Android WebView使用详解

最近项目中用到WebView， 就根据自己项目的需求重写了个WebView。 下面简单介绍一下使用情况，以作记忆~~

前面本人写过一个WebView加载进度显示的博客，有需要的可以去看看：WebView加载进度Progress的显示

一、WebView基本属性设置

下面只是根据个人项目需求设置的部分属性，还有其他属性，读者可以查看相关文档，选择自己需要的属性设置，不多说。

private void init(Context context) {//添加进度 条mProgressbar = new ProgressBar(context, null, android.R.attr.progressBarStyleHorizontal);mProgressbar.setLayoutParams(new LayoutParams(LayoutParams.MATCH_PARENT, 5, 0, 0));addView(mProgressbar);WebSettings webSettings = this.getSettings();webSettings.setJavaScriptEnabled(true);webSettings.setSupportZoom(true);//webSettings.setUseWideViewPort(true);this.requestFocus();this.setWebViewClient(mWebViewClient);this.setWebChromeClient(mWebChromeClient);this.setDownloadListener(mDownloadListener);this.loadUrl(mUrl);this.onResume();}

二、WebViewClient使用

       WebViewClient主要提供网页加载各个阶段的通知回调，比如网页开始加载的onPageStarted，网页结束加载onPageFinished等，所以有关网页加载的设计在这里实现。

private WebViewClient mWebViewClient = new WebViewClient() {@Overridepublic boolean shouldOverrideUrlLoading(WebView view, String url) {// TODO Auto-generated method stubLog.i(TAG, "shouldOverrideUrlLoading : ");return super.shouldOverrideUrlLoading(view, url);}@Overridepublic void onPageStarted(WebView view, String url, Bitmap favicon) {// TODO Auto-generated method stubLog.i(TAG, "onPageStarted : "+url);if (StringUtil.isStartWith(url, "market://")) {Log.i(TAG, "onPageStarted : start with market");if (PackageUtil.isApkAvailable(mActivity, "com.android.vending")) {//隐藏webview，显示google paly storeLog.i(TAG, "onPageStarted : google play");mActivity.moveTaskToBack(true);Uri uri = Uri.parse(url);Intent intent = new Intent(Intent.ACTION_VIEW, uri);mActivity.startActivity(intent);//统计GP打开的数量StatsHelper.statAdGoGP(Constants.GALabel.ADS_GoGP_BYGP, mId);mActivity.finish();} else {Log.i(TAG, "onPageStarted : no google play");url = StringUtil.replaceSubString(url, "market://", "https://play.google.com/store/apps/");Log.i(TAG, "onPageStarted replace : "+url);loadUrl(url);//统计web打开的数量StatsHelper.statAdGoWeb(Constants.GALabel.ADS_GoGP_BYWEB, mId);}}super.onPageStarted(view, url, favicon);}@Overridepublic void onPageFinished(WebView view, String url) {// TODO Auto-generated method stubLog.i(TAG, "onPageFinished : ");super.onPageFinished(view, url);}@Overridepublic void onReceivedError(WebView view, int errorCode,String description, String failingUrl) {// TODO Auto-generated method stubLog.i(TAG, "onReceivedError : ");super.onReceivedError(view, errorCode, description, failingUrl);}@Overridepublic void doUpdateVisitedHistory(WebView view, String url,boolean isReload) {// TODO Auto-generated method stubLog.i(TAG, "doUpdateVisitedHistory : ");super.doUpdateVisitedHistory(view, url, isReload);}};

三、WebChromeClient的使用

       WebChromeClient主要提供网页加载过程中用户需要的数据内容，比如返回网页的title/favicon，网页加载进度progress等。

private WebChromeClient mWebChromeClient = new WebChromeClient() {@Overridepublic void onProgressChanged(WebView view, int newProgress) {            if (newProgress == 100) {            mProgressbar.setVisibility(GONE);            } else {                if (mProgressbar.getVisibility() == GONE)                mProgressbar.setVisibility(VISIBLE);                mProgressbar.setProgress(newProgress);            }            super.onProgressChanged(view, newProgress);}@Overridepublic void onReceivedTitle(WebView view, String title) {// TODO Auto-generated method stubsuper.onReceivedTitle(view, title);}@Overridepublic void onReceivedTouchIconUrl(WebView view, String url,boolean precomposed) {// TODO Auto-generated method stubsuper.onReceivedTouchIconUrl(view, url, precomposed);}@Overridepublic boolean onCreateWindow(WebView view, boolean isDialog,boolean isUserGesture, Message resultMsg) {// TODO Auto-generated method stubreturn super.onCreateWindow(view, isDialog, isUserGesture, resultMsg);}};

