UIScrollview與景觀中的Autolayout內容大小

Question

我正試圖在我的應用程序中顯示一個簡單的設置屏幕，我正在使用Autolayout。 由於我的應用程序支持橫向，並且當手機處於橫向狀態時設置控件不完全適合垂直，我添加了UIScrollview。

似乎UIScrollview和Autolayout的組合在這里和其他地方是一個常見的問題。 我已經閱讀了一些關於它的文章，從它可以看出，似乎一個好的方法去做我想要做的是將我的各種控件放在一個視圖中，就像一個帶有約束的“contentView”在該視圖中對齊。 然后讓contentView成為UIScrollView的唯一子視圖。 我有contentView約束綁定到UIScrollView的邊緣。

UINavigationView -> UIScrollview -> contentView (UIView) -> Control Subviews

它在縱向工作正常，即使我在contentView中添加需要滾動查看的內容，但是當我去景觀時，它不會讓我向下滾動得足夠遠。 這就像我旋轉時內容大小重置為可見區域（或導航控制器superview的框架）的框架。

我想知道我是否需要檢查旋轉，然后再次設置內容大小？ 如果是這樣，有沒有辦法從視圖（contentView）動態獲取該大小？

謝謝你的盡心幫助！ 吉姆

Answer 1

有兩個組件可以自動布局正確處理滾動視圖：

1. 滾動視圖子視圖的約束：滾動視圖的contentSize將由滾動視圖的子視圖的約束決定。 因此，您需要為滾動視圖中的最后一個控件（即第二個開關）設置一個底部約束到其超級視圖（即滾動視圖）。 看起來你確實有這個。 滾動視圖的子視圖的這些約束將根據需要自動調整滾動視圖的contentSize 。

   順便說一下，這個第二個開關的底部約束的constant通常默認為與縱向布局相對應的一些較大的值。 您可能希望為最后一個控件選擇並編輯此底部約束，並將其更改為“標准”值。

   

2. 滾動視圖本身的約束：您需要確保滾動視圖本身具有底部約束到其超級視圖（並確保滾動視圖上沒有高度約束）。 這將在屏幕旋轉時調整滾動視圖的frame 。 我想知道你的項目中是否會遺漏這些內容。

   您可以通過在調試器中運行您的應用程序來確認這一點，點擊“暫停”按鈕：

   

