如何使用一个机器人处理程序更新UI线程一个TextView？

问题描述

我要更新的TextView 从Android应用程序的异步任务。什么是用最简单的方式处理程序？

I want to update a TextView from an asynchronous task in an Android application. What is the simplest way to do this with a Handler?

有一些类似的问题，比如这个：的Andr​​oid更新的TextView与处理程序的，但该实施例很复杂，没有出现应答。

There are some similar questions, such as this: Android update TextView with Handler, but the example is complicated and does not appear to be answered.

推荐答案

有几种方法来更新你的用户界面，并修改查看如的TextView 从UI线程之外。 A 处理程序只是其中的一个方法。

There are several ways to update your UI and modify a View such as a TextView from outside of the UI Thread. A Handler is just one method.

下面是一个例子，它允许一个单一的处理程序应对多种类型的请求。

Here is an example that allows a single Handler respond to various types of requests.

在类级别定义一个简单的处理程序：

At the class level define a simple Handler:

private final static int DO_UPDATE_TEXT = 0;
private final static int DO_THAT = 1;
private final Handler myHandler = new Handler() {
    public void handleMessage(Message msg) {
        final int what = msg.what;
        switch(what) {
        case DO_UPDATE_TEXT: doUpdate(); break;
        case DO_THAT: doThat(); break;
        }
    }
};

更新UI，在您的功能之一，这是现在在UI线程：

Update the UI in one of your functions, which is now on the UI Thread:

private void doUpdate() {
    myTextView.setText("I've been updated.");
}

这是在你的异步任务，发送邮件到处理程序。有几种方法可以做到这一点。这可能是最简单的：

From within your asynchronous task, send a message to the Handler. There are several ways to do it. This may be the simplest:

myHandler.sendEmptyMessage(DO_UPDATE_TEXT);

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