[真传弟子]JS-赵立鼐|2019年10月20日的日报-技能树.IT修真院

发表于： 2019-10-20 12:46:58

1 739

今日完成：

自动布局AutoLayout

基于约束：和以往的frame设置绝对位置和尺寸不同，AutoLayout位置的确定是以所谓相对位置的约束来定义的。比如X坐标是super view的中心，y坐标为屏幕底部上方10像素等。

这样就解决了不同分辨率和屏幕尺寸下view适配的问题。

下面写了一个关于自动布局的小demo：

//
//  ViewController.m
//  autoLayout_demo
//
//  Created by ptteng on 2019/10/20.
//  Copyright © 2019 ptteng. All rights reserved.
//
#import "ViewController.h"
@interface ViewController ()
@end
@implementation ViewController
- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view.
    
    //创建视图控件，并添加到self.view上
    UIView *view_1 = [[UIView alloc]init];
    view_1.backgroundColor = [UIColor redColor];
    [self.view addSubview:view_1];
    
    UIView *view_2 = [[UIView alloc]init];
    view_2.backgroundColor=[UIColor greenColor];
    [self.view addSubview:view_2];
    
    UIView *view_3 = [[UIView alloc]init];
    view_3.backgroundColor = [UIColor blackColor];
    [self.view addSubview:view_3];
    
    //关掉autoresizingMask
    view_1.translatesAutoresizingMaskIntoConstraints = NO;
    view_2.translatesAutoresizingMaskIntoConstraints = NO;
    view_3.translatesAutoresizingMaskIntoConstraints = NO;
    
    //添加约束
    //view_1.top与superview.top的约束
    NSLayoutConstraint *view_1TopToSuperViewTop = [NSLayoutConstraint
        constraintWithItem:view_1
        attribute:NSLayoutAttributeTop
        relatedBy:NSLayoutRelationEqual
        toItem:self.view
        attribute:NSLayoutAttributeTop
        multiplier:1 constant:30];
    //view_1.left与superview.left的约束
    NSLayoutConstraint *view_1LeftToSuperViewLeft = [NSLayoutConstraint
        constraintWithItem:view_1
        attribute:NSLayoutAttributeLeft
        relatedBy:NSLayoutRelationEqual
        toItem:self.view
        attribute:NSLayoutAttributeLeft
        multiplier:1 constant:30];
  
    //view_1.right与view_2.left的约束
    NSLayoutConstraint *view_1RightToview_2Left = [NSLayoutConstraint
        constraintWithItem:view_2
        attribute:NSLayoutAttributeLeft
        relatedBy:NSLayoutRelationEqual
        toItem:view_1
        attribute:NSLayoutAttributeRight
        multiplier:1 constant:30];
    //view_1.bottom与view_3.top的约束
    NSLayoutConstraint *view_1BottomToview_3Top = [NSLayoutConstraint
        constraintWithItem:view_1
        attribute:NSLayoutAttributeBottom
        relatedBy:NSLayoutRelationEqual
        toItem:view_3
        attribute:NSLayoutAttributeTop
        multiplier:1 constant:-30];
    //view_2.right与superview.right的约束
    NSLayoutConstraint *view_2RightToSuperviewRight = [NSLayoutConstraint
        constraintWithItem:view_2
        attribute:NSLayoutAttributeRight
        relatedBy:NSLayoutRelationEqual
        toItem:self.view
        attribute:NSLayoutAttributeRight
        multiplier:1 constant:-30];
    
    //view_1.centerY与view_2.centerY的约束
    NSLayoutConstraint *view_1CenterYToView_2CenterY = [NSLayoutConstraint
        constraintWithItem:view_1
        attribute:NSLayoutAttributeCenterY
        relatedBy:NSLayoutRelationEqual
        toItem:view_2
        attribute:NSLayoutAttributeCenterY
        multiplier:1 constant:0];
    
    //view_3.left与superview.left的约束
    NSLayoutConstraint *view_3LeftToSuperviewLeft = [NSLayoutConstraint
        constraintWithItem:view_3
        attribute:NSLayoutAttributeLeft
        relatedBy:NSLayoutRelationEqual
        toItem:self.view
        attribute:NSLayoutAttributeLeft
        multiplier:1 constant:30];
    
    //view_3.right与superview.right的约束
    NSLayoutConstraint *view_3RightToSuperviewRight = [NSLayoutConstraint
        constraintWithItem:view_3
        attribute:NSLayoutAttributeRight
        relatedBy:NSLayoutRelationEqual
        toItem:self.view
        attribute:NSLayoutAttributeRight
        multiplier:1 constant:-30];
    
    //view_3.bottom与superview.bottom的约束
    NSLayoutConstraint *view_3BottomToSuperviewBottom = [NSLayoutConstraint
        constraintWithItem:view_3
        attribute:NSLayoutAttributeBottom
        relatedBy:NSLayoutRelationEqual
        toItem:self.view
        attribute:NSLayoutAttributeBottom
        multiplier:1 constant:-30];
    //view_1.width与view_2.width的约束
    NSLayoutConstraint *view_1WidthToView_2Width = [NSLayoutConstraint
        constraintWithItem:view_1
        attribute:NSLayoutAttributeWidth
        relatedBy:NSLayoutRelationEqual
        toItem:view_2
        attribute:NSLayoutAttributeWidth
        multiplier:1 constant:0];
   
