UITextField leftView rightView

昨天在和同事聊天中发现自己一直也没怎么使用过 UITextField的leftView 属性，一直就是知道它，但就是没用过它，特此笔记下。

leftView rightView

直接使用的时候：

UIImageView *leftView = [[UIImageView alloc] init];
leftView.backgroundColor = [UIColor orangeColor];
textField.leftView =leftView;
textField.leftViewMode = UITextFieldViewModeAlways;

由于直接使用 leftView 属性,leftView会紧紧贴在输入框的边缘，所以需要写一个继承 TextField的，来改变那个边距设置的。

@implementation YSTextField

// 后来发现没必要这样写啦，直接用会更好
//- (instancetype)initWithFrame:(CGRect)frame iconLeftView:(UIView *)leftView iconRightView:(UIView *)rightView
//{
//    self = [super initWithFrame:frame];
//    if (self) {
//        if (leftView) {
//            self.leftView = leftView;
//            self.leftViewMode = UITextFieldViewModeAlways;
//        }
//        if (rightView) {
//            self.rightView = rightView;
//            self.rightViewMode = UITextFieldViewModeAlways;
//        }
//    }
//    return self;
//}

- (CGRect)leftViewRectForBounds:(CGRect)bounds {
    CGRect leftRect = [super leftViewRectForBounds:bounds];
    leftRect.origin.x += 10; //右边偏10
    return leftRect;
}

- (CGRect)rightViewRectForBounds:(CGRect)bounds {
    CGRect rightRect = [super rightViewRectForBounds:bounds];
    rightRect.origin.x -= 10; //左边偏10
    return rightRect;
}

@end

然后直接使用就 OK 了

UIImageView *leftView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, 20, 20)];
leftView.backgroundColor = [UIColor redColor];

// YSTextField *textField = [[YSTextField alloc] initWithFrame:CGRectZero
//                                              iconLeftView:leftView
//                                              iconRightView:nil];

// 这样写，可以更好的匹配 Masonry,同时符合原生
YSTextField *textField = [[YSTextField alloc] init];
textField.leftView = leftView;
textField.leftViewMode = UITextFieldViewModeAlways;

textField.placeholder = @"testTextField";
textField.borderStyle = UITextBorderStyleRoundedRect;
[self.view addSubview:textField];
[textField mas_makeConstraints:^(MASConstraintMaker *make) {
    make.top.equalTo(@100);
    make.leading.equalTo(@30);
    make.trailing.equalTo(@(-30));
    make.height.equalTo(@40);
}];

ps: UITextFieldViewMode

typedef NS_ENUM(NSInteger, UITextFieldViewMode) {
     UITextFieldViewModeNever,         //默认显示没有
     UITextFieldViewModeWhileEditing,  //输入时显示
     UITextFieldViewModeUnlessEditing, //不输入时显示
     UITextFieldViewModeAlways         //一直显示有
};

但是注意在使用 rightView 的时候，clearButton的会被覆盖带掉的哦。
另外编辑的时候，如果发现 placeholder 距离边界有问题的话可加上textRect这块的重写。

//UITextField 文字与输入框的距离
- (CGRect)textRectForBounds:(CGRect)bounds{
    if (self.leftView) {
        return CGRectInset(bounds, 40, 0);
    }
    return CGRectInset(bounds, 10, 0);
    
}
//控制编辑文本的位置
- (CGRect)editingRectForBounds:(CGRect)bounds{
    if (self.leftView) {
        return CGRectInset(bounds, 40, 0);
    }
    return CGRectInset(bounds, 10, 0);
}

备注

http://www.jianshu.com/p/f93b005dc9d4