ScrollView初步认识

最新推荐文章于 2025-05-17 14:46:11 发布

原创最新推荐文章于 2025-05-17 14:46:11 发布 · 366 阅读

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本文介绍如何使用UIScrollView调整视图以适应键盘弹出的情况，并通过监听键盘通知实现TextField不会被键盘遮挡的效果。主要内容包括设置contentSize，监听键盘显示与隐藏的通知，以及调整scrollView的frame。

ScrollView初步认识

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    //一般通过代码设置
    self.scrollView.contentSize = CGSizeMake(self.view.frame.size.width, 900);
    self.textField.delegate = self;
}

- (void)viewDidAppear:(BOOL)animated{
    [self.scrollView setContentOffset:CGPointMake(0, 110) animated:YES];

    //注册键盘广播
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardDidShow:) name:UIKeyboardDidShowNotification object:nil];
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardDidHide:) name:UIKeyboardDidHideNotification object:nil];
    [super viewDidAppear:animated];
}

- (void)viewDidDisappear:(BOOL)animated{
    [[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardDidShowNotification object:nil];
    [[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardDidHideNotification object:nil];
    [super viewDidDisappear:animated];
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

#pragma mark 放弃第一响应者
- (BOOL)textFieldShouldReturn:(UITextField *)textField{
    [textField resignFirstResponder];
    return YES;
}

#pragma mark 键盘显示
- (void)keyboardDidShow:(NSNotification *)notif{
    if (keyboardVisible) {
        return;
    }
    //获得见键盘的尺寸
    NSDictionary *info = [notif userInfo];
    NSValue *aValue = [info objectForKey:UIKeyboardFrameEndUserInfoKey];
    CGSize keyboardSize = [aValue CGRectValue].size;

    //重新定义ScorllView的尺寸
    CGRect viewFrame = self.scrollView.frame;
    viewFrame.size.height -= (keyboardSize.height);
    self.scrollView.frame = viewFrame;

    //滚动到当前文本框
    CGRect textFieldRect = [self.textField frame];
    [self.scrollView scrollRectToVisible:textFieldRect animated:YES];
    keyboardVisible = YES;
}
#pragma mark 键盘隐藏
- (void)keyboardDidHide:(NSNotification *)notif{
    NSDictionary *info = [notif userInfo];
    NSValue *aValue = [info objectForKey:UIKeyboardFrameEndUserInfoKey];
    CGSize keyboardSize = [aValue CGRectValue].size;

    CGRect viewFrame = self.scrollView.frame;
    viewFrame.size.height += keyboardSize.height;
    self.scrollView.frame = viewFrame;

    if (!keyboardVisible) {
        return;
    }
    keyboardVisible = NO;
}

//contentSize   内容的大小
//contentInset  给周围留的边框
//contentOffSet 偏移量