Android: come posso mostrare la barra di avanzamento durante il caricamento dei dati in WebView?

Question

Come posso mostrare la barra di avanzamento durante il caricamento dei dati nel mio webview? Il mio codice:

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    this.requestWindowFeature(Window.FEATURE_PROGRESS);
    getWindow().setFeatureInt( Window.FEATURE_PROGRESS, Window.PROGRESS_VISIBILITY_ON); 
    this.setProgressBarVisibility(true);
    setContentView(R.layout.layout_article);
    WebView webview = (WebView) findViewById(R.id.webView);
    final Activity activity = this;
    webview.setWebChromeClient(new WebChromeClient() {
        public void onProgressChanged(WebView view, int progress) {
            activity.setProgress(progress * 100);
        }
    });

    webView.loadUrl("http://google.com");
}

Answer 1

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        final ProgressBar progress = (ProgressBar) findViewById(R.id.progress);

        WebView webView = (WebView) findViewById(R.id.webview);
        webView.getSettings().setJavaScriptEnabled(true);
        webView.setWebViewClient(new WebViewClient() {
            @Override
            public boolean shouldOverrideUrlLoading(final WebView view, final String url) {
                return false;
            }

            @Override
            public void onPageStarted(final WebView view, final String url, final Bitmap favicon) {
                progress.setVisibility(View.VISIBLE);
                super.onPageStarted(view, url, favicon);
            }

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

        webView.loadUrl("http://google.com");
    }
}

E R.layout.activity_main:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
     android:layout_width="match_parent"
     android:layout_height="match_parent">

    <WebView
        android:id="@+id/webview"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

    <ProgressBar
        android:id="@+id/progress"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:visibility="gone"
        android:layout_centerInParent="true"/>
</RelativeLayout>

Answer 2

Prima di chiamare la funzione LoadData (), prova a mostrare ProgressDialog o mettere ProgressBar all'interno del layout.

E all'interno del WebViewClient, basta licenziare () il progressoDialog o rendere invisibile la barra di progresso.

per esempio:

// when finish loading page
public void onPageFinished(WebView view, String url) {
       if(mProgress.isShowing()) {
             mProgress.dismiss();
       }
}

FYI, chiama loadData () o loadURL () solo dopo aver finito con l'impostazione client Web.

Controlla questo esempio: Carica WebView con ProgressDialog

Answer 3

Prova a seguire il codice,

ProgressDialog progDailog = ProgressDialog.show( context,"Process ", "Loading Data...",true,true);

new Thread ( new Runnable()
{
     public void run()
     {
      // your data loading code goes here
     }
}).start();

 Handler progressHandler = new Handler() 
 {

     public void handleMessage(Message msg1) 
     {

         progDailog.dismiss();
         }
 }

Answer 4

Prima crea la classe WebView personalizzata e usalo su XML in questo modo,

 <com.app.ui.views.CustomWebView
        android:id="@+id/webView"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        >

    </com.app.ui.views.CustomWebView>

Assicurati, l'altezza non dovrebbe essere fissata, dovrebbe essere "wrap_content"

Ora crea una classe WebView personalizzata come questa,

 public class CustomWebView extends WebView {

    private ProgressBar progressBar;
    private Context context;
    private LinearLayout loaderLayout;

    public CustomWebView(Context context) {
    super(context);

    this.context = context;
    initProgressBar();

    loadUrlWithData();

}

public CustomWebView(Context context, AttributeSet attrs) {
    super(context, attrs);

    this.context = context;
    initProgressBar();

}

public CustomWebView(Context context, AttributeSet attrs, int defStyle) {
    super(context, attrs, defStyle);

    this.context = context;

    initProgressBar();

}

private void initProgressBar() {
    progressBar = new ProgressBar(context);
    progressBar.setIndeterminate(false);

}

private void setLoading(boolean isLoading) {

  if (isLoading) {

   progressBar.setVisibility(View.VISIBLE);

   loaderLayout = new LinearLayout(context);
   loaderLayout.setGravity(Gravity.CENTER);
   loaderLayout.setOrientation(LinearLayout.HORIZONTAL);

    LinearLayout.LayoutParams parentLayoutParams = new LinearLayout.LayoutParams(
                LinearLayout.LayoutParams.MATCH_PARENT,
                LinearLayout.LayoutParams.WRAP_CONTENT);
        loaderLayout.setLayoutParams(parentLayoutParams);

        LinearLayout.LayoutParams progressBarLayoutParams = new 
        LinearLayout.LayoutParams(75, 75);
        progressBar.setLayoutParams(progressBarLayoutParams);

        if (progressBar.getParent() != null) {
            ((ViewGroup) progressBar.getParent()).removeView(progressBar);
        }
        loaderLayout.addView(progressBar);

        // add this loaderLayout to your parent view in which your webview is added

        else {

           progressBar.setVisibility(View.GONE);
        }

  }

  private void loadUrlWithData(){
     setLoading(true);
     //Load your HTML data with url here

  }

 //When the content will be loaded, the webview will change it's height
 @Override
protected void onSizeChanged(int w, int h, int ow, int oh) {
    super.onSizeChanged(w, h, ow, oh);

    if (h > 400) {
        setLoading(false);
    }
}

}