Android 实现带进度条的WebView的实例

//加载本地资源loadUrl("file:///android_asset/example.html");//加载网络资源loadUrl("http://baidu.com");

<?xml version="1.0" encoding="utf-8"?><layer-list xmlns:android="http://schemas.android.com/apk/res/android">  <item android:id="@android:id/progress">    <clip>      <shape>        <solid android:color="#31CE15"/>        <corners android:radius="2dp"/>      </shape>    </clip>  </item></layer-list>

/** * 带进度条的WebView * @Author GQ */public class ProgressWebView extends WebView {  private ProgressBar progressbar;  private Context mContext;  public ProgressWebView(Context context, AttributeSet attrs) {    super(context, attrs);    this.mContext = context;    progressbar = new ProgressBar(context, null, android.R.attr.progressBarStyleHorizontal);    progressbar.setLayoutParams(new LayoutParams(LayoutParams.FILL_PARENT, 5, 0, 0));    Drawable drawable = context.getResources().getDrawable(R.drawable.view_progress_webview);    progressbar.setProgressDrawable(drawable);    addView(progressbar);    //主要处理解析，渲染网页等浏览器做的事情    setWebViewClient(new WebViewClient() {      @Override      public void onReceivedError(WebView view, int errorCode, String description, String failingUrl) {        super.onReceivedError(view, errorCode, description, failingUrl);        //加载失败时候,显示自定义的页面        if (errorListener != null) {          errorListener.onError();        }      }    });    //辅助WebView处理Javascript的对话框，网站图标，网站title，加载进度等    setWebChromeClient(new WebChromeClient());    getSettings().setSupportZoom(true);//是否可以缩放    getSettings().setBuiltInZoomControls(true);    getSettings().setJavaScriptEnabled(true);//支持JS    getSettings().setLayoutAlgorithm(WebSettings.LayoutAlgorithm.NARROW_COLUMNS);    getSettings().setUseWideViewPort(true);    getSettings().setLoadWithOverviewMode(true);    getSettings().setSaveFormData(true);    getSettings().setDomStorageEnabled(true);    //优先使用缓存    getSettings().setCacheMode(WebSettings.LOAD_CACHE_ELSE_NETWORK);    //禁用长按    setOnLongClickListener(new OnLongClickListener() {      @Override      public boolean onLongClick(View view) {        return true;      }    });    //如果在浏览器下载,调用浏览器默认下载+通知栏    setDownloadListener(new DownloadListener() {      @Override      public void onDownloadStart(String url, String userAgent, String contentDisposition, String mimetype, long contentLength) {        Uri uri = Uri.parse(url);        Intent intent = new Intent(Intent.ACTION_VIEW, uri);        mContext.startActivity(intent);      }    });  }  public class WebChromeClient extends android.webkit.WebChromeClient {    @Override    public void onProgressChanged(WebView view, int newProgress) {      if (newProgress == 100) {        progressbar.setVisibility(GONE);      } else {        if (progressbar.getVisibility() == GONE)          progressbar.setVisibility(VISIBLE);        progressbar.setProgress(newProgress);      }      super.onProgressChanged(view, newProgress);    }    @Override    public void onReceivedTitle(WebView view, String title) {      super.onReceivedTitle(view, title);      if (titleListener != null)        titleListener.getTitle(title);    }  }  @Override  protected void onScrollChanged(int l, int t, int oldl, int oldt) {    LayoutParams lp = (LayoutParams) progressbar.getLayoutParams();    lp.x = l;    lp.y = t;    progressbar.setLayoutParams(lp);    super.onScrollChanged(l, t, oldl, oldt);  }  private TitleListener titleListener;  public interface TitleListener {    void getTitle(String title);  }  public void setOnTitleListener(TitleListener titleListener) {    this.titleListener = titleListener;  }  private ErrorListener errorListener;  public interface ErrorListener {    void onError();  }  public void setOnErrorListener(ErrorListener errorListener) {    this.errorListener = errorListener;  }}

/*** 公共WebView*/public class BasicWebActivity extends Activity {  protected ProgressWebView progressWebView;  private TextView title;//标题栏  private TextView tv_none;//加载失败显示文字  @Override  protected void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentView(R.layout.common_webview);    title = (TextView) findViewById(R.id.title);    tv_none = (TextView) findViewById(R.id.tv_none);    progressWebView = (ProgressWebView) findViewById(R.id.progressWebView);    String url = getIntent().getStringExtra("url");    progressWebView.setOnTitleListener(new ProgressWebView.TitleListener() {      @Override      public void getTitle(String title) {        title.setText(title);      }    });    progressWebView.setOnErrorListener(new ProgressWebView.ErrorListener() {      @Override      public void onError() {        tv_none.setText("url资源失效");      }    });    //加载网页    progressWebView.loadUrl(url);  } //重写返回键  @Override  public boolean onKeyDown(int keyCode, KeyEvent event) {    if (keyCode == KeyEvent.KEYCODE_BACK) {      if (progressWebView.canGoBack()) {        progressWebView.goBack();//返回上一层页面        return true;      } else {        finish();//关闭页面      }    }    return super.onKeyDown(keyCode, event);  }}