如何禁用單個UI元素的自動布局（UIlabel）

Question

我需要在使用自動布局的Viewcontroller中更改標簽的位置。 在做之前，我曾經

[arriveTimeLabel setTranslatesAutoresizingMaskIntoConstraints:YES];
[departTimeLabel setTranslatesAutoresizingMaskIntoConstraints:YES];

但這會產生一些運行時警告

 Break on objc_exception_throw to catch this in the debugger.
The methods in the UIConstraintBasedLayoutDebugging category on UIView listed in <UIKit/UIView.h> may also be helpful.
2013-08-15 23:25:58.791 Vicinitime[78327:c07] Unable to simultaneously satisfy constraints.
    Probably at least one of the constraints in the following list is one you don't want. Try this: (1) look at each constraint and try to figure out which you don't expect; (2) find the code that added the unwanted constraint or constraints and fix it. (Note: If you're seeing NSAutoresizingMaskLayoutConstraints that you don't understand, refer to the documentation for the UIView property translatesAutoresizingMaskIntoConstraints) 
(
    "<NSLayoutConstraint:0x9173a20 UIScrollView:0x9580190.bottom == UIView:0x9173890.bottom>",
    "<NSLayoutConstraint:0x9171fe0 V:|-(138)-[UILabel:0x958cf70]   (Names: '|':UIScrollView:0x9580190 )>",
    "<NSLayoutConstraint:0x91739a0 V:|-(0)-[UIScrollView:0x9580190]   (Names: '|':UIView:0x9173890 )>",
    "<NSAutoresizingMaskLayoutConstraint:0xab6ec90 h=--& v=&-& UILabel:0x958cf70.midY == -6.3989*UIScrollView:0x9580190.height>",
    "<NSAutoresizingMaskLayoutConstraint:0xab6eef0 h=--& v=&-& V:[UILabel:0x958cf70(25)]>",
    "<NSAutoresizingMaskLayoutConstraint:0xab6dbd0 h=--& v=--& V:[UIView:0x9173890(455)]>"
)

Will attempt to recover by breaking constraint 
<NSLayoutConstraint:0x9171fe0 V:|-(138)-[UILabel:0x958cf70]   (Names: '|':UIScrollView:0x9580190 )>

因此，我環顧四周，發現要解決該問題，我必須設置[arriveTimeLabel setTranslatesAutoresizingMaskIntoConstraints：NO]; [departTimeLabel setTranslatesAutoresizingMaskIntoConstraints：NO];

到沒有 問題在於，現在標簽無法以編程方式更改位置。

如果您需要編碼以編程方式設置標簽：

    if(travelTimeInt <= activityTimeInt){

        [timeBreakdownButtonImage setBackgroundImage:[UIImage imageNamed:@"timeBreakdownBackground7.png"] forState:UIControlStateNormal];
        NSLog(@"got to setting label place");

        [self.arriveTimeLabel  setFrame:CGRectMake(67, 170, 41, 25)];

        [self.departTimeLabel  setFrame:CGRectMake(211, 170, 41, 25)];



    }
    if(travelTimeInt * 7 >= activityTimeInt){

            [timeBreakdownButtonImage setBackgroundImage:[UIImage imageNamed:@"timeBreakdownBackground6.png"] forState:UIControlStateNormal];

          NSLog(@"got to setting label place");

            self.arriveTimeLabel.frame = CGRectMake(71, 170, 41, 25);

       self.departTimeLabel.frame = CGRectMake(207, 170, 41, 25);

    }

那么有沒有辦法在自動布局打開的情況下更改uilabel的位置？ 也許禁用自動布局？

Answer 1

如果您使用自動布局，然后你UIViews是根據其定位NSLayoutConstraints 。

要移動它們，而不是設置它們的frames您需要更改約束。

Answer 2

可以按照以下說明禁用子視圖的自動布局 ： 我可以在運行時為特定子視圖禁用自動布局嗎？

另一種選擇是創建兩個情節提要，一個啟用自動布局，另一個禁用自動布局。 然后通過檢查“設備系統版本”來加載相應的故事板（假設您的目標也是iOS版本早於6）。 為此，將此宏添加到您的AppDelegate中：

#define SYSTEM_VERSION_GREATER_THAN_OR_EQUAL_TO(v) ([[[UIDevice currentDevice] systemVersion] compare:(v) options:NSNumericSearch] != NSOrderedAscending)

接着：

UIStoryboard *mainStoryboard = nil;

if (SYSTEM_VERSION_GREATER_THAN_OR_EQUAL_TO(@"6.0")) 
{
     mainStoryboard = [UIStoryboard storyboardWithName:@"AutoLayoutStoryboard" bundle:nil];
} 
else 
{
     mainStoryboard = [UIStoryboard storyboardWithName:@"NoAutoLayoutStoryboard" bundle:nil];
}

//load initial view controller
UIViewController *rootView = [mainStoryboard instantiateInitialViewController];
self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
self.window.rootViewController = rootView;
[self.window makeKeyAndVisible];

Answer 3

我正在使用自動布局啟動的項目，但是我需要動態調整代碼中的某些框架。 這是我不受自動生成的運行時約束（由自動布局提供）的影響：

1）不要在界面生成器中布置視圖或組件。

2）純粹以編程方式添加您的視圖，從alloc / init開始並適當地設置其框架。

3）完成。

希望有幫助！

PS。 您還可以嘗試使用以下方法從視圖中剝離約束：

[view removeConstraints：view.constraints]但是我對純代碼方法有更多的運氣。