,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:
[java] view plain copy 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:
<span style="color: rgb(255, 0, 0);">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`.</span>
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。
[java] view plain copy 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:
[java] view plain copy 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 :
[html] view plain copy <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="fill_parent" android:orientation="vertical" > <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="@string/app_name" /> <ListView android:id="@+id/list" android:layout_width="fill_parent" android:layout_height="fill_parent" ></ListView> </LinearLayout> 看下log:
[java] view plain copy 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:
[java] view plain copy <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="fill_parent" android:orientation="vertical" > <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="@string/app_name" /> <ListView android:id="@id/android:list" android:layout_width="fill_parent" android:layout_height="fill_parent" ></ListView> </LinearLayout> 在这里,就可以方便的设置listview的各个参数了。
