Android 无法Bind Service

时间:2024-04-07 22:37:43

今天帮同学看一个bindService的样例,说是无法bind service(他接触android时间不长),那代码是从网上找的一个样例,结果看了半天,才终于找到问题所在了),这个问题真是令人挺无语的!下面贴代码:

MusicService.java

package com.pan.music;

import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List; import android.app.Service;
import android.content.Intent;
import android.media.MediaPlayer;
import android.media.MediaPlayer.OnCompletionListener;
import android.os.Binder;
import android.os.IBinder;
import android.util.Log; public class MusicService extends Service { /** 音乐存放路径 */
private static final String MUSIC_PATH = "/sdcard/music"; private List<String> muiscList;
private MediaPlayer mediaPlayer; /** 服务绑定 */
public class MusicBinder extends Binder {
public MusicService getMusicService() {
return MusicService.this;
}
} private MusicBinder musicBinder; //错误代码,都没有new一个对象,导致那边获取到的对象为null,正确代码如下:private MusicBinder musicBinder = new MusicBinder(); @Override
public IBinder onBind(Intent intent) {
Log.i("INFO", "onBind");
return null; //此处直接返回了一个null,结果onServiceConnected方法中,获取到的值始终为null,应该return musicBinder;
} @Override
public void onCreate() {
// TODO Auto-generated method stub
Log.d("Info", "sfhahhhhhhhhhhhh");
super.onCreate();
} public int onStartCommand(Intent intent, int flags, int startId) {
Log.d("Info", "sfhahhhhhhhhhhhh");
super.onStartCommand(intent, flags, startId);
mediaPlayer = new MediaPlayer();
// musicListInit();
// playing(0); return 1;
} // @Override
// public void onStart(Intent intent, int startId) {
// // TODO Auto-generated method stub
//
// mediaPlayer = new MediaPlayer();
// } public void execute() {
Log.i("Info", "execute aaaaa");
} private void musicListInit() {
muiscList = new ArrayList<String>(10);
File objFile = new File(MUSIC_PATH);
String[] strMusicNames = objFile.list();
for (String strName : strMusicNames) {
muiscList.add(strName);
}
} public void onDestroy() {
super.onDestroy();
if (null != mediaPlayer) {
mediaPlayer.stop();
mediaPlayer.release();
}
} private void playing(int curent) {
// mediaPlayer = MediaPlayer.create(this, R.raw.test);
// AssetFileDescriptor fileDescriptor = null;
try {
// fileDescriptor = getAssets().openFd("test.mp3");
// mediaPlayer.setDataSource(fileDescriptor.getFileDescriptor());
mediaPlayer.reset();
String strMusicName = muiscList.get(curent);
mediaPlayer.setDataSource(MUSIC_PATH + "/" + strMusicName);
mediaPlayer.prepare();
} catch (IOException e) {
e.printStackTrace();
}
mediaPlayer.start();
OnCompletionListener listener = new OnCompletionListener() {
@Override
public void onCompletion(MediaPlayer mp) {
playing(2);
} };
mediaPlayer.setOnCompletionListener(listener);
}
}

MainActivity.java 在这里面绑定service,代码如下:

package com.pan.music;

import com.pan.music.MusicService.MusicBinder;

import android.app.Activity;
import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.content.ServiceConnection;
import android.os.Bundle;
import android.os.IBinder;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button; public class MainActivity extends Activity {
private MusicService musicService; @Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main); Button startButton = (Button) findViewById(R.id.start);
startButton.setOnClickListener(startClick);
Button stopButton = (Button) findViewById(R.id.stop);
stopButton.setOnClickListener(stopClick);
// Intent objIntent = new Intent(MainActivity.this, MusicService.class);
// this.bindService(objIntent, mConnection,
// Context.BIND_AUTO_CREATE); } private ServiceConnection mConnection = new ServiceConnection() { @Override
public void onServiceConnected(ComponentName name, IBinder service) {
Log.d("info", "zhixing");
musicService = ((MusicBinder) service)
.getMusicService();
//正因为service返回的为空,所以这里面始终都没有进来。
if (musicService != null) {
Log.i("info", "music service connect aaaa");
musicService.execute();
} else {
Log.i("info", "music service connect aaa");
} } @Override
public void onServiceDisconnected(ComponentName name) {
musicService = null;
} }; @Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.activity_main, menu);
return true;
} private OnClickListener startClick = new OnClickListener() {
public void onClick(View view) {
// Intent objIntent = new
// Intent("com.pan.music.service.MusicService");
Intent objIntent = new Intent(MainActivity.this, MusicService.class);
// startService(objIntent);
// musicConnection = new MusicConnection();
bindService(objIntent, mConnection, Context.BIND_AUTO_CREATE); }
}; private OnClickListener stopClick = new OnClickListener() {
public void onClick(View view) {
// Intent objIntent = new
// Intent("com.pan.music.service.MusicService");
// Intent objIntent = new Intent(MainActivity.this, MusicService.class);
// stopService(objIntent);
unbindService(mConnection);
}
}; }

这个问题其实很简单,但对于初学者来说,这就很难找到问题的所在了,所以说贴出一个代码出来,应该自己先调试下,看看有没有问题,不然会给其他人造成很大的困扰!