非UI线程无法修改界面

非UI线程无法修改界面

问题

如果从非UI线程去访问UI上的控件，会出现下面的问题：

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android.view.ViewRoot$CalledFromWrongThreadException: 
Only the original thread that created a view hierarchy can touch its views.

解决方法

把要运行的代码放到UI线程去执行

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runOnUiThread(new Runnable() {

    @Override
    public void run() {

        // Stuff that updates the UI

    }
});

对应的android文档：

runOnUiThread

代码示例

定义接口

https://github.com/zfdang/chinese-chess-android/blob/master/app/src/main/java/com/zfdang/chess/controllers/GameControllerListener.java

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public interface GameControllerListener {

    // create fun to send game over event
    public void onGameEvent(GameStatus event, String message);

    public void onGameEvent(GameStatus event);

    /** Run code on the GUI thread. */
    // https://stackoverflow.com/questions/5161951/android-only-the-original-thread-that-created-a-view-hierarchy-can-touch-its-vi
    // Android "Only the original thread that created a view hierarchy can touch its views."
    void runOnUIThread(Runnable runnable);
}

实现接口

https://github.com/zfdang/chinese-chess-android/blob/master/app/src/main/java/com/zfdang/chess/GameActivity.kt

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override fun runOnUIThread(runnable: Runnable?) {
        runOnUiThread(runnable);
    }

运行代码在Ui线程

https://github.com/zfdang/chinese-chess-android/blob/master/app/src/main/java/com/zfdang/chess/controllers/GameController.java

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private GameControllerListener gui = null;
public GameController(GameControllerListener cListener) {
    gui = cListener;
}

gui.runOnUIThread(() -> playerMovePiece(bestMove));