我们如何在ios中使用自动布局来减少代码?

Question

嗨，我是自动布局的初学者，我正在scrollview上插入"3"文本字段和"1"按钮

这里我的要求是根据iphone英寸"顶部空间"必须调整，当我点击文本框所有字段必须在键盘上方滚动，当我点击键盘中的"返回"按钮时，滚动必须像以前一样滚动

对于这个，我已经尝试了下面的代码，但这是太长的代码，谁能解释我这个概念使用短过程

我的代码:

#import "ViewController10.h"
@interface ViewController10 ()
{
    UIScrollView * scrollView;
    UITextField * emailTextField;
    UITextField * nameTextField;
    UITextField * passwword;
    UIButton * submit;
    NSDictionary * viewsDic;
    NSArray * verticalConstraints;
    int height;
}
@end
@implementation ViewController10
- (void)viewDidLoad {
    [super viewDidLoad];
    height = [UIScreen mainScreen].bounds.size.height;
    scrollView = [[UIScrollView alloc] init];
    scrollView.translatesAutoresizingMaskIntoConstraints = NO;
    [self.view addSubview:scrollView];
    emailTextField = [self createLabelWithText];
    emailTextField.delegate = self;
    [scrollView addSubview: emailTextField];
    nameTextField = [self createLabelWithText];
    nameTextField.delegate = self;
    [scrollView addSubview: nameTextField];
    passwword = [self createLabelWithText];
    passwword.delegate = self;
    [scrollView addSubview: passwword];
    submit = [[UIButton alloc]init];
    submit.backgroundColor = [UIColor orangeColor];
    [submit setTitle: @"Submit" forState: UIControlStateNormal];
    submit.translatesAutoresizingMaskIntoConstraints = NO;
    [scrollView addSubview:submit];
    viewsDic = NSDictionaryOfVariableBindings(scrollView,emailTextField,nameTextField,passwword,submit);
    //Applying autolayouts for scrolview
    [self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:[NSString stringWithFormat:@"H:|-0-[scrollView]-0-|"]
                                                                      options:0
                                                                      metrics:nil
                                                                        views:viewsDic]];
    [self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:[NSString stringWithFormat:@"V:|-0-[scrollView]-0-|"]
                                                                      options:0
                                                                      metrics:nil
                                                                        views:viewsDic]];

    //Applying autolayouts for textfields and button
    [scrollView addConstraint:[NSLayoutConstraint constraintWithItem:emailTextField
                                                           attribute:NSLayoutAttributeCenterX
                                                           relatedBy:NSLayoutRelationEqual
                                                              toItem:scrollView
                                                           attribute:NSLayoutAttributeCenterX
                                                          multiplier:1
                                                            constant:0]];
    NSArray * keys = @[@"emailTextField",@"nameTextField",@"passwword",@"submit"];
    for (NSString * key in keys) {
        [self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:[NSString stringWithFormat:@"H:|-10-[%@]-10-|",key]
                                                                          options:0
                                                                          metrics:nil
                                                                            views:viewsDic]];
    }
    if (height == 480.0) {
    verticalConstraints = [NSLayoutConstraint constraintsWithVisualFormat:@"V:|-30-[emailTextField(30)]-130-[nameTextField(30)]-130-[passwword(30)]-60-[submit(30)]-20-|"
                                                                      options:0
                                                                      metrics:nil
                                                                        views:viewsDic];
    }
    else if (height == 568.0){
       verticalConstraints = [NSLayoutConstraint constraintsWithVisualFormat:@"V:|-50-[emailTextField(30)]-130-[nameTextField(30)]-130-[passwword(30)]-60-[submit(30)]-20-|"
                                                                      options:0
                                                                      metrics:nil
                                                                        views:viewsDic];
    }
    else if(height == 667.0){
      verticalConstraints = [NSLayoutConstraint constraintsWithVisualFormat:@"V:|-80-[emailTextField(30)]-130-[nameTextField(30)]-130-[passwword(30)]-60-[submit(30)]-20-|"
                                                                      options:0
                                                                      metrics:nil
                                                                        views:viewsDic];
    }
    [scrollView addConstraints:verticalConstraints];
}
-(UITextField *)createLabelWithText{
    UITextField * textfield = [[UITextField alloc] init];
    textfield.textColor = [UIColor whiteColor];
    textfield.backgroundColor = [UIColor lightGrayColor];
    textfield.translatesAutoresizingMaskIntoConstraints = NO;
    return textfield;
}
- (void)textFieldDidBeginEditing:(UITextField *)textField{
    scrollView.contentSize = CGSizeMake(320, 700);
}
- (BOOL)textFieldShouldReturn:(UITextField *)textField{
    [textField resignFirstResponder];
    [scrollView removeConstraints:verticalConstraints];
    if (height == 480.0) {
        verticalConstraints = [NSLayoutConstraint constraintsWithVisualFormat:@"V:|-30-[emailTextField(30)]-130-[nameTextField(30)]-130-[passwword(30)]-60-[submit(30)]-20-|"
                                                                      options:0
                                                                      metrics:nil
                                                                        views:viewsDic];
    }
    else if (height == 568.0){
        verticalConstraints = [NSLayoutConstraint constraintsWithVisualFormat:@"V:|-50-[emailTextField(30)]-130-[nameTextField(30)]-130-[passwword(30)]-60-[submit(30)]-20-|"
                                                                      options:0
                                                                      metrics:nil
                                                                        views:viewsDic];
    }
    else if(height == 667.0){
        verticalConstraints = [NSLayoutConstraint constraintsWithVisualFormat:@"V:|-80-[emailTextField(30)]-130-[nameTextField(30)]-130-[passwword(30)]-60-[submit(30)]-20-|"
                                                                      options:0
                                                                      metrics:nil
                                                                        views:viewsDic];
    }
    [scrollView addConstraints:verticalConstraints];
    return YES;
}
@end

Answer 1

尝试砌筑，它可以减少代码，更容易维护和理解https://github.com/SnapKit/Masonry