField = getBrowserField(conn,

e.getOriginalEvent());

_callbackApplication.displayBrowserField(browserField);

break;

}

case Event.EVENT_CLOSE :

// Close the appication.

break;

case Event.EVENT_SET_HEADER :// no cache support

case Event.EVENT_SET_HTTP_COOKIE : // no cookie support

case Event.EVENT_HISTORY : // no history support

case Event.EVENT_LOADING_IMAGES :// no progress bar is supported

case Event.EVENT_EXECUTING_SCRIPT : // no progress bar is supported

case Event.EVENT_FULL_WINDOW : // no full window support

case Event.EVENT_STOP : // no stop loading support

default :

}

return null;

}

为呈现获取浏览器内容

getBrowserField()的实现为呈现获取浏览器内容. getBrowserField()方法调用RenderingSession.getBrowserField()获取一个浏览器域.应用程序不能直接实例化BrowserField

public BrowserField getBrowserField (String absoluteUrl) {

HttpConnection conn = null;

try {

conn = (HttpConnection) Connector.open(absoluteUrl);

// Set transcode to true.

conn.setRequestProperty( "x-rim-transcode-content", "*/*" );

}

catch (IOException e1) {

}

return getBrowserField(conn, null);

}

private BrowserField getBrowserField(HttpConnection conn, Event e) {

BrowserField field = null;

try {

field = _renderingSession.getBrowserField(conn, this, e);

}

catch (RenderingException re) {

return null;

}

// Add to the event queue a thread that invokes finishLoading().

Application.getApplication().invokeLater(new RenderingThread(field));

return field;

}

调用BrowserField.finishLoading().在下面的代码实例中, BrowserField.getBrowserField()将一个新的描绘线程加载到应用程序事件队列里来运行finishLoading().
注:HTML文件显示一个空白域,直到你调用BrowserField.finishLoading().在调用此方法前WML文件和图像可能加载 .在一个独立线程上运行finishLoading(),这样UI不会锁住.

class RenderingThread implements Runnable {

BrowserField _browserField;

RenderingThread(BrowserField field) {

_browserField = field;

}

public void run() {

try {

_browserField.finishLoading();

}

catch (RenderingException e) {

// Handle exception.

}

显示浏览器域

displayBrowserField()的实现删除屏幕内容,然后增加浏览器域到屏幕.

public void displayBrowserField(BrowserField browserField) {

synchronized (Application.getEventLock()) {

_vfm.deleteAll();

_vfm.add(browserField);

}

代码实例

下面的实例包含了3个文件: BasicRenderingApplication.java, BrowserFieldHandlerApplication.java, 以及 BrowserFieldSampleApp.java.

例:浏览器域实例

/**

* BasicRenderingApplication.java

package com.rim.samples.docs.browser;

import java.io.IOException;

import java.io.OutputStream;

import javax.microedition.io.Connector;

import javax.microedition.io.HttpConnection;

import net.rim.device.api.browser.field.*;

import net.rim.device.api.io.http.HttpHeaders;

import net.rim.device.api.io.http.HttpProtocolConstants;

import net.rim.device.api.system.Application;

import net.rim.device.api.ui.Graphics;

import net.rim.device.api.ui.component.Status;

import com.rim.samples.docs.browser.BrowserFieldHandlerApplication.*;

final public class BasicRenderingApplication implements RenderingApplication

{

RenderingSession _renderingSession;

BrowserFieldHandlerApplication _callbackApplication;

public BasicRenderingApplication(BrowserFieldHandlerApplication callBackApplication) {

_renderingSession = RenderingSession.getNewInstance();

_callbackApplication = callBackApplication;

}

/**

* * Simple method to get a browser field by specifying the URL.

* * This call blocks until the browser field is returned by RenderingSession.getBrowserField().

* * The browser field can continue to be rendered after the field is returned.

* *

* * @param absoluteUrl - absolute url of the page to render

* * @return rendered browser field

* */

public BrowserContent getBrowserField (String absoluteUrl) {

HttpConnection conn = null;

try {

conn = (HttpConnection) Connector.open(absoluteUrl);

// Set transcode to true.

conn.setRequestProperty( "x-rim-transcode-content", "*/*" );

}

catch (IOException e1) {

}

return getBrowserField(conn, null);

}

private BrowserContent getBrowserField(HttpConnection conn, Event e) {

BrowserContent field = null;

try {

field = _renderingSession.getBrowserContent(conn, this, e);

}

catch (RenderingException re) {

return null;

}

Application.getApplication().invokeLater(new RenderingThread(field));

return field;

}

/**

* * Invoked when an event occurs.

