#pragma mark - 创建UITextField对象
//开辟空间并初始化
UITextField *textField = [[UITextField alloc]initWithFrame:CGRectMake(100, 100, 200, 30)];
//设置颜色，使其可见
textField.backgroundColor = [UIColor redColor];
//添加到父视图上，以显示
[self.view addSubview:textField];
#pragma mark - UITextField核心功能主要有三个
//①文本显示
//②输入控制
//③外观配置
#pragma mark - 文本显示
//1、要显示的文本内容
textField.text = @"加油！加油!";
//2、文本的颜色
textField.textColor = [UIColor cyanColor];
//3、文本的对齐方式
textField.textAlignment = NSTextAlignmentCenter;
//4、文本的字体设置
textField.font = [UIFont systemFontOfSize:18];
//5、占位字符串
textField.placeholder = @"请输入正确的标语";
#pragma mark - 输入控制
//1、是否允许输入
//textField.enabled = NO;
//2、开始输入时是否清空
textField.clearsOnBeginEditing = YES;
//3、输入文本是否是密码模式
textField.secureTextEntry = YES;
//4、弹出键盘的类型
textField.keyboardType = UIKeyboardTypeNumberPad;
//5、键盘右下角return按钮类型(枚举值)
textField.returnKeyType = UIReturnKeyNext;
//6、自定义输入视图（默认是键盘）
UIView *userView = [[UIView alloc]initWithFrame:CGRectMake(100, 100, 100, 100)];
userView.backgroundColor = [UIColor redColor];
textField.inputView = userView;
//7、输入视图的辅助视图
UIView *accessoryView = [[UIView alloc]initWithFrame:CGRectMake(0, 0, self.view.frame.size.width, 50)];
accessoryView.backgroundColor = [UIColor yellowColor];
textField.inputAccessoryView = accessoryView;
#pragma mark - 外观控制
//1、边框样式(枚举值)
textField.borderStyle = UITextBorderStyleBezel;
//2、清除按钮模式（枚举值）
textField.clearButtonMode = UITextFieldViewModeAlways;
//3、输入框左视图(右视图)
UIView *leftView = [[UIView alloc]initWithFrame:CGRectMake(0, 0, 25, 25)];
leftView.backgroundColor = [UIColor blackColor];
UIView *rightView = [[UIView alloc]initWithFrame:CGRectMake(0, 0, 25, 25)];
rightView.backgroundColor = [UIColor blackColor];
textField.leftView = leftView;
textField.rightView = rightView;
//4、左视图的显示模式(右视图的显示模式)
textField.leftViewMode = UITextFieldViewModeAlways;
textField.rightViewMode = UITextFieldViewModeAlways;
