android筆記之在WebView中顯示ProgressBar的兩種方法

第一種方法是用系統的資源，這種方法只能將進度情況顯示到標題列中。英文是本文作者的一段嘮叨，很簡單，我就不用再翻譯了吧。

When using the webview, something that drives me crazy, specially if you are in a place with a very slow internet connection, is not knowing what is happening with the webpage, is it loading? Is it stuck? …. AAAhhhh Nothing is happening. Ok don’t desperate, I am going to show you how to add a progress bar to your Webview layout in you app. 
After you know what to do is easy (As always).     

// Sets the Chrome Client, and defines the onProgressChanged<br />// This makes the Progress bar be updated.<br />final Activity MyActivity = this;<br />mWebView.setWebChromeClient(new WebChromeClient() {<br /> public void onProgressChanged(WebView view, int progress)<br /> {<br /> //Make the bar disappear after URL is loaded, and changes string to Loading...<br /> MyActivity.setTitle("Loading...");<br /> MyActivity.setProgress(progress * 100); //Make the bar disappear after URL is loaded</p><p> // Return the app name after finish loading<br /> if(progress == 100)<br /> MyActivity.setTitle(R.string.app_name);<br /> }<br /> });<br /> 

          // Adds Progrss bar Support<br />this.getWindow().requestFeature(Window.FEATURE_PROGRESS);<br />setContentView(R.layout.main );<br /> <br />// Makes Progress bar Visible<br />getWindow().setFeatureInt( Window.FEATURE_PROGRESS, Window.PROGRESS_VISIBILITY_ON); 

package firsrdroid.tutorial.mywebview;<br /> <br />import android.app.Activity;<br />import android.os.Bundle;<br />import android.view.Window;<br />import android.webkit.WebChromeClient;<br />import android.webkit.WebView;<br /> <br />public class UsingMyWebview extends Activity {<br />    <br />   WebView mWebView;<br />    <br />   /** Called when the activity is first created. */<br />   @Override<br />   public void onCreate(Bundle savedInstanceState)<br />   {<br />      super.onCreate(savedInstanceState);<br />       <br />      // Adds Progrss bar Support<br />      this.getWindow().requestFeature(Window.FEATURE_PROGRESS);<br />      setContentView(R.layout.main );<br />       <br />      // Makes Progress bar Visible<br />      getWindow().setFeatureInt( Window.FEATURE_PROGRESS, Window.PROGRESS_VISIBILITY_ON);<br /> <br />       // Get Web view<br />       mWebView = (WebView) findViewById( R.id.MyWebview ); //This is the id you gave<br />                                              //to the WebView in the main.xml<br />       mWebView.getSettings().setJavaScriptEnabled(true);  <br />       mWebView.getSettings().setSupportZoom(true);       //Zoom Control on web (You don't need this<br />                                              //if ROM supports Multi-Touch     <br />       mWebView.getSettings().setBuiltInZoomControls(true); //Enable Multitouch if supported by ROM<br />       <br />       // Load URL<br />       mWebView.loadUrl("http://www.firstdroid.com/advertisement.htm");<br />        <br />        <br />       // Sets the Chrome Client, and defines the onProgressChanged<br />       // This makes the Progress bar be updated.<br />       final Activity MyActivity = this;<br />       mWebView.setWebChromeClient(new WebChromeClient() {<br />        public void onProgressChanged(WebView view, int progress)  <br />        {<br />         //Make the bar disappear after URL is loaded, and changes string to Loading...<br />         MyActivity.setTitle("Loading...");<br />         MyActivity.setProgress(progress * 100); //Make the bar disappear after URL is loaded<br /> <br />         // Return the app name after finish loading<br />            if(progress == 100)<br />               MyActivity.setTitle(R.string.app_name);<br />          }<br />        });<br />        <br />        <br />        <br />   }//End of Method onCreate<br />} 

下面是第二種方法：英文是本文作者的一段嘮叨，也很簡單，我就不用再翻譯了吧。和上面的方法不同的是，這個是進度沒有顯示在標題列而是顯示在頁面的上面。

I’ve seen a multitude of posts on how to embed the Android WebView object and how to use the built-in feature request PROGRESS, but I’ve yet to come across a demonstration on just how simple it is to integrate a ProgressDialog object. I specifically needed this for one of my projects because I did not want the title bar to render in my application. If the title is not rendered, then the Window Feature Request progress bar and indeterminant functions will not render at all.

<?xml version="1.0" encoding="utf-8"?><br /><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"<br /> android:orientation="vertical"<br /> android:layout_width="fill_parent"<br /> android:layout_height="fill_parent"<br /> ><br /> <WebView android:id="@string/webview"<br /> android:layout_width="fill_parent"<br /> android:layout_height="fill_parent"<br /> android:layout_weight="1" /><br /></LinearLayout> 

package com.maxpowersoft.example;</p><p>import android.app.Activity;<br />import android.app.AlertDialog;<br />import android.app.ProgressDialog;<br />import android.content.DialogInterface;<br />import android.content.Intent;<br />import android.net.Uri;<br />import android.os.Bundle;<br />import android.util.Log;<br />import android.view.Window;<br />import android.webkit.WebSettings;<br />import android.webkit.WebView;<br />import android.webkit.WebViewClient;<br />import android.widget.Toast;</p><p>public class Main extends Activity {<br /> private WebView webview;<br /> private static final String TAG = "Main";<br /> private ProgressDialog progressBar; </p><p> /** Called when the activity is first created. */<br /> @Override<br /> public void onCreate(Bundle savedInstanceState) {<br /> super.onCreate(savedInstanceState);</p><p> requestWindowFeature(Window.FEATURE_NO_TITLE);</p><p> setContentView(R.layout.main);</p><p> this.webview = (WebView)findViewById(R.string.webview);</p><p> WebSettings settings = webview.getSettings();<br /> settings.setJavaScriptEnabled(true);<br /> webview.setScrollBarStyle(WebView.SCROLLBARS_OUTSIDE_OVERLAY);</p><p> final AlertDialog alertDialog = new AlertDialog.Builder(this).create();</p><p> progressBar = ProgressDialog.show(Main.this, "MaxPowerSoft Example", "Loading...");</p><p> webview.setWebViewClient(new WebViewClient() {<br /> public boolean shouldOverrideUrlLoading(WebView view, String url) {<br /> Log.i(TAG, "Processing webview url click...");<br /> view.loadUrl(url);<br /> return true;<br /> }</p><p> public void onPageFinished(WebView view, String url) {<br /> Log.i(TAG, "Finished loading URL: " +url);<br /> if (progressBar.isShowing()) {<br /> progressBar.dismiss();<br /> }<br /> }</p><p> public void onReceivedError(WebView view, int errorCode, String description, String failingUrl) {<br /> Log.e(TAG, "Error: " + description);<br /> Toast.makeText(activity, "Oh no! " + description, Toast.LENGTH_SHORT).show();<br /> alertDialog.setTitle("Error");<br /> alertDialog.setMessage(description);<br /> alertDialog.setButton("OK", new DialogInterface.OnClickListener() {<br /> public void onClick(DialogInterface dialog, int which) {<br /> return;<br /> }<br /> });<br /> alertDialog.show();<br /> }<br /> });<br /> webview.loadUrl("http://www.google.com");<br /> }<br />}