1

My app force closes every time I mess with the Relative Layout's positioning now and then. I have to arbitrarily keep re-positioning them for the app to work again. Or position them all at the topmost left corner and then re arrange them.

I'm using Eclipse.

Why does this happen? Is there a way I can avoid this?

[EDIT]

07-22 21:39:22.042: D/dalvikvm(520): GC_EXTERNAL_ALLOC freed 291K, 52% free 2718K/5639K, external 741K/1038K, paused 51ms

07-22 21:39:22.422: D/AndroidRuntime(520): Shutting down VM 07-22 21:39:22.432: W/dalvikvm(520): threadid=1: thread exiting with uncaught exception (group=0x40015560)

07-22 21:39:22.443: E/AndroidRuntime(520): FATAL EXCEPTION: main 07-22 21:39:22.443: E/AndroidRuntime(520): java.lang.RuntimeException: Unable to start activity

ComponentInfo{com.android.tapme/com.android.tapme.TapMe}: java.lang.ClassCastException: android.widget.TextView

07-22 21:39:22.443: E/AndroidRuntime(520): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1647)

07-22 21:39:22.443: E/AndroidRuntime(520): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663)

07-22 21:39:22.443: E/AndroidRuntime(520): at android.app.ActivityThread.access$1500(ActivityThread.java:117)

07-22 21:39:22.443: E/AndroidRuntime(520): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931)

07-22 21:39:22.443: E/AndroidRuntime(520): at android.os.Handler.dispatchMessage(Handler.java:99)

07-22 21:39:22.443: E/AndroidRuntime(520): at android.os.Looper.loop(Looper.java:123)

07-22 21:39:22.443: E/AndroidRuntime(520): at android.app.ActivityThread.main(ActivityThread.java:3683)

07-22 21:39:22.443: E/AndroidRuntime(520): at java.lang.reflect.Method.invokeNative(Native Method)

07-22 21:39:22.443: E/AndroidRuntime(520): at java.lang.reflect.Method.invoke(Method.java:507)

07-22 21:39:22.443: E/AndroidRuntime(520): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)

07-22 21:39:22.443: E/AndroidRuntime(520): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)

07-22 21:39:22.443: E/AndroidRuntime(520): at dalvik.system.NativeStart.main(Native Method)

07-22 21:39:22.443: E/AndroidRuntime(520): Caused by: java.lang.ClassCastException: android.widget.TextView

07-22 21:39:22.443: E/AndroidRuntime(520): at com.android.tapme.TapMe.onCreate(TapMe.java:26)

07-22 21:39:22.443: E/AndroidRuntime(520): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)

07-22 21:39:22.443: E/AndroidRuntime(520): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1611) 07-22 21:39:22.443: E/AndroidRuntime(520): ... 11 more

[EDIT]

I edited the layout randomly and finally got it to work. I then added a progress bar and voila! Force close errors again. Here's the log.

07-26 00:06:57.445: D/AndroidRuntime(876): Shutting down VM

07-26 00:06:57.465: W/dalvikvm(876): threadid=1: thread exiting with uncaught exception (group=0x40015560)

07-26 00:06:57.486: E/AndroidRuntime(876): FATAL EXCEPTION: main

07-26 00:06:57.486: E/AndroidRuntime(876): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.android.tapme/com.android.tapme.TapMe}: java.lang.NullPointerException

07-26 00:06:57.486: E/AndroidRuntime(876): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1569)

07-26 00:06:57.486: E/AndroidRuntime(876): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663)

07-26 00:06:57.486: E/AndroidRuntime(876): at android.app.ActivityThread.access$1500(ActivityThread.java:117)

07-26 00:06:57.486: E/AndroidRuntime(876): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931)

07-26 00:06:57.486: E/AndroidRuntime(876): at android.os.Handler.dispatchMessage(Handler.java:99)

07-26 00:06:57.486: E/AndroidRuntime(876): at android.os.Looper.loop(Looper.java:123)

07-26 00:06:57.486: E/AndroidRuntime(876): at android.app.ActivityThread.main(ActivityThread.java:3683)

07-26 00:06:57.486: E/AndroidRuntime(876): at java.lang.reflect.Method.invokeNative(Native Method)

07-26 00:06:57.486: E/AndroidRuntime(876): at java.lang.reflect.Method.invoke(Method.java:507)

07-26 00:06:57.486: E/AndroidRuntime(876): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)

07-26 00:06:57.486: E/AndroidRuntime(876): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)

07-26 00:06:57.486: E/AndroidRuntime(876): at dalvik.system.NativeStart.main(Native Method)

07-26 00:06:57.486: E/AndroidRuntime(876): Caused by: java.lang.NullPointerException

07-26 00:06:57.486: E/AndroidRuntime(876): at android.app.Activity.findViewById(Activity.java:1647)

07-26 00:06:57.486: E/AndroidRuntime(876): at com.android.tapme.TapMe.(TapMe.java:17)

07-26 00:06:57.486: E/AndroidRuntime(876): at java.lang.Class.newInstanceImpl(Native Method)

07-26 00:06:57.486: E/AndroidRuntime(876): at java.lang.Class.newInstance(Class.java:1409)

07-26 00:06:57.486: E/AndroidRuntime(876): at android.app.Instrumentation.newActivity(Instrumentation.java:1021)

07-26 00:06:57.486: E/AndroidRuntime(876): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1561)

07-26 00:06:57.486: E/AndroidRuntime(876): ... 11 more

4

1 回答 1

0

在 RelativeLayout 中，所有子元素都相对于彼此放置。

这是一个代码片段。

android:layout_below="@id/elementOne"
android:layout_alignParentLeft="true"
android:layout_toLeftOf="@+id/elementTwo"

所以，弄乱其中一个，你就弄乱了一切。

于 2012-07-23T19:03:00.853 回答