AndroidAnnotations学习笔记--线程（五）

@Background
这个注解表明，这个方法将运行现UI线程以外的线程中

这个方法是在单独的线程上执行，但这并不一定意味着开启一个新的线程，因为会使用共享缓存线程池执行器，防止创建太多的线程。

@EActivity(R.layout.activity_test)
public class TestActivity extends Activity {
	
	@UiThread
	void Toast(String text, int time){
		Toast.makeText(this, text, time).show();
	}
	
	@Background
	public void testBackgroundThread(String res) {
		Toast("show String " + res, Toast.LENGTH_LONG);
	}
	
	@AfterViews
	void afterView(){
		
		testBackgroundThread("hello");
	}
}

如果你想取消后台任务，你可以使用ID字段进行取消。每个任务你都可以用BackgroundExecutor.cancelAll("id");进行取消。

@EActivity(R.layout.activity_test)
public class TestActivity extends Activity {
	
	@UiThread
	void Toast(String text, int time){
		Toast.makeText(this, text, time).show();
	}
	
	@Background(id="cancellable_task")
    public void testBackgroundThread(String res) {
        Toast("show String " + res, Toast.LENGTH_LONG);
    }
	
	@Click(R.id.bt_one)
	void cancelBackgroundThread(){
		BackgroundExecutor.cancelAll("cancellable_task", true);
	}
	
	@AfterViews
	void afterView(){
		
		testBackgroundThread("hello");
	}
}

在默认情况下，@Background是并行处理的。如果你想顺序的执行，您可以使用“serial”字段。所有的后台任务，如果具有相同的serial，将被按顺序执行。

@EActivity(R.layout.activity_test)
public class TestActivity extends Activity {
	
	@UiThread
	void Toast(String text, int time){
		Toast.makeText(this, text, time).show();
	}
	
	@Background(serial = "test")
    public void testBackgroundThread(String res,int index) {
        Toast("show String " + res + " , index = " + index, Toast.LENGTH_LONG);
        try {
			Thread.sleep(10000);
		} catch (InterruptedException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
    }
	
	@AfterViews
	void afterView(){
		for (int i = 0; i < 10; i++)
			testBackgroundThread("hello",i);
	}
}

如果你需要Background方法延迟一定时间运行，您可以使用delay参数：

@EActivity(R.layout.activity_test)
public class TestActivity extends Activity {
	
	@UiThread
	void Toast(String text, int time){
		Toast.makeText(this, text, time).show();
	}
	
	@Background(delay=2000)
    public void testBackgroundThread(String res,int index) {
        Toast("show String " + res + " , index = " + index, Toast.LENGTH_LONG);
        try {
			Thread.sleep(10000);
		} catch (InterruptedException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
    }
	
	@AfterViews
	void afterView(){
		testBackgroundThread("hello",1);
	}
}

• 如果在delay开始前，取消线程，线程不会执行
• 如果启动多个线程，线程名子一样的话，取消线程的话，所有相同名字的线程都会取消
• 如果串行执行时取消线程，后续的线程不会执行。

@UiThread

@UIThread 表明该方法将运行在UI线程上

代码示例

@EActivity(R.layout.activity_test)
public class TestActivity extends Activity {
	
	@UiThread
	void Toast(String text, int time){
		Toast.makeText(this, text, time).show();
	}
	
	@Background(delay=2000)
    public void testBackgroundThread(String res,int index) {
        Toast("show String " + res + " , index = " + index, Toast.LENGTH_LONG);
    }
	
	@AfterViews
	void afterView(){
		testBackgroundThread("hello",1);
	}
}

如果你需要该方法延迟一定时间运行，您可以使用delay参数：

@EActivity(R.layout.activity_test)
public class TestActivity extends Activity {
	
	@UiThread(delay=2000)
	void Toast(String text, int time){
		Toast.makeText(this, text, time).show();
	}
	
	@Background(delay=2000)
    public void testBackgroundThread(String res,int index) {
        Toast("show String " + res + " , index = " + index, Toast.LENGTH_LONG);
    }
	
	@AfterViews
	void afterView(){
		testBackgroundThread("hello",1);
	}
}

如果你要优化UI Thread的调用，你需要设置propagation = Propagation.REUSE这个参数。

@EActivity(R.layout.activity_test)
public class TestActivity extends Activity {
	
	@UiThread(propagation = Propagation.REUSE)
	void Toast(String text, int time){
		Toast.makeText(this, text, time).show();
	}
	
	@Background(delay=2000)
    public void testBackgroundThread(String res,int index) {
        Toast("show String " + res + " , index = " + index, Toast.LENGTH_LONG);
    }
	
	@AfterViews
	void afterView(){
		testBackgroundThread("hello",1);
	}
}

@SupposeBackground、@SupposeUiThread

这两个注解可以保证方法是在正确的线程中调用

• @SupposeBackground 这个注解确保从后台线程调用，如果不是在后台进行调用会引发 IllegalStateException
• @SupposeUiThread 这个注解确保从UI线程调用。如果不是，那么就会抛出IllegalStateException。

示例代码

@EBean
public class MyBean {

	@SupposeBackground
	void someMethodThatShouldNotBeCalledFromUiThread() {
	//if this method will be called from the UI-thread an exception will be thrown
	}

	@SupposeBackground(serial = {"serial1", "serial2"})
	void someMethodThatShouldBeCalledFromSerial1OrSerial2() {
	//if this method will be called from another thread then a background thread with a
	//serial "serial1" or "serial2", an exception will be thrown
	}
	
	@SupposeUiThread
	void someMethodThatShouldBeCalledOnlyFromUiThread() {
	//if this method will be called from a background thread an exception will be thrown
	}
}