子线程转化到Ui主线程

通过private Handler handler = new Handler(Looper.getMainLooper());

在子线程中调用：

  handler.post(new Runnable() {

                   @Override
                   public void run() {

                   }
               });

具体例子：

public class BitmapDispatcger extends Thread {

    private BlockingQueue<BitmapRequest> requests;

    private Handler handler = new Handler(Looper.getMainLooper());

    public BitmapDispatcger(BlockingQueue<BitmapRequest> requests) {
        this.requests = requests;
    }

    @Override
    public void run() {
        //子线程
        while (!isInterrupted()) {
            //取出任务，如果队列中没有任务就会一直阻塞在这里，不往下进行
            try {
                BitmapRequest request = requests.take();
                //先展示loading

                showLoadingImage(request);


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


    private void showLoadingImage(BitmapRequest request) {
        if (request.getLoadingResId() > 0) {
            final ImageView imageView = request.getImageView();
            final int redId = request.getLoadingResId();
            if (imageView != null) {
                //子线程调用主线程
                handler.post(new Runnable() {

                    @Override
                    public void run() {
                        //更新ui
                        imageView.setImageResource(redId);
                    }
                });

            }
        }
    }
}