IOS 自定义 UIDatePicker 背景图片

来源：互联网发布：头发毛躁知乎编辑：程序博客网时间：2024/06/08 10:10

IOS 中默认的 UIDatePicker subViews 为只有一个UIView ，可以这样获得

UIView *v1 = [[datePicker subviews] objectAtIndex:0];

在这个UIView的subViews中有21层（3行时），27层（4行时）：

 (    "<UIView: 0x5d65350; frame = (0 0; 312 180); autoresize = W+H; userInteractionEnabled = NO; layer = <CALayer: 0x5d65380>>",    "<_UIOnePartImageView: 0x5d65ce0; frame = (20 50; 1 48); opaque = NO; autoresize = TM; userInteractionEnabled = NO; layer = <CALayer: 0x5d65d90>>",    "<_UIPickerWheelView: 0x5d67790; frame = (21 0; 142 180); autoresize = W+TM+H; userInteractionEnabled = NO; layer = <CALayer: 0x5d67840>>",    "<_UIPickerViewSelectionBar: 0x5d67b70; frame = (21 86; 150 44); userInteractionEnabled = NO; layer = <CALayer: 0x5d67c20>>",    "<UIPickerTable: 0x5d68160; frame = (21 0; 138 180); clipsToBounds = YES; opaque = NO; autoresize = W+TM+H; layer = <CALayer: 0x5d677d0>>",    "<_UIOnePartImageView: 0x5d68640; frame = (21 0; 142 180); opaque = NO; autoresize = W+TM+H; userInteractionEnabled = NO; layer = <CALayer: 0x5d60de0>>",    "<_UIOnePartImageView: 0x5d67bd0; frame = (21 65; 142 47); opaque = NO; autoresize = W+TM+H; userInteractionEnabled = NO; layer = <CALayer: 0x5d68340>>",    "<_UIOnePartImageView: 0x5d68470; frame = (171 50; 2 48); opaque = NO; autoresize = TM; userInteractionEnabled = NO; layer = <CALayer: 0x5d684a0>>",    "<_UIPickerWheelView: 0x5d684d0; frame = (173 0; 40 180); autoresize = W+TM+H; userInteractionEnabled = NO; layer = <CALayer: 0x5d68500>>",    "<_UIPickerViewSelectionBar: 0x5d68530; frame = (173 86; 48 44); userInteractionEnabled = NO; layer = <CALayer: 0x5d68560>>",    "<UIPickerTable: 0x5d68940; frame = (173 0; 36 180); clipsToBounds = YES; opaque = NO; autoresize = W+TM+H; layer = <CALayer: 0x5d68590>>",    "<_UIOnePartImageView: 0x5d68b70; frame = (173 0; 40 180); opaque = NO; autoresize = W+TM+H; userInteractionEnabled = NO; layer = <CALayer: 0x5d68c40>>",    "<_UIOnePartImageView: 0x5d68d10; frame = (173 65; 40 47); opaque = NO; autoresize = W+TM+H; userInteractionEnabled = NO; layer = <CALayer: 0x5d68d40>>",    "<_UIOnePartImageView: 0x5d68d70; frame = (221 50; 2 48); opaque = NO; autoresize = TM; userInteractionEnabled = NO; layer = <CALayer: 0x5d68da0>>",    "<_UIPickerWheelView: 0x5d68dd0; frame = (223 0; 68 180); autoresize = W+TM+H; userInteractionEnabled = NO; layer = <CALayer: 0x5d68e60>>",    "<_UIPickerViewSelectionBar: 0x5d68e90; frame = (223 86; 76 44); userInteractionEnabled = NO; layer = <CALayer: 0x5d68ec0>>",    "<UIPickerTable: 0x5d68ef0; frame = (223 0; 64 180); clipsToBounds = YES; opaque = NO; autoresize = W+TM+H; layer = <CALayer: 0x5d690d0>>",    "<_UIOnePartImageView: 0x5d69130; frame = (223 0; 68 180); opaque = NO; autoresize = W+TM+H; userInteractionEnabled = NO; layer = <CALayer: 0x5d69230>>",    "<_UIOnePartImageView: 0x5d69290; frame = (223 65; 68 47); opaque = NO; autoresize = W+TM+H; userInteractionEnabled = NO; layer = <CALayer: 0x5d692c0>>",    "<_UIOnePartImageView: 0x5d69340; frame = (299 50; 1 48); opaque = NO; autoresize = TM; userInteractionEnabled = NO; layer = <CALayer: 0x5d69370>>",    "<_UIPickerViewTopFrame: 0x5d5ef60; frame = (0 0; 312 180); opaque = NO; autoresize = W+H; layer = <CALayer: 0x5d48a00>>")

最低层为一个 UIView，我们可以通过下列语句获得，并且可以改变背景色

UIView *v3 = [[v1 subviews] objectAtIndex:0 ];v3.backgroundColor = [UIColor redColor];

之后为一个UIOnePartImageView 对象，在UIKit的头文件中定义如下，通过这个更改背景色失败，不知为何？继续探索中。。。

/* *     Generated by class-dump 3.1.1. * *     class-dump is Copyright (C) 1997-1998, 2000-2001, 2004-2006 by Steve Nygard. */#import <UIKit/UIView.h>@class UIImage;@interface UIOnePartImageView : UIView{    struct CGRect _fromRect;    UIImage *_image;}- (void)dealloc;// IMP=0x32412104- (void)drawRect:(struct CGRect)fp8;// IMP=0x324121a0- (void)setFromRect:(struct CGRect)fp8;// IMP=0x32412184- (void)setImage:(id)fp8;// IMP=0x3241215c@end

之后从第3层到第20层为 18层，分为 3个部分，包含 3 列，但是这不分不可更改见属性 userInteractionEnabled = NO；

最后第21层为系统自带的那个黑色边框，可以通过下面的代码获得，并设置为透明

UIView *v2 = [[v1 subviews] objectAtIndex:20];v2.alpha = 0.0;

最后，也是最重要的，自定义图片样式，创建一个UIImageView，如下面这样添加在最上面的22层，就可以啦

UIImageView *img = [[UIImageView alloc] initWithFrame:CGRectMake(-4, -34, 320, 218)];    img.image = [UIImage imageNamed:@"bg.png"];    img.alpha = 1.0;    [v1 addSubview:img];

记住，如果你的图片为透明的话一定要把第21层的黑色方框设置为透明啊