service是运行在后台的服务,你可以启动一个服务Service来播放音乐，或者记录你地理信息位置的改变，或者启动一个服务来运行并一直监听某种动作。
接下来分析一下service 的生命周期：
1：actiivty_main.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"> <Button
android:id="@+id/btn_bind_service"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Bind Service"/> <Button
android:id="@+id/btn_stop_bind"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_below="@id/btn_bind_service"
android:text="Stop Bind"/> <Button
android:id="@+id/btn_start_service"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_below="@id/btn_stop_bind"
android:text="Start Service"/> <Button
android:id="@+id/btn_stop_service"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_below="@id/btn_start_service"
android:text="Stop Service"/>
</RelativeLayout>
2:ServiceDemo.java
public class ServiceDemo extends Service{
private static final String TAG="ServiceDemo";
public static final String ACTION="com.yan.service.ServiceDemo";
@Override
public IBinder onBind(Intent arg0) {
Log.i(TAG, "onBind");
return null;
}
@Override
public void onCreate() {
Log.i(TAG,"onCreate");
super.onCreate();
}
@Override
@Deprecated
public void onStart(Intent intent, int startId) {
Log.i(TAG, "onStart");
super.onStart(intent, startId);
}
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
Log.i(TAG, "onStartCommand");
return super.onStartCommand(intent, flags, startId);
}
@Override
public void onDestroy() {
Log.i(TAG, "onDestroy");
super.onDestroy();
}
@Override
public boolean onUnbind(Intent intent) {
Log.i(TAG, "onUnbind");
return super.onUnbind(intent);
}
}3:MainActivity.java
public class MainActivity extends Activity {
private Button btnBindService=null;
private Button btnStopBind=null;
private Button btnStartService=null;
private Button btnStopService=null;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
btnBindService=(Button)findViewById(R.id.btn_bind_service);
btnStopBind=(Button)findViewById(R.id.btn_stop_bind);
btnStartService=(Button)findViewById(R.id.btn_start_service);
btnStopService=(Button)findViewById(R.id.btn_stop_service);
btnBindService.setOnClickListener(new OnClickListener(){
public void onClick(View view){
Intent intent=new Intent(ServiceDemo.ACTION);
bindService(intent,sc,BIND_AUTO_CREATE);
}
});
btnStopBind.setOnClickListener(new OnClickListener(){
public void onClick(View view){
unbindService(sc);
}
});
btnStartService.setOnClickListener(new OnClickListener(){
public void onClick(View view){
Intent intent=new Intent(ServiceDemo.ACTION);
startService(intent);
}
});
btnStopService.setOnClickListener(new OnClickListener(){
public void onClick(View view){
Intent intent=new Intent(ServiceDemo.ACTION);
stopService(intent);
}
});
}
ServiceConnection sc=new ServiceConnection(){
@Override
public void onServiceConnected(ComponentName arg0, IBinder arg1) {
Log.i("SC", "onServiceConnected");
}
@Override
public void onServiceDisconnected(ComponentName arg0) {
Log.i("SC", "onServiceDisconnected");
}
};
}4:AndroidManifest.xml
<service
android:name="com.yan.service.ServiceDemo">
<intent-filter>
<action android:name="com.yan.service.ServiceDemo"/>
</intent-filter>
</service>
5:运行结果分析。
（1）点击StartService:
执行 onCreate()->onStartCommand()->onStart()
（2）点击StopService:
执行 onDestroy()
（3）点击BindService
执行 onCreate()->onBind()
（4）点击StopBind
执行 onUnbind()->onDestory()