iOS开发之UITextField

UITextField基本知识

UITextField展示的是一些可编辑的内容，并且与用户有一些交互。比如当你在虚拟键盘上按下return键时，一般会关联到键盘隐藏事件上。UITextField的一些状态大多在UITextFieldDelegate协议中有相应的方法。

UITextField的初始化及一些属性

	//姓名输入域
	UITextField *nameField = [[UITextField alloc] initWithFrame:CGRectMake(30, 30, 200, 44)];
	nameField.tag = 100;
    nameField.delegate = self;
    //默认文字
    nameField.placeholder = @"name";
    nameField.font = [UIFont systemFontOfSize:16.0f];
    nameField.textColor = [UIColor blackColor];
    //输入框的背景图片(还可以选择设置背景颜色)
    nameField.background = [UIImage imageNamed:@"textFieldBackgroundImage"];
    //nameField.backgroundColor = [UIColor lightGrayColor];
    //清除按钮
    nameField.clearButtonMode = UITextFieldViewModeAlways;
    //键盘类型
    nameField.keyboardType = UIKeyboardTypeDefault;
    [self.view addSubview:nameField];
    电话输入域
    UITextField *phoneField = [[UITextField alloc] initWithFrame:CGRectMake(30, nameField.frame.origin.y + nameField.bounds.size.height+10, 200, 44)];
    phoneField.tag = 101;
    phoneField.delegate = self;
    phoneField.placeholder = @"phone";
    phoneField.keyboardType = UIKeyboardTypeDecimalPad;
    phoneField.clearButtonMode = UITextFieldViewModeAlways;
    [self.view addSubview:phoneField];
    //邮箱输入域
    UITextField *emailField = [[UITextField alloc] initWithFrame:CGRectMake(30, phoneField.frame.origin.y + phoneField.bounds.size.height + 10, 200, 44)];
    emailField.tag = 102;
    emailField.delegate = self;
    emailField.placeholder = @"email";
    emailField.keyboardType = UIKeyboardTypeEmailAddress;
    emailField.clearButtonMode = UITextFieldViewModeAlways;
    [self.view addSubview:emailField];	
	

UITextField隐藏键盘

1.点击键盘的return来隐藏键盘

这个方法需要在相应的.h文件文件中实现UITextFieldDelegate协议。并在.m文件中添加如下方法

- (BOOL)textFieldShouldReturn:(UITextField *)textField
{
    [textField resignFirstResponder];
    return YES;
}

2.点击界面空白处来隐藏键盘

这个方法的实现主要是给当前的view增加点击事件，并未点击事件增加相应的处理方法，此处是为了隐藏键盘，所以我们可以在点击事件对应的方法中让UITextField放弃第一响应者。

- (void)dismissKeyboard
{
    NSArray *subViews = [self.view subviews];
    for (id inputText in subViews) {
        if ([inputText isKindOfClass:[UITextField class]]) {
            if ([inputText isFirstResponder]) {
                [inputText resignFirstResponder];
            }
        }
    }
}

为当前的view增加点击事件

UITapGestureRecognizer *dismissKeyboardTap = [[UITapGestureRecognizer alloc] 												initWithTarget:self 												action:@selector(dismissKeyboard)];
[self.view addGestureRecognizer: dismissKeyboardTap];

UITextField－－为内容增加校验

- (BOOL)textFieldShouldEndEditing:(UITextField *)textField
{
    switch (textField.tag) {
        case 100://name
        {
            NSLog(@"this is nameField");
            //添加校验name的代码
            break;
        }
        case 101://phone
        {
            NSLog(@"this is phoneField");
            //添加校验phone的代码
            break;
        }
        case 102://email
        {
            NSLog(@"this is emailField");
            //添加校验email的代码
            break;
        }        
        default:
            break;
    }
    return YES;
}