进度条无法显示
跟着老师敲的，但进度条无法显示，大神帮忙看看
package com.whu.webview;
import android.app.Activity;
import android.app.ProgressDialog;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.view.KeyEvent;
import android.webkit.WebChromeClient;
import android.webkit.WebSettings;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.widget.Toast;
public class Android_webviewActivity extends Activity {
private ProgressDialog dialog;
private WebView webview;
/** Called when the activity is first created. */
private String url = "http://2014.qq.com/";
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.web);
//Uri uri = Uri.parse(url);//url 为你要 链接的地址
//Intent intent = new Intent (Intent.ACTION_VIEW,uri);
// startActivity(intent);
init();
}
private void init() {
// TODO Auto-generated method stub
webview = (WebView) findViewById(R.id.webView);
//WebView 加载本地资源
//webview.loadUrl("file:///android_asset/);
//WebView 加载web资源
webview.loadUrl(url);
//覆盖WebView默认通过第三方或系统浏览器打开网页的行为，使得网页可以在WebView中打开
webview.setWebViewClient(new WebViewClient(){
@Override
public boolean shouldOverrideUrlLoading(WebView view, String url) {
// TODO Auto-generated method stub
//
/*
* 返回值是true的时候控制网页在WebView中打开，
*为false时通过第三方或系统浏览器打开网页
*/
view.loadUrl(url);
return true;
}
//WebViewClient帮助WebView处理一些页面控制或请求通知
});
//启用支持JavaScript
WebSettings settings = webview.getSettings();
settings.setJavaScriptEnabled(true);
//WebView 加载页面优先使用加载缓存
settings.setCacheMode(WebSettings.LOAD_CACHE_ELSE_NETWORK);
webview.setWebChromeClient(new WebChromeClient(){
public void onProgerssChanged(WebView view,int newProgress){
//newProgress 1-100之间的整数
if(newProgress==100){
//网页加载完毕,关闭ProgressDialog
closeDialog();
}
else{
//网页正在加载,打开ProgressDialog
openDialog(newProgress);
}
}
private void openDialog(int newProgress) {
// TODO Auto-generated method stub
if(dialog==null){
dialog = new ProgressDialog(Android_webviewActivity.this);
dialog.setTitle("正在加载");
dialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
dialog.setProgress(newProgress);
dialog.show();
}
else{
dialog.setProgress(newProgress);
}
}
private void closeDialog() {
// TODO Auto-generated method stub
if(dialog!=null&&dialog.isShowing()){
dialog.dismiss();
dialog = null;
}
}
});
}
//改写物理按键--返回的逻辑
public boolean onKeyDown(int keyCode, KeyEvent event){
if(keyCode == KeyEvent.KEYCODE_BACK){
if(webview.canGoBack())
{
Toast.makeText(this, webview.getUrl(),Toast.LENGTH_SHORT).show();
webview.goBack();//返回上一页面
return true;
}
else
{
System.exit(0);//退出程序
}
}
return super.onKeyDown( keyCode, event);
}
}
