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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
用户反馈
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