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

```objc

//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

```objc

• (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。

```objc

• (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

```objc

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

```

UITextField－－为内容增加校验

```objc

• (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; }

```