四、下载监听DownloadListener使用

       当用户点击网页跳转到下载时，用户又应该如何监听该下载呢？ 答案很简单，就是用DownloadListener进行监听。

private DownloadListener mDownloadListener = new DownloadListener() {@Overridepublic void onDownloadStart(String url, String userAgent,String contentDisposition, String mimetype, long contentLength) {// TODO Auto-generated method stubLog.i(TAG, "onDownloadStart url = "+url);//DownloaderTask task=new DownloaderTask();//task.execute(url);try {  //调用系统下载管理器DownloadBySystem download = new DownloadBySystem(mActivity);download.download(mId, url);//统计下载StatsHelper.statAdDownload(Constants.GALabel.ADS_LOAD_SYSTEM, mId);} catch (Exception e) {  //如果手机下载管理器关闭或不能使用，则使用webview下载// TODO: handle exception//DownloaderTask task = new DownloaderTask();//task.execute(url);DownloadByMyself download = new DownloadByMyself(mActivity);download.download(mId, url);//统计下载StatsHelper.statAdDownload(Constants.GALabel.ADS_LOAD_WEBVIEW, mId);}}};

五、如何回退上一页

       如果在webview中进行了多次跳转，按back键只会回退到上一个页面，而不是直接退出webview，又应该如何实现？这个也不难，只要监听到back键的事件，然后让webview来消耗该事件，实现webview的回退功能，就OK~~

@Overridepublic boolean onKeyDown(int keyCode, KeyEvent event) {// TODO Auto-generated method stubif (keyCode == KeyEvent.KEYCODE_BACK && this.canGoBack()) {this.goBack();return true;}return false;} 

六、监听webview的滚动

       滚动在webview设置在有进度条时很有必要，比如，webview在头部设置了进度条，如果你不再做一些处理，那么在webview向上滚动时，进度条就会向上滚动，当然也就隐藏掉了。所以在onScrollChanged中做一些处理十分必要

protected void onScrollChanged(int l, int t, int oldl, int oldt) {// TODO Auto-generated method stub        LayoutParams lp = (LayoutParams) mProgressbar.getLayoutParams();        lp.x = l;        lp.y = t;        mProgressbar.setLayoutParams(lp);        super.onScrollChanged(l, t, oldl, oldt);}