* */

public Object eventOccurred(Event event) {

int eventId = event.getUID();

switch (eventId) {

case Event.EVENT_URL_REQUESTED : {

UrlRequestedEvent e = (UrlRequestedEvent) event;

// this is a regular request

String absoluteUrl = e.getURL();

HttpConnection conn = null;

OutputStream out = null;

try {

conn = (HttpConnection) Connector.open(absoluteUrl);

byte[] postData = e.getPostData();

if (postData == null) {

conn.setRequestMethod(HttpConnection.GET);

}

else {

conn.setRequestMethod(HttpConnection.POST);

conn.setRequestProperty( HttpProtocolConstants.HEADER_CONTENT_LENGTH,

String.valueOf(postData.length));

out = conn.openOutputStream();

out.write(postData);

}

HttpHeaders requestHeaders = e.getHeaders();

if (requestHeaders != null) {

/* From http://www.w3.org/Protocols/rfc2616/rfc2616-sec15.html#sec15.1.3

* …

* Clients SHOULD NOT include a Referer header field in a

* (non-secure) HTTP request if the referring page was

* transferred with a secure protocol.

* */

String referer = requestHeaders.getPropertyValue("referer");

boolean sendReferrer = true;

if (referer != null && referer.startsWith("https:") &&

!absoluteUrl.startsWith("https:")) {

sendReferrer = false;

}

int size = requestHeaders.size();

for (int i = 0; i < size; i++) {

String header = requestHeaders.getPropertyKey(i);

// Remove refer header if needed.

if ( !sendReferrer && header.equals("referrer")) {

requestHeaders.removeProperty(i);

continue;

}

conn.setRequestProperty( header,

requestHeaders.getPropertyValue( i ) );

}

catch (IOException e1) {

}

finally {

if (out != null) {

try {

out.close();

}

catch (IOException e2) {

}

BrowserContent browserField = getBrowserField(conn, e);

_callbackApplication.displayBrowserField(browserField);

break;

}

case Event.EVENT_BROWSER_CONTENT_CHANGED : {

// Browser field title might have changed. Update title.

break;

}

case Event.EVENT_REDIRECT : {

RedirectEvent e = (RedirectEvent) event;

switch (e.getType()) {

// Show redirect message.

Application.getApplication().invokeAndWait(new Runnable() {

public void run() {

Status.show("");

}

});

break;

case RedirectEvent.TYPE_JAVASCRIPT :

case RedirectEvent.TYPE_META :

case RedirectEvent.TYPE_300_REDIRECT :

}

String absoluteUrl = e.getLocation();

HttpConnection conn = null;

try {

conn = (HttpConnection) Connector.open(absoluteUrl);

}

catch (IOException e1) {

}

BrowserContent browserField = getBrowserField(conn, e.getOriginalEvent());

_callbackApplication.displayBrowserField(browserField);

break;

}

case Event.EVENT_CLOSE :

// Close the appication.

break;

case Event.EVENT_TICK_CONTENT_READ : // No progress bar is supported.

case Event.EVENT_SET_HEADER : // No cache support.

case Event.EVENT_SET_HTTP_COOKIE : // No cookie support.

case Event.EVENT_HISTORY : // No history support

case Event.EVENT_LOADING_IMAGES : // No progress bar is supported.

case Event.EVENT_EXECUTING_SCRIPT : // No progress bar is supported.

case Event.EVENT_FULL_WINDOW : // No full window support.

case Event.EVENT_STOP : // No stop loading support.

default :

}

return null;

}

/**

* * Retrieves the pixels of height available for provided browser content.

* * @param browserField Content for which to retrieve available pixels of height.

* * @return Height available.

* */

public int getAvailableHeight(BrowserContent browserField) {

// Field has full screen.

return Graphics.getScreenHeight();

}

/**

* * Retrieves the pixels of width available for provided browser content.

* */

public int getAvailableWidth(BrowserContent browserField) {

// Field has full screen.

return Graphics.getScreenWidth();

}

/**

* * Retrieves the history position for provided browser content.

