Why does keyboard-slide crash my app?

android crash viewflipper
Brad Hein picture Brad Hein · Jun 11, 2010 · Viewed 8.3k times · Source

If I physically slide out the keyboard on my Moto Droid A855, it crashes my test app with the stack trace pasted below. I don't understand why?

Also, if I start my app with the keyboard out, my app crashes immediately on startup.

The app consists of an activity, which contains a viewflipper as the main view layout. The viewflipper contains two linearlayouts...

Stack trace: 

06-10 21:10:17.652 E/AndroidRuntime( 3785): Uncaught handler: thread main exiting due to uncaught exception
06-10 21:10:17.668 E/AndroidRuntime( 3785): java.lang.IllegalArgumentException: Receiver not registered: android.widget.ViewFlipper$1@447af0b8
06-10 21:10:17.668 E/AndroidRuntime( 3785):     at android.app.ActivityThread$PackageInfo.forgetReceiverDispatcher(ActivityThread.java:667)
06-10 21:10:17.668 E/AndroidRuntime( 3785):     at android.app.ApplicationContext.unregisterReceiver(ApplicationContext.java:747)
06-10 21:10:17.668 E/AndroidRuntime( 3785):     at android.content.ContextWrapper.unregisterReceiver(ContextWrapper.java:321)
06-10 21:10:17.668 E/AndroidRuntime( 3785):     at android.widget.ViewFlipper.onDetachedFromWindow(ViewFlipper.java:104)
06-10 21:10:17.668 E/AndroidRuntime( 3785):     at android.view.View.dispatchDetachedFromWindow(View.java:5835)
06-10 21:10:17.668 E/AndroidRuntime( 3785):     at android.view.ViewGroup.dispatchDetachedFromWindow(ViewGroup.java:1076)
06-10 21:10:17.668 E/AndroidRuntime( 3785):     at android.view.ViewGroup.dispatchDetachedFromWindow(ViewGroup.java:1074)
06-10 21:10:17.668 E/AndroidRuntime( 3785):     at android.view.ViewGroup.dispatchDetachedFromWindow(ViewGroup.java:1074)
06-10 21:10:17.668 E/AndroidRuntime( 3785):     at android.view.ViewGroup.dispatchDetachedFromWindow(ViewGroup.java:1074)
06-10 21:10:17.668 E/AndroidRuntime( 3785):     at android.view.ViewRoot.dispatchDetachedFromWindow(ViewRoot.java:1570)
06-10 21:10:17.668 E/AndroidRuntime( 3785):     at android.view.ViewRoot.doDie(ViewRoot.java:2556)
06-10 21:10:17.668 E/AndroidRuntime( 3785):     at android.view.ViewRoot.die(ViewRoot.java:2526)
06-10 21:10:17.668 E/AndroidRuntime( 3785):     at android.view.WindowManagerImpl.removeViewImmediate(WindowManagerImpl.java:218)
06-10 21:10:17.668 E/AndroidRuntime( 3785):     at android.view.Window$LocalWindowManager.removeViewImmediate(Window.java:436)
06-10 21:10:17.668 E/AndroidRuntime( 3785):     at android.app.ActivityThread.handleDestroyActivity(ActivityThread.java:3498)
06-10 21:10:17.668 E/AndroidRuntime( 3785):     at android.app.ActivityThread.handleRelaunchActivity(ActivityThread.java:3599)
06-10 21:10:17.668 E/AndroidRuntime( 3785):     at android.app.ActivityThread.access$2300(ActivityThread.java:119)
06-10 21:10:17.668 E/AndroidRuntime( 3785):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1867)
06-10 21:10:17.668 E/AndroidRuntime( 3785):     at android.os.Handler.dispatchMessage(Handler.java:99)
06-10 21:10:17.668 E/AndroidRuntime( 3785):     at android.os.Looper.loop(Looper.java:123)
06-10 21:10:17.668 E/AndroidRuntime( 3785):     at android.app.ActivityThread.main(ActivityThread.java:4363)
06-10 21:10:17.668 E/AndroidRuntime( 3785):     at java.lang.reflect.Method.invokeNative(Native Method)
06-10 21:10:17.668 E/AndroidRuntime( 3785):     at java.lang.reflect.Method.invoke(Method.java:521)
06-10 21:10:17.668 E/AndroidRuntime( 3785):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860)
06-10 21:10:17.668 E/AndroidRuntime( 3785):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
06-10 21:10:17.668 E/AndroidRuntime( 3785):     at dalvik.system.NativeStart.main(Native Method)
06-10 21:10:17.684 I/Process ( 1017): Sending signal. PID: 3785 SIG: 3

EDIT: added XML layout and relevant snippets from main activity.

