FragmentRetainInstanceSupport.java中的UI更改

Question

我正在使用one of the examples作爲v4兼容性應用程序。我注意到，在這一部分：

mPosition++; 
max = mProgressBar.getMax(); 
mProgressBar.setProgress(mPosition); 

如果我添加一個TextView.setText()：

01-29 18:55:08.889: W/dalvikvm(14565): threadid=11: thread exiting with uncaught exception (group=0x40a791f8) 
01-29 18:55:08.889: E/AndroidRuntime(14565): FATAL EXCEPTION: Thread-1035 
01-29 18:55:08.889: E/AndroidRuntime(14565): android.view.ViewRootImpl$CalledFromWrongThreadException: Only the original thread that created a view hierarchy can touch its views. 
01-29 18:55:08.889: E/AndroidRuntime(14565): at android.view.ViewRootImpl.checkThread(ViewRootImpl.java:3939) 
01-29 18:55:08.889: E/AndroidRuntime(14565): at android.view.ViewRootImpl.requestLayout(ViewRootImpl.java:701) 
01-29 18:55:08.889: E/AndroidRuntime(14565): at android.view.View.requestLayout(View.java:12555) 
01-29 18:55:08.889: E/AndroidRuntime(14565): at android.view.View.requestLayout(View.java:12555) 
01-29 18:55:08.889: E/AndroidRuntime(14565): at android.view.View.requestLayout(View.java:12555) 
01-29 18:55:08.889: E/AndroidRuntime(14565): at android.view.View.requestLayout(View.java:12555) 
01-29 18:55:08.889: E/AndroidRuntime(14565): at android.view.View.requestLayout(View.java:12555) 
01-29 18:55:08.889: E/AndroidRuntime(14565): at android.widget.RelativeLayout.requestLayout(RelativeLayout.java:268) 
01-29 18:55:08.889: E/AndroidRuntime(14565): at android.view.View.requestLayout(View.java:12555) 
01-29 18:55:08.889: E/AndroidRuntime(14565): at android.widget.TextView.checkForRelayout(TextView.java:6716) 
01-29 18:55:08.889: E/AndroidRuntime(14565): at android.widget.TextView.setText(TextView.java:3256) 
01-29 18:55:08.889: E/AndroidRuntime(14565): at android.widget.TextView.setText(TextView.java:3110) 
01-29 18:55:08.889: E/AndroidRuntime(14565): at android.widget.TextView.setText(TextView.java:3085) 
01-29 18:55:08.889: E/AndroidRuntime(14565): at com.mytest.ui.PreActivity$RetainedFragment$1.run(PreActivity.java:111) 

爲什麼出現這種情況：

mPosition++; 
max = mProgressBar.getMax(); 
mProgressBar.setProgress(mPosition); 
mStatus.setText(String.valueOf(max)); // here, just to test stuff! 

它具有以下例外放棄？或者更好的是，如何修改文檔示例以使用TextView而不是ProgressView？

Answer 1

可能是不同的UI線程調用retain的Fragment的情況。可以用getActivity().runOnUIThread(some code)來解決。只是我的建議。