iOS：转储视图和约束的层次结构树

Posted 2023-03-08

【中文标题】iOS：转储视图和约束的层次结构树

【英文标题】：iOS: Dumping hierarchy tree of views and constraints

【发布时间】：2016-11-14 11:37:47

【问题描述】：

在 ios 中调试自动布局可能很烦人。我们正在寻找一种方法来转储子视图及其约束，以便进行更好的调试。

有两种有用的方法可以使用调试器获取一些信息：

转储视图树：po [[UIWindow keyWindow] recursiveDescription] 跟踪约束：po [[UIWindow keyWindow] _autolayoutTrace];

*** 中有几个答案，其中包含转储视图的想法但没有相应的约束。有什么有用的方法吗？

【参考方案1】：

以下函数可用于很好地转储视图及其相应的自动布局约束的树：

void dumpViewRecursivelyWithConstraints(UIView *vw, NSString *title)

    if (!vw) 
        vw = [[[[UIApplication sharedApplication] keyWindow] subviews] lastObject];
    
    void (^dumpViewRecursively)(UIView*, NSString*, NSMutableString*); //local var definition
    void (^ __block __weak weakDumpViewRecursively)(UIView*, NSString*, NSMutableString*); //weak copy for recursion
    weakDumpViewRecursively = dumpViewRecursively = ^void(UIView *vw, NSString* gap, NSMutableString *mStr) 
        [mStr appendFormat:@"%@.%@\n", gap, vw];
        for (NSLayoutConstraint *c in vw.constraints) 
            NSString *cStr = [NSString stringWithFormat:@"%@", c];
            NSInteger space = [cStr rangeOfString:@" "].location; //skipping up to space for a neater output
            [mStr appendFormat:@"%@| %@\n", gap, [cStr substringFromIndex:space+1]];
        
        [mStr appendFormat:@"%@`----------------------------\n", gap];
        NSString *nextGap = [gap stringByAppendingString:@"      "];
        NSArray *subs = [vw subviews];
        for (int i=0; i<[subs count]; i++) 
            weakDumpViewRecursively(subs[i], nextGap, mStr); //call myself recursively
        
    ;
    NSMutableString *mStr = [[NSMutableString alloc] init];
    [mStr appendFormat:@"\n\n************** %@: **************\n", title];
    dumpViewRecursively(vw, @"", mStr);
    NSLog(@"%@", mStr);

输出如下：

.<UIView: 0x12c5bcb10; frame = (0 45; 1024 703); autoresize = W+H; gestureRecognizers = <NSArray: 0x12e436c70>; layer = <CALayer: 0x12c5b8580>>
| UIScrollView:0x12d176a00.width == UIView:0x12c5bcb10.width>
| UIScrollView:0x12d176a00.height == UIView:0x12c5bcb10.height>
| UIScrollView:0x12d176a00.centerX == UIView:0x12c5bcb10.centerX>
| UIScrollView:0x12d176a00.centerY == UIView:0x12c5bcb10.centerY>
| PlayerView:0x12c5bda20.width == UIView:0x12c5bcb10.width>
`----------------------------
    .<UIScrollView: 0x12d176a00; frame = (0 0; 1024 703); clipsToBounds = YES; gestureRecognizers = <NSArray: 0x12e18b6e0>; layer = <CALayer: 0x12e054ec0>; contentOffset: 0, 0; contentSize: 1848, 703>
    | V:|-(0)-[UIView:0x12c5d1860]   (Names: '|':UIScrollView:0x12d176a00 )>
    | H:|-(0)-[UIView:0x12c5d1860](LTR)   (Names: '|':UIScrollView:0x12d176a00 )>
    | UIView:0x12c5d1860.height == UIScrollView:0x12d176a00.height>
    `----------------------------
          .<UIView: 0x12c5d1860; frame = (0 0; 1848 703); layer = <CALayer: 0x12c5ad540>>
          | H:[UIView:0x12c5d1860(1848)]>
          | H:|-(0)-[PlayerView:0x12c5bda20](LTR)   (Names: '|':UIView:0x12c5d1860 )>
          | V:|-(0)-[PlayerView:0x12c5bda20]   (Names: '|':UIView:0x12c5d1860 )>
          | PlayerView:0x12c5bda20.height == UIView:0x12c5d1860.height>
          | UIView:0x12e02bf50.top == UIView:0x12c5d1860.centerY - 10>