错误信息:

java.lang.ClassCastException: android.widget.LinearLayout$LayoutParams cannot be cast to android.widget.RelativeLayout$LayoutParams

at android.widget.RelativeLayout$DependencyGraph.findRoots(RelativeLayout.java:1317)

at android.widget.RelativeLayout$DependencyGraph.getSortedViews(RelativeLayout.java:1264)

at android.widget.RelativeLayout.sortChildren(RelativeLayout.java:292)

at android.widget.RelativeLayout.onMeasure(RelativeLayout.java:314)

at android.view.View.measure(View.java:12728)

at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4698)

at android.widget.FrameLayout.onMeasure(FrameLayout.java:293)

at android.view.View.measure(View.java:12728)

at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4698)

at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1369)

at android.widget.LinearLayout.measureVertical(LinearLayout.java:660)

at android.widget.LinearLayout.onMeasure(LinearLayout.java:553)

at android.view.View.measure(View.java:12728)

at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4698)

at android.widget.FrameLayout.onMeasure(FrameLayout.java:293)

at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2095)

at android.view.View.measure(View.java:12728)

at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1064)

at android.view.ViewRootImpl.handleMessage(ViewRootImpl.java:2442)

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

at android.os.Looper.loop(Looper.java:137)

at android.app.ActivityThread.main(ActivityThread.java:4426)

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

at java.lang.reflect.Method.invoke(Method.java:511)

at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:788)

at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:555)

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

解决办法:

如果你要将一个view添加到另一个布局中，你必须设定该View的布局参数为其父类所使用的布局参数类型。

RelativeLayout.LayoutParams layoutParams=new RelativeLayout.

LayoutParams(LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT);

layoutParams.setMargins(0, 120, 0, 0);