尋找子視圖ChangeChange委託方法

Question

我正在尋找某種委託方法，將子視圖添加到視圖時會觸發。我需要這個，因爲iOS7地圖上的指南針視圖在開始旋轉時添加到mapview中（它以前不存在且未隱藏）。但是，當我嘗試操作regionWillChangeAnimated中的指南針視圖時，它不會觸發，直到用戶放開地圖。

基本上我需要沿線的任何東西： subviewWasAdded,subviewsDidChange，或類似的東西。

編輯：經過Daij-Djan的建議，我做了MPOMapView.m和MPOMapView。

#import "MPOMapView.h" 

@implementation MPOMapView 

- (id)initWithFrame:(CGRect)frame 
{ 
    self = [super initWithFrame:frame]; 
    if (self) { 
     // Initialization code 
    } 
    return self; 
} 

- (void)addSubview:(UIView *)view { 
    [super addSubview:view]; 

    [self moveCompass:&view]; 
} 


- (void)moveCompass:(UIView **)view { 

    if([[[UIDevice currentDevice] systemVersion] floatValue] < 7) { 
     return; 
    } 

    if(![*view isKindOfClass:NSClassFromString(@"MKCompassView")]) { 
     return; 
    } 

    //Gets here 
    NSLog(@"Was the compass"); 

    float width = (*view).frame.size.width; 
    float height = (*view).frame.size.height; 

    (*view).frame = CGRectMake(40, self.frame.size.height - 50, width, height); 

    //Frame doesn't change 
    NSLog(@"Frame should change"); 
} 

@end 

該方法被調用，但框架不會改變。我也試過：

- (void)addSubview:(UIView *)view { 
    [super addSubview:view]; 

    [self moveCompass:view]; 
} 


- (void)moveCompass:(UIView *)view { 

    if([[[UIDevice currentDevice] systemVersion] floatValue] < 7) { 
     return; 
    } 

    if(![view isKindOfClass:NSClassFromString(@"MKCompassView")]) { 
     return; 
    } 

    //Gets here 
    NSLog(@"Was the compass"); 

    float width = view.frame.size.width; 
    float height = view.frame.size.height; 

    view.frame = CGRectMake(40, self.frame.size.height - 50, width, height); 

    //Frame doesn't change 
    NSLog(@"Frame should change"); 
} 

但是這也行不通。最後一點....

- (void)addSubview:(UIView *)view { 
    [super addSubview:[self movedCompass:view]]; 
} 


- (UIView *)movedCompass:(UIView *)view { 

    if([[[UIDevice currentDevice] systemVersion] floatValue] < 7) { 
     return view; 
    } 

    if(![view isKindOfClass:NSClassFromString(@"MKCompassView")]) { 
     return view; 
    } 

    //Gets here 
    NSLog(@"Was the compass"); 

    float width = view.frame.size.width; 
    float height = view.frame.size.height; 

    view.frame = CGRectMake(40, self.frame.size.height - 50, width, height); 

    //Frame doesn't change 
    NSLog(@"Frame should change"); 

    return view; 
} 

無法正常工作或

Answer 1

沒有這樣的代表。

但

所有你能做的就是子類的MKMapView和實施insertSubview和addSubview，並建立自己的解決方案。

但

看到更好的辦法

- (void)layoutSubviews { 
    [super layoutSubviews]; 

       if([[[UIDevice currentDevice] systemVersion] floatValue] < 7) { 
        return; 
       } 

    for(id view in self.subviews) { 
       if(![view isKindOfClass:NSClassFromString(@"MKCompassView")]) { 
        continue; 
       } 

       [self moveCompass:view]]; 
    } 
} 

- (void)moveCompass:(UIView *)view { 
    //Gets here 
    NSLog(@"Was the compass"); 

    float width = view.frame.size.width; 
    float height = view.frame.size.height; 

    //view.frame = CGRectMake(40, self.frame.size.height - 50, width, height); 
    view.frame = CGRectMake(40, self.bounds.size.height - 50, width, height); 

} 

Answer 2

我不知道這是否會工作，買你可以嘗試使用密鑰值與MapView類的camera，其中有一個heading特性觀察。

Answer 3

Daij-Djan發佈了正確答案，相信他！

這只是我的感覺的改善是太多代碼：

- (void)layoutSubviews 
{ 
    [super layoutSubviews]; 

    for(id view in self.subviews) 
    { 
     if([view isKindOfClass:NSClassFromString(@"MKCompassView")]) 
      [self moveCompass:view]]; 
    } 
} 

- (void)moveCompass:(UIView *)view 
{ 
    //change compass frame as shown by Daij-Djan 
}