java.lang.IllegalStateException: Can not perform this action after onSaveInstanceState
2016-08-02
公司app线上这个报错量一直很高，这次修复了下，分析下整个原因：
整个报错栈信息如下：
java.lang.IllegalStateException: Can not perform this action after onSaveInstanceState
at android.support.v4.app.FragmentManagerImpl.checkStateLoss(SourceFile:1527)
at android.support.v4.app.FragmentManagerImpl.enqueueAction(SourceFile:1545)
at android.support.v4.app.BackStackRecord.commitInternal(SourceFile:654)
at android.support.v4.app.BackStackRecord.commit(SourceFile:621)
at android.support.v4.app.FragmentTabHost.onAttachedToWindow(SourceFile:282)
at android.view.View.dispatchAttachedToWindow(View.java:13326)
at android.view.ViewGroup.dispatchAttachedToWindow(ViewGroup.java:2601)
at android.view.ViewGroup.dispatchAttachedToWindow(ViewGroup.java:2608)
at android.view.ViewGroup.dispatchAttachedToWindow(ViewGroup.java:2608)
at android.view.ViewGroup.dispatchAttachedToWindow(ViewGroup.java:2608)
at android.view.ViewGroup.dispatchAttachedToWindow(ViewGroup.java:2608)
at android.view.ViewGroup.dispatchAttachedToWindow(ViewGroup.java:2608)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1334)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1096)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:6057)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:793)
at android.view.Choreographer.doCallbacks(Choreographer.java:606)
at android.view.Choreographer.doFrame(Choreographer.java:575)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:779)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5539)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:960)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:755)1、栈顶原因分析：
FragmentManager.checkStateLoss这里抛的异常，翻下源码会发现：如果FragmentTransaction.commit时候activity的状态被保存（即调用了onsaveInstance回调后），就会在这个地方抛这样的异常；
2、相关知识点：
a、在android HONEYCOMB（Api11）之前：onsaveinstance回调是在onpause之前，在Api11之后调整到了opause之后onstop之前；
b、从报错信息栈里可以看出我这个项目里用了：FragmentTabHost控件，FragmentTabHost在调用addTab时候会调事务的commit；
c、FragmentTransaction.commit接口是不允许在activity的状态保存之后调用（即调用了onsaveInstance回调后）
3、解决方案：
a、由于v4支持包中FragmentActivity的onsaveInstance回调存在bug，在回调这个方法时候有可能会有异常，这里重写这个方法不去调用super：
@Override
protected void onSaveInstanceState(Bundle outState) {
// super.onSaveInstanceState(outState);
//No call for super(). Bug on API Level > 11.
}b、使用FragmentTransaction.commitAllowingStateLoss来提交事务，但由于我这里提交事务是在源码里的，无法复写，故没法处理了；
c、通过复写FragmentTabHost的onAttachedToWindow方法捕获异常：
@Override
protected void onAttachedToWindow() {
try {
super.onAttachedToWindow();
} catch (IllegalStateException e) {
//由于ft.commit();
}
}