这里只介绍一种，这种方便扩展，可以占位文字颜色.
我们继承一个UITextView:
#import <UIKit/UIKit.h> @interface MyTextView : UITextView /** 占位文字 */
@property (nonatomic, copy) NSString *placeholder;
/** 占位文字颜色 */
@property (nonatomic, strong) UIColor *placeholderColor; @end
#import "MyTextView.h" @implementation MyTextView - (instancetype)initWithFrame:(CGRect)frame
{
if (self = [super initWithFrame:frame]) {
// 设置默认字体
self.font = [UIFont systemFontOfSize:]; // 设置默认颜色
self.placeholderColor = [UIColor grayColor]; // 使用通知监听文字改变
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(textDidChange:) name:UITextViewTextDidChangeNotification object:self];
}
return self;
} - (void)textDidChange:(NSNotification *)note
{
// 会重新调用drawRect:方法
[self setNeedsDisplay];
} - (void)dealloc
{
[[NSNotificationCenter defaultCenter] removeObserver:self];
} /**
* 每次调用drawRect:方法，都会将以前画的东西清除掉
*/
- (void)drawRect:(CGRect)rect
{
// 如果有文字，就直接返回，不需要画占位文字
if (self.hasText) return; // 属性
NSMutableDictionary *attrs = [NSMutableDictionary dictionary];
attrs[NSFontAttributeName] = self.font;
attrs[NSForegroundColorAttributeName] = self.placeholderColor; // 画文字
rect.origin.x = ;
rect.origin.y = ;
rect.size.width -= * rect.origin.x;
[self.placeholder drawInRect:rect withAttributes:attrs];
} - (void)layoutSubviews
{
[super layoutSubviews]; [self setNeedsDisplay];
} #pragma mark - setter
- (void)setPlaceholder:(NSString *)placeholder
{
_placeholder = [placeholder copy]; [self setNeedsDisplay];
} - (void)setPlaceholderColor:(UIColor *)placeholderColor
{
_placeholderColor = placeholderColor; [self setNeedsDisplay];
} - (void)setFont:(UIFont *)font
{
[super setFont:font]; [self setNeedsDisplay];
} - (void)setText:(NSString *)text
{
[super setText:text]; [self setNeedsDisplay];
} - (void)setAttributedText:(NSAttributedString *)attributedText
{
[super setAttributedText:attributedText]; [self setNeedsDisplay];
}
调用:
MyTextView *my = [[MyTextView alloc] initWithFrame:CGRectMake(, , [UIScreen mainScreen].bounds.size.width-, )];
my.placeholder = @"请输入文字";
//不设置颜色，默认是灰色.
my.placeholderColor = [UIColor orangeColor];
//添加边框
my.layer.borderColor = [UIColor grayColor].CGColor; my.layer.borderWidth =1.0; my.layer.cornerRadius =5.0; [self.view addSubview:my];