ProgessBar Android durante il caricamento di WebView

Question

Nella mia applicazione, ho un WebView che carica qualsiasi URL da Internet. Ora, a volte a causa di reti lente, la pagina impiega molto tempo per essere caricata e l'utente vede solo uno schermo vuoto.

Voglio mostrare un ProgressBar mentre il WebView viene caricato e nascondere ProgessBar quando il WebView viene caricato completamente.

So usare lo ProgressBar e AsyncTask s, ma ecco il mio problema.

Questo è il codice che utilizzo per caricare il mio WebView.

mWebView = (WebView) findViewById(R.id.webview); 
    mWebView.getSettings().setJavaScriptEnabled(true); 
    mWebView.setWebViewClient(new HelloWebViewClient()); 
    mWebView.loadUrl(web_URL); 

E questa mia abitudine WebViewClient classe

private class HelloWebViewClient extends WebViewClient { 
    @Override 
    public boolean shouldOverrideUrlLoading(WebView view, String url) { 
     view.loadUrl(url); 
     return true; 
    } 
} 

Ora, se provo a mostrare il ProgressBar utilizzando AsyncTask s allora credo che avrei dovuto dare il codice per caricare l'URL nella Funzione doInBackGround() del mio AsyncTask e mostra l'avanzamento attraverso la funzione onProgressUpdate().

Ma, come faccio a caricare l'URL all'interno del doInBackground() come doInBackground() corre sul filo non-UI e Non sarò in grado di utilizzare mWebView.loadUrl(web_URL) al suo interno.

Qualche suggerimento? Mi manca qualcosa di ovvio? Per favore guidami.

Answer 1

Controllare il codice sorgente. Aiutarti e risolvere il tuo problema ...

public class AppWebViewClients extends WebViewClient { 
    private ProgressBar progressBar; 

    public AppWebViewClients(ProgressBar progressBar) { 
     this.progressBar=progressBar; 
     progressBar.setVisibility(View.VISIBLE); 
    } 
    @Override 
    public boolean shouldOverrideUrlLoading(WebView view, String url) { 
     // TODO Auto-generated method stub 
     view.loadUrl(url); 
     return true; 
    } 

    @Override 
    public void onPageFinished(WebView view, String url) { 
     // TODO Auto-generated method stub 
     super.onPageFinished(view, url); 
     progressBar.setVisibility(View.GONE); 
    } 
} 

Penso che sia di aiuto.

Grazie.

Answer 2

Voglio mostrare una barra di progresso mentre la webView viene caricata e nascondere la progessBar quando il webView viene caricato completamente.

Lo snippet seguente ti aiuterà.

main.xml

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

principale.Classe

public class Main extends Activity { 
    private WebView webview; 
    private static final String TAG = "Main"; 
    private ProgressDialog progressBar; 

    /** Called when the activity is first created. */@Override 
    public void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 

     requestWindowFeature(Window.FEATURE_NO_TITLE); 

     setContentView(R.layout.main); 

     this.webview = (WebView) findViewById(R.id.webview); 

     WebSettings settings = webview.getSettings(); 
     settings.setJavaScriptEnabled(true); 
     webview.setScrollBarStyle(WebView.SCROLLBARS_OUTSIDE_OVERLAY); 

     final AlertDialog alertDialog = new AlertDialog.Builder(this).create(); 

     progressBar = ProgressDialog.show(Main.this, "Showing ProgressDialog", "Loading..."); 

     webview.setWebViewClient(new WebViewClient() { 
      public boolean shouldOverrideUrlLoading(WebView view, String url) { 
       Log.i(TAG, "Processing webview url click..."); 
       view.loadUrl(url); 
       return true; 
      } 

      public void onPageFinished(WebView view, String url) { 
       Log.i(TAG, "Finished loading URL: " + url); 
       if (progressBar.isShowing()) { 
        progressBar.dismiss(); 
       } 
      } 

      public void onReceivedError(WebView view, int errorCode, String description, String failingUrl) { 
       Log.e(TAG, "Error: " + description); 
       Toast.makeText(Main.this, "Oh no! " + description, Toast.LENGTH_SHORT).show(); 
       alertDialog.setTitle("Error"); 
       alertDialog.setMessage(description); 
       alertDialog.setButton("OK", new DialogInterface.OnClickListener() { 
        public void onClick(DialogInterface dialog, int which) { 
         return; 
        } 
       }); 
       alertDialog.show(); 
      } 
     }); 
     webview.loadUrl("http://www.google.com"); 
    } 
} 

