当音频插孔已连接或正忙时，在Fragment内切换图像

Question

我正在尝试检测耳机是否插入音频插孔，并在此基础上尝试更改附有片段的布局中的图像。

我试图在youtube上的幻灯片视频上了解Fragment的生命周期，老实说，我一个字都听不懂他想解释什么。据我所知，当Fragment第一次加载UI元素时，CreateView方法只运行一次。

在这里，我一直在根据音频插孔的状态更改UI元素，这是一种实时的布局动态更新。

现在我可以切换图像，但问题是我需要关闭应用程序或转到其他活动，然后返回Fragment查看更改。我理解为什么会发生这种情况，onCreateView只运行一次。

有人能帮我做这个吗？

第二：我在其他片段中也遇到了类似的问题，在我退出活动并再次返回之前，即使在向数据库添加新条目后，人员列表也不会更新。

MeasureFragment.classs

import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.media.AudioManager;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;
import com.example.kevin.sugar.R;
import java.util.logging.Handler;
import java.util.logging.LogRecord;
/**
 * A simple {@link Fragment} subclass.
 */
public class MeasureFragment extends Fragment{
    Handler handler;
    public MeasureFragment() {
        // Required empty public constructor
    }

    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.measure_layout, container, false);
        return view;
    }
    public void onActivityCreated(Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
        ImageView img = (ImageView) getActivity().findViewById(R.id.phone);
        IntentFilter iFilter = new IntentFilter(Intent.ACTION_HEADSET_PLUG);
        Intent iStatus = getActivity().registerReceiver(null, iFilter);
        boolean isConnected = iStatus.getIntExtra("state",0) == 1;
        if(isConnected){
            img.setImageResource(R.drawable.phone_connected);
            TextView button = (TextView)getActivity().findViewById(R.id.start_button);
            button.setVisibility(View.VISIBLE);
        }else{
            img.setImageResource(R.drawable.phone_disconnected);
            TextView button = (TextView)getActivity().findViewById(R.id.start_button);
            button.setVisibility(View.GONE);
        }
    }
    public void onStart(){
        super.onStart();
    }
}

Answer 1

以下是我所做的工作，效果非常好。如果你们中有人有比这更好的解决方案，请在这里发帖。

据我所知，它运行良好。

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.media.AudioManager;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;
import com.example.kuro.bloodpressure.R;
import android.os.Handler;
/**
 * A simple {@link Fragment} subclass.
 */
public class MeasureFragment extends Fragment {
    ImageView img;
    IntentFilter intentFilter = new IntentFilter(Intent.ACTION_HEADSET_PLUG);
    public MeasureFragment() {
        // Required empty public constructor
    }

    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.measure_layout, container, false);
        img = (ImageView) view.findViewById(R.id.phone);
        return view;
    }
    public void onViewCreated(View view, Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);
    }
    public void onActivityCreated(Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
    }

    public void onStart() {
        super.onStart();
    }
    public void onResume() {
        getActivity().registerReceiver(bcReceived, intentFilter);
        super.onResume();
    }
    //
    private BroadcastReceiver bcReceived = new BroadcastReceiver() {
        public void onReceive(Context ctx, Intent intent) {
//            AudioManager audioManager = (AudioManager) ctx.getSystemService(Context.AUDIO_SERVICE);
            if (intent.getAction().equals(Intent.ACTION_HEADSET_PLUG)) {
                int state = intent.getIntExtra("state", -1);
                switch (state) {
                    case 0:
                        Log.d("TAG", "NOT CONNECTED");
                        img.setImageResource(R.drawable.phone_disconnected);
                        TextView button2 = (TextView) getActivity().findViewById(R.id.start_button);
                        button2.setVisibility(View.GONE);
                        break;
                    case 1:
                        Log.d("TAG", "CONNECTED");
                        img.setImageResource(R.drawable.phone_connected);
                        TextView button1 = (TextView) getActivity().findViewById(R.id.start_button);
                        button1.setVisibility(View.VISIBLE);
                        button1.setOnClickListener(new View.OnClickListener() {
                            @Override
                            public void onClick(View v) {
                                Log.d("TAG", "CLICKED");
                            }
                        });
                        break;
                    default:
                        Log.d("TAG", "I have no idea what the headset state is");
                }
            }
        }
    };
    @Override
    public void onPause() {
        getActivity().unregisterReceiver(bcReceived);
        super.onPause();
    }

}