七、 代码

         下面是我重写的WebView的全部代码，仅供参考：

package com.mobisummer.ads.banner;import java.io.File;import java.io.FileOutputStream;import java.io.InputStream;import java.net.HttpURLConnection;import java.net.URL;import java.net.URLDecoder;import android.annotation.SuppressLint;import android.app.Activity;import android.content.Context;import android.content.Intent;import android.graphics.Bitmap;import android.net.Uri;import android.os.AsyncTask;import android.os.Environment;import android.os.Message;import android.util.Log;import android.view.KeyEvent;import android.webkit.DownloadListener;import android.webkit.WebChromeClient;import android.webkit.WebSettings;import android.webkit.WebView;import android.webkit.WebViewClient;import android.widget.ProgressBar;import com.mobisummer.ads.banner.util.Constants;import com.mobisummer.ads.banner.util.DownloadByMyself;import com.mobisummer.ads.banner.util.DownloadBySystem;import com.mobisummer.ads.banner.util.FileUtil;import com.mobisummer.ads.banner.util.PackageUtil;import com.mobisummer.ads.banner.util.StatsHelper;import com.mobisummer.ads.banner.util.StringUtil;public class AdsWebView extends WebView {private static final String TAG = "wxx";private Activity mActivity;private String mUrl;private int mId;private ProgressBar mProgressbar;public AdsWebView(Context context, int id, String url) {super(context);this.mActivity = (Activity) context;this.mUrl = url;this.mId = id;init(context);}@SuppressLint({ "SetJavaScriptEnabled", "NewApi" })private void init(Context context) {//添加进度 条mProgressbar = new ProgressBar(context, null, android.R.attr.progressBarStyleHorizontal);mProgressbar.setLayoutParams(new LayoutParams(LayoutParams.MATCH_PARENT, 5, 0, 0));addView(mProgressbar);WebSettings webSettings = this.getSettings();webSettings.setJavaScriptEnabled(true);webSettings.setSupportZoom(true);//webSettings.setUseWideViewPort(true);this.requestFocus();this.setWebViewClient(mWebViewClient);this.setWebChromeClient(mWebChromeClient);this.setDownloadListener(mDownloadListener);this.loadUrl(mUrl);this.onResume();}private WebViewClient mWebViewClient = new WebViewClient() {@Overridepublic boolean shouldOverrideUrlLoading(WebView view, String url) {// TODO Auto-generated method stubLog.i(TAG, "shouldOverrideUrlLoading : ");return super.shouldOverrideUrlLoading(view, url);}@Overridepublic void onPageStarted(WebView view, String url, Bitmap favicon) {// TODO Auto-generated method stubLog.i(TAG, "onPageStarted : "+url);if (StringUtil.isStartWith(url, "market://")) {Log.i(TAG, "onPageStarted : start with market");if (PackageUtil.isApkAvailable(mActivity, "com.android.vending")) {//隐藏webview，显示google paly storeLog.i(TAG, "onPageStarted : google play");mActivity.moveTaskToBack(true);Uri uri = Uri.parse(url);Intent intent = new Intent(Intent.ACTION_VIEW, uri);mActivity.startActivity(intent);//统计GP打开的数量StatsHelper.statAdGoGP(Constants.GALabel.ADS_GoGP_BYGP, mId);mActivity.finish();} else {Log.i(TAG, "onPageStarted : no google play");url = StringUtil.replaceSubString(url, "market://", "https://play.google.com/store/apps/");Log.i(TAG, "onPageStarted replace : "+url);loadUrl(url);//统计web打开的数量StatsHelper.statAdGoWeb(Constants.GALabel.ADS_GoGP_BYWEB, mId);}}super.onPageStarted(view, url, favicon);}@Overridepublic void onPageFinished(WebView view, String url) {// TODO Auto-generated method stubLog.i(TAG, "onPageFinished : ");super.onPageFinished(view, url);}@Overridepublic void onReceivedError(WebView view, int errorCode,String description, String failingUrl) {// TODO Auto-generated method stubLog.i(TAG, "onReceivedError : ");super.onReceivedError(view, errorCode, description, failingUrl);}@Overridepublic void doUpdateVisitedHistory(WebView view, String url,boolean isReload) {// TODO Auto-generated method stubLog.i(TAG, "doUpdateVisitedHistory : ");super.doUpdateVisitedHistory(view, url, isReload);}};private WebChromeClient mWebChromeClient = new WebChromeClient() {@Overridepublic void onProgressChanged(WebView view, int newProgress) {            if (newProgress == 100) {            mProgressbar.setVisibility(GONE);            } else {                if (mProgressbar.getVisibility() == GONE)                mProgressbar.setVisibility(VISIBLE);                mProgressbar.setProgress(newProgress);            }            super.onProgressChanged(view, newProgress);}@Overridepublic void onReceivedTitle(WebView view, String title) {// TODO Auto-generated method stubsuper.onReceivedTitle(view, title);}@Overridepublic void