Android Studio - 无法捕获异常锁定表面

Question

您好，我在 Android Studio 中制作了一款游戏。有时，当我在模拟器上关闭并重新启动应用程序时，我会在 logcat 中收到以下垃圾邮件：

Exception locking surface
java.lang.IllegalStateException: Surface was already locked

我尝试用 try-catch 块包围canvas = this.surfaceHolder.lockCanvas();，但没有捕获到异常。有没有办法在尝试锁定之前检查画布是否已锁定？

这是我在 MainThread.java 类中的代码

    while (running) {
        startTime = System.nanoTime();
        canvas = null;

    try {
     canvas = this.surfaceHolder.lockCanvas();
            synchronized (surfaceHolder) {
                // update game state
                this.gamePanel.update();
                // draws the canvas on the panel
                this.gamePanel.draw(canvas);
            }

        } catch(Exception e){e.printStackTrace();}finally {
            // in case of an exception the surface is not left in
            // an inconsistent state
            if (canvas != null) {
                try {

                    surfaceHolder.unlockCanvasAndPost(canvas);

                }
                catch(Exception e){e.printStackTrace();}
            }
    }

Answer 1

您可以识别并使用布尔常量进行检查；

    //create the boolean;
private boolean cLocked = false;


//Locking
 if (!cLocked){
    canvas = this.surfaceHolder.lockCanvas();
    cLocked = true;
}

//Unlocking
if (cLocked) {
    surfaceHolder.unlockCanvasAndPost(canvas);
    cLocked = false;
}

这将防止异常。已锁定时不锁定，反之亦然。