Question

我正在开发一个应用程序，每个选项卡有3个选项卡和片段。从选项卡中选择列表项时，新片段将替换同一选项卡中的当前片段。我在这个新片段中使用了一个onclicklistener按钮。但是，当实现onClickMethod时，应用程序甚至会在加载选项卡之前崩溃。

 public class ChatWindow extends Fragment {

ArrayList<String> listItems=new ArrayList<String>();

//DEFINING STRING ADAPTER WHICH WILL HANDLE DATA OF LISTVIEW
ArrayAdapter<String> adapter;
View view; 

  @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, 
        Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        return inflater.inflate(R.layout.chat_window, container, false);
    }

public void onStart()
{
     Button btn=(Button)getActivity().findViewById(R.id.btnSend);
       Log.v("HI","Button Created !!");
       OnClickListener listener = new OnClickListener() {                       
            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                //adapter=new ArrayAdapter<String>    (getActivity(),android.R.layout.simple_list_item_1,listItems);
                //setListAdapter(adapter);
                Log.v("HI","Button  !!");
               Toast toast = Toast.makeText(getActivity().getBaseContext(), "Hello",10000);
              toast.show();
            }
        };

        btn.setOnClickListener(listener);
}
}

这是logcat ::

    01-09 18:02:22.126: D/gralloc_goldfish(623): Emulator without GPU emulation  detected.
    01-09 18:02:22.156: W/TextLayoutCache(623): computeValuesWithHarfbuzz -- need to force to single run
    01-09 18:02:36.805: V/AB(623): Main Tab Activity
    01-09 18:02:36.855: V/HI(623): Button Created !!
    01-09 18:02:36.855: D/AndroidRuntime(623): Shutting down VM
    01-09 18:02:36.865: W/dalvikvm(623): threadid=1: thread exiting with uncaught exception (group=0x409961f8)
    01-09 18:02:36.885: E/AndroidRuntime(623): FATAL EXCEPTION: main
    01-09 18:02:36.885: E/AndroidRuntime(623): android.app.SuperNotCalledException: Fragment ChatWindow{41099e70 #1 id=0x7f040011} did not call through to super.onStart()
    01-09 18:02:36.885: E/AndroidRuntime(623):  at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:831)
    01-09 18:02:36.885: E/AndroidRuntime(623):  at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:998)
    01-09 18:02:36.885: E/AndroidRuntime(623):  at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:981)
    01-09 18:02:36.885: E/AndroidRuntime(623):  at android.app.FragmentManagerImpl.dispatchStart(FragmentManager.java:1700)
    01-09 18:02:36.885: E/AndroidRuntime(623):  at android.app.Activity.performStart(Activity.java:4481)
    01-09 18:02:36.885: E/AndroidRuntime(623):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1928)
    01-09 18:02:36.885: E/AndroidRuntime(623):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1980)
    01-09 18:02:36.885: E/AndroidRuntime(623):  at android.app.ActivityThread.access$600(ActivityThread.java:122)
    01-09 18:02:36.885: E/AndroidRuntime(623):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1146)
    01-09 18:02:36.885: E/AndroidRuntime(623):  at android.os.Handler.dispatchMessage(Handler.java:99)
    01-09 18:02:36.885: E/AndroidRuntime(623):  at android.os.Looper.loop(Looper.java:137)
    01-09 18:02:36.885: E/AndroidRuntime(623):  at android.app.ActivityThread.main(ActivityThread.java:4340)
    01-09 18:02:36.885: E/AndroidRuntime(623):  at java.lang.reflect.Method.invokeNative(Native Method)
    01-09 18:02:36.885: E/AndroidRuntime(623):  at java.lang.reflect.Method.invoke(Method.java:511)
    01-09 18:02:36.885: E/AndroidRuntime(623):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
    01-09 18:02:36.885: E/AndroidRuntime(623):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
    01-09 18:02:36.885: E/AndroidRuntime(623):  at dalvik.system.NativeStart.main(Native Method)

在评论onclicklistener代码时，应用程序可以正常运行。

Answer 1

替换

Button btn=(Button)getActivity().findViewById(R.id.btnSend);

带

Button btn=(Button)getView().findViewById(R.id.btnSend);

甚至在onClick()内，它不需要getBaseContext()。简单getActivity()绰绰有余。

 Toast toast = Toast.makeText(getActivity(), "Hello",10000);

Answer 2

更改按钮的代码，如下所示..

Button btn=(Button)findViewById(R.id.btnSend);           
           Log.v("HI","Button Created !!");
           btn.setOnClickListener(new OnClickListener() {                       
                @Override
                public void onClick(View v) {
                    // TODO Auto-generated method stub
                    //adapter=new ArrayAdapter<String>    (getActivity(),android.R.layout.simple_list_item_1,listItems);
                    //setListAdapter(adapter);
                    Log.v("HI","Button  !!");
                    Toast.makeText(getApplicationContext(), "Hello",10000).show(); 
                }
            };

将此替换为上述代码

 Button btn=(Button)getActivity().findViewById(R.id.btnSend);
   Log.v("HI","Button Created !!");
   OnClickListener listener = new OnClickListener() {                       
        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub
            //adapter=new ArrayAdapter<String>    (getActivity(),android.R.layout.simple_list_item_1,listItems);
            //setListAdapter(adapter);
            Log.v("HI","Button  !!");
           Toast toast = Toast.makeText(getActivity().getBaseContext(), "Hello",10000);
          toast.show();
        }
    };

    btn.setOnClickListener(listener);

实现onClickListener时应用程序崩溃

2 个答案: