Masonry 实现输入框随键盘位置改变

Github: https://github.com/saitjr/MasonryDemo

直接上代码:

#import "ViewController4.h"

#import "Masonry.h"

@interface ViewController4 ()

@property (strong, nonatomic) UITextField *textField;

@end

@implementation ViewController4

- (void)dealloc {

    [[NSNotificationCenter defaultCenter] removeObserver:self];

}

- (void)viewDidLoad {

    [super viewDidLoad];

    // Do any additional setup after loading the view.

    _textField = [UITextField new];

    _textField.backgroundColor = [UIColor redColor];

    [self.view addSubview:_textField];

    [_textField mas_makeConstraints:^(MASConstraintMaker *make) {

        make.left.mas_equalTo(10);

        make.centerX.equalTo(self.view);

        make.bottom.mas_equalTo(0);

        make.height.mas_equalTo(40);

    }];

    // 注册键盘通知

    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillChangeFrameNotification:) name:UIKeyboardWillChangeFrameNotification object:nil];

    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillHideNotification:) name:UIKeyboardWillHideNotification object:nil];

}

- (void)keyboardWillChangeFrameNotification:(NSNotification *)notification {

    // 获取键盘基本信息（动画时长与键盘高度）

    NSDictionary *userInfo = [notification userInfo];

    CGRect rect = [userInfo[UIKeyboardFrameEndUserInfoKey] CGRectValue];

    CGFloat keyboardHeight = CGRectGetHeight(rect);

    CGFloat keyboardDuration = [userInfo[UIKeyboardAnimationDurationUserInfoKey] doubleValue];

    // 修改下边距约束

    [_textField mas_updateConstraints:^(MASConstraintMaker *make) {

        make.bottom.mas_equalTo(-keyboardHeight);

    }];

    // 更新约束

    [UIView animateWithDuration:keyboardDuration animations:^{

        [self.view layoutIfNeeded];

    }];

}

- (void)keyboardWillHideNotification:(NSNotification *)notification {

    // 获得键盘动画时长

    NSDictionary *userInfo = [notification userInfo];

    CGFloat keyboardDuration = [userInfo[UIKeyboardAnimationDurationUserInfoKey] doubleValue];

    // 修改为以前的约束（距下边距0）

    [_textField mas_updateConstraints:^(MASConstraintMaker *make) {

        make.bottom.mas_equalTo(0);

    }];

    // 更新约束

    [UIView animateWithDuration:keyboardDuration animations:^{

        [self.view layoutIfNeeded];

    }];

}

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {

    [super touchesBegan:touches withEvent:event];

    [self.view endEditing:YES];

}

@end