* */

public int getHistoryPosition(BrowserContent browserField) {

// No history support.

return 0;

}

/**

* * Retrieves cookies associated with a provided URL.

* */

public String getHTTPCookie(String url) {

// No cookie support.

return null;

}

/**

* * Retrieves the specified resource.

public HttpConnection getResource( RequestedResource resource, BrowserContent referrer)

{

if (resource == null) {

return null;

}

// Check if this is cache-only request.

if (resource.isCacheOnly()) {

// No cache support.

return null;

}

String url = resource.getUrl();

if (url == null) {

return null;

}

// If referrer is null, return the connection.

if (referrer == null) {

HttpConnection conn;

try {

return (HttpConnection) Connector.open(resource.getUrl());

}

catch (IOException e) {

return null;

}

else {

// If referrer is provided, set up the connection on a

// separate thread.

Application.getApplication().invokeLater(

new RetrieveThread(resource, referrer));

}

return null;

}

/**

* * Invokes the provided runnable object.

* */

public void invokeRunnable(Runnable runnable) {

(new Thread(runnable)).run();

}

class RenderingThread implements Runnable {

BrowserContent _browserField;

RenderingThread(BrowserContent field) {

_browserField = field;

}

public void run() {

try {

_browserField.finishLoading();

}

catch (RenderingException e) {

}

class RetrieveThread implements Runnable {

BrowserContent _browserField;

RequestedResource _resource;

RetrieveThread(RequestedResource resource, BrowserContent referrer) {

_browserField = referrer;

_resource = resource;

}

public void run() {

HttpConnection conn;

try {

conn = (HttpConnection) Connector.open(_resource.getUrl());

}

catch (IOException e) {

return;

}

_resource.setHttpConnection(conn);

_browserField.resourceReady(_resource);

}

/**

* BasicRenderingApplication.java

package com.rim.samples.docs.browser;

import java.io.IOException;

import java.io.OutputStream;

import javax.microedition.io.Connector;

import javax.microedition.io.HttpConnection;

import net.rim.device.api.browser.field.*;

import net.rim.device.api.io.http.HttpHeaders;

import net.rim.device.api.io.http.HttpProtocolConstants;

import net.rim.device.api.system.Application;

import net.rim.device.api.ui.Graphics;

import net.rim.device.api.ui.component.Status;

import com.rim.samples.docs.browser.BrowserFieldHandlerApplication.*;

final public class BasicRenderingApplication implements RenderingApplication {

RenderingSession _renderingSession;

BrowserFieldHandlerApplication _callbackApplication;

public BasicRenderingApplication(BrowserFieldHandlerApplication callBackApplication) {

_renderingSession = RenderingSession.getNewInstance();

_callbackApplication = callBackApplication;

}

/**

* * Simple method to get a browser field by specifying the URL.

* * This call blocks until the browser field is returned by RenderingSession.getBrowserField().

* * The browser field can continue to be rendered after the field is returned.

* *

* * @param absoluteUrl - absolute url of the page to render

* * @return rendered browser field

* */

public BrowserContent getBrowserField (String absoluteUrl) {

HttpConnection conn = null;

try {

conn = (HttpConnection) Connector.open(absoluteUrl);

// Set transcode to true.

conn.setRequestProperty("x-rim-transcode-content", "*/*" );

}

catch (IOException e1) {

}

return getBrowserField(conn, null);

}

private BrowserContent getBrowserField(HttpConnection conn, Event e) {

BrowserContent field = null;

try {

field = _renderingSession.getBrowserContent(conn, this, e);

}

catch (RenderingException re) {

return null;

}

Application.getApplication().invokeLater(new RenderingThread(field));

return field;

}

/**

* * Invoked when an event occurs.

* */

public Object eventOccurred(Event event) {

int eventId = event.getUID();

switch (eventId) {

case Event.EVENT_URL_REQUESTED : {

UrlRequestedEvent e = (UrlRequestedEvent) event;

// this is a regular request

String absoluteUrl = e.getURL();

HttpConnection conn = null;

OutputStream out = null;

try {

conn = (HttpConnection) Connector.open(absoluteUrl);

byte[] postData = e.getPostData();

if (postData == null) {

conn.setRequestMethod(HttpConnection.GET);

}

else {

conn.setRequestMethod(HttpConnection.POST);

conn.setRequestProperty( HttpProtocolConstants.HEADER_CONTENT_LENGTH,

String.valueOf(postData.length));

out = conn.openOutputStream();

out.write(postData);

