onKeyDown在片段

Question

当任何人按下按钮，片段时，我会尝试制作警告对话框。我尝试了几种方式，但我无法做到。有没有办法在片段内做到这一点。

package com.topicsfeedback.www.mypackage.activity;

/**
 * Created by hasib on 2/22/2016.
 */
import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.content.Intent;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.KeyEvent;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import com.topicsfeedback.www.mypackage.R;

import java.net.Inet4Address;


public class MessagesFragment extends Fragment {

    public MessagesFragment() {
        // Required empty public constructor
    }

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

    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        View vv = inflater.inflate(R.layout.fragment_messages, container, false);

        return vv;
    }


    @Override
    public void onAttach(Activity activity) {
        super.onAttach(activity);
    }
  
  // Back button press start

    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        if (keyCode == KeyEvent.KEYCODE_BACK) {
            new AlertDialog.Builder(getActivity())
                    .setIcon(android.R.drawable.ic_dialog_alert)
                    .setTitle("Exit This Apps")
                    .setMessage("Do You want to exit?")
                    .setPositiveButton("YES", new DialogInterface.OnClickListener() {
                        @Override
                        public void onClick(DialogInterface dialog, int which) {
                            Intent myinnn = new Intent(getActivity(), HomeFragment.class);
                            startActivity(myinnn);
                        }
                    })
                    .setNegativeButton("NO", null)

                    .show();
            return true;
        }
  
 
        else {
            return super.onKeyDown(keyCode, event);  //Here onKeyDown can't resolve 
        }


    }

//Backbutton press end
    
    @Override
    public void onDetach() {
        super.onDetach();

    }
}

Answer 1

要按回按钮的回调，您需要在活动中覆盖此方法：

@Override
public void onBackPressed() {
    super.onBackPressed();
    // Your code here
}