那些年，在Fragment中犯的错

         ，这题目起的够骚情了，原创傲慢的上校哦，转载请标明：http://blog.csdn.net/aomandeshangxiao/article/details/7753421

其实有些方法也是从网上找来的，拿来主义，共同分享下（Fragment其他资料：android之Fragment（官网资料翻译））。

第一个错误：FragmentManagerImpl.saveFragmentBasicState

下面是log：

        

E/AndroidRuntime(29923): FATAL EXCEPTION: main
E/AndroidRuntime(29923): java.lang.NullPointerException
E/AndroidRuntime(29923):     at android.app.FragmentManagerImpl.saveFragmentBasicState(FragmentManager.java:1544)
E/AndroidRuntime(29923):     at android.app.FragmentManagerImpl.saveAllState(FragmentManager.java:1574)
E/AndroidRuntime(29923):     at android.app.Activity.onSaveInstanceState(Activity.java:1213)
E/AndroidRuntime(29923):     at android.app.Activity.performSaveInstanceState(Activity.java:1162)
E/AndroidRuntime(29923):     at android.app.Instrumentation.callActivityOnSaveInstanceState(Instrumentation.java:1287)
E/AndroidRuntime(29923):     at android.app.ActivityThread.performStopActivityInner(ActivityThread.java:3208)
E/AndroidRuntime(29923):     at android.app.ActivityThread.handleStopActivity(ActivityThread.java:3266)
E/AndroidRuntime(29923):     at android.app.ActivityThread.access$900(ActivityThread.java:139)
E/AndroidRuntime(29923):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1279)
E/AndroidRuntime(29923):     at android.os.Handler.dispatchMessage(Handler.java:99)
E/AndroidRuntime(29923):     at android.os.Looper.loop(Looper.java:156)
E/AndroidRuntime(29923):     at android.app.ActivityThread.main(ActivityThread.java:5005)
E/AndroidRuntime(29923):     at java.lang.reflect.Method.invokeNative(Native Method)
E/AndroidRuntime(29923):     at java.lang.reflect.Method.invoke(Method.java:511)
E/AndroidRuntime(29923):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
E/AndroidRuntime(29923):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
E/AndroidRuntime(29923):     at dalvik.system.NativeStart.main(Native Method)

看老半天log,没有琢磨明白，在网上找了下，说出现这个问题，主要是以下两个因素：

       一是用了android.support.v4包,

       二是FragmentActivity.

       本人正是在从Fragment跳转到另一个Activity时候报的错，据说是个官方Bug，已经有程序员把这个问题提交到官方了， https://android-review.googlesource.com/#/c/31261/。

下面看看他们提交的内容：

        

If a fragment's saved view state is null and the user visible hint is true then the `result` bundle will have
never been initialized to a value resulting in a `NullPointerException`.

        如果一个Fragment保存的视图状态为Null并且用户可见提示为true，那么'result' bundle(要保存的Bundle)会有一个微博初始化的值，然后导致空指针异常。

        如何解决此问题呢？问题出在Save上，在有Fragment的Activity中重写onSaveInstanceState()方法，并且注释掉super.onSaveInstanceState（），这样就不会调用父类的onSaveInstanceState(outState)方法了，就不会报异常了。

outState 对象为空..在onSaveInstanceState()函数中不使用到outState即可.

[java] view plaincopy
@Override  
    protected void onSaveInstanceState(Bundle outState) {  
        // TODO Auto-generated method stub   
        //super.onSaveInstanceState(outState);  
          
    }  

第二个、使用ListFragment：java.lang.RuntimeException: Content has view with id attribute 'android.R.id.list' that is not a ListView class

            在ListFragment中，想当然的以为，像其他Fragment一样：

public class ListFragmentTest extends ListFragment {

	@Override
	public View onCreateView(LayoutInflater inflater, ViewGroup container,
			Bundle savedInstanceState) {
		View root = inflater.inflate(R.layout.list, null);
		return root;
	}