}

HttpHeaders requestHeaders = e.getHeaders();

if (requestHeaders != null) {

/* From http://www.w3.org/Protocols/rfc2616/rfc2616-sec15.html#sec15.1.3

* …

* Clients SHOULD NOT include a Referer header field in a

* (non-secure) HTTP request if the referring page was

* transferred with a secure protocol.*/

String referer = requestHeaders.getPropertyValue("referer");

boolean sendReferrer = true;

if (referer != null && referer.startsWith("https:")

&& !absoluteUrl.startsWith("https:")) {

sendReferrer = false;

}

int size = requestHeaders.size();

for (int i = 0; i < size; i++) {

String header = requestHeaders.getPropertyKey(i);

// Remove refer header if needed.

if ( !sendReferrer && header.equals("referrer")) {

requestHeaders.removeProperty(i);

continue;

}

conn.setRequestProperty( header, requestHeaders.getPropertyValue( i ) );

}

catch (IOException e1) {

}

finally {

if (out != null) {

try {

out.close();

}

catch (IOException e2) {

}

BrowserContent browserField = getBrowserField(conn, e);

_callbackApplication.displayBrowserField(browserField);

break;

}

case Event.EVENT_BROWSER_CONTENT_CHANGED : {

// Browser field title might have changed. Update title.

break;

}

case Event.EVENT_REDIRECT : {

RedirectEvent e = (RedirectEvent) event;

switch (e.getType()) {

case RedirectEvent.TYPE_SINGLE_FRAME_REDIRECT :

// Show redirect message.

Application.getApplication().invokeAndWait(new Runnable() {

public void run() {

Status.show("");

}

});

break;

case RedirectEvent.TYPE_JAVASCRIPT :

case RedirectEvent.TYPE_META :

case RedirectEvent.TYPE_300_REDIRECT :

}

String absoluteUrl = e.getLocation();

HttpConnection conn = null;

try {

conn = (HttpConnection) Connector.open(absoluteUrl);

}

catch (IOException e1) {

}

BrowserContent browserField = getBrowserField(conn, e.getOriginalEvent());

_callbackApplication.displayBrowserField(browserField);

break;

}

case Event.EVENT_CLOSE :

// Close the appication.

break;

case Event.EVENT_TICK_CONTENT_READ : // No progress bar is supported.

case Event.EVENT_SET_HEADER : // No cache support.

case Event.EVENT_SET_HTTP_COOKIE : // No cookie support.

case Event.EVENT_HISTORY : // No history support.

case Event.EVENT_LOADING_IMAGES : // No progress bar is supported.

case Event.EVENT_EXECUTING_SCRIPT : // No progress bar is supported

case Event.EVENT_FULL_WINDOW : // No full window support

case Event.EVENT_STOP : // No stop loading support.

default :

}

return null;

}

/**

* * Retrieves the pixels of height available for provided browser content.

* * @param browserField Content for which to retrieve available pixels of height.

* * @return Height available.

* */

public int getAvailableHeight(BrowserContent browserField) {

// Field has full screen.

return Graphics.getScreenHeight();

}

/**

* * Retrieves the pixels of width available for provided browser content.

* */

public int getAvailableWidth(BrowserContent browserField) {

// Field has full screen.

return Graphics.getScreenWidth();

}

/**

* * Retrieves the history position for provided browser content.

* */

public int getHistoryPosition(BrowserContent browserField) {

// No history support.

return 0;

}

/**

* * Retrieves cookies associated with a provided URL.

* */

public String getHTTPCookie(String url) {

// No cookie support.

return null;

}

/**

* * Retrieves the specified resource.

* */

public HttpConnection getResource( RequestedResource resource, BrowserContent referrer)

{

if (resource == null) {

return null;

}

// Check if this is cache-only request.

if (resource.isCacheOnly()) {

// No cache support.

return null;

}

String url = resource.getUrl();

if (url == null) {

return null;

}

// If referrer is null, return the connection.

if (referrer == null) {

HttpConnection conn;

try {

return (HttpConnection) Connector.open(resource.getUrl());

}

catch (IOException e) {

return null;

}

else {

// If referrer is provided, set up the connection on a

// separate thread.

Application.getApplication().invokeLater(

new RetrieveThread(resource, referrer));

}

return null;

}

/**

* * Invokes the provided runnable object.

