综合运用BroadcastReceiver和Service模拟下载

关于BroadcastReceiver和Service的指示可以参考文章
http://blog.csdn.net/taoolee/article/details/48297183；
http://blog.csdn.net/taoolee/article/details/48299467
整体实现思路
【1】实现服务
1新建MyService类实现服务
2在AndroidManifest.xml当中注册
3点击事件启动相应Intent的服务
【2】
1MyService当中的onStartCommand（）方法启动在此方法中新建一个线程发送广播
【3】
1MainActivity当中接收广播
2onReceive（）方法接收广播并得到下载进度滑动滚动条

1MyService.java

public class MyService extends Service {    private  int count;    private static final String  DOWN_LOAD_ACTION="com.service.test";    @Override    //当该Service被第一次创建后将立即回调该方法    public void onCreate() {        super.onCreate();        Log.d("11111111onCreate","onCreate");    }    @Override    //每次客户端调用startService（Intent）方法启动该Service时，都会回调该方法    public int onStartCommand(final Intent intent, int flags, int startId) {        new Thread(new Runnable() {            @Override            public void run() {                while(true){                    if(count>100){                        count=0;                    }                    count++;                    //线程当中启动广播                    Intent intent1=new Intent();                    intent1.setAction(DOWN_LOAD_ACTION);                    intent1.putExtra("count", count);                    sendBroadcast(intent1);                    try {                        Thread.sleep(200);                    } catch (InterruptedException e) {                        e.printStackTrace();                    }                }            }        }).start();        Log.d("11111111onStartCommand","onStartCommand");        return super.onStartCommand(intent, flags, startId);    }    @Override    //Service被关闭之前回调    public void onDestroy() {        super.onDestroy();        Log.d("1onDestroy", "111111111");    }    @Nullable    @Override    //Service子类必须实现的方法，该方法返回一个IBinder对象，应用程序可以通过该对象与Service组件通信    public IBinder onBind(Intent intent) {        Log.d("onBind", "11111111");        return null;    }}

AndroidManifest.xml

 <service android:name=".MyIntentService">          <intent-filter>              <action android:name="com.service"></action>          </intent-filter>      </service>

MainActivity.java

public class MainActivity extends AppCompatActivity implements View.OnClickListener{    private Button button_start;    private Button button_stop;    private Button start_download;    private ProgressBar progressBar;    private MyReceiver receiver;    private MyService service;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        button_start= (Button) findViewById(R.id.button_start);        button_stop= (Button) findViewById(R.id.button_stop);        button_start.setOnClickListener(this);        button_stop.setOnClickListener(this);        start_download= (Button) findViewById(R.id.start_download);        progressBar= (ProgressBar) findViewById(R.id.progressbar);        start_download.setOnClickListener(this);        progressBar.setOnClickListener(this);       //registerReceiver接收广播        receiver=new MyReceiver();        IntentFilter filter=new IntentFilter("com.service");        registerReceiver(receiver, filter);    }    //接收后需要onDestroy    @Override    protected void onDestroy() {        super.onDestroy();        unregisterReceiver(receiver);    }    @Override    public void onClick(View v) {        switch (v.getId()){            case R.id.button_start:               // Intent intent=new Intent(getApplicationContext(),MyService.class);                Intent intent=new Intent("com.service");                startService(intent);                break;            case R.id.button_stop:               // Intent intent1=new Intent(getApplicationContext(),MyService.class);                Intent intent1=new Intent("com.service");                stopService(intent1);                break;            case R.id.start_download:                Intent intent2=new Intent("com.service");                startService(intent2);                break;            default:                break;        }    }    //接收广播     class MyReceiver extends BroadcastReceiver {        @Override        public void onReceive(Context context, Intent intent) {        int count= intent.getIntExtra("count",1);        progressBar.setProgress(count);        }    }}

上面MyService在onStartCommand（）方法中使用线程耗时模拟耗时任务，由于普通Service的执行会阻塞主线程，因此该线程会导致程序异常下一篇文章将会讲解IntentService解决上述问题