使用RecyclerView碰到的若干问题
RecyclerView碰到的若干问题
RecyclerView控件非常好用，横向和纵向的滑动都能有很好的效果，而且view的重用，听说效率很高（不知道真实情况如何）。在使用的过程中遇到过几个bug，现在将bug list都贴出来，并分别说明每一种bug出现的原因以及其解决方法。
一、使用RecyclerView肯定要用到support-v7包，所以导入v7包，再直接在布局文件中使用该控件。
直接这样做的后果是很可能会产生这个RecyclerView无法解析的bug list：
08-28 15:41:12.982: E/AndroidRuntime(9259): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.recyclerviewtest/com.example.recyclerviewtest.MainActivity}: android.view.InflateException: Binary XML file line #19: Error inflating class android.support.v7.widget.RecyclerView
08-28 15:41:12.982: E/AndroidRuntime(9259): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2195)
08-28 15:41:12.982: E/AndroidRuntime(9259): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
08-28 15:41:12.982: E/AndroidRuntime(9259): at android.app.ActivityThread.access$800(ActivityThread.java:135)
08-28 15:41:12.982: E/AndroidRuntime(9259): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
08-28 15:41:12.982: E/AndroidRuntime(9259): at android.os.Handler.dispatchMessage(Handler.java:102)
08-28 15:41:12.982: E/AndroidRuntime(9259): at android.os.Looper.loop(Looper.java:136)
08-28 15:41:12.982: E/AndroidRuntime(9259): at android.app.ActivityThread.main(ActivityThread.java:5017)
08-28 15:41:12.982: E/AndroidRuntime(9259): at java.lang.reflect.Method.invokeNative(Native Method)
08-28 15:41:12.982: E/AndroidRuntime(9259): at java.lang.reflect.Method.invoke(Method.java:515)
08-28 15:41:12.982: E/AndroidRuntime(9259): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:788)
08-28 15:41:12.982: E/AndroidRuntime(9259): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:604)
08-28 15:41:12.982: E/AndroidRuntime(9259): at dalvik.system.NativeStart.main(Native Method)
08-28 15:41:12.982: E/AndroidRuntime(9259): Caused by: android.view.InflateException: Binary XML file line #19: Error inflating class android.support.v7.widget.RecyclerView
08-28 15:41:12.982: E/AndroidRuntime(9259): at android.view.LayoutInflater.createView(LayoutInflater.java:620)
08-28 15:41:12.982: E/AndroidRuntime(9259): at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:696)
08-28 15:41:12.982: E/AndroidRuntime(9259): at android.view.LayoutInflater.rInflate(LayoutInflater.java:755)
08-28 15:41:12.982: E/AndroidRuntime(9259): at android.view.LayoutInflater.inflate(LayoutInflater.java:492)
08-28 15:41:12.982: E/AndroidRuntime(9259): at android.view.LayoutInflater.inflate(LayoutInflater.java:397)
08-28 15:41:12.982: E/AndroidRuntime(9259): at android.view.LayoutInflater.inflate(LayoutInflater.java:353)
08-28 15:41:12.982: E/AndroidRuntime(9259): at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:290)
08-28 15:41:12.982: E/AndroidRuntime(9259): at android.app.Activity.setContentView(Activity.java:1953)
08-28 15:41:12.982: E/AndroidRuntime(9259): at com.example.recyclerviewtest.MainActivity.onCreate(MainActivity.java:12)
08-28 15:41:12.982: E/AndroidRuntime(9259): at android.app.Activity.performCreate(Activity.java:5273)
08-28 15:41:12.982: E/AndroidRuntime(9259): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1101)
08-28 15:41:12.982: E/AndroidRuntime(9259): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2159)
08-28 15:41:12.982: E/AndroidRuntime(9259): ... 11 more
08-28 15:41:12.982: E/AndroidRuntime(9259): Caused by: java.lang.reflect.InvocationTargetException
08-28 15:41:12.982: E/AndroidRuntime(9259): at java.lang.reflect.Constructor.constructNative(Native Method)
08-28 15:41:12.982: E/AndroidRuntime(9259): at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
08-28 15:41:12.982: E/AndroidRuntime(9259): at android.view.LayoutInflater.createView(LayoutInflater.java:594)
08-28 15:41:12.982: E/AndroidRuntime(9259): ... 22 more
08-28 15:41:12.982: E/AndroidRuntime(9259): Caused by: java.lang.NoClassDefFoundError: android.support.v4.util.Pools$SimplePool
08-28 15:41:12.982: E/AndroidRuntime(9259): at android.support.v7.widget.AdapterHelper.(AdapterHelper.java:56)
08-28 15:41:12.982: E/AndroidRuntime(9259): at android.support.v7.widget.AdapterHelper.(AdapterHelper.java:71)
08-28 15:41:12.982: E/AndroidRuntime(9259): at android.support.v7.widget.RecyclerView.initAdapterManager(RecyclerView.java:373)
08-28 15:41:12.982: E/AndroidRuntime(9259): at android.support.v7.widget.RecyclerView.(RecyclerView.java:282)
08-28 15:41:12.982: E/AndroidRuntime(9259): at android.support.v7.widget.RecyclerView.(RecyclerView.java:266)
