Android 更新 Thread 和 Runnable 中的 TextView
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原文地址: http://stackoverflow.com/questions/12716850/
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Android update TextView in Thread and Runnable
提问by user1718339
I want to make a simple timer in Android that updates a TextView every second. It simply counts seconds like in Minesweeper.
我想在 Android 中制作一个简单的计时器，每秒更新一个 TextView。它只是像扫雷一样计算秒数。
The problem is when i ignore the tvTime.setText(...) (make it //tvTime.setText(...), in LogCat will be printed the following number every second. But when i want to set this number to a TextView (created in another Thread), the program crashes.
问题是当我忽略 tvTime.setText(...)（使它成为 //tvTime.setText(...)，在 LogCat 中将每秒打印以下数字。但是当我想将此数字设置为TextView（在另一个线程中创建），程序崩溃。
Does anyone have an idea how to solve this easily?
有谁知道如何轻松解决这个问题？
Here's the code (method is called on startup):
这是代码（方法在启动时调用）：
private void startTimerThread() {
Thread th = new Thread(new Runnable() {
private long startTime = System.currentTimeMillis();
public void run() {
while (gameState == GameState.Playing) {
System.out.println((System.currentTimeMillis() - this.startTime) / 1000);
tvTime.setText("" + ((System.currentTimeMillis() - this.startTime) / 1000));
try {
Thread.sleep(1000);
}
catch (InterruptedException e) {
e.printStackTrace();
}
}
}
});
th.start();
}
EDIT:
编辑：
Finally, I got it. Here is the solution, for those who are interested in.
最后我明白了。这是解决方案，对于那些有兴趣的人。
private void startTimerThread() {
Thread th = new Thread(new Runnable() {
private long startTime = System.currentTimeMillis();
public void run() {
while (gameState == GameState.Playing) {
runOnUiThread(new Runnable() {
@Override
public void run() {
tvTime.setText(""+((System.currentTimeMillis()-startTime)/1000));
}
});
try {
Thread.sleep(1000);
}
catch (InterruptedException e) {
e.printStackTrace();
}
}
}
});
th.start();
}
回答by Chris Conway
The UserInterface can only be updated by the UI Thread. You need a Handler, to post to the UI Thread:
UserInterface 只能由 UI 线程更新。你需要一个Handler来发布到 UI 线程：
private void startTimerThread() {
Handler handler = new Handler();
Runnable runnable = new Runnable() {
private long startTime = System.currentTimeMillis();
public void run() {
while (gameState == GameState.Playing) {
try {
Thread.sleep(1000);
}
catch (InterruptedException e) {
e.printStackTrace();
}
handler.post(new Runnable(){
public void run() {
tvTime.setText("" + ((System.currentTimeMillis() - this.startTime) / 1000));
}
});
}
}
};
new Thread(runnable).start();
}
回答by dennisdrew
Alternatively, you can also just do this in your thread whenever you want to update a UI element:
或者，只要您想更新 UI 元素，您也可以在线程中执行此操作：
runOnUiThread(new Runnable() {
public void run() {
// Update UI elements
}
});
回答by Jorgesys
As an option use runOnUiThread()to change de views properties in the main thread.
作为一个选项，使用runOnUiThread()来更改主线程中的视图属性。
runOnUiThread(new Runnable() {
@Override
public void run() {
textView.setText("Stackoverflow is cool!");
}
});
回答by zienkikk
You cannot access UI elements from non-UI threads. Try surrounding the call to setText(...)with another Runnableand then look into the View.post(Runnable)method.
您无法从非 UI 线程访问 UI 元素。尝试setText(...)用另一个调用 to ，Runnable然后查看该View.post(Runnable)方法。
