Service的两种启动方式+生命周期+IntentService的特点

Service服务

两种启动方式

1. 启动方式
   开启服务：startService()
   停止服务：stopService()

2. 绑定方式
   绑定服务：bindService()
   解除绑定：unbindService()

生命周期

1. 启动方式的生命周期
   onCreate() —— onStartCommand() —— onDestroy()
2. 绑定方式的生命周期
   onCreate() —— onBind() —— onUnbind() —— onDestroy()
3. 先启动后绑定
   onCreate() —— onStartCommand() —— onBind() —— onUnbind() —— onDestroy()

StartService代码

• 自定义类继承Service服务

public class MyService extends Service {
    @Override
    public void onCreate() {
        super.onCreate();
        Toast.makeText(this, "没毛病", Toast.LENGTH_SHORT).show();
    }
    @Nullable
    @Override
    public IBinder onBind(Intent intent) {
        return null;
    }
}

• 清单文件注册服务

<service android:name=".MyService"></service>

• 启动或停止服务

public class MainActivity extends AppCompatActivity {
    private Intent intent;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        intent =new Intent(this,MyService.class);
        startService(intent);
    }
    
    @Override
    protected void onDestroy() {
        super.onDestroy();
        stopService(intent);
    }
}

bindService代码

• 自定义类继承Service并在里面声明方法

public class MyService extends Service {
    @Nullable
    @Override
    public IBinder onBind(Intent intent) {
        return new MyBinder();
    }
    class MyBinder extends Binder{
        public MyService getService(){
            return MyService.this;
        }
    }
    public void show(){
        Toast.makeText(this, "没毛病", Toast.LENGTH_SHORT).show();
    }
}

• 清单文件注册服务

<service android:name=".MyService"></service>

• 绑定服务和解除绑定

public class MainActivity extends AppCompatActivity {
    private Intent intent;
    private MyService myService;
    private ServiceConnection connection=new ServiceConnection() {
        @Override
        public void onServiceConnected(ComponentName name, IBinder service) {
            myService = ((MyService.MyBinder)service).getService();
        }
        @Override
        public void onServiceDisconnected(ComponentName name) {
        }
    };
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        intent =new Intent(this,MyService.class);
        bindService(intent,connection, Service.BIND_AUTO_CREATE);
    }
    @Override
    protected void onDestroy() {
        super.onDestroy();
        unbindService(connection);
    }
    public void show(){
        myService.show();
    }
    
}

IntentService

IntentService的优点：不用开启线程，直接进行耗时操作
IntentService的缺点：使用广播向activity传值
IntentService代码

• 自定义类继承IntentService并从网络下载

public class MyIntentService extends IntentService {
    public MyIntentService(){
        super("MyIntentService");
    }

    public MyIntentService(String name) {
        super(name);
    }
    @Override
    protected void onHandleIntent(@Nullable Intent intent) {
        StringBuffer sb=new StringBuffer();
        HttpURLConnection connection=null;
        InputStream inputStream=null;
        try {
            URL url=new URL("http://www.qubaobei.com/ios/cf/dish_list.php?stage_id=1&limit=20&page=1");
            connection = (HttpURLConnection) url.openConnection();
            connection.setReadTimeout(5*1000);
            connection.setConnectTimeout(5*1000);

            if(connection.getResponseCode()==200){
                inputStream  = connection.getInputStream();
                byte[] b=new byte[1024];
                int len=0;
                while((len=inputStream.read(b))!=-1){
                    sb.append(new String(b,0,len));
                }
                Intent intent1=new Intent();
                intent1.setAction("com.bawei.intentservice");
                Bundle bundle = new Bundle();
                bundle.putString("json",sb.toString());
                intent1.putExtras(bundle);
                sendBroadcast(intent1);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }finally{
            if(inputStream!=null){
                try {
                    inputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if(connection!=null){
                connection.disconnect();
            }
        }
    }
}

• 清单文件注册服务

 <service android:name=".Intentservice.MyIntentService" ></service>

• Activity代码

public class MainActivity extends AppCompatActivity {
    private  MyReceiver myReceiver;
    private Intent intent;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        IntentFilter intentFilter=new IntentFilter();
        intentFilter.addAction("com.bawei.intentservice");
        myReceiver=new MyReceiver();
        registerReceiver(myReceiver,intentFilter);
        intent=new Intent(this,MyIntentService.class);
        startService(intent);


    }
    @Override
    protected void onDestroy() {
        super.onDestroy();
        unregisterReceiver(myReceiver);
        stopService(intent);
    }

    class MyReceiver extends BroadcastReceiver{
        @Override
        public void onReceive(Context context, Intent intent) {
            String action=intent.getAction();
            if("com.bawei.intentservice".equals(action)){
                Bundle bundle = intent.getExtras();
                String json = bundle.getString("json", "");
                Toast.makeText(context, ""+json, Toast.LENGTH_SHORT).show();

            }
        }
    }
}

以上就是我所掌握的Service的两种启动方式+生命周期+IntentService的特点