android - 当音频插孔连接或忙碌时在 fragment 内切换图像

Question

我正在尝试检测耳机是否插入了音频插孔，并基于此尝试更改带有Fragment的布局中的图像。

我试图通过youtube上的幻灯视频来了解Fragment的生命周期，说实话，我听不懂他想解释的一个词。据我了解，当Fragment第一次加载UI元素时，onCreateView方法仅运行一次。

在这里，我一直在基于Audio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，但是问题是我需要关闭应用程序或进行其他 Activity ，然后返回Fragment查看更改。我知道为什么发生这种情况，onCreateView只运行一次。

有人可以帮我吗？

第二:我在其他片段中也遇到了类似的问题，即使在向数据库添加新条目之后，直到我退出 Activity 并再次回来，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

这是我所做的，并且效果很好。如果您有任何更好的解决方案，请在此处发布。

据我所知，它工作正常。

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();
    }


}