1

我在名为 GameLoop 的类中有此代码（类似于 LunarLander 示例的代码）

while( running ) {
    Canvas canvas = null;
    try {
        canvas = mSurfaceHolder.lockCanvas(null);
        long t = System.currentTimeMillis();
        if( t - old[0] >= frame ) {
            old[0] = t;
            synchronized( mSurfaceHolder ) {
                mGame.update();
                mGame.onDraw(canvas);
            }
        }
    }
    finally {
        // Do this in finally so that if an exception is thrown
        // we don't leave the Surface in an inconsistent state
        if( canvas != null ) mSurfaceHolder.unlockCanvasAndPost(canvas);
    }

        }

父类是GameView（参考mGame）。
当mGame.update()试图调用他自己的announce方法时，

public class GameView extends SurfaceView implements SurfaceHolder.Callback {

. . .
    private void announce(int resId) {
        synchronized( mSurfaceHolder ) {
            tv_announcement.setText(getContext().getString(resId));
            ObjectAnimator anim = ObjectAnimator.ofFloat(tv_announcement, "alpha", 0, 1);
            anim.setDuration(ANNOUNCE_DURATION).start();
        }
    }
. . .

我得到这个例外： 

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

这里有两个线程，UI 线程，运行 GameView 并拥有 SurfaceView，以及 GameLoop，它是 Thread 的扩展，只运行更新绘制循环。

据我了解，异常告诉我只有 UI 线程可以触摸 TextView tv_announcement。
但是不是announce在 UI 线程中运行吗？我在这里想念什么？

这是announce后异常的logcat：

03-22 07:20:19.096: D/GameView(28250): + update(): state:IDLE, next state:CHOOSE_SIDE
03-22 07:20:19.096: D/GameView(28250): + announce(resId:2131361803)
03-22 07:20:19.096: W/dalvikvm(28250): threadid=10: thread exiting with uncaught exception (group=0xb3040180)
03-22 07:20:19.096: E/AndroidRuntime(28250): FATAL EXCEPTION: Thread-192
03-22 07:20:19.096: E/AndroidRuntime(28250): android.view.ViewRootImpl$CalledFromWrongThreadException: Only the original thread that created a view hierarchy can touch its views.
03-22 07:20:19.096: E/AndroidRuntime(28250):    at android.view.ViewRootImpl.checkThread(ViewRootImpl.java:4039)
03-22 07:20:19.096: E/AndroidRuntime(28250):    at android.view.ViewRootImpl.requestLayout(ViewRootImpl.java:709)
03-22 07:20:19.096: E/AndroidRuntime(28250):    at android.view.View.requestLayout(View.java:12675)
03-22 07:20:19.096: E/AndroidRuntime(28250):    at android.view.View.requestLayout(View.java:12675)
03-22 07:20:19.096: E/AndroidRuntime(28250):    at android.view.View.requestLayout(View.java:12675)
03-22 07:20:19.096: E/AndroidRuntime(28250):    at android.view.View.requestLayout(View.java:12675)
03-22 07:20:19.096: E/AndroidRuntime(28250):    at android.view.View.requestLayout(View.java:12675)
03-22 07:20:19.096: E/AndroidRuntime(28250):    at android.widget.RelativeLayout.requestLayout(RelativeLayout.java:268)
03-22 07:20:19.096: E/AndroidRuntime(28250):    at android.view.View.requestLayout(View.java:12675)
03-22 07:20:19.096: E/AndroidRuntime(28250):    at android.widget.TextView.checkForRelayout(TextView.java:6773)
03-22 07:20:19.096: E/AndroidRuntime(28250):    at android.widget.TextView.setText(TextView.java:3306)
03-22 07:20:19.096: E/AndroidRuntime(28250):    at android.widget.TextView.setText(TextView.java:3162)
03-22 07:20:19.096: E/AndroidRuntime(28250):    at android.widget.TextView.setText(TextView.java:3137)
03-22 07:20:19.096: E/AndroidRuntime(28250):    at <package>.GameView.announce(GameView.java:436)
03-22 07:20:19.096: E/AndroidRuntime(28250):    at  <package>.GameView.update(GameView.java:314)
03-22 07:20:19.096: E/AndroidRuntime(28250):    at  <package>.GameView$GameLoop.run(GameView.java:495)
03-22 07:20:19.126: D/GameView(28250): + onWindowFocusChanged(hasWindowFocus:true)
03-22 07:20:19.126: D/GameView(28250): - onWindowFocusChanged()
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1 回答 1

2

只有创建视图层次结构的原始线程才能接触其视图。

抛出您的错误是因为您肯定是从非 UI 线程修改 UI，可能来自工作线程。

如果您想使用 Thread 中执行的操作或仅来自 Thread 中执行的某些进程的某些信息来更新 UI，您只能使用：

于 2013-03-22T09:28:36.920 回答