Android app crashes with NullPointerException in ChoreoGrapher

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Happy的楠姐
Happy的楠姐 2021-01-02 02:06

I have the following code, trying to create a simple ListAdapter in a ListView (I had this code working before and this is the only place I have changed something):

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  •  离开以前
    2021-01-02 02:47

    I have this bug in my app only on Android 4.4.

    In the debugger it shows the same message as the question asker. However when not debugging the full stacktrace in DDMS is:

    Full stacktrace:

    11-13 16:34:53.088: E/AndroidRuntime(1964): FATAL EXCEPTION: main
    11-13 16:34:53.088: E/AndroidRuntime(1964): Process: appname, PID: 1964
    11-13 16:34:53.088: E/AndroidRuntime(1964): java.lang.NullPointerException
    11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.widget.TextView.makeNewLayout(TextView.java:6124)
    11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.widget.TextView.onMeasure(TextView.java:6419)
    11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.view.View.measure(View.java:16458)
    11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.widget.Spinner.setUpChild(Spinner.java:632)
    11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.widget.Spinner.makeView(Spinner.java:585)
    11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.widget.Spinner.getBaseline(Spinner.java:431)
    11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.widget.LinearLayout.measureHorizontal(LinearLayout.java:1262)
    11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.widget.LinearLayout.onMeasure(LinearLayout.java:590)
    11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.view.View.measure(View.java:16458)
    11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125)
    11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1404)
    11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.widget.LinearLayout.measureVertical(LinearLayout.java:695)
    11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.widget.LinearLayout.onMeasure(LinearLayout.java:588)
    11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.view.View.measure(View.java:16458)
    11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125)
    11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
    11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.view.View.measure(View.java:16458)
    11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125)
    11-13 16:34:53.088: E/AndroidRuntime(1964):     at com.android.internal.widget.ActionBarOverlayLayout.onMeasure(ActionBarOverlayLayout.java:327)
    11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.view.View.measure(View.java:16458)
    11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125)
    11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
    11-13 16:34:53.088: E/AndroidRuntime(1964):     at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2289)
    11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.view.View.measure(View.java:16458)
    11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:1914)
    11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1111)
    11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1293)
    11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:998)
    11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5582)
    11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.view.Choreographer$CallbackRecord.run(Choreographer.java:749)
    11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.view.Choreographer.doCallbacks(Choreographer.java:562)
    11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.view.Choreographer.doFrame(Choreographer.java:532)
    11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:735)
    11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.os.Handler.handleCallback(Handler.java:733)
    11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.os.Handler.dispatchMessage(Handler.java:95)
    11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.os.Looper.loop(Looper.java:137)
    11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.app.ActivityThread.main(ActivityThread.java:4998)
    11-13 16:34:53.088: E/AndroidRuntime(1964):     at java.lang.reflect.Method.invokeNative(Native Method)
    11-13 16:34:53.088: E/AndroidRuntime(1964):     at java.lang.reflect.Method.invoke(Method.java:515)
    11-13 16:34:53.088: E/AndroidRuntime(1964):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:777)
    11-13 16:34:53.088: E/AndroidRuntime(1964):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:593)
    11-13 16:34:53.088: E/AndroidRuntime(1964):     at dalvik.system.NativeStart.main(Native Method)
    

    Looking through the 4.4 sourcecode of TextView at line 6124, it turns out that this is caused by missing layout params when ellipsing. This is strange, since the code is failing inside a ListAdapter, where you don't supply layout params in getView.

    I used to inflate android.R.layout.simple_spinner_item for standard spinner items. It looks like this item uses ellipsing. So in my getView I now call:

    view.setEllipsize(null);
    

    This fixes my problems on Android 4.4.

    Edit

    It turns out the problem is not the ellipsing, but improper inflating of a view in getView.

    inflater.inflate(android.R.layout.simple_spinner_item, null);//WRONG
    inflater.inflate(android.R.layout.simple_spinner_item, parent, false);//GOOD
    

    Note that you supply false to not attach the view immediately to the parent, because this is in a adapter that attaches children when needed. Otherwise you will get errors.

    When you inflate properly, you don't need to set ellipseSize to null. This is because when you inflate the good way, with a parent, it handles the LayoutParams properly, causing the ellipse code not to raise NullPointerException.

    So, inflate properly, and then you don't have to worry anymore.

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