Handling UI from other thread

问题

I have a class which extends the Runnable. This class performs some heavy operation (basically downloads the image from network) in different thread. I want to update the UI (display the downloaded image to an ImageView) from this class. I have tried using handler but did not succeed. Here is my code:

class DataReceiver implements Runnable
{
    public Bitmap bmp;
    Public Handler uiHandle;
    @Override
    public void run()
    {
        while(true)
        {
            //do image download process here
        }
    }
}

In main activity

ImageView img = (ImageView)findViewById(R.id.dispImg);
DataReceiver dr=new DataReceiver();

Handler uiHandler = new Handler()
{
    @Override
    public void handleMessage(Message msg)
    {
        updateUI();
    }
}

dr.uiHandle = uiHandler;
(new Thread(dr)).start();

public void updateUI()
{
    img.setBitmap(dr.bmp);
}

Is it the correct method for updating UI?

回答1:

almost ;D you need on the class thread add the that linebefore while do:

while(true)
    {
      //do image download process here
    }
uiHandle.sendEmptyMessage(0);

回答2:

You could use AsyncTask instead, do what you're currently doing in run() in doInBackground, and then do the UI update in the task's onPostExecute.

回答3:

To update the UI from another thread use

activity.runOnUIThread(new Runnable());

来源：https://stackoverflow.com/questions/5991178/handling-ui-from-other-thread