Startservice与Bindservice的使用

Startservice

① starservice启动服务的特点:可以看作为没有界面的activity,可以进行后台运行,主要的使用场景为wifi下自动更新软件,音乐的后台播放,即时通信软件的消息推送等
② startservice的使用方法:创建一个类,继承Service并重写里面的生命周期方法
③ 注意:多次调用startservice时,oncreate只会执行一次,onstartcommand会执行多次,需要停止startservice时,使用stopservice,stopservice可以多次调用,但是,只有第一次有效,会执行ondestroy把服务销毁.
④ startservice开启的服务,与开启它的组件没有关系,会长期在后台运行,只要用户不手动停止服务,服务就会一直运行下去,只有当系统内存不足的是否,才有可能会被系统回收

电话录音机案例

代码示例

public class MainActivity extends AppCompatActivity {@Overrideprotected void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentView(R.layout.activity_main);}public void open(View view) {    Intent intent = new Intent(this,MyService.class);    startService(intent);}}package com.example.day15;public MyService() {}@Overridepublic IBinder onBind(Intent intent) {    // TODO: Return the communication channel to the service.    throw new UnsupportedOperationException("Not yet implemented");}//创建服务@Overridepublic void onCreate() {    super.onCreate();    //获取TelephonyManager对象,监听打电话状态的改变    TelephonyManager manager = (TelephonyManager) getSystemService(TELEPHONY_SERVICE);    MyPhoneListener listener = new MyPhoneListener();    //创建一个监听器对象,    manager.listen(listener,PhoneStateListener.LISTEN_CALL_STATE);}//开启服务@Overridepublic ComponentName startService(Intent service) {    return super.startService(service);}//销毁服务@Overridepublic void onDestroy() {    super.onDestroy();}//创建一个内部类,监听打电话的状态public class MyPhoneListener extends PhoneStateListener{    private MediaRecorder recorder;    private final String TAG = this.getClass().getSimpleName();    @Override    public void onCallStateChanged(int state, String incomingNumber) {        switch (state){            //电话处于挂断状态            case TelephonyManager.CALL_STATE_IDLE:                Log.e(TAG,"电话处于挂断状态");                if (recorder!=null){                    recorder.stop();                    recorder.reset();//重置录音                    recorder.release();//解除对录音资源的占用                }                break;            case TelephonyManager.CALL_STATE_RINGING:                Log.e(TAG,"电话处于响铃状态");                //准备一个录音机                recorder = new MediaRecorder();                //设置音频源                recorder.setAudioSource(MediaRecorder.AudioSource.MIC);                //设置保存的格式                recorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);                //设置编码器                recorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);                //设置存放的路径                String path = getFilesDir().getAbsolutePath()+"/"+incomingNumber+"3gp";                recorder.setOutputFile(path);                //开始准备录音                try {                    recorder.prepare();                } catch (IOException e) {                    e.printStackTrace();                }                break;            case TelephonyManager.CALL_STATE_OFFHOOK:                Log.e(TAG,"电话处于接听状态");                //开始录音                if (recorder!=null){                    recorder.start();                }                break;        }    }}}

bindservice

① bindservice开启的服务,通过unbindservice关闭,方法只能调用一次,第一次调用可以关闭服务,多次调用会抛出异常
② bindservice和开启它的组件建立了绑定关系,不求同生,但求同死
③ activity通过bindservice开启了一个服务,关闭的时候必须解除绑定
④ bindservice开启的服务不是后台服务,当开启它的组件销毁时,它也会销毁
⑤ 只有用startservice开启的服务,才会让当前的进程处于服务进程状态

通过bindservice调用服务中的方法##

代码示例

activity

public class MainActivity extends AppCompatActivity {private Myconn myconn;private MyService.MyBinder binder;@Overrideprotected void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentView(R.layout.activity_main);}//绑定服务public void bind(View view) {    Intent intent = new Intent(this,MyService.class);    myconn = new Myconn();    bindService(intent,myconn,BIND_AUTO_CREATE);}public class Myconn implements ServiceConnection{    private final String TAG = this.getClass().getSimpleName();    @Override    public void onServiceConnected(ComponentName name, IBinder service) {        Log.e(TAG,"onServiceConnected");        binder = (MyService.MyBinder) service;    }    @Override    public void onServiceDisconnected(ComponentName name) {        Log.e(TAG,"onServiceDisconnected");    }}public void unbind(View view) {    unbindService(myconn);}public void call(View view) {    binder.callMethod("hello");}}

Myservice

public class MyService extends Service {private final String TAG = this.getClass().getSimpleName();public MyService() {}@Overridepublic IBinder onBind(Intent intent) {    Log.e(TAG,"onBind");   return new MyBinder();}public class MyBinder extends Binder{    public void callMethod(String s){        method(s);    }}@Overridepublic void onCreate() {    super.onCreate();}@Overridepublic int onStartCommand(Intent intent, int flags, int startId) {    Log.e(TAG,"onStartCommand");    return super.onStartCommand(intent, flags, startId);}@Overridepublic void onDestroy() {    Log.e(TAG,"onDestroy");    super.onDestroy();}public void method(String s){    Toast.makeText(this, s, Toast.LENGTH_SHORT).show();}}

音乐播放器框架

代码示例

activity

package com.example.it;import android.content.ComponentName;import android.content.Intent;import android.content.ServiceConnection;import android.os.IBinder;import android.support.v7.app.AppCompatActivity;import android.os.Bundle;import android.util.Log;import android.view.View;public class MainActivity extends AppCompatActivity {private final String TAG = this.getClass().getSimpleName();private MyService.MyBinder myBinder;private Myconn myconn;@Overrideprotected void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentView(R.layout.activity_main);    Intent intent = new Intent(this,MyService.class);    myconn = new Myconn();    bindService(intent,myconn,BIND_AUTO_CREATE);    startService(intent);}public void top(View view) {    myBinder.playtop();}public void play(View view) {    myBinder.play();}public void stoop(View view) {    myBinder.stop();}public void next(View view) {    myBinder.playnext();}public class Myconn implements ServiceConnection{    @Override    public void onServiceConnected(ComponentName name, IBinder service) {        Log.e(TAG,"打开播放器");        myBinder = (MyService.MyBinder) service;    }    @Override    public void onServiceDisconnected(ComponentName name) {        Log.e(TAG,"退出播放器");    }}}

Myservice

package com.example.it;import android.app.Service;import android.content.Intent;import android.os.Binder;import android.os.IBinder;import android.util.Log;public class MyService extends Service {private final String TAG = this.getClass().getSimpleName();public MyService() {}@Overridepublic IBinder onBind(Intent intent) {    Log.e(TAG,"音乐播放器 onBind");    return new MyBinder();}public class MyBinder extends Binder{    public void playtop(){        Log.e(TAG,"播放上一首");    }    public void playnext(){        Log.e(TAG,"播放下一首");    }    public void play(){        Log.e(TAG,"播放");    }    public void stop(){        Log.e(TAG,"暂停");    }}@Overridepublic void onCreate() {    Log.e(TAG,"创建一个播放器");    super.onCreate();}@Overridepublic void onDestroy() {    Log.e(TAG,"退出播放器");    super.onDestroy();}}