方向更改上的DialogFragment回调

Question

下面是一个简单对话框的示例代码：

public class DialogTest extends DialogFragment {

public interface DialogTestListener {
    public void onDialogPositiveClick(DialogFragment dialog);
}

// Use this instance of the interface to deliver action events
static DialogTestListener mListener;

public static DialogTest newInstance(Activity activity, int titleId, int messageId) {
    udateListener(activity);
    DialogTest frag = new DialogTest();
    Bundle args = new Bundle();
    args.putInt("titleId", titleId);
    args.putInt("messageId", messageId);
    frag.setArguments(args);
    return frag;
}

public static void udateListener(Activity activity) {
    try {
        // Instantiate the NoticeDialogListener so we can send events with it
        mListener = (DialogTestListener) activity;
    } catch (ClassCastException e) {
        // The activity doesn't implement the interface, throw exception
        throw new ClassCastException(activity.toString() + " must implement DialogTestListener");
    }
}


@Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
    int titleId = getArguments().getInt("titleId");
    int messageId = getArguments().getInt("messageId");

    AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
    // dialog title
    builder.setTitle(titleId);
    // dialog message
    builder.setMessage(messageId);

    // dialog negative button
    builder.setNegativeButton("No", new OnClickListener() {
               public void onClick(DialogInterface dialog, int id) {}});
    // dialog positive button
    builder.setPositiveButton("Yes", new OnClickListener() {
        public void onClick(DialogInterface dialog, int id) {
            mListener.onDialogPositiveClick(DialogTest.this);
        }});

    // create the Dialog object and return it
    return builder.create();
}}

下面是一些活动代码：

public class SomeActivity extends FragmentActivity implements DialogTestListener {
private EditText mUserName;
@Override
public void onCreate(Bundle savedInstanceState) {
    // setup ui
    super.onCreate(savedInstanceState);
    setContentView(R.layout.ui_user_edit);
    // name input
    mUserName = (EditText) findViewById(R.id.userEdit_editTextName);
}

@Override
public void onDialogPositiveClick(DialogFragment dialog) {
    Log.d(TAG, this.toString());
    mUserName.setText(mUserName.getText() + "1");
}

private void showDialog() {
    DialogTest test = DialogTest.newInstance(SomeActivity.this, R.string.someTitleText, R.string.someMessageText);
    test.show(getSupportFragmentManager(), "testDialog");
}}

代码与您所看到的引用大致相同。问题是，一旦您改变了方向，当显示对话框时，它就停止了预期的工作-->由于活动生命周期的原因，活动和对话框都被重新构建，并且对话框现在没有对重新构建的新活动的正确引用。

    @Override
protected void onResume() {
    super.onResume();
    DialogTest.udateListener(this);
}

致以最诚挚的问候

Answer 1

有更好的解决方案，而不是使用静态方法和变量，因为它只适用于对话框的一个实例。最好将回调存储为非静态成员

private DialogTestListener mListener;
public void setListener (DialogTestListener listener){
  mListener = listener;
}

然后应该使用如下标记显示对话框mdialogfragment.show(getSupportFragmentManager(),DIALOG_TAG)；

然后，在活动的onresume方法中，您可以重置监听器

protected void onResume() {
   super.onResume();
   mDialogFragment = (CMFilterDialogFrg) getSupportFragmentManager().findFragmentByTag(DIALOG_TAG);
   if(mDialogFragment  != null){
       mDialogFragment.setListener(yourListener)
   }
}