   然后在(lldb)提示符下鍵入po [[UIWindow keyWindow] recursiveDescription] ，你應該看到類似的東西：

    (lldb) po [[UIWindow keyWindow] recursiveDescription] <UIWindow: 0x8b97ff0; frame = (0 0; 320 480); autoresize = W+H; gestureRecognizers = <NSArray: 0x8b98450>; layer = <UIWindowLayer: 0x8b97af0>> | <UIView: 0x8b9a830; frame = (0 0; 320 480); transform = [0, -1, 1, 0, 0, 0]; autoresize = RM+BM; layer = <CALayer: 0x8b9a240>> | | <UIScrollView: 0x8b9aa50; frame = (0 0; 480 320); clipsToBounds = YES; autoresize = RM+TM; gestureRecognizers = <NSArray: 0x8b9a6c0>; layer = <CALayer: 0x8b9a130>; contentOffset: {0, 0}> | | | <UILabel: 0x8b9ade0; frame = (20 20; 63 21); text = 'Settings'; clipsToBounds = YES; opaque = NO; autoresize = RM+BM; userInteractionEnabled = NO; layer = <CALayer: 0x8b9aec0>> | | | <UILabel: 0x8b9d590; frame = (20 49; 51 21); text = 'View 1'; clipsToBounds = YES; opaque = NO; autoresize = RM+BM; userInteractionEnabled = NO; layer = <CALayer: 0x8b9d6b0>> | | | <UILabel: 0x8b9db70; frame = (408 49; 51 21); text = 'View 2'; clipsToBounds = YES; opaque = NO; autoresize = RM+BM; userInteractionEnabled = NO; layer = <CALayer: 0x8b9dc10>> | | | <UIView: 0x8b9de60; frame = (335 78; 124 53); autoresize = RM+BM; layer = <CALayer: 0x8b9dec0>> | | | <UIView: 0x8b9e000; frame = (20 78; 284 53); autoresize = RM+BM; layer = <CALayer: 0x8b9e060>> | | | <UILabel: 0x8b9e250; frame = (20 139; 59 21); text = 'Slider 1'; clipsToBounds = YES; opaque = NO; autoresize = RM+BM; userInteractionEnabled = NO; layer = <CALayer: 0x8b9e2f0>> | | | <UISlider: 0x8b9e460; frame = (18 238; 444 34); opaque = NO; autoresize = RM+BM; layer = <CALayer: 0x8b9e5c0>; value: 0.500000> | | | | <UIView: 0x8ace410; frame = (2 16; 440 2); userInteractionEnabled = NO; layer = <CALayer: 0x8ace470>> | | | | | <UIView: 0x8ace610; frame = (221 0; 219 2); clipsToBounds = YES; opaque = NO; userInteractionEnabled = NO; layer = <CALayer: 0x8ace670>> | | | | | | <UIView: 0x8ace6e0; frame = (-221 0; 440 2); clipsToBounds = YES; opaque = NO; userInteractionEnabled = NO; layer = <CALayer: 0x8ace740>> | | | | | | | <CAGradientLayer: 0x8ace7b0> (layer) | | | | | <UIView: 0x8ace7e0; frame = (0 0; 221 2); clipsToBounds = YES; opaque = NO; userInteractionEnabled = NO; layer = <CALayer: 0x8ace840>> | | | | <UIImageView: 0x8ace9d0; frame = (207 1; 31 31); opaque = NO; userInteractionEnabled = NO; layer = <CALayer: 0x8acea60>> | | | | | <UIImageView: 0x8ace8b0; frame = (-13 -6.5; 57 43.5); opaque = NO; userInteractionEnabled = NO; layer = <CALayer: 0x8ace940>> | | | <UISlider: 0x8b9e850; frame = (17 168; 444 34); opaque = NO; autoresize = RM+BM; layer = <CALayer: 0x8b9e930>; value: 0.500000> | | | | <UIView: 0x8ba5430; frame = (2 16; 440 2); userInteractionEnabled = NO; layer = <CALayer: 0x8ba5490>> | | | | | <UIView: 0x8acc190; frame = (221 0; 219 2); clipsToBounds = YES; opaque = NO; userInteractionEnabled = NO; layer = <CALayer: 0x8acae30>> | | | | | | <UIView: 0x8acc3f0; frame = (-221 0; 440 2); clipsToBounds = YES; opaque = NO; userInteractionEnabled = NO; layer = <CALayer: 0x8ac84d0>> | | | | | | | <CAGradientLayer: 0x8accb90> (layer) | | | | | <UIView: 0x8acdf50; frame = (0 0; 221 2); clipsToBounds = YES; opaque = NO; userInteractionEnabled = NO; layer = <CALayer: 0x8acdfb0>> | | | | <UIImageView: 0x8ace070; frame = (207 1; 31 31); opaque = NO; userInteractionEnabled = NO; layer = <CALayer: 0x8ace100>> | | | | | <UIImageView: 0x8acdfe0; frame = (-13 -6.5; 57 43.5); opaque = NO; userInteractionEnabled = NO; layer = <CALayer: 0x8acdc80>> | | | <UILabel: 0x8b9e9c0; frame = (20 209; 59 21); text = 'Slider 2'; clipsToBounds = YES; opaque = NO; autoresize = RM+BM; userInteractionEnabled = NO; layer = <CALayer: 0x8b9ea60>> | | | <UISwitch: 0x8b9ece0; frame = (411 279; 51 31); opaque = NO; autoresize = RM+BM; layer = <CALayer: 0x8b9edd0>> | | | | <_UISwitchInternalViewNeueStyle1: 0x8b9f0c0; frame = (0 0; 51 31); gestureRecognizers = <NSArray: 0x8b723f0>; layer = <CALayer: 0x8b9f1c0>> | | | | | <UIView: 0x8b9f750; frame = (35.5 0; 15.5 31); clipsToBounds = YES; layer = <CALayer: 0x8b9f7b0>> | | | | | | <UIView: 0x8b9f3b0; frame = (-35.5 0; 51 31); layer = <CALayer: 0x8b9f410>> | | | | | <UIView: 0x8b9f6c0; frame = (0 0; 35.5 31); clipsToBounds = YES; layer = <CALayer: 0x8b9f720>> | | | | | | <UIView: 0x8b9f440; frame = (0 0; 51 31); layer = <CALayer: 0x8b9f4a0>> | | | | | <UIView: 0x8ba11e0; frame = (0 0; 51 31); layer = <CALayer: 0x8ba1240>> | | | | | | <UIImageView: 0x8ba0f10; frame = (39 16; 0 0); alpha = 0; userInteractionEnabled = NO; layer = <CALayer: 0x8ba10f0>> | | | | | | <UIImageView: 0x8ba1120; frame = (12 16; 0 0); userInteractionEnabled = NO; layer = <CALayer: 0x8ba11b0>> | | | | | <UIImageView: 0x8b9fab0; frame = (7 -6; 57 43.5); opaque = NO; userInteractionEnabled = NO; layer = <CALayer: 0x8ba0a40>> | | | <UISwitch: 0x8b974b0; frame = (411 318; 51 31); opaque = NO; autoresize = RM+BM; layer = <CALayer: 0x8b75570>> | | | | <_UISwitchInternalViewNeueStyle1: 0x8b7d6a0; frame = (0 0; 51 31); gestureRecognizers = <NSArray: 0x8b845e0>; layer = <CALayer: 0x8b78750>> | | | | | <UIView: 0x8b7df70; frame = (35.5 0; 15.5 31); clipsToBounds = YES; layer = <CALayer: 0x8b7be00>> | | | | | | <UIView: 0x8b72410; frame = (-35.5 0; 51 31); layer = <CALayer: 0x8b7a660>> | | | | | <UIView: 0x8b7ba80; frame = (0 0; 35.5 31); clipsToBounds = YES; layer = <CALayer: 0x8b7bd00>> | | | | | | <UIView: 0x8b78dd0; frame = (0 0; 51 31); layer = <CALayer: 0x8b7ba20>> | | | | | <UIView: 0x8b81580; frame = (0 0; 51 31); layer = <CALayer: 0x8b77ee0>> | | | | | | <UIImageView: 0x8b97880; frame = (39 16; 0 0); alpha = 0; userInteractionEnabled = NO; layer = <CALayer: 0x8b7e1a0>> | | | | | | <UIImageView: 0x8b77460; frame = (12 16; 0 0); userInteractionEnabled = NO; layer = <CALayer: 0x8b7e350>> | | | | | <UIImageView: 0x8b80670; frame = (7 -6; 57 43.5); opaque = NO; userInteractionEnabled = NO; layer = <CALayer: 0x8b80700>> | | | <UILabel: 0x8b97cf0; frame = (335 284; 67 21); text = 'Switch 1'; clipsToBounds = YES; opaque = NO; autoresize = RM+BM; userInteractionEnabled = NO; layer = <CALayer: 0x8b808b0>> | | | <UILabel: 0x8b79d60; frame = (335 323; 67 21); text = 'Switch 2'; clipsToBounds = YES; opaque = NO; autoresize = RM+BM; userInteractionEnabled = NO; layer = <CALayer: 0x8b77b90>> | | | <UIImageView: 0x8ac44f0; frame = (476 473; 3 7); alpha = 0; opaque = NO; autoresize = LM; userInteractionEnabled = NO; layer = <CALayer: 0x8a89130>> | | | <UIImageView: 0x8ac2be0; frame = (313 316; 7 3); alpha = 0; opaque = NO; autoresize = TM; userInteractionEnabled = NO; layer = <CALayer: 0x8ac2c70>> | | <_UILayoutGuide: 0x8b9cb20; frame = (0 0; 0 20); hidden = YES; layer = <CALayer: 0x8b9e5f0>> | | <_UILayoutGuide: 0x8ac4440; frame = (0 320; 0 0); hidden = YES; layer = <CALayer: 0x8a90370>> 

   檢查UIScrollView的frame （例如上面是iPhone上的橫向），並確保它對應於屏幕的大小。 如果尚未定義滾動視圖與其超級視圖之間的約束，則此frame可能不正確。

Answer 2

也許其他人會為此提供更好的解決方案，但是最快而不會對當前版本進行太多改動就是完全按照你所說的做法： 檢查輪換然后再次設置內容大小 。 它將在您的設置視圖控制器實現文件中以這樣的方式完成：

- (void)didRotateFromInterfaceOrientation:(UIInterfaceOrientation)fromInterfaceOrientation
{
    self.scrollView.contentSize = self.contentView.bounds.size;
}

...假設您已將相同的文件出口添加到UIScrollView並且您的UIView分別名為scrollView和contentView 。