* */

public void invokeRunnable(Runnable runnable) {

(new Thread(runnable)).run();

}

class RenderingThread implements Runnable {

BrowserContent _browserField;

RenderingThread(BrowserContent field) {

_browserField = field;

}

public void run() {

try {

browserField.finishLoading();

}

catch (RenderingException e) {

}

class RetrieveThread implements Runnable {

BrowserContent _browserField;

RequestedResource _resource;

RetrieveThread(RequestedResource resource, BrowserContent referrer) {

_browserField = referrer;

_resource = resource;

}

public void run() {

HttpConnection conn;

try {

conn = (HttpConnection) Connector.open(_resource.getUrl());

}

catch (IOException e) {

return;

}

_resource.setHttpConnection(conn);

_browserField.resourceReady(_resource);

}

支持附加MIME类型

浏览器页面API在net.rim.device.api.browser.plugin包中,它允许第三方应用程序向描绘库将它们自己注册为BlackBerry浏览器不支持的MIME类型的描绘提供者.
注: 如果你试着注册一个BlackBerry浏览器已经支持的MIME类型，BrowserFieldProviderRegistry.register()方法会抛出一个异常.为得到支持的MIME类型列表,调用RenderingSession.getSupportedMimeType().

注册一个MIME类型的呈现提供者

为支持附加的MIME类型,需要扩展BrowserContentProvider抽象类.为了指定显示特性,例如没有滚动条显示或全屏显示,需要实现BrowserPageContext接口.

呈现的类库调用BrowserContentProvider.getAccept()和BrowserContentProvider.getSupportedMimeTypes()标志提供者呈现的MIME类型.

列出接受的MIME类型

getAccept()和getSupportedMimeTypes()的实现列出了提供者接受的MIME类型,它们给定了一组呈现的选项. getAccept()方法考虑到已经设置的呈现选项.这个例子假设没有设置呈现选项.为得到更多信息.参看API参考的RenderingOptions

public String[] getAccept(RenderingOptions context) {

// Return subset of getSupportedMimeTypes() if accept depends on rendering

// options. For example, HTML can be turned off in the rendering options.

// This would cause HTMLConverter to remove HTML MIME types.

return ACCEPT;

}

public String[] getSupportedMimeTypes() {

return ACCEPT;

}

指定显示特征

BrowserPageContext接口的实现指定了显示的特征.如果没有实现此接口,将使用缺省的值.

在本例中,所有属性都是整型.一个带有Boolean,String,和Object属性的应用程序将实现对应的方法.

public boolean getPropertyWithBooleanValue(int id, boolean defaultValue) {

// TODO Implement.

return false;

}

public int getPropertyWithIntValue(int id, int defaultValue) {

if (id == BrowserPageContext.DISPLAY_STYLE) {

// Turn off the scroll bar.

return BrowserPageContext.STYLE_NO_VERTICAL_SCROLLBAR;

}

return 0;

}

public Object getPropertyWithObjectValue(int id, Object defaultValue) {

// TODO Implement.

return null;

}

public String getPropertyWithStringValue(int id, String defaultValue) {

// TODO Implement.

return null;

}

获取一个域呈现内容

实现getBrowserContent(BrowserContentProviderContext)方法.

public BrowserContent getBrowserContent( BrowserContentProviderContext context)

throws RenderingException {

if (context == null) {

throw new RenderingException("No Context is passed into Provider");

}

BrowserContentBaseImpl browserContentBaseImpl = new

BrowserContentBaseImpl(context.getHttpConnection().getURL(), null,

context.getRenderingApplication(),

context.getRenderingSession().getRenderingOptions(), context.getFlags());

VerticalFieldManager vfm = new VerticalFieldManager(Manager.VERTICAL_SCROLL);

vfm.add(new LabelField("Mime type: ") );

vfm.add(new LabelField(ACCEPT[0]));

vfm.add(new SeparatorField());

vfm.add(new LabelField("Content of the resource file: \n"));

vfm.add(new SeparatorField());

try {

HttpConnection conn = context.getHttpConnection();

InputStream in = conn.openInputStream();

byte[] data = IOUtilities.streamToBytes(in);

vfm.add(new LabelField(new String(data)));

}

catch (IOException e) {

// TODO Implement.

e.printStackTrace();

}

browserContentBaseImpl.setContent(vfm);

browserContentBaseImpl.setTitle(ACCEPT[0]);

// Set browser page context, this will tell the browser how to display this

// field.

browserContentBaseImpl.setBrowserPageContext(this);

return browserContentBaseImpl;

}

在BlackBerry启动时注册

创建一个类库工程,将它的属性设置为启动时自动运行.在libMain()里,调用BrowserFieldProviderRegistry.getInstance()方法,然后再调用invoke register().

public static void libMain( String[] args ) {

BrowserContentProviderRegistry converterRegistry =

BrowserContentProviderRegistry.getInstance();

if (converterRegistry != null) {

converterRegistry.register(new BrowserPlugin());

}

代码实例

下面的例子包含2个文件, LoaderApp.java和BrowserPlugin.java.当BlackBerry设备启动时LoaderApp.java增加一个新支持的MIME类型. BrowserPlugin.java包含了一个扩展了BrowserContentProvider的类.

例: BrowserPlugin.java和LoaderApp.java

/**

* LoaderApp.java

package com.rim.samples.docs.browser;

import net.rim.device.api.browser.plugin.BrowserContentProviderRegistry;

final class LoaderApp {

public static void libMain( String[] args ) {

BrowserContentProviderRegistry converterRegistry =

BrowserContentProviderRegistry.getInstance();

if (converterRegistry != null) {

converterRegistry.register(new BrowserPlugin());

}

/**

* BrowserPlugin.java

package com.rim.samples.docs.browser;

import java.io.IOException;

import java.io.InputStream;

import javax.microedition.io.HttpConnection;

import net.rim.device.api.browser.field.*;

import net.rim.device.api.browser.plugin.*;

import net.rim.device.api.ui.Manager;

import net.rim.device.api.ui.component.LabelField;

import net.rim.device.api.ui.component.SeparatorField;

import net.rim.device.api.ui.container.VerticalFieldManager;

/**

* Create a file with xxtest extension and associate that type with

* application/x-vnd.rim.xxxtest mime type on any server.

public final class BrowserPlugin extends BrowserContentProvider

implements BrowserPageContext {

private static final String[] ACCEPT = {"application/x-vnd.rim.xxxtest"};

/**

* Retrieves list of mime types this provider can accept given a set of rendering options.

* * @param context Rendering options in place this provider should consider.

* * @return Array of mime types this provider will accept, given the provided rendering

* options.

**/

public String[] getAccept(RenderingOptions context) {

// Return subset of getSupportedMimeTypes() if accept depends in rendering options.

// For example HTML can be disabled in the rendering options, and HTMLConverter would remove

// html MIME types.

return ACCEPT;

}

/**

* Retrieves a browser content capable of rendering the mime content this provider

* can handle.

* @param context Provider context object provided by rendering session.

* @return Browser content to render specialized content.

public BrowserContent getBrowserContent( BrowserContentProviderContext context)

throws RenderingException {

if (context == null) {

throw new RenderingException("No Context is passed into Provider");

}

BrowserContentBaseImpl browserContentBaseImpl =

new BrowserContentBaseImpl(context.getHttpConnection().getURL(),

null, context.getRenderingApplication(),

context.getRenderingSession().getRenderingOptions(),

context.getFlags());

VerticalFieldManager vfm = new VerticalFieldManager(Manager.VERTICAL_SCROLL);

vfm.add(new LabelField("Mime type: ") );

vfm.add(new LabelField(ACCEPT[0]));

vfm.add(new SeparatorField());

vfm.add(new LabelField("Content of the resource file: \n"));

vfm.add(new SeparatorField());

try {

HttpConnection conn = context.getHttpConnection();

InputStream in = conn.openInputStream();

int numBytes = in.available();

byte[] data = new byte[numBytes];

in.read(data, 0, numBytes);

vfm.add(new LabelField(new String(data)));

}

catch (IOException e) {

e.printStackTrace();

}

browserContentBaseImpl.setContent(vfm);

browserContentBaseImpl.setTitle(ACCEPT[0]);

// Set browser page context. This tells the browser how to display this field.

browserContentBaseImpl.setBrowserPageContext(this);

return browserContentBaseImpl;

}

/**

* * Retrieves all the mime content types supported by this provider.

* * @return Mime types this converter supports.

* */

public String[] getSupportedMimeTypes() {

return ACCEPT;

}

/**

* * Retrieves value of specified property as a boolean value.