Entire XML layout file

<?xml version="1.0" encoding="utf-8"?>


<ViewFlipper
        xmlns:android="http://schemas.android.com/apk/res/android"
        android:id="@+id/vFlipper"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content">

                <!--  Linear Layout 1: messages and overview.  -->
                <LinearLayout
                    android:orientation="vertical"
                    android:layout_width="fill_parent"
                    android:layout_height="fill_parent"
                    >

                <TableRow android:id="@+id/TableRow01" android:layout_width="fill_parent" android:layout_height="wrap_content">
                <TextView
                        android:text="Connection info"
                        android:id="@+id/tvCon1"
                        android:layout_width="fill_parent"
                        android:layout_height="wrap_content"
                        android:background="#F0F0F0"
                        android:textColor="#FF0000"
                        />
                </TableRow>


                <ScrollView
                        android:id="@+id/ScrollView01"
                        android:layout_width="fill_parent"
                        android:layout_height="fill_parent">

                                <TextView  
                                        android:id="@+id/tvMessages"
                                    android:layout_width="fill_parent"
                                    android:layout_height="fill_parent"
                                    android:text=""
                                    />

                </ScrollView>

        </LinearLayout>


        <!--  Linear Layout 2: settings -->
        <LinearLayout
                    android:orientation="vertical"
                    android:layout_width="fill_parent"
                    android:layout_height="fill_parent"
                    >


                <TableRow
                        android:id="@+id/TableRow03"
                        android:layout_width="fill_parent"
                        android:layout_height="wrap_content">

                                <TextView
                                android:text="hello world"
                                android:id="@+id/asdfasdf2"
                                android:layout_width="fill_parent"
                                android:layout_height="wrap_content"
                                />
                </TableRow>                

        </LinearLayout>

</ViewFlipper>

Code snippets from Main Activity: 

/**
 * Attempt (not currently working) to work around this bug: http://code.google.com/p/android/issues/detail?id=6191
 * TODO: make it work.
 */
@Override
public void onDetachedFromWindow() {
        Log.d("Dash","OnDetachedFromWindow()");

        try {
        super.onDetachedFromWindow();
    }
    catch (Exception e) {
        ViewFlipper v = (ViewFlipper)findViewById(R.id.vFlipper);
        if (v != null) {
                Log.d("Dash","De-Bug hit. e=" + e.getMessage());
                v.stopFlipping();
        }
    }
}

Answer

Brad Hein picture Brad Hein · Jun 12, 2010

To resolve this issue you must

  • Define a new class called MyViewFlipper which overrides ViewFlipper (see below)
  • Reference that new class anywhere you would have previously referenced ViewFlipper
  • Define your class and layout as shown below:

New class called MyViewFlipper. Contains the following: 

package com.gtosoft.dash; // change this to match your own app. 

import android.content.Context;
import android.util.AttributeSet;
import android.util.Log;
import android.widget.ViewFlipper;

public class MyViewFlipper extends ViewFlipper {

    public MyViewFlipper(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    @Override
    protected void onDetachedFromWindow() {
        try{
            super.onDetachedFromWindow();
        }catch(Exception e) {
            Log.d("MyViewFlipper","Stopped a viewflipper crash");
            stopFlipping();
        }
    }
}

Now to use this "fixed" version of ViewFlipper you have to reference it in the xml layout. Since it is basically a "custom view", you have to fully qualify the package path to MyViewFlipper, as seen here: 

<com.gtosoft.dash.MyViewFlipper
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/vFlipper"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content">

    (insert all the other old layout code here)

</com.gtosoft.dash.MyViewFlipper>

Now the app no longer crashes on the keyboard slide event or if the app is started with slide already out. Look for this in the log: 

06-11 20:08:15.811 D/MyViewFlipper( 6106): Stopped a viewflipper crash

Credit: http://code.google.com/p/android/issues/detail?id=6191

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