IOS8下利用自动布局实现键盘的弹出效果

ゝ一世哀愁。 2023-10-16 20:49 108阅读 0赞

-(void)keyboardChange:(NSNotification*)notice
    {
        NSValue *value = [[notice userInfo] objectForKey:@"UIKeyboardFrameEndUserInfoKey"];
        float keyEnd_y = [value CGRectValue].origin.y;
        float animationDuration = [[notice userInfo][@"UIKeyboardAnimationDurationUserInfoKey"] floatValue];
        
        CGRect frame = [[UIScreen mainScreen]bounds];//屏幕尺寸
        int SCREEN_WIDTH = frame.size.width;
        int SCREEN_HEIGHT = frame.size.height;
        
        if(!shouldResignFirstResponder){
            UIView *alphaCoverView = [[[UIApplication sharedApplication].delegate window] viewWithTag:10001];
            if (!alphaCoverView) {
                alphaCoverView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, SCREEN_WIDTH, keyEnd_y - 40)];
                [alphaCoverView setBackgroundColor:[UIColor blackColor]];
                alphaCoverView.alpha = 0.0;
                alphaCoverView.tag = 10001;
                UITapGestureRecognizer *tapToResignirstResponder = [[UITapGestureRecognizer alloc]initWithTarget:self action:@selector(textFielfWillResignFirstResponder)];
                [alphaCoverView addGestureRecognizer:tapToResignirstResponder];
                [[[UIApplication sharedApplication].delegate window] addSubview:alphaCoverView];
            }
            [UIView animateWithDuration:animationDuration animations:^{
                alphaCoverView.alpha = 0.4;
                alphaCoverView.frame = CGRectMake(0, 0, SCREEN_WIDTH, keyEnd_y - 40);//40是编辑框视图的高
            }];
        }
        float constant = 0.0;
        if (shouldResignFirstResponder) {
            //收回键盘时，将约束的值复原
            constant = SCREEN_HEIGHT - keyEnd_y;
            [UIView animateWithDuration:animationDuration animations:^{
                _m_spaceToBottom.constant = constant;
                [self.view layoutIfNeeded];
            }];
            shouldResignFirstResponder = NO;
        }else{
            constant = SCREEN_HEIGHT - keyEnd_y-46;//46是编辑框距离屏幕底部的距离
            [UIView animateWithDuration:animationDuration animations:^{
                _m_spaceToBottom.constant = constant;
                [self.view layoutIfNeeded];
            }];
        }
    }
    - (void)textFielfWillResignFirstResponder{
        UIView *view = [[[UIApplication sharedApplication].delegate window] viewWithTag:10001];
        [view removeFromSuperview];
        shouldResignFirstResponder = YES;
        [self.view endEditing:YES];
    }

//键盘变化监听
        [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardChange:) name:@"UIKeyboardWillChangeFrameNotification" object:nil];

借鉴文章：

http://blog.csdn.net/u013016828/article/details/42102411