Android开发中怎样获取WebView的内容宽度高度

The extensive Android SDK allows you to do many great things with particular views like the WebView for displaying webpages on Android powered devices

Android SDK 的扩展通过使用特定的view允许你做许多事情比如WebView用来在Android手机上展示网页

As of lately while I was experimenting with the Android SDK I was using a WebView in one of my activities

最近我在体验Android SDK的时候在一个Activity中用到了WebView

From that particular WebView I needed to know the ContentHeight but also the ContentWidth

从WebView我不但想要知道ContentHeight还想知道ContentWidth

Now getting the contentHeight is easy like so:

现在的情况是获取contentHeight很easy如下

webviewgetContentHeight();

Unfortunately getting the contentWidth from a WebView is rather more difficult since there is not a simple method like:

不幸的是从一个WebView获取contentWidth是相当困难因为SDK中没有一个像这样的方法

// THIS METHOD DOES NOT EXIST!

webviewgetContentWidth();

There are ways to get the contentWidth of the rendered HTML page and that is through Javascript If Javascript can get it for you then you can also have them in your Java code within your Android App

当然是有方法获取contentWidth的就是通过Javascript来获取如果你能够支持Javascript那么你就可以在你的Android 程序中使用java代码来获取宽度

By using a JavascriptInterface with your WebView you can let Javascript communicate with your Android App Java code by invoking methods on a registered object that you can embed using the JavascriptInterface

通过在你的WebView中使用JavascriptInterface通过调用你注册的JavascriptInterface方法可以让Javascript和你的Android程序的java代码相互连通

So how does this work

怎么做呢？

For a quick example I created a simple Activity displaying a webview that loads a webpage wich displays a log message and a Toast message with the contentWidth wich was determined using Javascript Note that this happens AFTER the page was finished loading because before the page is finished loading the width might not be fully rendered Also keep in mind that if there is content loaded asynchronously that it doesnt affect widths (most likely only heights will be affected as the width is almost always fully declared in CSS files unless you have a % width webpage)

搭建一个快速的例子创建一个简单的展示webView的Activity一个LogCat消息一个Toast消息用来显示我们通过 Javascript获取的宽度注意这些会在网页完全加载之后显示因为在网页加载完成之前宽度可能不能够正确的获取到同时也要注意到如果是异 步加载这并不影响宽度（最多高度会受影响因为宽度总是在CSS文件中做了完全的定义除非在网页中你用了%宽度）

Below is the code of the Activity Mainjava:

下面的代码是Activity的代码

package compimmosandroidsampleswebviewcontentwidth;

import androidappActivity;

import androidosBundle;

import androidutilLog;

import androidwebkitWebView;

import androidwebkitWebViewClient;

import androidwidgetToast;

publicclass Main extends Activity {

privatefinalstatic String LOG_TAG = "WebViewContentWidth";

privatefinal Activity activity = this;

privatestaticint webviewContentWidth = ;

privatestatic WebView webview;

/ Called when the activity is first created /

@Override

publicvoid onCreate(Bundle savedInstanceState) {

superonCreate(savedInstanceState);

setContentView(Rlayoutmain);

webview = (WebView) findViewById(Ridwebview);

webviewgetSettings()setJavaScriptEnabled(true);

webviewsetSaveEnabled(true);

webviewaddJavascriptInterface(new JavaScriptInterface() "HTMLOUT");

webviewsetWebViewClient(new WebViewClient() {

@Override

publicvoid onPageFinished(WebView view String url) {

webviewloadUrl("javascript:windowHTMLOUTgetContentWidth(documentgetElementsByTagName(html)[]scrollWidth);");

}

});

webviewloadUrl(";);

}

class JavaScriptInterface {

publicvoid getContentWidth(String value) {

if (value != null) {

webviewContentWidth = IntegerparseInt(value);

Logd(LOG_TAG "Result from javascript: " + webviewContentWidth);

ToastmakeText( activity

"ContentWidth of webpage is: " +

webviewContentWidth +

"px" ToastLENGTH_SHORT)show();

}

}

}

}

Below is the XML layout used with the Activity wich only contains a simple WebView:

下面是Activity的Layout主要就是一个简单的WebView

<xml version="" encoding="utf">

<LinearLayout

xmlns:android=";

android:orientation="vertical"

android:layout_width="fill_parent"

android:layout_height="fill_parent">

<WebView android:id="@+id/webview"

android:layout_width="fill_parent"

android:layout_height="fill_parent" />

</LinearLayout>

AndroidManifestxml layout:

AndroidManifestxml代码

<xml version="" encoding="utf">

<manifest

xmlns:android=";

package="compimmosandroidsampleswebviewcontentwidth"

android:versionCode="" android:versionName="">

<application android:icon="@drawable/icon"

android:label="@string/app_name">

<activity android:name="Main"

android:label="@string/app_name">

<intentfilter>

<action android:name="androidintentactionMAIN" />

<category

android:name="androidintentcategoryLAUNCHER" />

</intentfilter>

</activity>

</application>

<usessdk android:minSdkVersion="" />

<usespermission android:name="androidpermissionINTERNET" />

</manifest>

You can also download the full source of Android Application WebViewContentWidth!

需要在AndroidManifestxml中加权限。

<uses-permission android:name="comandroidbrowserpermissionREAD_HISTORY_BOOKMARKS"></uses-permission>

String string = null;

ContentResolver contentResolver = getContentResolver();

Cursor cursor = contentResolverquery(Uriparse("content://browser/bookmarks"), new String[]{"url"}, null, null, null);

while (cursor != null && cursormoveToNext()) {

string = cursorgetString(cursorgetColumnIndex("url"));

Logd("debug", string == null "null":string);

}

首先，也是很重要的一步，就是下载jar包，丢到libs里面

Android studio玩家可以不下载jar包,在Gradle里面加入

dependencies {undefined

compile 'orgjsoup:jsoup:192'

}复制代码

然后，找到你心仪的网页去抓取数据

这里我们我继续使用美食的网页，然后右键查看网页源码，或者按F12，接下来可以看到一大堆标签：

Paste_Imagepng

找到需要的，例如上图这个 “美食天下” ，可以看到 “美食天下” 是放在以

为节点的 中，要获取这个“美食天下”，代码可以这样写:

try {undefined

//从一个URL加载一个Document对象。

Document doc = Jsoupconnect(">

protected void onCreate(Bundle savedInstanceState)

{

x = (WebView)thisfindViewById(RidwebView_viewTable);

xsetScrollBarStyle(ViewSCROLLBARS_INSIDE_OVERLAY);

xgetSettings()setBuiltInZoomControls(true);

xgetSettings()setJavaScriptEnabled(true);

xaddJavascriptInterface(new JsToJava(), "stub"); //JsToJava是内部类，代码在后面。stub是接口名字。

//xloadUrl(">

1作为演示，如下图所示，在界面中的链接按钮，目标是点击链接按钮调用手机浏览器打开特定的网站，首先建立响应方法：

linksetOnClickListener(buttonListener);

//

此外需要响应方法：

case RidimageButton1:

link();

break;

2在工程适当部分添加如下代码：

//press @link button and open brower to >

private void link() {

// TODO Auto-generated method stub

String url = ">

Intent intent = new Intent(IntentACTION_VIEW);

intentsetData(Uriparse(url));

startActivity(intent);

}

3导入相应类：String、Content、Uri等，编译无错后运行测试，可以发现触发事件发生时就可以调用手机浏览器打开特定网页，示例中网址可以替换成你需要的网址！运行后效果如下所示：

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