在list.xml里面：

看下log：

07-16 15:43:22.026: E/AndroidRuntime(605): FATAL EXCEPTION: main
07-16 15:43:22.026: E/AndroidRuntime(605): java.lang.RuntimeException: Unable to start activity ComponentInfo{cn.demo/cn.demo.FragmentTestActivity}: android.view.InflateException: Binary XML file line #23: Error inflating class fragment
07-16 15:43:22.026: E/AndroidRuntime(605): 	at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1956)
07-16 15:43:22.026: E/AndroidRuntime(605): 	at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1981)
07-16 15:43:22.026: E/AndroidRuntime(605): 	at android.app.ActivityThread.access$600(ActivityThread.java:123)
07-16 15:43:22.026: E/AndroidRuntime(605): 	at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1147)
07-16 15:43:22.026: E/AndroidRuntime(605): 	at android.os.Handler.dispatchMessage(Handler.java:99)
07-16 15:43:22.026: E/AndroidRuntime(605): 	at android.os.Looper.loop(Looper.java:137)
07-16 15:43:22.026: E/AndroidRuntime(605): 	at android.app.ActivityThread.main(ActivityThread.java:4424)
07-16 15:43:22.026: E/AndroidRuntime(605): 	at java.lang.reflect.Method.invokeNative(Native Method)
07-16 15:43:22.026: E/AndroidRuntime(605): 	at java.lang.reflect.Method.invoke(Method.java:511)
07-16 15:43:22.026: E/AndroidRuntime(605): 	at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
07-16 15:43:22.026: E/AndroidRuntime(605): 	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
07-16 15:43:22.026: E/AndroidRuntime(605): 	at dalvik.system.NativeStart.main(Native Method)
07-16 15:43:22.026: E/AndroidRuntime(605): Caused by: android.view.InflateException: Binary XML file line #23: Error inflating class fragment
07-16 15:43:22.026: E/AndroidRuntime(605): 	at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:697)
07-16 15:43:22.026: E/AndroidRuntime(605): 	at android.view.LayoutInflater.rInflate(LayoutInflater.java:739)
07-16 15:43:22.026: E/AndroidRuntime(605): 	at android.view.LayoutInflater.inflate(LayoutInflater.java:489)
07-16 15:43:22.026: E/AndroidRuntime(605): 	at android.view.LayoutInflater.inflate(LayoutInflater.java:396)
07-16 15:43:22.026: E/AndroidRuntime(605): 	at android.view.LayoutInflater.inflate(LayoutInflater.java:352)
07-16 15:43:22.026: E/AndroidRuntime(605): 	at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:251)
07-16 15:43:22.026: E/AndroidRuntime(605): 	at android.app.Activity.setContentView(Activity.java:1835)
07-16 15:43:22.026: E/AndroidRuntime(605): 	at cn.demo.FragmentTestActivity.onCreate(FragmentTestActivity.java:11)
07-16 15:43:22.026: E/AndroidRuntime(605): 	at android.app.Activity.performCreate(Activity.java:4465)
07-16 15:43:22.026: E/AndroidRuntime(605): 	at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1049)
07-16 15:43:22.026: E/AndroidRuntime(605): 	at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1920)
07-16 15:43:22.026: E/AndroidRuntime(605): 	... 11 more
07-16 15:43:22.026: E/AndroidRuntime(605): Caused by: java.lang.RuntimeException: Content has view with id attribute 'android.R.id.list' that is not a ListView class
07-16 15:43:22.026: E/AndroidRuntime(605): 	at android.app.ListFragment.ensureList(ListFragment.java:402)
07-16 15:43:22.026: E/AndroidRuntime(605): 	at android.app.ListFragment.onViewCreated(ListFragment.java:203)
07-16 15:43:22.026: E/AndroidRuntime(605): 	at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:811)
07-16 15:43:22.026: E/AndroidRuntime(605): 	at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:1010)
07-16 15:43:22.026: E/AndroidRuntime(605): 	at android.app.FragmentManagerImpl.addFragment(FragmentManager.java:1108)
07-16 15:43:22.026: E/AndroidRuntime(605): 	at android.app.Activity.onCreateView(Activity.java:4243)
07-16 15:43:22.026: E/AndroidRuntime(605): 	at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:673)
07-16 15:43:22.026: E/AndroidRuntime(605): 	... 21 more

        为什么呢？因为ListFragment里面已经提供了系统自带的ListView，这样写，当然出错。可以直接不重写OnCreatView方法，使用getListView()获取系统提供的ListView，但是获取的ListView设置Item间隔线只能getListView().setDivider(divider)，其参数为Drawable类型。当然如果只想简单的设置下Divider的颜色呢？

        其实ListFragment当然运行自定义布局，但是Listview要用系统的：

在这里，就可以方便的设置listview的各个参数了。