UIView忽略方向或底部到底容器

Question

我想在縱向模式下在屏幕底部顯示UIView，所以當手機旋轉和水平方向將重新定位/調整所有子視圖時，該UIView將保留它在哪裏，具有相同的尺寸和原始位置（即，如果它位於縱向模式的底部，則位於水平方向的右端）。

有沒有很好的方法來做到這一點？

Answer 1

您可以設置自動尺寸面具是這樣的：

myView.autorezisingmask = UIViewAutorezingMaskFlexibleTopMargin; 

這將保持在底部的視圖。

Answer 2

我可以想到幾種方法來做到這一點。一種方式，我在下面展示的僅僅依賴於使用約束。爲了這個工作，3個按鈕不應該在他們自己的透明視圖中，而只是你想要旋轉的視圖的子視圖（在我的例子中是self.view）。我並不認爲這三個按鈕的原始約束很重要，因爲我在旋轉時移除了它們，但是我開始的約束條件是中心按鈕具有centerX約束，固定距離到底部，標準水平距離到左邊，右鍵，並且所有三個按鈕的基線對齊。在viewDidLoad中，我遍歷所有self.view的約束，並確定與這些按鈕有關的所有內容，並將它們放入數組中，以便我可以刪除它們並在稍後添加它們。

@interface ViewController() 
@property (strong,nonatomic) NSMutableArray *portraitConstraints; 
@property (strong,nonatomic) NSMutableArray *landscapeConstraints; 
@end 

@implementation ViewController 

- (void)viewDidLoad { 
    [super viewDidLoad]; 
    self.portraitConstraints = [NSMutableArray array]; 
    self.landscapeConstraints = [NSMutableArray array]; 
    for (NSLayoutConstraint *con in self.view.constraints) { 
     if (con.firstItem == self.leftButton || con.secondItem == self.leftButton || con.firstItem == self.centerButton || con.secondItem == self.centerButton || con.firstItem == self.rightButton || con.secondItem == self.rightButton) { 
      [self.portraitConstraints addObject:con]; 
     } 
    } 
} 

- (void)willAnimateRotationToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation duration:(NSTimeInterval)duration { 

    switch (interfaceOrientation) { 
     case UIInterfaceOrientationLandscapeRight:{ 
      [self.view removeConstraints:self.portraitConstraints]; 
      [self.view removeConstraints:self.landscapeConstraints]; 
      [self.landscapeConstraints removeAllObjects]; 
      NSLayoutConstraint *centerYCon = [NSLayoutConstraint constraintWithItem:self.centerButton attribute:NSLayoutAttributeCenterY relatedBy:0 toItem:self.view attribute:NSLayoutAttributeCenterY multiplier:1 constant:0]; 
      NSLayoutConstraint *rightCon = [NSLayoutConstraint constraintWithItem:self.centerButton attribute:NSLayoutAttributeRight relatedBy:0 toItem:self.view attribute:NSLayoutAttributeRight multiplier:1 constant:-8]; 
      NSArray *stackCons= [NSLayoutConstraint constraintsWithVisualFormat:@"V:[left]-[center]-[right]" options:NSLayoutFormatAlignAllLeading metrics:nil views:@{@"left":self.leftButton, @"center":self.centerButton, @"right":self.rightButton}]; 
      [self.landscapeConstraints addObject:centerYCon]; 
      [self.landscapeConstraints addObject:rightCon]; 
      [self.landscapeConstraints addObjectsFromArray:stackCons]; 
      [self.view addConstraints:self.landscapeConstraints]; 
      break; 
     } 
     case UIInterfaceOrientationLandscapeLeft:{ 
      [self.view removeConstraints:self.portraitConstraints]; 
      [self.view removeConstraints:self.landscapeConstraints]; 
      [self.landscapeConstraints removeAllObjects]; 
      NSLayoutConstraint *centerYCon2 = [NSLayoutConstraint constraintWithItem:self.centerButton attribute:NSLayoutAttributeCenterY relatedBy:0 toItem:self.view attribute:NSLayoutAttributeCenterY multiplier:1 constant:0]; 
      NSLayoutConstraint *leftCon = [NSLayoutConstraint constraintWithItem:self.centerButton attribute:NSLayoutAttributeLeft relatedBy:0 toItem:self.view attribute:NSLayoutAttributeLeft multiplier:1 constant:8]; 
      NSArray *stackCons2= [NSLayoutConstraint constraintsWithVisualFormat:@"V:[left]-[center]-[right]" options:NSLayoutFormatAlignAllLeading metrics:nil views:@{@"left":self.leftButton, @"center":self.centerButton, @"right":self.rightButton}]; 
      [self.landscapeConstraints addObject:centerYCon2]; 
      [self.landscapeConstraints addObject:leftCon]; 
      [self.landscapeConstraints addObjectsFromArray:stackCons2]; 
      [self.view addConstraints:self.landscapeConstraints]; 
      break; 
     } 
     case UIInterfaceOrientationPortrait:{ 
      [self.view removeConstraints:self.landscapeConstraints]; 
      [self.view addConstraints:self.portraitConstraints]; 
      break; 
     } 
     default: 
      break; 
    } 
}