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我有一个联系人列表，可将用户带到联系人编辑屏幕。我正在尝试关闭编辑活动/片段（联系人编辑），具体取决于我当前使用的是哪个。因此，如果我正在使用片段，我希望它在保存或从数据库中删除后关闭片段，但是当我在小型设备上处于纵向/横向模式并运行活动时也是如此。当我处于双窗格模式时，我有以下代码会弹出一个错误（如我所料）。基本上，我希望用户查看联系人列表，编辑联系人，然后查看更新的联系人列表加上或减去他们的编辑。

// Set the save button to check the required fields, save the contact and finish
saveButton.setOnClickListener(new View.OnClickListener() {
  public void onClick(View view) {
    if (TextUtils.isEmpty(mLastName.getText().toString()) ||
            TextUtils.isEmpty(mFirstName.getText().toString())) {
      makeToast();
    } else {   
        FragmentManager fragmentManager = getFragmentManager();
        fragmentManager.popBackStackImmediate();
        getActivity().finish();
   }
  }
});

// Set the delete button to delete the contact and close the fragment
deleteButton.setOnClickListener(new View.OnClickListener() {
    public void onClick(View view) {
        // Delete the contactUri created from an ID passed in from contactActivity
        getActivity().getContentResolver().delete(contactUri, null, null);

        FragmentManager fragmentManager = getFragmentManager();
        fragmentManager.popBackStackImmediate();
        getActivity().finish();
    }
  });  
return aView;

使用上面的代码，我在 contactEditFragment.onClick 处得到 NullPointerException

我想我需要一种方法来区分活动和片段。

05-05 05:40:57.200: E/AndroidRuntime(1350): FATAL EXCEPTION: main
05-05 05:40:57.200: E/AndroidRuntime(1350): java.lang.NullPointerException
05-05 05:40:57.200: E/AndroidRuntime(1350):     at com.somestuff.ContactEditFragment$1.onClick(ContactEditFragment.java:106)
05-05 05:40:57.200: E/AndroidRuntime(1350):     at android.view.View.performClick(View.java:4204)
05-05 05:40:57.200: E/AndroidRuntime(1350):     at android.view.View$PerformClick.run(View.java:17355)
05-05 05:40:57.200: E/AndroidRuntime(1350):     at android.os.Handler.handleCallback(Handler.java:725)
05-05 05:40:57.200: E/AndroidRuntime(1350):     at android.os.Handler.dispatchMessage(Handler.java:92)
05-05 05:40:57.200: E/AndroidRuntime(1350):     at android.os.Looper.loop(Looper.java:137)
05-05 05:40:57.200: E/AndroidRuntime(1350):     at android.app.ActivityThread.main(ActivityThread.java:5041)
05-05 05:40:57.200: E/AndroidRuntime(1350):     at java.lang.reflect.Method.invokeNative(Native Method)
05-05 05:40:57.200: E/AndroidRuntime(1350):     at java.lang.reflect.Method.invoke(Method.java:511)
05-05 05:40:57.200: E/AndroidRuntime(1350):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
05-05 05:40:57.200: E/AndroidRuntime(1350):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
05-05 05:40:57.200: E/AndroidRuntime(1350):     at dalvik.system.NativeStart.main(Native Method)

这是 onContactSelected：

public void onContactSelected(String id) {
        if (mTwoPane)
        {
            Log.i("SECOND INSIDE OF ONITEMSELECTED TWO PANE MODE !!! IN CONTACTS ACTIVITY - THE ID IS:", id);
            // In two-pane mode, show the contact edit view in this activity by
            // adding or replacing the detail fragment using a
            // fragment transaction.

                // Create new fragment and transaction
                Bundle arguments = new Bundle();
                arguments.putString(ContactEditFragment.CONTACT_ID, id);
                ContactEditFragment contactEditFragment = new ContactEditFragment();
                contactEditFragment.setArguments(arguments);
                FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();

                // Replace whatever is in the fragment_container view with this fragment,
                // and add the transaction to the back stack
                transaction.replace(R.id.item_detail_container, contactEditFragment);
                transaction.addToBackStack(null);

                // Commit the transaction
                transaction.commit();

        } else {
            // In single-pane mode, simply start the detail activity
            // for the selected contact ID.
            Intent detailIntent = new Intent(this, ContactEditActivity.class);
            detailIntent.putExtra(ContactEditFragment.CONTACT_ID, id);
            startActivity(detailIntent);
                }
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1 回答 1

1

我已经尝试了以下代码，到目前为止它按我的预期工作：

   // Set the save button to check the required fields, save the contact and finish
        saveButton.setOnClickListener(new View.OnClickListener() {
          public void onClick(View view) {
            if (TextUtils.isEmpty(mLastName.getText().toString()) ||
                    TextUtils.isEmpty(mFirstName.getText().toString())) {
              makeToast();
            } else {  
                if (getActivity().findViewById(R.id.item_detail_container) != null){
                FragmentManager fragmentManager = getFragmentManager();
                fragmentManager.popBackStackImmediate();
                }
                else{getActivity().finish();}
           }
          }
        });

        // Set the delete button to delete the contact and close the fragment
    deleteButton.setOnClickListener(new View.OnClickListener() {
        public void onClick(View view) {
            // Delete the contactUri created from an ID passed in from contactActivity
            getActivity().getContentResolver().delete(contactUri, null, null);

                if (getActivity().findViewById(R.id.item_detail_container) != null){
                FragmentManager fragmentManager = getFragmentManager();
                fragmentManager.popBackStackImmediate();
                }
                else{getActivity().finish();}
        }
      });  
    return aView;
于 2013-05-05T07:25:50.683 回答