在程序開(kāi)發(fā)中，設(shè)計(jì)人員給我們的圖片可能是像下圖一樣的。顏色是使用十六進(jìn)制表示的

69E286D3-11E1-4833-AAB8-9BB095C6F7F3.png

此時(shí)，我們需要將顏色轉(zhuǎn)換成我們需要的RGB值，這就需要使用像下面的這段代碼

調(diào)用方法

- (void)viewDidLoad {
    [super viewDidLoad];

    for (int i = 0; i < 5; i++) {
        UIView * view1 = [[UIView alloc] init];
        view1.frame = CGRectMake(100, 100*i + 100, 80, 80);
    switch (i) {
            /*
             case 0、case1、case4:調(diào)用方法3 ，方法3可處理以“#和0X開(kāi)頭的16進(jìn)制字符串”
             case1：調(diào)用方法1，其alpha是固定的，只處理十六進(jìn)制數(shù)"0X"開(kāi)頭
             case2：方法2，顏色的alpha可以改變
             */
        case 0:
            view1.backgroundColor = [UIColor colorWithHexString:@"#e5e589"];
            break;
        case 1:
            view1.backgroundColor = [UIColor colorWithHexString:@"0Xe5e589"];
            break;
        case 2:
            view1.backgroundColor = [UIColor colorWithHex:0Xe5e589];
            break;
        case 3:
            view1.backgroundColor = [UIColor colorWithHex:0Xe5e589 alpha:0.5];
            break;
        case 4:
            view1.backgroundColor = [UIColor colorWithHexString:@"#784679"];
            break;
            
        default:
            break;
    }
    
    [self.view addSubview:view1];
  }
}

封裝成一個(gè)工具類(lèi)，使用Category添加UIColor的類(lèi)目

// 顏色轉(zhuǎn)換：iOS中十六進(jìn)制的顏色轉(zhuǎn)換為UIColor(RGB)
#import <UIKit/UIKit.h>

@interface UIColor (Hex)
// 透明度固定為1，以0x開(kāi)頭的十六進(jìn)制轉(zhuǎn)換成的顏色
+ (UIColor *)colorWithHex:(long)hexColor;
// 0x開(kāi)頭的十六進(jìn)制轉(zhuǎn)換成的顏色,透明度可調(diào)整
+ (UIColor *)colorWithHex:(long)hexColor alpha:(float)opacity;
// 顏色轉(zhuǎn)換三：iOS中十六進(jìn)制的顏色（以#開(kāi)頭）轉(zhuǎn)換為UIColor
+ (UIColor *) colorWithHexString: (NSString *)color;

@end
#import "UIColor+Hex.h"

@implementation UIColor (Hex)
// 透明度固定為1，以0x開(kāi)頭的十六進(jìn)制轉(zhuǎn)換成的顏色
+ (UIColor*) colorWithHex:(long)hexColor;
{
    return [UIColor colorWithHex:hexColor alpha:1.];
}
// 0x開(kāi)頭的十六進(jìn)制轉(zhuǎn)換成的顏色,透明度可調(diào)整
+ (UIColor *)colorWithHex:(long)hexColor alpha:(float)opacity
{
    float red = ((float)((hexColor & 0xFF0000) >> 16))/255.0;
    float green = ((float)((hexColor & 0xFF00) >> 8))/255.0;
    float blue = ((float)(hexColor & 0xFF))/255.0;
    return [UIColor colorWithRed:red green:green blue:blue alpha:opacity];
}
// 顏色轉(zhuǎn)換三：iOS中十六進(jìn)制的顏色（以#開(kāi)頭）轉(zhuǎn)換為UIColor
+ (UIColor *) colorWithHexString: (NSString *)color
{
    NSString *cString = [[color stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]] uppercaseString];

    // String should be 6 or 8 characters
    if ([cString length] < 6) {
        return [UIColor clearColor];
    }

    // 判斷前綴并剪切掉
    if ([cString hasPrefix:@"0X"])
        cString = [cString substringFromIndex:2];
    if ([cString hasPrefix:@"#"])
        cString = [cString substringFromIndex:1];
    if ([cString length] != 6)
        return [UIColor clearColor];

    // 從六位數(shù)值中找到RGB對(duì)應(yīng)的位數(shù)并轉(zhuǎn)換
    NSRange range;
    range.location = 0;
    range.length = 2;

    //R、G、B
    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];
}
@end