    //view_1.height与view_2.height的约束
    NSLayoutConstraint *view_1HeightToView_2Height = [NSLayoutConstraint
        constraintWithItem:view_1
        attribute:NSLayoutAttributeHeight
        relatedBy:NSLayoutRelationEqual
        toItem:view_2
        attribute:NSLayoutAttributeHeight
        multiplier:1 constant:0];
    //view_1.height与view_3.height的约束
    NSLayoutConstraint *view_1HeightToView_3Height = [NSLayoutConstraint
        constraintWithItem:view_1
        attribute:NSLayoutAttributeHeight
        relatedBy:NSLayoutRelationEqual
        toItem:view_3
        attribute:NSLayoutAttributeHeight
        multiplier:1 constant:0];
    
    
    
    [self.view addConstraints:@[view_1TopToSuperViewTop,view_1LeftToSuperViewLeft,view_1RightToview_2Left,view_1BottomToview_3Top,
        view_2RightToSuperviewRight,view_1CenterYToView_2CenterY,view_3LeftToSuperviewLeft,view_3RightToSuperviewRight,
         view_3BottomToSuperviewBottom,view_1WidthToView_2Width,view_1HeightToView_2Height,view_1HeightToView_3Height]];
  
    [self.view layoutIfNeeded];
    
}
@end

横屏：

昨天的登录页面UI布局横竖屏的对比：

在昨天代码中加入AutoLayout自动布局（去掉控件中关于farme的设置）：

// 自动布局
    //phoneField.top与superview.top的约束
    NSLayoutConstraint *phoneFieldTopTOSuperviewTop = [NSLayoutConstraint constraintWithItem:phoneField attribute:NSLayoutAttributeTop relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeTop multiplier:1 constant:100];
    
    //phoneField.left与superview.left的约束
    NSLayoutConstraint *phoneFieldLeftTOSuperviewLeft = [NSLayoutConstraint constraintWithItem:phoneField attribute:NSLayoutAttributeLeft relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeLeft multiplier:1 constant:30];
    
    //phoneField.right与superview.right的约束
    NSLayoutConstraint *phoneFieldRightTOSuperviewRight = [NSLayoutConstraint constraintWithItem:phoneField attribute:NSLayoutAttributeRight relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeRight multiplier:1 constant:-30];
    
    //passwdField.top与phoneField.bottom的约束
    NSLayoutConstraint *passwdFieldTopTOPhoneFieldBottom = [NSLayoutConstraint constraintWithItem:passwdField attribute:NSLayoutAttributeTop relatedBy:NSLayoutRelationEqual toItem:phoneField attribute:NSLayoutAttributeBottom multiplier:1 constant:30];
    
    //passwdField.left与superView.left的约束
    NSLayoutConstraint *passwdFieldLeftTOSuperViewLeft = [NSLayoutConstraint constraintWithItem:passwdField attribute:NSLayoutAttributeLeft relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeLeft multiplier:1 constant:30];
    
    //passwdField.right与superView.left的约束
    NSLayoutConstraint *passwdFieldRightTOSuperViewRight = [NSLayoutConstraint constraintWithItem:passwdField attribute:NSLayoutAttributeRight relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeRight multiplier:1 constant:-30];
    
    //loginBtn.top与passwdField.bottom的约束
    NSLayoutConstraint *loginBtnTopToPasswdFieldBottom = [NSLayoutConstraint constraintWithItem:loginBtn attribute:NSLayoutAttributeTop relatedBy:NSLayoutRelationEqual toItem:passwdField attribute:NSLayoutAttributeBottom multiplier:1 constant:30];
    
    //loginBtn.left与superView.left的约束
    NSLayoutConstraint *loginBtnLeftTOSuperViewLeft = [NSLayoutConstraint constraintWithItem:loginBtn attribute:NSLayoutAttributeLeft relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeLeft multiplier:1 constant:30];
       
    //loginBtn.right与superView.left的约束
    NSLayoutConstraint *loginBtnRightTOSuperViewRight = [NSLayoutConstraint constraintWithItem:loginBtn attribute:NSLayoutAttributeRight relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeRight multiplier:1 constant:-30];
    
    //forgetButton.bottom与superView.bottom的约束
    NSLayoutConstraint *forgetButtonBottomToSuperViewBottom = [NSLayoutConstraint constraintWithItem:forgetButton attribute:NSLayoutAttributeBottom relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeBottom multiplier:1 constant:-30];
    
    //forgetButton.left与superView.left的约束
    NSLayoutConstraint *forgetButtonLeftToSuperViewLeft = [NSLayoutConstraint constraintWithItem:forgetButton attribute:NSLayoutAttributeLeft relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeLeft multiplier:1 constant:30];
    
    //rigisterButton.right与superView.right的约束
    NSLayoutConstraint *rigisterButtonRightToSuperViewRight = [NSLayoutConstraint constraintWithItem:rigisterButton attribute:NSLayoutAttributeRight relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeRight multiplier:1 constant:-30];
   
    //rigisterButton.bottom与superView.bottom的约束
    NSLayoutConstraint *rigisterButtonBottomToSuperViewBottom = [NSLayoutConstraint constraintWithItem:rigisterButton attribute:NSLayoutAttributeBottom relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeBottom multiplier:1 constant:-30];
      
    
    [self.view addConstraints:@[phoneFieldTopTOSuperviewTop,phoneFieldLeftTOSuperviewLeft,phoneFieldRightTOSuperviewRight,passwdFieldTopTOPhoneFieldBottom,passwdFieldLeftTOSuperViewLeft,passwdFieldRightTOSuperViewRight,forgetButtonBottomToSuperViewBottom,forgetButtonLeftToSuperViewLeft,rigisterButtonRightToSuperViewRight,rigisterButtonBottomToSuperViewBottom,loginBtnTopToPasswdFieldBottom,loginBtnLeftTOSuperViewLeft,loginBtnRightTOSuperViewRight]];
    
    [self.view layoutIfNeeded]; 