java - 使用 webview 显示进度条

Question

**我正在开发一个带有 webview 的 android 应用程序。我需要在 webview 中加载内容时显示进度条。内容加载完成后应关闭进度。对于 webview 部分，我使用下面的代码。我使用 thread.sleep 来设置 JavaScriptEnabled(true)，因为我首先设置 JavaScriptEnabled(false)，然后在 15 秒后设置 JavaScriptEnabled(true)。我应该怎么做

public class Activity1 extends Activity {

private WebView webView;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    setContentView(R.layout.activity_activity1);
    Toast.makeText(getApplicationContext(), "welcome", Toast.LENGTH_LONG).show();
    String url = "http://student.iaun.ac.ir";
    webView = (WebView) findViewById(R.id.webview);

    webView.setWebViewClient(new myWebViewClient());
    webView.getSettings().setJavaScriptEnabled(false);
    webView.getSettings().setLoadWithOverviewMode(true);
    webView.getSettings().setUseWideViewPort(true);
    webView.getSettings().setBuiltInZoomControls(true);
    webView.loadUrl(url);
    webView.getSettings().setSavePassword(false);

    new Thread(new Runnable() {

        @Override
        public void run() {
            try {
                startDelay();
                webView.getSettings().setJavaScriptEnabled(true);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }).start();

}

void startDelay() throws InterruptedException {
    Thread.sleep(15000);
}

public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.activity1, menu);
    return true;

}

public boolean onKeyDown(int keyCode, KeyEvent event) {
    // Check if the key event was the Back button and if there's history
    if ((keyCode == KeyEvent.KEYCODE_BACK) && webView.canGoBack()) {
        webView.goBack();
        return true;
    }
    // If it wasn't the Back key or there's no web page history, bubble up to the default
    // system behavior (probably exit the activity)
    return super.onKeyDown(keyCode, event);
}
}

Answer 1

你可以用更简单的方式实现进度条

protected static ProgressBar progressBar;

//Some Codes
WebView loginwebview = (WebView) activity.findViewById(R.id.login_webview);
loginwebview.setWebChromeClient
    (
       new WebChromeClient()
       {
         @Override
          public void onProgressChanged(WebView view, int newProgress) 
           {
             activity.setTitle("Loading...Please wait");
             startSpinner();
             activity.setProgress(newProgress * 100);
             if(newProgress == 100)
               {
                    activity.setTitle(R.string.app_name);
                    stopSpinner();
               }
         }
      });

loginwebview.setWebViewClient(new WebViewClient() 
    {
        @Override
        public boolean shouldOverrideUrlLoading(WebView view, String url) 
        {
           view.loadUrl(url);
           return true;

    }

以及 startSpinner() 和 stopSpinner() 方法

 protected static void startSpinner(){progressBar.setVisibility(WebView.VISIBLE);}
 protected static void stopSpinner(){progressBar.setVisibility(WebView.GONE);}