//透明度的的设定
    self.textfield.alpha = 1;
    
    //设定是否隐藏
    self.textfield.hidden = NO;
    
    //背景的设置
    self.textfield.backgroundColor = [UIColor clearColor];
    
    //设置文本信息
    self.textfield.text = @"123";
    
    //设置文本的字体的颜色
    self.textfield.textColor = [UIColor purpleColor];
    
    //设置文本对其方式
    self.textfield.textAlignment = NSTextAlignmentLeft;
    
    //设置文本边框的样式
    self.textfield.borderStyle = UITextBorderStyleRoundedRect;
    
    //设置提示输入信息
    self.textfield.placeholder = @"请输入。。。。。";
    
    //设置再次成为第一响应者的时候是否清空当前内容
    self.textfield.clearsOnBeginEditing = YES;
    
    //设置右侧的clear Button 什么时候显示
    self.textfield.clearButtonMode = UITextFieldViewModeAlways;
    
    
    UIView *vi = [self create_A_View];
    //设置左视图
    self.textfield.leftView = vi;
    
    //设置return 键上显示的文字
    self.textfield.returnKeyType = UIReturnKeyDone;
    
    //设置弹出键盘的样式
    self.textfield.keyboardType = UIKeyboardTypeNumberPad;
    
    //设置输入的文本是否加密
    self.textfield.secureTextEntry = NO;
    
    //设置边框的颜色
    self.textfield.layer.borderColor = [UIColor redColor].CGColor;
    
    //设置 是否提示大小写
    self.textfield.autocapitalizationType = UITextAutocorrectionTypeNo;
    
    //设置字体的大小
    self.textfield.font = [UIFont systemFontOfSize:14];

代理方法
#pragma mark - 是否可以开始编辑
-(BOOL)textFieldShouldBeginEditing:(UITextField *)textField
{
    return YES;
}
#pragma mark - textFieldDidBeginEditing
-(void)textFieldDidBeginEditing:(UITextField *)textField
{
    NSLog(@"textFieldDidBeginEditing");
}
#pragma mark - 是否可以点击键盘的ruturn按钮
-(BOOL)textFieldShouldReturn:(UITextField *)textField
{
    return YES;
}
#pragma mark -  是否可以结束编辑
-(BOOL)textFieldShouldEndEditing:(UITextField *)textField
{
    return YES;
}
#pragma mark - 点击右侧的清楚按钮是否有效
-(BOOL)textFieldShouldClear:(UITextField *)textField
{
    return YES;
}
-(BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
    if (textField.text.length > 10 && string.length > 0)
    {
        return NO;
    }
    return YES;
}

target - action 文本框中内容发生改变的时候触发
[_textfield addTarget:self action:@selector(edtingChanged:) forControlEvents:UIControlEventEditingChanged];
-(void)edtingChanged:(UITextField *)sender
{
    NSLog(@"*****  %@  *****",sender.text);
}