用户反馈

用户反馈, 输入用户反馈信息的时候, 会有如下图所示的需求:

输入框可以多行输入, 并且包含占位文字, UITextField可以有占位符 但不支持多行输入, 所以不能使用UITextField. UITextView可以多行输入, 只需要添加上占位文字功能即可.

声明文件如下:.h文件

 1 #import <UIKit/UIKit.h>
 2
 3 @interface PlaceholderTextView : UITextView
 4
 5 @property (nonatomic, strong) UILabel * placeHolderLabel;
 6
 7 @property (nonatomic, copy) NSString * placeholder;
 8
 9 @property (nonatomic, strong) UIColor * placeholderColor;
10
11 - (void)textChanged:(NSNotification * )notification;
12
13 @end

实现文件如下:.m文件

 1 #import "PlaceholderTextView.h"
 2
 3 @implementation PlaceholderTextView
 4
 5 -(instancetype)initWithFrame:(CGRect)frame{
 6
 7     if (self = [super initWithFrame:frame]) {
 8
 9         [self setPlaceholder:@""];
10
11         [self setPlaceholderColor:[UIColor lightGrayColor]];
12
13         [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(textChanged:) name:UITextViewTextDidChangeNotification object:nil];
14
15     }
16
17     return self;
18 }
19
20 -(void)setPlaceholder:(NSString *)placeholder{
21
22     if (_placeholder != placeholder) {
23
24         _placeholder = placeholder;
25
26         [self.placeHolderLabel removeFromSuperview];
27
28         self.placeHolderLabel = nil;
29
30         [self setNeedsDisplay];
31
32
33     }
34
35 }
36
37 - (void)textChanged:(NSNotification *)notification{
38
39     if ([[self placeholder] length] == 0) {
40         return;
41     }
42
43     if ([[self text] length] == 0) {
44         [[self viewWithTag:999] setAlpha:1.0];
45     }
46
47     else{
48
49         [[self viewWithTag:999] setAlpha:0];
50     }
51
52 }
53
54 -(void)drawRect:(CGRect)rect{
55
56     [super drawRect:rect];
57
58     if ([[self placeholder] length] > 0) {
59         if (_placeHolderLabel == nil) {
60             _placeHolderLabel = [[UILabel alloc]initWithFrame:CGRectMake(8, 8, self.bounds.size.width - 16, 0)];
61             _placeHolderLabel.lineBreakMode = NSLineBreakByWordWrapping;
62             _placeHolderLabel.numberOfLines = 0;
63             _placeHolderLabel.font = self.font;
64             _placeHolderLabel.backgroundColor = [UIColor clearColor];
65             _placeHolderLabel.textColor = self.placeholderColor;
66             _placeHolderLabel.alpha = 0;
67             _placeHolderLabel.tag = 999;
68             [self addSubview:_placeHolderLabel];
69         }
70         _placeHolderLabel.text = self.placeholder;
71         [_placeHolderLabel sizeToFit];
72         [self sendSubviewToBack:_placeHolderLabel];
73     }
74
75     if ([[self text] length] == 0 && [[self placeholder] length] >0) {
76         [[self viewWithTag:999] setAlpha:1.0];
77     }
78
79 }
80
81
82
83 @end