* * @param id ID of property to query.

* * @param defaultValue Expected default value of property.

* * @return Current value of property.

* */

public boolean getPropertyWithBooleanValue(int id, boolean defaultValue) {

return false;

}

/**

* Retrieves value of specified property as an int.

* @param id ID of property to query.

* @param defaultValue Expected default value of property.

* @return Current value of property.

public int getPropertyWithIntValue(int id, int defaultValue) {

if (id == BrowserPageContext.DISPLAY_STYLE) {

// Disable the scroll bar.

return BrowserPageContext.STYLE_NO_VERTICAL_SCROLLBAR;

}

return 0;

}

/**

* Retrieves value of specified property as an object.

* @param id ID of property to query.

* @param defaultValue Expected default value of property.

* @return Current value of property.

public Object getPropertyWithObjectValue(int id, Object defaultValue) {

return null;

}

/* Retrieves value of specified property as a String value.

* @param id - ID of property to query.

* @param defaultValue - Expected default value of property.

* @return Current value of property.

public String getPropertyWithStringValue(int id, String defaultValue) {

return null;

}

注册一个HTTP过滤器

HTTP过滤器API(net.rim.device.api.io.http)允许应用程序向浏览器注册一个指定URL的提供者.当用户数输入指定的URL时,连接栈(connection stack)会重新路由到指定的应用程序.
注: 当应用程序第一次访问HTTP 过滤器API时,检查一个 NoClassDefFoundError.如果系统管理员通过应用程序控制限制访问HTTP过滤器API,将抛出此错误. 为获得更多信息,参看BlackBerry应用程序开发者指南 第2卷:高级第1卷:基础.

注册一个HTTP 过滤器

调用HttpFilterRegistry.registerFilter().提供拦截的URL以及定义拦截行为的应用程序包名作为参数.

HttpFilterRegistry.registerFilter("content.blackberry.com",

"com.rim.samples.device.httpfilterdemo.precanned");

启动时完成注册

创建一个类库工程,然后将它的属性设置为启动时自动运行.调用libMain()里的registerFilter().

代码实例

下面的实例包含2个文件: PackageManager.java,它在启动时注册过滤器,以及Protocol.java,它定义过滤器的行为.

例: HTTP 过滤器实例

/**

* PackageManager.java

package com.rim.samples.docs.httpfilterdemo;

import net.rim.device.api.io.http.HttpFilterRegistry;

/**

* This class runs on startup of the device and registers the necessary http filters.

final class PackageManager

{

public static void libMain(String[] args) {

HttpFilterRegistry.registerFilter("www.blackberry.com",

"com.rim.samples.docs.httpfilterdemo.filter");

}

/**

* Protocol.java

package com.rim.samples.docs.httpfilterdemo.filter;

import net.rim.device.api.io.FilterBaseInterface;

import java.io.*;

import javax.microedition.io.*;

/**

* This class implements a simple pass through mechanism that writes out the http response headers to System.out.

public final class Protocol implements FilterBaseInterface, HttpConnection {

private HttpConnection _subConnection;

/**

* Defined by FilterBaseInterface.

* This method opens a filtered Http Connection.

public Connection openFilter( String name, int mode, boolean timeouts )

throws IOException {

_subConnection = (HttpConnection)Connector.open("http:" + name +

";usefilter=false", mode, timeouts);

if (_subConnection != null) {

return this;

}

// Filed to open the sub connection; so let us fail too.

return null;

}

// Return a string representation of the URL for this connection.

public String getURL() {

return _subConnection.getURL();

}

// Returns the protocol name of the URL of this HttpConnection. e.g., http or https.

public String getProtocol() {

return _subConnection.getProtocol();

}

// Returns the host information of the URL of this HttpConnection.

//e.g. host name or IPv4 address.

public String getHost() {

return _subConnection.getHost();

}

// Returns the file portion of the URL of this HttpConnection.

public String getFile() {

return _subConnection.getFile();

}

/**

* Returns the ref portion of the URL of this HttpConnection.

* RFC2396 specifies the optional fragment identifier as the the text after the crosshatch (#)

* character in the URL. This information may be used by the user agent as additional

* reference information after the resource is successfully retrieved. The format and

* interpretation of the fragment identifier is dependent on the media type[RFC2046] of

* the retrieved information.

public String getRef() {

return _subConnection.getRef();

}

// Returns the network port number of the URL for this HttpConnection.

public int getPort() {

return _subConnection.getPort();

}

// Returns the query portion of the URL of this HttpConnection.