onReceivedTouchIconUrl(WebView view, String url,boolean precomposed) {// TODO Auto-generated method stubsuper.onReceivedTouchIconUrl(view, url, precomposed);}@Overridepublic boolean onCreateWindow(WebView view, boolean isDialog,boolean isUserGesture, Message resultMsg) {// TODO Auto-generated method stubreturn super.onCreateWindow(view, isDialog, isUserGesture, resultMsg);}};private DownloadListener mDownloadListener = new DownloadListener() {@Overridepublic void onDownloadStart(String url, String userAgent,String contentDisposition, String mimetype, long contentLength) {// TODO Auto-generated method stubLog.i(TAG, "onDownloadStart url = "+url);//DownloaderTask task=new DownloaderTask();//task.execute(url);try {  //调用系统下载管理器DownloadBySystem download = new DownloadBySystem(mActivity);download.download(mId, url);//统计下载StatsHelper.statAdDownload(Constants.GALabel.ADS_LOAD_SYSTEM, mId);} catch (Exception e) {  //如果手机下载管理器关闭或不能使用，则使用webview下载// TODO: handle exception//DownloaderTask task = new DownloaderTask();//task.execute(url);DownloadByMyself download = new DownloadByMyself(mActivity);download.download(mId, url);//统计下载StatsHelper.statAdDownload(Constants.GALabel.ADS_LOAD_WEBVIEW, mId);}}};private class DownloaderTask extends AsyncTask<String, Integer, String> {     public DownloaderTask() {     }@Overrideprotected String doInBackground(String... params) {// TODO Auto-generated method stubLog.i(TAG, "doInBackground");String path = params[0];String fileName = path.substring(path.lastIndexOf("/")+1);fileName = StringUtil.getFrontSubString(fileName, ".apk");fileName = URLDecoder.decode(fileName);Log.i(TAG, "fileName="+fileName);String directory = Environment.getExternalStorageDirectory().toString() + "/download/";File apkFile = new File(directory,fileName);if(apkFile.exists()){Log.i(TAG, "The file has already exists.");if (PackageUtil.getUninallApkInfo(mActivity, apkFile.getAbsolutePath())) {return fileName;} else {Log.d(TAG, "apk is not all...");FileUtil.deleteFile(apkFile);}}try {URL url = new URL(path);HttpURLConnection connection = (HttpURLConnection) url.openConnection();connection.connect();if (connection.getResponseCode() == HttpURLConnection.HTTP_OK) {InputStream is = connection.getInputStream();FileOutputStream fos = new FileOutputStream(apkFile);int length = connection.getContentLength();byte buf[] = new byte[1024];int count = 0;int read = 0;int progress = 0;while (true) {read = is.read(buf);if (read <= 0) {break;}count += read;progress = (int) (((float)count / length) * 100);Log.i(TAG, "download progress = "+progress);publishProgress(progress);fos.write(buf, 0, read);}fos.close();is.close();Log.i(TAG, "download success....");}} catch (Exception e) {// TODO: handle exceptione.printStackTrace();}return fileName;}@Overrideprotected void onCancelled() {// TODO Auto-generated method stubsuper.onCancelled();}@Overrideprotected void onPostExecute(String result) {// TODO Auto-generated method stubsuper.onPostExecute(result);Log.i(TAG, "onPostExecute");String directory = Environment.getExternalStorageDirectory().toString() + "/download/";File file = new File(directory,result);//判断是否下载完整if (PackageUtil.getUninallApkInfo(mActivity, file.getAbsolutePath())) {Log.d(TAG, "download is all....");//统计下载成功StatsHelper.statAdLoadSuccess(Constants.GALabel.ADS_LOAD_WEBVIEW, mId);Uri uri = Uri.fromFile(file);String mime = FileUtil.getMimeType(file.getName());    Intent intent = new Intent("android.intent.action.VIEW");    intent.addCategory("android.intent.category.DEFAULT");    intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);    intent.setDataAndType(uri, mime);mActivity.startActivity(intent);} else {Log.d(TAG, "download not all....");}}@Overrideprotected void onPreExecute() {// TODO Auto-generated method stubsuper.onPreExecute();}@Overrideprotected void onProgressUpdate(Integer... values) {// TODO Auto-generated method stubsuper.onProgressUpdate(values);//mProgressbar.setProgress(values[0]);} }//保证向下流动webView时，Progress正常显示，而非隐藏@Overrideprotected void onScrollChanged(int l, int t, int oldl, int oldt) {// TODO Auto-generated method stub        LayoutParams lp = (LayoutParams) mProgressbar.getLayoutParams();        lp.x = l;        lp.y = t;        mProgressbar.setLayoutParams(lp);        super.onScrollChanged(l, t, oldl, oldt);}//设置WebView能够回退上一页，而非直接退出@Overridepublic boolean onKeyDown(int keyCode, KeyEvent event) {// TODO Auto-generated method stubif (keyCode == KeyEvent.KEYCODE_BACK && this.canGoBack()) {this.goBack();return true;}return false;} }