java.lang.ClassCastException: android.view.ViewGroup$LayoutParams without LayoutParams usage

Question

I use a view which has RelativeLayout -> ScrollView -> LinearLayout. I get exception:

11-22 11:17:24.605: ERROR/AndroidRuntime(5161): FATAL EXCEPTION: main
11-22 11:17:24.605: ERROR/AndroidRuntime(5161): java.lang.ClassCastException: android.view.ViewGroup$LayoutParams
11-22 11:17:24.605: ERROR/AndroidRuntime(5161):     at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:3131)
11-22 11:17:24.605: ERROR/AndroidRuntime(5161):     at android.widget.FrameLayout.onMeasure(FrameLayout.java:245)
11-22 11:17:24.605: ERROR/AndroidRuntime(5161):     at android.view.View.measure(View.java:8172)
11-22 11:17:24.605: ERROR/AndroidRuntime(5161):     at android.view.ViewRoot.performTraversals(ViewRoot.java:805)
11-22 11:17:24.605: ERROR/AndroidRuntime(5161):     at android.view.ViewRoot.handleMessage(ViewRoot.java:1744)
11-22 11:17:24.605: ERROR/AndroidRuntime(5161):     at android.os.Handler.dispatchMessage(Handler.java:99)
11-22 11:17:24.605: ERROR/AndroidRuntime(5161):     at android.os.Looper.loop(Looper.java:144)
11-22 11:17:24.605: ERROR/AndroidRuntime(5161):     at android.app.ActivityThread.main(ActivityThread.java:4937)
11-22 11:17:24.605: ERROR/AndroidRuntime(5161):     at java.lang.reflect.Method.invokeNative(Native Method)
11-22 11:17:24.605: ERROR/AndroidRuntime(5161):     at java.lang.reflect.Method.invoke(Method.java:521)
11-22 11:17:24.605: ERROR/AndroidRuntime(5161):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
11-22 11:17:24.605: ERROR/AndroidRuntime(5161):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
11-22 11:17:24.605: ERROR/AndroidRuntime(5161):     at dalvik.system.NativeStart.main(Native Method)

Why does it happen only occassionally? Why is there no detail of where the code failed?

Update: I suspect it should fail around this code:

EditText input = new EditText(context);
input.setLayoutParams(new LayoutParams(LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT));

LayoutParams is RelativeLayout.LayoutParams

Answer 1

Use new LinearLayout.LayoutParams(...) instead of new LayoutParams(...)

You always need to use the parent layout's class for the LayoutParams . Eg if EditText is inside FrameLayout then FrameLayout.LayoutParams must be used.