// RFC2396 defines the query component as the text after the first

// question-mark (?) character in the URL.

public String getQuery() {

return _subConnection.getQuery();

}

// Get the current request method. e.g. HEAD, GET, POST The default value is GET.

public String getRequestMethod() {

return _subConnection.getRequestMethod();

}

// Set the method for the URL request, one of: GET, POST, HEAD,

//subject to protocol restrictions. The default method is GET.

public void setRequestMethod(String method) throws IOException {

_subConnection.setRequestMethod(method);

}

// Returns the value of the named general request property for this connection.

public String getRequestProperty(String key) {

return _subConnection.getRequestProperty(key);

}

// Sets the general request property. If a property with the key already exists, overwrite its value with the new value.

// Note: HTTP requires all request properties which can legally have multiple instances with the

// same key to use a comma-separated list syntax which enables multiple properties to be appended into a single property.

public void setRequestProperty(String key, String value) throws IOException {

System.out.println("Request property : " + key + ", " + value );

_subConnection.setRequestProperty(key, value);

}

// Returns the HTTP response status code.

public int getResponseCode() throws IOException {

return _subConnection.getResponseCode();

}

// Gets the HTTP response message, if any, returned along with

//the response code from a server.

public String getResponseMessage() throws IOException {

return _subConnection.getResponseMessage();

}

// Returns the value of the expires header field.

public long getExpiration() throws IOException {

return _subConnection.getExpiration();

}

// Returns the value of the date header field.

public long getDate() throws IOException {

return _subConnection.getDate();

}

// Returns the value of the last-modified header field.

//The result is the number of milliseconds since January 1, 1970 GMT.

public long getLastModified() throws IOException {

return _subConnection.getLastModified();

}

// Returns the value of the named header field.

public String getHeaderField(String name) throws IOException

{

String value = _subConnection.getHeaderField(name);

System.out.println("Response property : " + name + ", " + value );

return value;

}

// Returns the value of the named field parsed as a number.

public int getHeaderFieldInt(String name, int def)

throws IOException {

return _subConnection.getHeaderFieldInt(name, def);

}

// Returns the value of the named field parsed as date. The result is the

// number of milliseconds since January 1, 1970 GMT represented by the named field.

public long getHeaderFieldDate(String name, long def) throws IOException {

return _subConnection.getHeaderFieldDate(name, def);

}

// Gets a header field value by index.

public String getHeaderField(int n) throws IOException {

return _subConnection.getHeaderField(n);

}

// Gets a header field key by index.

public String getHeaderFieldKey(int n) throws IOException {

return _subConnection.getHeaderFieldKey(n);

}

// Returns the type of content that the resource connected to is providing.

public String getType() {

return _subConnection.getType();

}

// Returns a string describing the encoding of the content

//which the resource connected to is providing.

public String getEncoding() {

return _subConnection.getEncoding();

}

// Returns the length of the content which is being provided.

public long getLength() {

return _subConnection.getLength();

}

// Opens and returns an input stream for a connection.

public InputStream openInputStream() throws IOException {

return _subConnection.openInputStream();

}

// Opens and returns a data input stream for a connection.

public DataInputStream openDataInputStream() throws IOException {

return _subConnection.openDataInputStream();

}

// Opens and returns an output stream for a connection.

public OutputStream openOutputStream() throws IOException {

return _subConnection.openOutputStream();

}

// Opens and returns a data output stream for a connection.

public DataOutputStream openDataOutputStream() throws IOException {

return _subConnection.openDataOutputStream();

}

// Closes the connection.

public void close() throws IOException {

_subConnection.close();

}

Last Updated:2007年1月30日

专注于blackberry » browser

每周一技：HyperLinkField

BlackBerry 应用程序开发者指南 第二卷：高级–第5章 BlackBerry浏览器

第5章 BlackBerry浏览器

在浏览器里显示Web内容

请求一个Web页面

在浏览器域显示Web内容

支持附加MIME类型

注册一个MIME类型的呈现提供者

注册一个HTTP过滤器

注册一个HTTP 过滤器

BlackBerry 应用程序开发者指南第二卷：高级–第5章 BlackBerry浏览器