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; }

```

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