android - 从线程更新 textView

Question

在我的 OnCreate 方法中，我创建了一个线程来监听传入的消息!

In OnCreate() {

//Some code

myThread = new Thread() {

            @Override

            public void run() {

                receiveMyMessages();

            }
        };
myThread.start();

// Some code related to sending out by pressing button etc.

}

Then, receiveMyMessage() functions…

Public void receiveMyMessage()
{

//Receive the message and put it in String str;

str = receivedAllTheMessage();

// <<    here I want to be able to update this str to a textView. But, How?
}

我检查了this article但它对我不起作用，运气不好!

Answer 1

Android 应用程序中对 UI 的任何更新都必须在 UI 线程中进行。如果您生成一个线程在后台工作，您必须在触摸 View 之前将结果编码回 UI 线程。您可以使用 Handler 类来执行编码(marshal)处理:

public class TestActivity extends Activity {
    // Handler gets created on the UI-thread
    private Handler mHandler = new Handler();

    // This gets executed in a non-UI thread:
    public void receiveMyMessage() {
        final String str = receivedAllTheMessage();
        mHandler.post(new Runnable() {
            @Override
            public void run() {
                // This gets executed on the UI thread so it can safely modify Views
                mTextView.setText(str);
            }
        });
}

AsyncTask 类为您简化了很多细节，您也可以研究一下。例如，我相信它为您提供了一个线程池，以帮助减轻每次您想执行后台工作时生成新线程的相关成本。