Question

我需要在用户按下音量增大按钮时发出通知，我无法直接在sherlockfragment上获得keydown，所以我创建了一个从sherlockfragmentactivity调用的方法，但我得到一个空指针异常intent.putExtras（束）

这是我的SherlockFragmentActivity的代码：

 @Override
 public boolean onKeyDown(int keyCode, KeyEvent event) {     

    ((MyFragment) mTabsAdapter.getItem(0)).myOnKeyDown(keyCode);            

    return super.onKeyDown(keyCode, event);
  }

SherlockFragment中的代码：

    @Override
public void onActivityCreated (Bundle savedInstanceState)
{
intent = new Intent(getActivity(), NotifyService.class);    
}


  public void myOnKeyDown(int key_code){

    if(key_code == KeyEvent.KEYCODE_VOLUME_UP){
      notifyBar();                  
    }
  }

服务意图方法：

public void notifyBar(){                                
    Bundle bundle = new Bundle();
    bundle.putLong("data1", d1);        
    bundle.putLong("data2", d2);                    

    intent.putExtras(bundle); // NPE HERE           
    getActivity().startService(intent);
}

Log cat：

07-28 00:04:28.587: E/AndroidRuntime(1737): FATAL EXCEPTION: main
07-28 00:04:28.587: E/AndroidRuntime(1737): java.lang.NullPointerException
07-28 00:04:28.587: E/AndroidRuntime(1737):     at com.my.app.MyFragment.notifyBar(MyFragment.java:692)
07-28 00:04:28.587: E/AndroidRuntime(1737):     at com.my.app.MyFragment.myOnKeyDown(MyFragment.java:393)
07-28 00:04:28.587: E/AndroidRuntime(1737):     at com.my.app.MyFragmentActivity.onKeyDown(MyFragmentActivity.java:171)
07-28 00:04:28.587: E/AndroidRuntime(1737):     at android.view.KeyEvent.dispatch(KeyEvent.java:1037)
07-28 00:04:28.587: E/AndroidRuntime(1737):     at android.app.Activity.dispatchKeyEvent(Activity.java:2068)
07-28 00:04:28.587: E/AndroidRuntime(1737):     at com.actionbarsherlock.app.SherlockFragmentActivity.dispatchKeyEvent(SherlockFragmentActivity.java:122)
07-28 00:04:28.587: E/AndroidRuntime(1737):     at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchKeyEvent(PhoneWindow.java:1643)
07-28 00:04:28.587: E/AndroidRuntime(1737):     at android.view.ViewRoot.deliverKeyEventToViewHierarchy(ViewRoot.java:2471)
07-28 00:04:28.587: E/AndroidRuntime(1737):     at android.view.ViewRoot.handleFinishedEvent(ViewRoot.java:2441)
07-28 00:04:28.587: E/AndroidRuntime(1737):     at android.view.ViewRoot.handleMessage(ViewRoot.java:1735)
07-28 00:04:28.587: E/AndroidRuntime(1737):     at android.os.Handler.dispatchMessage(Handler.java:99)
07-28 00:04:28.587: E/AndroidRuntime(1737):     at android.os.Looper.loop(Looper.java:123)
07-28 00:04:28.587: E/AndroidRuntime(1737):     at android.app.ActivityThread.main(ActivityThread.java:4627)
07-28 00:04:28.587: E/AndroidRuntime(1737):     at java.lang.reflect.Method.invokeNative(Native Method)
07-28 00:04:28.587: E/AndroidRuntime(1737):     at java.lang.reflect.Method.invoke(Method.java:521)
07-28 00:04:28.587: E/AndroidRuntime(1737):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
07-28 00:04:28.587: E/AndroidRuntime(1737):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
07-28 00:04:28.587: E/AndroidRuntime(1737):     at dalvik.system.NativeStart.main(Native Method)

Answer 1

您能告诉我们更多信息吗？有两个类：

片段（包含您在FragmentActivity中单击按钮后要处理的控件）
FragmentActivity（包含您要点击并通知片段的按钮）

如果那是你想要的，我可以给你一个建议：

你应该创建一个这样的界面：

interface INotifyBar {
   void notify(Object valueForTransfer); // If you want to transfer :D
}

在 FragmentActivity 中就在这里，请创建一个INotifyBar实例

private INotifyBar mINotifyBar;

onKeyDown() {
    mINotifyBar.notify(keyCode); // Here is just example. :D
}

并在片段中实现notify（）;

@Override
public void notify(Object obj) {
    // Handle something with or without obj. It's up to you.
}

我可以比你更多地帮助你，但我需要了解更多。：d

Null指针异常从其他类启动意图

1 个答案: