标题说得很清楚,不过为了以防万一,我会给出一个代码示例。这是来自 Android SDK 中的 LunarLander 示例:
@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);
}
}
}
}
lockCanvas()
的文档说必须重新绘制所有像素,而 lockCanvas(Rect dirty)
说您只需要重新绘制像素脏
。我看到将 null
传递给此函数有两种可能的解释:它不需要重新绘制任何像素,或者其行为方式与 lockCanvas()
相同。
最佳答案
它是开源的
public Canvas lockCanvas() {
return internalLockCanvas(null);
}
public Canvas lockCanvas(Rect dirty) {
return internalLockCanvas(dirty);
}
关于Android:lockCanvas() 和 lockCanvas(null) 有什么区别?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/12293835/