remove and add view NPE, honeycomb, android

Question

I have LinearLayout areaForGalleries programmatically filled with Gallery components, one after another. onItemClick method in each gallery removes it from areaForGalleries and adds it to RelativeLayout parentLayout which is parent of areaForGalleries. See code below.

LinearLayout areaForGalleries;
RelativeLayout parentLayout;

...
private void showGallery() {
final CustomGallery mGallery = new CustomGallery(mContext);

mGallery.setOnItemClickListener(new CustomAdapterView.OnItemClickListener() {
        public void onItemClick(CustomAdapterView<?> parent, View v, int position, long id) {
            areaForGalleries.removeView(mGallery);
            parentLayout.addView(mGallery);
        }
    });

CustomGallery is my implementation of Android Gallery component. I've only changed alignment of the gallery to the left - one line of code has changed. Code works perfectly on Android 2.1 - 2.3.3, but when tried it on Honeycomb or ICS it crashes with following error:

01-31 10:31:49.596: E/AndroidRuntime(1536): FATAL EXCEPTION: main
01-31 10:31:49.596: E/AndroidRuntime(1536): java.lang.NullPointerException
01-31 10:31:49.596: E/AndroidRuntime(1536):     at android.view.GestureDetector.onTouchEvent(GestureDetector.java:587)
01-31 10:31:49.596: E/AndroidRuntime(1536):     at com.my.example.pullrefreshgallery.CustomGallery.onTouchEvent(CustomGallery.java:812)
01-31 10:31:49.596: E/AndroidRuntime(1536):     at android.view.View.dispatchTouchEvent(View.java:5486)
01-31 10:31:49.596: E/AndroidRuntime(1536):     at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:1953)
01-31 10:31:49.596: E/AndroidRuntime(1536):     at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1714)
01-31 10:31:49.596: E/AndroidRuntime(1536):     at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:1959)
01-31 10:31:49.596: E/AndroidRuntime(1536):     at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1728)
01-31 10:31:49.596: E/AndroidRuntime(1536):     at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:1959)
01-31 10:31:49.596: E/AndroidRuntime(1536):     at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1728)
01-31 10:31:49.596: E/AndroidRuntime(1536):     at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:1959)
01-31 10:31:49.596: E/AndroidRuntime(1536):     at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1728)
01-31 10:31:49.596: E/AndroidRuntime(1536):     at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:1959)
01-31 10:31:49.596: E/AndroidRuntime(1536):     at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1728)
01-31 10:31:49.596: E/AndroidRuntime(1536):     at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:1959)
01-31 10:31:49.596: E/AndroidRuntime(1536):     at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1728)
01-31 10:31:49.596: E/AndroidRuntime(1536):     at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:1959)
01-31 10:31:49.596: E/AndroidRuntime(1536):     at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1728)
01-31 10:31:49.596: E/AndroidRuntime(1536):     at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:1959)
01-31 10:31:49.596: E/AndroidRuntime(1536):     at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1728)
01-31 10:31:49.596: E/AndroidRuntime(1536):     at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:1959)
01-31 10:31:49.596: E/AndroidRuntime(1536):     at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1728)
01-31 10:31:49.596: E/AndroidRuntime(1536):     at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:1959)
01-31 10:31:49.596: E/AndroidRuntime(1536):     at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1728)
01-31 10:31:49.596: E/AndroidRuntime(1536):     at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchTouchEvent(PhoneWindow.java:1892)
01-31 10:31:49.596: E/AndroidRuntime(1536):     at com.android.internal.policy.impl.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1371)
01-31 10:31:49.596: E/AndroidRuntime(1536):     at android.app.Activity.dispatchTouchEvent(Activity.java:2364)
01-31 10:31:49.596: E/AndroidRuntime(1536):     at com.my.example.Home.dispatchTouchEvent(Home.java:883)
01-31 10:31:49.596: E/AndroidRuntime(1536):     at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:1840)
01-31 10:31:49.596: E/AndroidRuntime(1536):     at android.view.View.dispatchPointerEvent(View.java:5662)
01-31 10:31:49.596: E/AndroidRuntime(1536):     at android.view.ViewRootImpl.deliverPointerEvent(ViewRootImpl.java:2863)
01-31 10:31:49.596: E/AndroidRuntime(1536):     at android.view.ViewRootImpl.handleMessage(ViewRootImpl.java:2442)
01-31 10:31:49.596: E/AndroidRuntime(1536):     at android.os.Handler.dispatchMessage(Handler.java:99)
01-31 10:31:49.596: E/AndroidRuntime(1536):     at android.os.Looper.loop(Looper.java:137)
01-31 10:31:49.596: E/AndroidRuntime(1536):     at android.app.ActivityThread.main(ActivityThread.java:4340)
01-31 10:31:49.596: E/AndroidRuntime(1536):     at java.lang.reflect.Method.invokeNative(Native Method)
01-31 10:31:49.596: E/AndroidRuntime(1536):     at java.lang.reflect.Method.invoke(Method.java:511)
01-31 10:31:49.596: E/AndroidRuntime(1536):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
01-31 10:31:49.596: E/AndroidRuntime(1536):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
01-31 10:31:49.596: E/AndroidRuntime(1536):     at dalvik.system.NativeStart.main(Native Method)

NullPointerException refers to CustomGallery method, which I haven't changed at all:

@Override
public boolean onTouchEvent(MotionEvent event) {

    // Give everything to the gesture detector
    boolean retValue = mGestureDetector.onTouchEvent(event);

    int action = event.getAction();
    if (action == MotionEvent.ACTION_UP) {
        // Helper method for lifted finger
        onUp();
    } else if (action == MotionEvent.ACTION_CANCEL) {
        onCancel();
    }

    return retValue;

}

When I comment out lines which removes and adds mGallery everything works perfectly! There was similar problem, but I'm not using fragments.

Any ideas what is wrong? Thanks!

score 6 · Answer 1 · answered Apr 04 '12 at 11:50

I now it is not the answer you were waiting for but I just had the same problem only on ICS on the original Gallery widget (not overloaded).

After some test I fnally uses the easy way : try...catch

@Override
public boolean onTouchEvent(MotionEvent event) {
    try {
        return super.onTouchEvent(event);
    } catch (Throwable t) {
        return true;
    }
}

The Galley is still working correctly and so is the onClickListener so there is no side effect for me.

remove and add view NPE, honeycomb, android

1 Answers1