Answer 3

passare l'URL in questo metodo

private void startWebView(String url) { 

      WebSettings settings = webView.getSettings(); 

      settings.setJavaScriptEnabled(true); 
      webView.setScrollBarStyle(View.SCROLLBARS_OUTSIDE_OVERLAY); 

      webView.getSettings().setBuiltInZoomControls(true); 
      webView.getSettings().setUseWideViewPort(true); 
      webView.getSettings().setLoadWithOverviewMode(true); 

      progressDialog = new ProgressDialog(ContestActivity.this); 
      progressDialog.setMessage("Loading..."); 
      progressDialog.show(); 

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

       @Override 
       public void onPageFinished(WebView view, String url) { 
        if (progressDialog.isShowing()) { 
         progressDialog.dismiss(); 
        } 
       } 

       @Override 
       public void onReceivedError(WebView view, int errorCode, String description, String failingUrl) { 
        Toast.makeText(ContestActivity.this, "Error:" + description, Toast.LENGTH_SHORT).show(); 

       } 
      }); 
      webView.loadUrl(url); 
     } 

Answer 4

myThanh.setScrollBarStyle(WebView.SCROLLBARS_OUTSIDE_OVERLAY); 

    final AlertDialog alertDialog = new AlertDialog.Builder(this).create(); 

    progressBar = ProgressDialog.show(MainActivity.this,"Đang tải dữ liệu", "Vui lòng chờ..."); 

    myThanh.setWebViewClient(new WebViewClient() { 


     public void onPageFinished(WebView view, String url) { 
      if (progressBar.isShowing()) { 
       progressBar.dismiss(); 
      } 
     } 
    }); 

Answer 5

Questa semplice soluzione ha funzionato per me in Kotlin:

private fun setupWebView() { 

    val webViewClient: WebViewClient = object: WebViewClient() { 

     override fun shouldOverrideUrlLoading(view: WebView?, request: WebResourceRequest?): Boolean { 
      view?.loadUrl(request?.url.toString()) 
      return super.shouldOverrideUrlLoading(view, request) 
     } 

     override fun onPageStarted(view: WebView?, url: String?, favicon: Bitmap?) { 
      showProgressDialog() 
      super.onPageStarted(view, url, favicon) 
     } 

     override fun onPageFinished(view: WebView?, url: String?) { 
      hideProgressDialog() 
      super.onPageFinished(view, url) 
     } 
    } 
    webView.webViewClient = webViewClient 

    webView.settings.javaScriptEnabled = true 
    webView.settings.defaultTextEncodingName = "utf-8" 
} 

Answer 6

String url = "https://stackoverflow.com/questions/11241513/android-progessbar-while-loading-webview"; 
progressBar.setVisibility(View.VISIBLE); 

webView.setWebViewClient(new WebViewClient() { 
    @Override 
    public void onPageStarted(WebView view, String url, Bitmap favicon) { 
     super.onPageStarted(view, url, favicon); 
     setProgressBarVisibility(View.VISIBLE); 
    } 

    @Override 
    public void onPageFinished(WebView view, String url) { 
     super.onPageFinished(view, url); 
     setProgressBarVisibility(View.GONE); 
    } 

    @Override 
    public void onReceivedError(WebView view, WebResourceRequest request, WebResourceError error) { 
     super.onReceivedError(view, request, error); 
     setProgressBarVisibility(View.GONE); 
    } 
}); 

webView.loadUrl(url); 

aggiungere anche m etodo:

private void setProgressBarVisibility(int visibility) { 
    progressBar.setVisibility(visibility); 
}