UI_UITextFile(单行文本输入框)

- (void)viewDidLoad {
    [super viewDidLoad];


    UITextField *firstTextField = [[UITextField alloc] initWithFrame:CGRectMake(0, 20, 320, 44)];
   
<span style="font-size:24px;color:#FF0000;">//UITextField的属性们</span>

<span style="font-size:18px;">//UITextField中的属性 定义边框/提示文字/左右视图/自定义键盘等</span>
    firstTextField.borderStyle   = UITextBorderStyleNone;//输入框的边界样式,
    firstTextField.placeholder   = @"邮箱/账号";//提示文字

    UIView *leftView             = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 30, 30)];//左视图
    leftView.backgroundColor     = [UIColor redColor];
    firstTextField.leftView      = leftView;
    firstTextField.leftViewMode  = UITextFieldViewModeAlways;

    UIView *rightView            = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 30, 30)];//右视图
    rightView.backgroundColor    = [UIColor greenColor];
    firstTextField.rightView     = rightView;
    firstTextField.rightViewMode = UITextFieldViewModeAlways;

    UIView *customKeyBoard       = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 320, 210)];//自定义键盘
    firstTextField.inputView     = customKeyBoard;
    
<span style="font-size:18px;">//UITextInputTraits 中的属性</span>

    firstTextField.autocorrectionType     = UITextAutocorrectionTypeYes;//自动联想补正英语单词

    firstTextField.autocapitalizationType = UITextAutocapitalizationTypeAllCharacters;//自动大写第一个字母

    firstTextField.clearButtonMode        = UITextFieldViewModeAlways;//显示一键清空输入框

    firstTextField.secureTextEntry        = YES;//输入框 显示输入为 密文

    firstTextField.keyboardType           = UIKeyboardTypeDefault;//键盘类型 可为纯数字/Url/英文等

    firstTextField.returnKeyType          = UIReturnKeyDefault;//键盘右下角的returnkey的类型 ,搜索/Google/下一页 等

<span style="font-size:18px;">//Textfile的代理</span>
    firstTextField.delegate = self;
    
<span style="font-size:18px;">//通过对TextFile添加Target 实现对输入框长度限制</span>
    [firstTextField addTarget:self action:@selector(textFieldDidChange:) forControlEvents:UIControlEventValueChanged];
}

<pre name="code" class="objc">//限制输入框长度20
-(void)textFieldDidChange:(UITextField*)textFiled
{
    if (textFiled ==self.firstPsw)
    {
        if (textFiled.text.length >20)
        {
            textFiled.text = [textFiled.text substringToIndex:20];
        }
    }
}

#pragma mark UITextField Delegate

//当textfield被点击,键盘弹出的时候，就会调用下面这个代理方法-(void)textFieldDidBeginEditing:(UITextField *)textField{}

//当键盘右下角的return键被点击的时候，会调用这个方法，这个代理方法只有iphone能用，ipad没有

-(BOOL)textFieldShouldReturn:(UITextField *)textField

{

//收起键盘的两种方法:

[textField resignFirstResponder];      //移除这个textfield的第一响应

[self.view endEditing:YES];     //当前View结束编辑 return YES;

}