Android的LunarLander例子似乎并没有使用'无效' [英] Android LunarLander example does not seem to use 'invalidate'

问题描述

我学习在Android样本code中的LunarLander例如： HTTP ：//developer.android.com/resources/samples/LunarLander/index.html

I am studying the LunarLander example in the Android sample code: http://developer.android.com/resources/samples/LunarLander/index.html

我百思不得其解，因为意见在几个地方的code使用'无效'触发重绘说。但我不能找到它在code。

I am puzzled because the comments say in several places that the code uses 'invalidate' to trigger redrawing. But I can't find it in the code.

更重要的是我认为，图纸上应在视图的OnDraw总会发生，而不是在一个线程内联别处。

More importantly I believe that drawing should always happen in a View's onDraw and not inline elsewhere in a thread.

有没有人研究了例子，对于自己为何无效（评论）不会被调用？

Has anyone studied that example and have comments about why invalidate() is not being called?

感谢您分享您的见解！

- 皮托

推荐答案

这不是在一个线程内联，但它是从一个线程调用。

It isn't inlined in a Thread but it is called from a Thread.

@Override
public void run() {
    while (mRun) {
        Canvas c = null;
        try {
            c = mSurfaceHolder.lockCanvas(null);
            synchronized (mSurfaceHolder) {
                if (mMode == STATE_RUNNING) updatePhysics();
                doDraw(c);
            }
        } finally {
            // do this in a finally so that if an exception is thrown
            // during the above, we don't leave the Surface in an
            // inconsistent state
            if (c != null) {
                mSurfaceHolder.unlockCanvasAndPost(c);
            }
        }
    }
}

图纸本身应该始终从一个线程调用，当你做二维图形...

The drawing itself should always be called from a Thread when you do 2D graphics...

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