ios 如何为背景设置十六进制颜色代码
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how to set hex color code for background
提问by SuperString
Possible Duplicate:
How can I create a UIColor from a hex string?
可能的重复：
如何从十六进制字符串创建 UIColor？
I want to programmatically set the color of the UIView Background.
我想以编程方式设置 UIView 背景的颜色。
It doesn't seem like I can do it through Interfacebuilder. How should I do it if I want to set it to some hex code color?
似乎我不能通过 Interfacebuilder 做到这一点。如果我想将它设置为某种十六进制代码颜色，我该怎么做？
回答by WrightsCS
I like to use this little piece of code to use HTML web colors in my apps.
我喜欢使用这段代码在我的应用程序中使用 HTML 网页颜色。
Usage:
用法：
[self.view setBackgroundColor: [self colorWithHexString:@"FFFFFF"]]; /* white */
The Code:
编码：
-(UIColor*)colorWithHexString:(NSString*)hex
{
NSString *cString = [[hex stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]] uppercaseString];
// String should be 6 or 8 characters
if ([cString length] < 6) return [UIColor grayColor];
// strip 0X if it appears
if ([cString hasPrefix:@"0X"]) cString = [cString substringFromIndex:2];
if ([cString length] != 6) return [UIColor grayColor];
// Separate into r, g, b substrings
NSRange range;
range.location = 0;
range.length = 2;
NSString *rString = [cString substringWithRange:range];
range.location = 2;
NSString *gString = [cString substringWithRange:range];
range.location = 4;
NSString *bString = [cString substringWithRange:range];
// Scan values
unsigned int r, g, b;
[[NSScanner scannerWithString:rString] scanHexInt:&r];
[[NSScanner scannerWithString:gString] scanHexInt:&g];
[[NSScanner scannerWithString:bString] scanHexInt:&b];
return [UIColor colorWithRed:((float) r / 255.0f)
green:((float) g / 255.0f)
blue:((float) b / 255.0f)
alpha:1.0f];
}
回答by Tomasz Rybakiewicz
Here's simple category on UIColor that helps you create color from 8bit int value
and from hex value ("#a2ffc0").
这是 UIColor 上的简单类别，可帮助您从 8 位
整数值和十六进制值（“#a2ffc0”）创建颜色。
UIColor+CreateMethods.h
UIColor+CreateMethods.h
//
// UIColor+CreateMethods.h
//
// Created by Tomasz Rybakiewicz on 1/13/12.
//
#import <UIKit/UIKit.h>
@interface UIColor (CreateMethods)
// wrapper for [UIColor colorWithRed:green:blue:alpha:]
// values must be in range 0 - 255
+ (UIColor*)colorWith8BitRed:(NSInteger)red green:(NSInteger)green blue:(NSInteger)blue alpha:(CGFloat)alpha;
// Creates color using hex representation
// hex - must be in format: #FF00CC
// alpha - must be in range 0.0 - 1.0
+ (UIColor*)colorWithHex:(NSString*)hex alpha:(CGFloat)alpha;
@end
UIColor+CreateMethods.m
UIColor+CreateMethods.m
//
// UIColor+CreateMethods.m
//
// Created by Tomasz Rybakiewicz on 1/13/12.
//
#import "UIColor+CreateMethods.h"
@implementation UIColor (CreateMethods)
+ (UIColor*)colorWith8BitRed:(NSInteger)red green:(NSInteger)green blue:(NSInteger)blue alpha:(CGFloat)alpha {
return [UIColor colorWithRed:(red/255.0) green:(green/255.0) blue:(blue/255.0) alpha:alpha];
}
+ (UIColor*)colorWithHex:(NSString*)hex alpha:(CGFloat)alpha {
assert(7 == [hex length]);
assert('#' == [hex characterAtIndex:0]);
NSString *redHex = [NSString stringWithFormat:@"0x%@", [hex substringWithRange:NSMakeRange(1, 2)]];
NSString *greenHex = [NSString stringWithFormat:@"0x%@", [hex substringWithRange:NSMakeRange(3, 2)]];
NSString *blueHex = [NSString stringWithFormat:@"0x%@", [hex substringWithRange:NSMakeRange(5, 2)]];
unsigned redInt = 0;
NSScanner *rScanner = [NSScanner scannerWithString:redHex];
[rScanner scanHexInt:&redInt];
unsigned greenInt = 0;
NSScanner *gScanner = [NSScanner scannerWithString:greenHex];
[gScanner scanHexInt:&greenInt];
unsigned blueInt = 0;
NSScanner *bScanner = [NSScanner scannerWithString:blueHex];
[bScanner scanHexInt:&blueInt];
return [UIColor colorWith8BitRed:redInt green:greenInt blue:blueInt alpha:alpha];
}
@end
Enjoy.
享受。
回答by Dan F
UIView's setBackgroundColormethod. You can create a UIColor from hex with UIColor initWithRed:green:blue:alphait takes floats so you'll need to do bitshifts and math to get the appropriate components. This is how I manage it
UIView 的setBackgroundColor方法。您可以使用 UIColor 从十六进制创建 UIColorinitWithRed:green:blue:alpha它需要浮点数，因此您需要进行位移和数学运算才能获得适当的组件。这就是我管理它的方式
