回调从DialogFragment一个片段 [英] Callback to a Fragment from a DialogFragment

问题描述

问：怎样才能创建一个从DialogFragment到另一个片段回调。在我的情况下，所涉及的活动应该是完全不知道DialogFragment的。

Question: How does one create a callback from a DialogFragment to another Fragment. In my case, the Activity involved should be completely unaware of the DialogFragment.

考虑我

public class MyFragment extends Fragment implements OnClickListener

然后，在某些时候，我的可以的办

DialogFragment dialogFrag = MyDialogFragment.newInstance(this);
dialogFrag.show(getFragmentManager, null);

在哪里MyDialogFragment看起来像

Where MyDialogFragment looks like

protected OnClickListener listener;
public static DialogFragment newInstance(OnClickListener listener) {
    DialogFragment fragment = new DialogFragment();
    fragment.listener = listener;
    return fragment;
}

但也不能保证听者将围绕如果DialogFragment暂停和继续通过它的生命周期。在片段的唯一保证是那些通过setArguments和getArguments传递通过捆绑。

But there is no guarantee that the listener will be around if the DialogFragment pauses and resumes through its lifecycle. The only guarantees in a Fragment are those passed in through a Bundle via setArguments and getArguments.

有一种方法，以引用的活动，如果它应该侦听：

There is a way to reference the activity if it should be the listener:

public Dialog onCreateDialog(Bundle bundle) {
    OnClickListener listener = (OnClickListener) getActivity();
    ....
    return new AlertDialog.Builder(getActivity())
        ........
        .setAdapter(adapter, listener)
        .create();
}

不过，我不希望活动侦听事件，我需要一个片段。真的，它可能是实现OnClickListener任何Java对象。

But I don't want the Activity to listen for events, I need a Fragment. Really, it could be any Java object that implements OnClickListener.

考虑一个片段presents通过DialogFragment一个AlertDialog的具体例子。它是/否按钮。我怎样才能把这些按钮presses回到创建它的片段？

Consider the concrete example of a Fragment that presents an AlertDialog via DialogFragment. It has Yes/No buttons. How can I send these button presses back to the Fragment that created it?

推荐答案

涉及的活动是完全不知道DialogFragment的。

Activity involved is completely unaware of the DialogFragment.

片段类：

public class MyFragment extends Fragment {
int mStackLevel = 0;
public static final int DIALOG_FRAGMENT = 1;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    if (savedInstanceState != null) {
        mStackLevel = savedInstanceState.getInt("level");
    }
}

@Override
public void onSaveInstanceState(Bundle outState) {
    super.onSaveInstanceState(outState);
    outState.putInt("level", mStackLevel);
}

void showDialog(int type) {

    mStackLevel++;

    FragmentTransaction ft = getActivity().getFragmentManager().beginTransaction();
    Fragment prev = getActivity().getFragmentManager().findFragmentByTag("dialog");
    if (prev != null) {
        ft.remove(prev);
    }
    ft.addToBackStack(null);

    switch (type) {

        case DIALOG_FRAGMENT:

            DialogFragment dialogFrag = MyDialogFragment.newInstance(123);
            dialogFrag.setTargetFragment(this, DIALOG_FRAGMENT);
            dialogFrag.show(getFragmentManager().beginTransaction(), "dialog");

            break;
    }
}

@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
        switch(requestCode) {
            case DIALOG_FRAGMENT:

                if (resultCode == Activity.RESULT_OK) {
                    // After Ok code.
                } else if (resultCode == Activity.RESULT_CANCELED){
                    // After Cancel code.
                }

                break;
        }
    }
}

}

DialogFragment类：

DialogFragment class:

public class MyDialogFragment extends DialogFragment {

public static MyDialogFragment newInstance(int num){

    MyDialogFragment dialogFragment = new MyDialogFragment();
    Bundle bundle = new Bundle();
    bundle.putInt("num", num);
    dialogFragment.setArguments(bundle);

    return dialogFragment;

}

@Override
public Dialog onCreateDialog(Bundle savedInstanceState) {

    return new AlertDialog.Builder(getActivity())
            .setTitle(R.string.ERROR)
            .setIcon(android.R.drawable.ic_dialog_alert)
            .setPositiveButton(R.string.ok_button,
                    new DialogInterface.OnClickListener() {
                        public void onClick(DialogInterface dialog, int whichButton) {
                            getTargetFragment().onActivityResult(getTargetRequestCode(), Activity.RESULT_OK, getActivity().getIntent());
                        }
                    }
            )
            .setNegativeButton(R.string.cancel_button, new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface dialog, int whichButton) {
                    getTargetFragment().onActivityResult(getTargetRequestCode(), Activity.RESULT_CANCELED, getActivity().getIntent());
                }
            })
            .create();
}
}

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