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这些图标是放在 UITabBar 和 UINavigationBar 里的。所以只要遍历它们的 subViews，找到类型是 UIButton 的就可以了。
所有想获取它们的相对位置很容易。
但我有个需求是需要在整个屏幕覆盖一层 UIView，然后在 这些图标旁画一些图案（其实我是在做应用教程）。这时候就需要获取他们在整个视图中相对于最外层的 UIViewController 的位置。这就没有那么容易了。
我的应用中，最外层有一个UITabBarController，里面嵌套一个 UINavigationController，里面在嵌套一个 UIViewController。由于 UITabBarController 位于最外层，所以获取到的位置就是想要的位置。而 UINavigationBar 里的图标就需要做些调整。也就是需要加入 UITabBarController 的 layout margin。经过测试，一般尺寸的 iPhone 这个值为16，而 iPhone 6plus，iPad 这个值20。
所以我想要的位置就是:
1. 左侧的图标
获取的相对位置＋layoutMargin.left
2. 右侧的图标
获取的相对位置－layoutMargin.right
获取相对位置的代码：
+ (CGPoint)centerForTabInTabBar:(UITabBar*)tabBar withIndex:(NSUInteger)index { NSMutableArray *tabBarItems = [NSMutableArray arrayWithCapacity:[tabBar.items count]]; for (UIView *view in tabBar.subviews) { if ([view isKindOfClass:NSClassFromString(@"UITabBarButton")] && [view respondsToSelector:@selector(frame)]) { // check for the selector -frame to prevent crashes in the very unlikely case that in the future // objects thar don‘t implement -frame can be subViews of an UIView [tabBarItems addObject:view]; } } if ([tabBarItems count] == 0) { // no tabBarItems means either no UITabBarButtons were in the subView, or none responded to -frame // return CGRectZero to indicate that we couldn‘t figure out the frame return CGPointZero; } // sort by origin.x of the frame because the items are not necessarily in the correct order [tabBarItems sortUsingComparator:^NSComparisonResult(UIView *view1, UIView *view2) { if (view1.frame.origin.x < view2.frame.origin.x) { return NSOrderedAscending; } if (view1.frame.origin.x > view2.frame.origin.x) { return NSOrderedDescending; } NSAssert(NO, @"%@ and %@ share the same origin.x. This should never happen and indicates a substantial change in the framework that renders this method useless.", view1, view2); return NSOrderedSame; }]; CGPoint center = CGPointZero; if (index < [tabBarItems count]) { // viewController is in a regular tab UIView *tabView = tabBarItems[index]; center = tabView.center; } else { // our target viewController is inside the "more" tab UIView *tabView = [tabBarItems lastObject]; center = tabView.center; } return center; }
+ (CGPoint)centerForItemInNavigationBar:(UINavigationBar *)navigationBar withIndex:(NSUInteger)index { NSMutableArray *navigationBarItems = [NSMutableArray arrayWithCapacity:[navigationBar.items count]]; for (UIView *view in navigationBar.subviews) { if ([view isKindOfClass:NSClassFromString(@"UIButton")] && [view respondsToSelector:@selector(frame)]) { // check for the selector -frame to prevent crashes in the very unlikely case that in the future // objects thar don‘t implement -frame can be subViews of an UIView [navigationBarItems addObject:view]; } } if ([navigationBarItems count] == 0) { // no tabBarItems means either no UITabBarButtons were in the subView, or none responded to -frame // return CGRectZero to indicate that we couldn‘t figure out the frame return CGPointZero; } // sort by origin.x of the frame because the items are not necessarily in the correct order [navigationBarItems sortUsingComparator:^NSComparisonResult(UIView *view1, UIView *view2) { if (view1.frame.origin.x < view2.frame.origin.x) { return NSOrderedAscending; } if (view1.frame.origin.x > view2.frame.origin.x) { return NSOrderedDescending; } NSAssert(NO, @"%@ and %@ share the same origin.x. This should never happen and indicates a substantial change in the framework that renders this method useless.", view1, view2); return NSOrderedSame; }]; CGPoint point = CGPointZero; if (index < [navigationBarItems count]) { // viewController is in a regular tab UIView *navigationView = navigationBarItems[index]; if ([navigationView respondsToSelector:@selector(frame)]) { point = navigationView.center; } } else { // our target viewController is inside the "more" tab UIView *navigationView = [navigationBarItems lastObject]; if ([navigationView respondsToSelector:@selector(frame)]) { point = navigationView.center; } } return point; }
iOS 获取 UITabViewController 和 UINavigationController 的图标位置
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原文地址：http://www.cnblogs.com/davesuen/p/5033468.html
