AJ分享,必須精品java
因爲系統自帶的UITextField:和UITextView:不能知足咱們的需求,因此咱們須要本身設計一個。markdown
UITextField:
1.文字永遠是一行,不能顯示多行文字
2.有placehoder屬性設置佔位文字
3.繼承自UIControl
4.監聽行爲
1> 設置代理
2> addTarget:action:forControlEvents:
3> 通知:UITextFieldTextDidChangeNotificationapp
UITextView:
1.能顯示任意行文字
2.不能設置佔位文字
3.繼承自UIScollView
4.監聽行爲
1> 設置代理
2> 通知:UITextViewTextDidChangeNotificationdom
//
// Created by apple on 14-10-20.
// Copyright (c) 2014年 heima. All rights reserved.
// 加強:帶有佔位文字
#import <UIKit/UIKit.h>
@interface NYTextView : UITextView
/** 佔位文字 */
@property (nonatomic, copy) NSString *placeholder;
/** 佔位文字的顏色 */
@property (nonatomic, strong) UIColor *placeholderColor;
@end
// Created by apple on 14-10-20.
// Copyright (c) 2014年 heima. All rights reserved.
//
#import "NYTextView.h"
@implementation NYTextView
- (id)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self) {
// 不要設置本身的delegate爲本身
// self.delegate = self;
// 通知
// 當UITextView的文字發生改變時,UITextView本身會發出一個UITextViewTextDidChangeNotification通知
[NYNotificationCenter addObserver:self selector:@selector(textDidChange) name:UITextViewTextDidChangeNotification object:self];
}
return self;
}
- (void)dealloc
{
[NYNotificationCenter removeObserver:self];
}
/** * 監聽文字改變 */
- (void)textDidChange
{
// 重繪(從新調用)
[self setNeedsDisplay];
}
- (void)setPlaceholder:(NSString *)placeholder
{
_placeholder = [placeholder copy];
[self setNeedsDisplay];
}
- (void)setPlaceholderColor:(UIColor *)placeholderColor
{
_placeholderColor = placeholderColor;
[self setNeedsDisplay];
}
- (void)setText:(NSString *)text
{
[super setText:text];
// setNeedsDisplay會在下一個消息循環時刻,調用drawRect:
[self setNeedsDisplay];
}
- (void)setFont:(UIFont *)font
{
[super setFont:font];
[self setNeedsDisplay];
}
- (void)drawRect:(CGRect)rect
{
// [NYRandomColor set];
// UIRectFill(CGRectMake(20, 20, 30, 30));
// 若是有輸入文字,就直接返回,不畫佔位文字
if (self.hasText) return;
// 文字屬性
NSMutableDictionary *attrs = [NSMutableDictionary dictionary];
attrs[NSFontAttributeName] = self.font;
attrs[NSForegroundColorAttributeName] = self.placeholderColor?self.placeholderColor:[UIColor grayColor];
// 畫文字
// [self.placeholder drawAtPoint:CGPointMake(5, 8) withAttributes:attrs];
CGFloat x = 5;
CGFloat w = rect.size.width - 2 * x;
CGFloat y = 8;
CGFloat h = rect.size.height - 2 * y;
CGRect placeholderRect = CGRectMake(x, y, w, h);
[self.placeholder drawInRect:placeholderRect withAttributes:attrs];
}
@end