[CB-3766] Introduced bug causes Android stacktrace during cleanup of CordovaWebView

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.7.0
• Component/s: cordova-android
• Assignee: Joey Robert Bowser
• Reporter: Peter
• Created: 11/Jun/13 23:15
• Updated: 23/Aug/18 07:33
• Resolved: 18/Jun/13 20:11

Description

This was already reprted on the PG Forum, where it was confirmed as a Cordova bug.
https://groups.google.com/forum/?fromgroups#!topic/phonegap/NXRvkE8Euls

I am using Cordova v2.7.0.

My Main Android Activity looks like this:

public class MainActivity extends Activity implements CordovaInterface {

CordovaWebView cwv;

...

//Destruction code is as follows

@Override
public void onDestroy() {
  if (cwv != null) {
      cwv.handlePause(true);
      cwv.handleDestroy();
      cwv.removeAllViews();
      cwv.destroy();
      cwv = null;
  }               
  super.onDestroy();
}

After 1st page is rendered, I cause the destroy event by pressing the device BACK button.

This is always resulting in a stacktrace:

06-11 00:49:57.446: I/Web Console(823): onPause() called at file:///android_asset/app1/index.html:11
06-11 00:49:58.762: W/IInputConnectionWrapper(823): showStatusIcon on inactive InputConnection
06-11 00:50:02.222: D/webviewglue(823): nativeDestroy view: 0x2a24bdb0
06-11 00:50:22.292: D/AndroidRuntime(823): Shutting down VM
06-11 00:50:22.292: W/dalvikvm(823): threadid=1: thread exiting with uncaught exception (group=0x40a71930)
06-11 00:50:22.334: E/AndroidRuntime(823): FATAL EXCEPTION: main
06-11 00:50:22.334: E/AndroidRuntime(823): java.lang.NullPointerException
06-11 00:50:22.334: E/AndroidRuntime(823):     at android.webkit.WebViewClassic.stopLoading(WebViewClassic.java:2645)
06-11 00:50:22.334: E/AndroidRuntime(823):     at android.webkit.WebView.stopLoading(WebView.java:895)
06-11 00:50:22.334: E/AndroidRuntime(823):     at org.apache.cordova.CordovaWebView$2.run(CordovaWebView.java:421)
06-11 00:50:22.334: E/AndroidRuntime(823):     at android.os.Handler.handleCallback(Handler.java:725)
06-11 00:50:22.334: E/AndroidRuntime(823):     at android.os.Handler.dispatchMessage(Handler.java:92)
06-11 00:50:22.334: E/AndroidRuntime(823):     at android.os.Looper.loop(Looper.java:137)
06-11 00:50:22.334: E/AndroidRuntime(823):     at android.app.ActivityThread.main(ActivityThread.java:5041)
06-11 00:50:22.334: E/AndroidRuntime(823):     at java.lang.reflect.Method.invokeNative(Native Method)
06-11 00:50:22.334: E/AndroidRuntime(823):     at java.lang.reflect.Method.invoke(Method.java:511)
06-11 00:50:22.334: E/AndroidRuntime(823):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
06-11 00:50:22.334: E/AndroidRuntime(823):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
06-11 00:50:22.334: E/AndroidRuntime(823):     at dalvik.system.NativeStart.main(Native Method)

It appears CordovaWebView.handleDestroy() is calling loadUrlIntoView(url) which reinitialises plugins and spawns a thread to handle potential timeouts.
My stacktrace seems caused by the timeout thread (in CordovaWebView) thinking that a timeout has occurred (because the flag loadUrlTimeout does not indicate otherwise)

—

I believe my cleanup code onDestroy() is implemented correctly. If not, then how should I do it?

BTW, This same problem did not occur in Cordova v2.4

More notes:

• I am suspicious that the problem is introduced by the fix for CB-2458. To deliberately cause plugin initialization during destruction seems strange.

• I am suspicious that the removal of baseUrl in CB-2534, means the CB-2458 is maybe not even needed anymore, so perhaps original code can be re-instated.

Issue Links

• relates to: CB-3767 Timers error out when closing an app using CordovaWebView