android给listview添加下拉刷新崩溃

Question

logcat：
10-09 15:17:36.549 15984-15984/com.example.jkd.fchangshi D/dalvikvm﹕ VFY: replacing opcode 0x6f at 0x0000
10-09 15:17:36.549 15984-15984/com.example.jkd.fchangshi I/dalvikvm﹕ Could not find method android.view.ViewGroup.onStopNestedScroll, referenced from method android.support.v7.internal.widget.ActionBarOverlayLayout.onStopNestedScroll
10-09 15:17:36.549 15984-15984/com.example.jkd.fchangshi W/dalvikvm﹕ VFY: unable to resolve virtual method 12221: Landroid/view/ViewGroup;.onStopNestedScroll (Landroid/view/View;)V
10-09 15:17:36.549 15984-15984/com.example.jkd.fchangshi D/dalvikvm﹕ VFY: replacing opcode 0x6f at 0x0000
10-09 15:17:36.549 15984-15984/com.example.jkd.fchangshi I/dalvikvm﹕ Could not find method android.support.v7.internal.widget.ActionBarOverlayLayout.stopNestedScroll, referenced from method android.support.v7.internal.widget.ActionBarOverlayLayout.setHideOnContentScrollEnabled
10-09 15:17:36.549 15984-15984/com.example.jkd.fchangshi W/dalvikvm﹕ VFY: unable to resolve virtual method 9785: Landroid/support/v7/internal/widget/ActionBarOverlayLayout;.stopNestedScroll ()V
10-09 15:17:36.549 15984-15984/com.example.jkd.fchangshi D/dalvikvm﹕ VFY: replacing opcode 0x6e at 0x000e
10-09 15:17:36.549 15984-15984/com.example.jkd.fchangshi I/dalvikvm﹕ Could not find method android.content.res.TypedArray.getChangingConfigurations, referenced from method android.support.v7.internal.widget.TintTypedArray.getChangingConfigurations
10-09 15:17:36.549 15984-15984/com.example.jkd.fchangshi W/dalvikvm﹕ VFY: unable to resolve virtual method 396: Landroid/content/res/TypedArray;.getChangingConfigurations ()I
10-09 15:17:36.549 15984-15984/com.example.jkd.fchangshi D/dalvikvm﹕ VFY: replacing opcode 0x6e at 0x0002
10-09 15:17:36.549 15984-15984/com.example.jkd.fchangshi I/dalvikvm﹕ Could not find method android.content.res.TypedArray.getType, referenced from method android.support.v7.internal.widget.TintTypedArray.getType
10-09 15:17:36.549 15984-15984/com.example.jkd.fchangshi W/dalvikvm﹕ VFY: unable to resolve virtual method 418: Landroid/content/res/TypedArray;.getType (I)I
10-09 15:17:36.549 15984-15984/com.example.jkd.fchangshi D/dalvikvm﹕ VFY: replacing opcode 0x6e at 0x0002
10-09 15:17:36.549 15984-15984/com.example.jkd.fchangshi I/dalvikvm﹕ Could not find method android.content.res.Resources.getDrawable, referenced from method android.support.v7.internal.widget.ResourcesWrapper.getDrawable
10-09 15:17:36.549 15984-15984/com.example.jkd.fchangshi W/dalvikvm﹕ VFY: unable to resolve virtual method 359: Landroid/content/res/Resources;.getDrawable (ILandroid/content/res/Resources$Theme;)Landroid/graphics/drawable/Drawable;
10-09 15:17:36.549 15984-15984/com.example.jkd.fchangshi D/dalvikvm﹕ VFY: replacing opcode 0x6e at 0x0002
10-09 15:17:36.549 15984-15984/com.example.jkd.fchangshi I/dalvikvm﹕ Could not find method android.content.res.Resources.getDrawableForDensity, referenced from method android.support.v7.internal.widget.ResourcesWrapper.getDrawableForDensity
10-09 15:17:36.549 15984-15984/com.example.jkd.fchangshi W/dalvikvm﹕ VFY: unable to resolve virtual method 361: Landroid/content/res/Resources;.getDrawableForDensity (IILandroid/content/res/Resources$Theme;)Landroid/graphics/drawable/Drawable;
10-09 15:17:36.549 15984-15984/com.example.jkd.fchangshi D/dalvikvm﹕ VFY: replacing opcode 0x6e at 0x0002
10-09 15:17:36.599 15984-15984/com.example.jkd.fchangshi I/dalvikvm-heap﹕ Grow heap (frag case) to 26.484MB for 9000016-byte allocation
10-09 15:17:36.629 15984-15984/com.example.jkd.fchangshi D/AndroidRuntime﹕ Shutting down VM
10-09 15:17:36.629 15984-15984/com.example.jkd.fchangshi W/dalvikvm﹕ threadid=1: thread exiting with uncaught exception (group=0x415e8d58)
10-09 15:17:36.629 15984-15984/com.example.jkd.fchangshi E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.example.jkd.fchangshi, PID: 15984
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.jkd.fchangshi/com.example.jkd.fchangshi.MainActivity}: java.lang.NullPointerException
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2190)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2250)
at android.app.ActivityThread.access$800(ActivityThread.java:139)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1200)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5049)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:818)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:634)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at com.example.jkd.fchangshi.MainActivity$PlaceholderFragment.onCreateView(MainActivity.java:295)
at android.support.v4.app.Fragment.performCreateView(Fragment.java:1786)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:953)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1136)
at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:739)
at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1499)
at android.support.v4.app.FragmentActivity.onStart(FragmentActivity.java:548)
at android.app.Instrumentation.callActivityOnStart(Instrumentation.java:1171)
at android.app.Activity.performStart(Activity.java:5303)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2163)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2250)
            at android.app.ActivityThread.access$800(ActivityThread.java:139)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1200)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:136)
            at android.app.ActivityThread.main(ActivityThread.java:5049)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:515)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:818)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:634)
            at dalvik.system.NativeStart.main(Native Method)
10-09 15:17:36.759 15984-16013/com.example.jkd.fchangshi I/System.out﹕ 获取成功
10-09 15:17:36.829 15984-16013/com.example.jkd.fchangshi I/System.out﹕ 转字符串成功

Answer 1

 Caused by: java.lang.NullPointerException
at com.example.jkd.fchangshi.MainActivity$PlaceholderFragment.onCreateView(MainActivity.java:295)

此处空指针了。