查View的源码可知：
postInvalidate是使用handler发送消息，即可以使用在非UI线程中，而invalidate直接修改布局，所以只能用在UI线程里了。
public void invalidate() {
invalidate(true);
}
void invalidate(boolean invalidateCache) {
if (ViewDebug.TRACE_HIERARCHY) {
ViewDebug.trace(this, ViewDebug.HierarchyTraceType.INVALIDATE);
}
if (skipInvalidate()) {
return;
}
if ((mPrivateFlags & (DRAWN | HAS_BOUNDS)) == (DRAWN | HAS_BOUNDS) ||
(invalidateCache && (mPrivateFlags & DRAWING_CACHE_VALID) == DRAWING_CACHE_VALID) ||
(mPrivateFlags & INVALIDATED) != INVALIDATED || isOpaque() != mLastIsOpaque) {
mLastIsOpaque = isOpaque();
mPrivateFlags &= ~DRAWN;
mPrivateFlags |= DIRTY;
if (invalidateCache) {
mPrivateFlags |= INVALIDATED;
mPrivateFlags &= ~DRAWING_CACHE_VALID;
}
final AttachInfo ai = mAttachInfo;
final ViewParent p = mParent;
//noinspection PointlessBooleanExpression,ConstantConditions
if (!HardwareRenderer.RENDER_DIRTY_REGIONS) {
if (p != null && ai != null && ai.mHardwareAccelerated) {
// fast-track for GL-enabled applications; just invalidate the whole hierarchy
// with a null dirty rect, which tells the ViewAncestor to redraw everything
p.invalidateChild(this, null);
return;
}
}
if (p != null && ai != null) {
final Rect r = ai.mTmpInvalRect;
r.set(0, 0, mRight - mLeft, mBottom - mTop);
// Don‘t call invalidate -- we don‘t want to internally scroll
// our own bounds
p.invalidateChild(this, r);
}
}
}
public void postInvalidate() {
postInvalidateDelayed(0);
}
public void postInvalidateDelayed(long delayMilliseconds) {
// We try only with the AttachInfo because there‘s no point in invalidating
// if we are not attached to our window
AttachInfo attachInfo = mAttachInfo;
if (attachInfo != null) {
Message msg = Message.obtain();
msg.what = AttachInfo.INVALIDATE_MSG;
msg.obj = this;
attachInfo.mHandler.sendMessageDelayed(msg, delayMilliseconds);
}
}
通过查看源码，查看invalidate和postInvalidate的区别,布布扣,bubuko.com