Uncauch java error

Hello,

Sometimes, i catch uncaught exception:

{Java.Lang.NullPointerException: Exception of type

'Java.Lang.NullPointerException' was thrown.

--- End of managed exception

stack trace --- java.lang.NullPointerException

at android.view.ViewGroup.dispatchDetachedFromWindow(ViewGroup.java:1162)

at android.view.ViewGroup.dispatchDetachedFromWindow(ViewGroup.java:1162)

at android.view.ViewGroup.dispatchDetachedFromWindow(ViewGroup.java:1162)

at android.view.ViewGroup.finishAnimatingView(ViewGroup.java:3268)

at android.view.ViewGroup.drawChild(ViewGroup.java:1667)

at android.view.ViewGroup.dispatchDraw(ViewGroup.java:1392)

at android.view.ViewGroup.drawChild(ViewGroup.java:1644)

at android.view.ViewGroup.dispatchDraw(ViewGroup.java:1373)

at android.view.View.draw(View.java:6936)

at android.widget.FrameLayout.draw(FrameLayout.java:357)

at android.view.ViewGroup.drawChild(ViewGroup.java:1646)

at android.view.ViewGroup.dispatchDraw(ViewGroup.java:1373)

at android.view.View.draw(View.java:6936)

at android.widget.FrameLayout.draw(FrameLayout.java:357)

at com.android.internal.policy.impl.PhoneWindow$DecorView.draw

(PhoneWindow.java:1917)

at android.view.ViewRoot.draw(ViewRoot.java:1530)

at android.view.ViewRoot.performTraversals(ViewRoot.java:1266)

at android.view.ViewRoot.handleMessage(ViewRoot.java:1868)

at android.os.Handler.dispatchMessage(Handler.java:99)

at android.os.Looper.loop(Looper.java:130)

at android.app.ActivityThread.main(ActivityThread.java:3691)

at java.lang.reflect.Method.invokeNative(Native Method)

at java.lang.reflect.Method.invoke(Method.java:507)

at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run

(ZygoteInit.java:907)

at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:665) at

dalvik.system.NativeStart.main(Native Method) }

Why? ^( I'm using custom ListView