Android WebView not stopping after user presses back

问题

I am playing a YouTube video inside a WebView. I am able to play it, but when the person leaves the screen, I am not able to stop the audio from playing.

I tried various things inside onDestroy and onPause, or taking them out entirely, but they didn't seem to make a difference.

Would anyone know why the audio keeps playing and doesn't stop even after the app is turned off and the user opens other apps?

Here is my code for the whole class:

import com.flurry.android.FlurryAgent;

import utils.SendEmail;
import android.app.Activity;
import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.preference.PreferenceManager;
import android.view.KeyEvent;
import android.view.View;
import android.webkit.WebChromeClient;
import android.webkit.WebSettings;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.webkit.WebSettings.PluginState;
import android.widget.Button;

public class YoutubeActivity extends Activity
{
    WebView webview = null;

    @Override
    public void onCreate(Bundle savedInstanceState) 
    {
        super.onCreate(savedInstanceState);
        webview = new WebView(this);

            setContentView(webview);

            webview.getSettings().setAppCacheEnabled(false);
            webview.getSettings().setJavaScriptEnabled(true);
            webview.setInitialScale(1);
            webview.getSettings().setPluginState(PluginState.ON);

            WebSettings webSettings = webview.getSettings();

            webSettings.setLoadsImagesAutomatically(true);
            webSettings.setLoadWithOverviewMode(true);
            webSettings.setBuiltInZoomControls(true);        
            webSettings.setUseWideViewPort(true);

            webview.setWebViewClient(new WebViewClient() {
                public boolean shouldOverrideUrlLoading(WebView view, String url) {
                    view.loadUrl(url);              
                    return false;
                }
            });        


            webview.setWebChromeClient(new WebChromeClient(){});

            webSettings.setDomStorageEnabled(true);
            webSettings.setAppCacheEnabled(true);
                        webSettings.setAppCachePath(getApplicationContext().getFilesDir().getAbsolutePath() + "/cache");            

            webSettings.setDatabaseEnabled(true);
            webSettings.setDatabasePath(getApplicationContext().getFilesDir().getAbsolutePath() + "/databases");

            SharedPreferences prefs = 
                    PreferenceManager.getDefaultSharedPreferences( YoutubeActivity.this);
            String url_to_watch = prefs.getString( "url_to_watch" , null ); 


            webview.loadUrl(url_to_watch);
    }



    @Override
    public void onPause()
    {
       super.onPause();

       try
       {
           if ( webview != null )
           {
               webview.clearCache(true); 
               webview.getSettings().setAppCacheEnabled(false);
               webview.stopLoading();
               webview.destroy();           
               sendEmail ("in pause " , "");
               webview = new WebView(this);
           }

           this.finish();
       }
       catch ( Exception e )
       {

       }
    }


    @Override
    public void onDestroy()
    {
       super.onDestroy();

       try
       {
           if ( webview != null )
           {
               webview = new WebView(this); // To try to reset the webview - didn't work.
           }
       }
       catch ( Exception e )
       {

       }    
    }

    @Override
    public void onStop()
    {
       super.onStop();

       FlurryAgent.onEndSession(this);

       try
       {
           if ( webview != null )
           {
               webview.clearView();
               webview.getSettings().setAppCacheEnabled(false);
               webview.stopLoading();
               webview.destroy();

               sendEmail ("in stop " , "");
           }
       }
       catch ( Exception e )
       {

       }

       this.finish();
    }   

    @Override
    protected void onResume() 
    {
        super.onResume();

        try
        {
            webview.onResume();
        }
        catch ( Exception  e )
        {

        }
    }

    @Override
    protected void onRestart() 
    {
        super.onRestart();
    }    


    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) 
    {
        if ((keyCode == KeyEvent.KEYCODE_BACK) && webview.canGoBack()) 
        {
            webview.goBack();
            return true;
        }
        return super.onKeyDown(keyCode, event);
    }   

    // Subject , body
    public void sendEmail( String subject , String body )
    {
        String[] params = new String[] { "http://www.problemio.com/problems/send_email_mobile.php", subject, body };

        SendEmail task = new SendEmail();
        task.execute(params);               
    }  


    //@Override 
    public void onPageFinished(WebView view, String url) 
    { 
        //super.onPageFinished(view, url); 
        view.clearCache(true); 
    }

    public void onBackPressed ( )
    {   
        final AlertDialog.Builder linkedin_builder = new AlertDialog.Builder(this);

             linkedin_builder.setMessage("" +
                    "Go back to the home screen?")
                .setCancelable(false)            
                .setNegativeButton("YES", new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int id) 
                    {
                        if ( webview != null )
                        {
                            webview.destroy();
                        }

                        Intent myIntent = new Intent(YoutubeActivity.this, MainActivity.class);
                        YoutubeActivity.this.startActivity(myIntent);
                    }
                })              
                .setPositiveButton("NO", new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int id) 
                    {
                        dialog.cancel();                  
                    }
                })
;
         AlertDialog alert = linkedin_builder.create();
         alert.show();      
    }


    @Override
    protected void onStart()
    {
        super.onStart();
        FlurryAgent.onStartSession(this, "4VYNFK3V6RCZ53CZ3J32");
    }    
}

Any thoughts on what might stop the audio from playing and what may be causing it? Thank you!

回答1:

try this, hope it helps:

@Override
public void onPause() {
    myWebView.onPause();
    myWebView.pauseTimers();
    super.onPause();
}

@Override
public void onResume() {
    super.onResume();
    myWebView.resumeTimers();
    myWebView.onResume();
}


@Override
protected void onDestroy() {
    myWebView.destroy();
    myWebView = null;
    super.onDestroy();
}

回答2:

You should call:

webView.loadUrl("about:blank");

It will destroy all audio/video as well as Javasript objects and stop all running functions on webview

回答3:

Taken from https://stackoverflow.com/a/17690221/3032209:

You should call through to the WebView's onPause() and onResume() from your Activity's onPause() and onResume(), respectively.

Pauses any extra processing associated with this WebView and its associated DOM, plugins, JavaScript etc. For example, if this WebView is taken offscreen, this could be called to reduce unnecessary CPU or network traffic. When this WebView is again "active", call onResume().

回答4:

Nothing worked for me in some or all devices. This is the exact solution I guess. Worked for me well.

How to stop youtube video playing in Android webview?

alternatively for API >= 11 you can use _webview.onPause(); on the activity's / fragment's onPause

public void onPause() {
        // TODO Auto-generated method stub
        super.onPause();
        _webview.onPause();
}

回答5:

In activity's onDestroy() do:

@Override
protected void onDestroy() {
    super.onDestroy();
    webView.destroy();
}

回答6:

You can do it using the method onPause() of your Activity :

@override
public void onPause() {
    super.onPause();
    if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
        webview.onPause();
    }
}

adding a validation for use in API >= 11 (Honeycomb)

来源：https://stackoverflow.com/questions/19252948/android-webview-not-stopping-after-user-presses-back

标签

android

webview

android-webview