08-28 15:41:12.982: E/AndroidRuntime(9259): ... 25 more
08-28 15:41:13.102: I/Process(9259): Sending signal. PID: 9259 SIG: 9 这个bug list产生的情况是最多的，也曾经让我不知道问题在哪里。仔细分析得知，是v7 jar包和v4 jar包的版本不同造成的，根据一个说法就是从官网同一个地方下载的v4和v7一般就不会有这样的问题。我这里有可以匹配的v4 和v7 jar，提供大家下载。用这两个jar基本可以保证不会出现此类的bug
二、RecyclerView没有进行设置setLayoutManager。这个问题就会直接导致空指针。
08-28 17:24:29.782: D/TextLayoutCache(11127): Using debug level = 0 - Debug Enabled = 0
08-28 17:24:30.292: D/AndroidRuntime(11127): Shutting down VM
08-28 17:24:30.292: W/dalvikvm(11127): threadid=1: thread exiting with uncaught exception (group=0x41676ba8)
08-28 17:24:30.322: D/dalvikvm(11127): GC_FOR_ALLOC freed 146K, 12% free 1372K/1548K, paused 12ms, total 12ms
08-28 17:24:30.322: E/AndroidRuntime(11127): FATAL EXCEPTION: main
08-28 17:24:30.322: E/AndroidRuntime(11127): Process: com.example.testrecycler, PID: 11127
08-28 17:24:30.322: E/AndroidRuntime(11127): java.lang.NullPointerException
08-28 17:24:30.322: E/AndroidRuntime(11127): at android.support.v7.widget.RecyclerView.addFocusables(RecyclerView.java:1332)
08-28 17:24:30.322: E/AndroidRuntime(11127): at android.view.ViewGroup.addFocusables(ViewGroup.java:914)
08-28 17:24:30.322: E/AndroidRuntime(11127): at android.view.ViewGroup.addFocusables(ViewGroup.java:914)
08-28 17:24:30.322: E/AndroidRuntime(11127): at android.view.ViewGroup.addFocusables(ViewGroup.java:914)
08-28 17:24:30.322: E/AndroidRuntime(11127): at android.view.ViewGroup.addFocusables(ViewGroup.java:914)
08-28 17:24:30.322: E/AndroidRuntime(11127): at android.view.View.addFocusables(View.java:6711)
08-28 17:24:30.322: E/AndroidRuntime(11127): at android.view.FocusFinder.findNextFocus(FocusFinder.java:92)
08-28 17:24:30.322: E/AndroidRuntime(11127): at android.view.FocusFinder.findNextFocus(FocusFinder.java:65)
08-28 17:24:30.322: E/AndroidRuntime(11127): at android.view.ViewRootImpl.focusSearch(ViewRootImpl.java:5234)
08-28 17:24:30.322: E/AndroidRuntime(11127): at android.view.ViewRootImpl.leaveTouchMode(ViewRootImpl.java:3361)
08-28 17:24:30.322: E/AndroidRuntime(11127): at android.view.ViewRootImpl.ensureTouchModeLocally(ViewRootImpl.java:3294)
08-28 17:24:30.322: E/AndroidRuntime(11127): at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1262)
08-28 17:24:30.322: E/AndroidRuntime(11127): at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1000)
08-28 17:24:30.322: E/AndroidRuntime(11127): at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5672)
08-28 17:24:30.322: E/AndroidRuntime(11127): at android.view.Choreographer$CallbackRecord.run(Choreographer.java:772)
08-28 17:24:30.322: E/AndroidRuntime(11127): at android.view.Choreographer.doCallbacks(Choreographer.java:585)
08-28 17:24:30.322: E/AndroidRuntime(11127): at android.view.Choreographer.doFrame(Choreographer.java:555)
08-28 17:24:30.322: E/AndroidRuntime(11127): at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:758)
08-28 17:24:30.322: E/AndroidRuntime(11127): at android.os.Handler.handleCallback(Handler.java:733)
08-28 17:24:30.322: E/AndroidRuntime(11127): at android.os.Handler.dispatchMessage(Handler.java:95)
08-28 17:24:30.322: E/AndroidRuntime(11127): at android.os.Looper.loop(Looper.java:136)
08-28 17:24:30.322: E/AndroidRuntime(11127): at android.app.ActivityThread.main(ActivityThread.java:5017)
08-28 17:24:30.322: E/AndroidRuntime(11127): at java.lang.reflect.Method.invokeNative(Native Method)
08-28 17:24:30.322: E/AndroidRuntime(11127): at java.lang.reflect.Method.invoke(Method.java:515)
08-28 17:24:30.322: E/AndroidRuntime(11127): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:788)
08-28 17:24:30.322: E/AndroidRuntime(11127): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:604)
08-28 17:24:30.322: E/AndroidRuntime(11127): at dalvik.system.NativeStart.main(Native Method)
08-28 17:24:30.702: I/Process(11127): Sending signal. PID: 11127 SIG: 9这个问题的解决方式就太简单了，初始化该RecyclerView（即findViewById来找到，然后设置setLayoutManager就行了）
public class MainActivity extends Activity {
private RecyclerView mRecyclerView;
private MyAdapter myAdaper;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
this.mRecyclerView = (RecyclerView) this.findViewById(R.id.channelmanager_recyclerview);
this.mRecyclerView.setHasFixedSize(true);
this.mRecyclerView.setLayoutManager(new LinearLayoutManager(this));
//this.myAdaper = new MyAdapter();
//this.mRecyclerView.setAdapter(myAdaper);
}如上adapter 即使没有设置，也不会有任何 bug 问题，解决简单。
至此，基本上再没有关于RecyclerView的任何问题了…………