IntentService使用解析

源码解析

IntentService 是一个继承Service 的服务。在内部封装一个叫ServiceHandler的Handler类，在handleMessage中处理数据时调用onHandleIntent(),而onHandleIntent是一个抽象方法，由子类去实现。

private final class ServiceHandler extends Handler {
    public ServiceHandler(Looper looper) {
        super(looper);
    }

    @Override
    public void handleMessage(Message msg) {
        onHandleIntent((Intent)msg.obj);
        stopSelf(msg.arg1);
    }
}


 @WorkerThread
    protected abstract void onHandleIntent(Intent intent);

使用解析

首先创建一个Service继承IntentService，并重写onHandleIntent()方法。

@Override
    protected void onHandleIntent(@Nullable Intent intent) {

        try {
            isRunning = true;
            count = 0;
            while (isRunning){
                count++;
                if(count >= 100){
                    isRunning = false;
                }
                sendThreadProgress(count);
                Thread.sleep(1000);
            }

        } catch (InterruptedException e) {
            e.printStackTrace();
        }

onHandleIntent 这个是在子线程中运行的，所以可进行耗时操作。

完整实例代码

TestIntentService.java

public class TestIntentService extends IntentService {

    private boolean isRunning = true;
    private int count = 0;
    
    //用一个本地广播发送数据
    private LocalBroadcastManager mLocalBroadcastManager;

    public TestIntentService() {
        super("TestIntentService");
    }

    @Override
    public void onCreate() {
        super.onCreate();
        mLocalBroadcastManager = LocalBroadcastManager.getInstance(this);
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
    }

    @Override
    protected void onHandleIntent(@Nullable Intent intent) {

        try {
            isRunning = true;
            count = 0;
            while (isRunning){
                count++;
                if(count >= 100){
                    isRunning = false;
                }
                sendThreadProgress(count);
                Thread.sleep(1000);
            }

        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }

    private void sendThreadProgress(int progress){
        Intent intent = new Intent(IntentServiceActivity.ACTION_TYPE_THREAD);
        intent.putExtra("progress", progress);
        mLocalBroadcastManager.sendBroadcast(intent);

    }
}

IntentServiceActivity.java

public class IntentServiceActivity extends BaseActivity {

    public static final String ACTION_TYPE_THREAD = "action.type.thread";

    private Button mBtn;
    private TextView mText;
    private ProgressBar mBar;

    private LocalBroadcastManager mLocalBroadcastManager;
    private MyBroadcastReceiver mBroadcastReceiver;

    @Override
    protected void loadViewLayout() {
        setContentView(R.layout.test_asyn_task_activity);

        mLocalBroadcastManager = LocalBroadcastManager.getInstance(mContext);
        mBroadcastReceiver = new MyBroadcastReceiver();
        IntentFilter intentFilter = new IntentFilter();
        intentFilter.addAction(ACTION_TYPE_THREAD);
        mLocalBroadcastManager.registerReceiver(mBroadcastReceiver, intentFilter);
    }

    @Override
    protected void loadIntent() {

    }

    @Override
    protected void bindViews() {
        mBtn = (Button) findViewById(R.id.start);
        mText = (TextView) findViewById(R.id.text);
        mBar = (ProgressBar) findViewById(R.id.pba);
    }

    @Override
    protected void processLogic(Bundle savedInstanceState) {

    }

    @Override
    protected void setListener() {
        findViewById(R.id.start).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent startIntent = new Intent(mContext, TestIntentService.class);
                startService(startIntent);
            }
        });

        findViewById(R.id.end).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent startIntent = new Intent(mContext, TestIntentService.class);
                stopService(startIntent);

            }
        });
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        mLocalBroadcastManager.unregisterReceiver(mBroadcastReceiver);
    }

    class MyBroadcastReceiver extends BroadcastReceiver {

        @Override
        public void onReceive(Context context, Intent intent) {
            switch (intent.getAction()) {
                case ACTION_TYPE_THREAD:
                    int progress = intent.getIntExtra("progress", 0);
                    mBar.setProgress(progress);
                    mText.setText(progress + "%");
                    break;
            }
        }
    }
}