70.自定义异步任务

public abstract class YTAsyncTask<T> {
    private static final HandlerThread handlerThread = new HandlerThread(YTAsyncTask.class.getName(), 10);
    public YTAsyncTask() {
    }
    protected abstract void onPreExecute();
    protected abstract T doInBackground();
    protected abstract void onPostExecute(T param);
    public final YTAsyncTask<T> execute() {
        final Handler mainHandler = new Handler(Looper.getMainLooper());
        Handler bgHandler = new Handler(handlerThread.getLooper());
        this.onPreExecute();
        bgHandler.post(new Runnable() {
            public void run() {
                final T param= YTAsyncTask.this.doInBackground();
                mainHandler.post(new Runnable() {
                    public void run() {
                        YTAsyncTask.this.onPostExecute(param);
                    }
                });
            }
        });
        return this;
    }
    static {
        handlerThread.start();
    }
}

public class MainActivity extends AppCompatActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        testAsyncTask();
    }
    private void testAsyncTask() {
        new YTAsyncTask<String>() {
            @Override
            protected void onPreExecute() {
                Log.e("ytr", "onPreExecute,currentThread=" + Thread.currentThread().getName());
            }
            @Override
            protected String doInBackground() {
                Log.e("ytr", "doInBackground,currentThread=" + Thread.currentThread().getName());
                return "Hello World";
            }
            @Override
            protected void onPostExecute(String param) {
                Log.e("ytr", "onPostExecute,currentThread=" + Thread.currentThread().getName()+"\tparam="+param);
            }
        }.execute();
    }
}