ios - 过滤表情(包括新增的表情)

在有些特殊的业务中，要禁止表情输入，如果你搜一下大部分会得到这样的参考代码，但是这只是过滤掉大部分的表情，还有部分系统新增的表情无法过滤到的。

//表情符号的判断
- (BOOL)stringContainsEmoji:(NSString *)string {
    __block BOOL returnValue = NO;
    [string enumerateSubstringsInRange:NSMakeRange(0, [string length])
                               options:NSStringEnumerationByComposedCharacterSequences
                            usingBlock:^(NSString *substring, NSRange substringRange, NSRange enclosingRange, BOOL *stop) {
                                const unichar hs = [substring characterAtIndex:0];
                                if (0xd800 <= hs && hs <= 0xdbff) {
                                    if (substring.length > 1) {
                                        const unichar ls = [substring characterAtIndex:1];
                                        const int uc = ((hs - 0xd800) * 0x400) + (ls - 0xdc00) + 0x10000;
                                        if (0x1d000 <= uc && uc <= 0x1f77f) {
                                            returnValue = YES;
                                        }
                                    }
                                } else if (substring.length > 1) {
                                    const unichar ls = [substring characterAtIndex:1];
                                    if (ls == 0x20e3) {
                                        returnValue = YES;
                                    }
                                } else {
                                    if (0x2100 <= hs && hs <= 0x27ff) {
                                        if (0x278b <= hs && hs <= 0x2792) {
                                            //自带九宫格拼音键盘
                                            returnValue = NO;;
                                        }else if (0x263b == hs) {
                                            returnValue = NO;;
                                        }else {
                                            returnValue = YES;
                                        }                                        
                                    } else if (0x2B05 <= hs && hs <= 0x2b07) {
                                        returnValue = YES;
                                    } else if (0x2934 <= hs && hs <= 0x2935) {
                                        returnValue = YES;
                                    } else if (0x3297 <= hs && hs <= 0x3299) {
                                        returnValue = YES;
                                    } else if (hs == 0xa9 || hs == 0xae || hs == 0x303d || hs == 0x3030 || hs == 0x2b55 || hs == 0x2b1c || hs == 0x2b1b || hs == 0x2b50) {
                                        returnValue = YES;
                                    }
                                }
                            }];

    return returnValue;
}

这时你可能得换种算法，或者在上面的方法中添加这部分新增表情的过滤判断，但对于没规则标识的表情，你只能特殊处理（很麻烦），接下来你不妨用下面的另外一种过滤表情的算法，经过测试此方法基本上过滤掉了包括一些新增的表情。具体代码如下：

//
-(BOOL)stringContainsEmoji:(NSString *)string{
   
    UILabel *characterRender = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, 1, 1)];
    characterRender.text = string;
    characterRender.backgroundColor = [UIColor blackColor];//needed to remove subpixel rendering colors
    [characterRender sizeToFit];

    CGRect rect = [characterRender bounds];
    UIGraphicsBeginImageContextWithOptions(rect.size,YES,0.0f);
    CGContextRef contextSnap = UIGraphicsGetCurrentContext();
    [characterRender.layer renderInContext:contextSnap];
    UIImage *capturedImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    CGImageRef imageRef = [capturedImage CGImage];
    NSUInteger width = CGImageGetWidth(imageRef);
    NSUInteger height = CGImageGetHeight(imageRef);
    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
    unsigned char *rawData = (unsigned char*) calloc(height * width * 4, sizeof(unsigned char));
    NSUInteger bytesPerPixel = 4;
    NSUInteger bytesPerRow = bytesPerPixel * width;
    NSUInteger bitsPerComponent = 8;
    CGContextRef context = CGBitmapContextCreate(rawData, width, height,
                                                 bitsPerComponent, bytesPerRow, colorSpace,
                                                 kCGImageAlphaPremultipliedLast | kCGBitmapByteOrder32Big);
    CGColorSpaceRelease(colorSpace);

    CGContextDrawImage(context, CGRectMake(0, 0, width, height), imageRef);
    CGContextRelease(context);

    BOOL colorPixelFound = NO;

    int x = 0;
    int y = 0;
    while (y < height && !colorPixelFound) {
        while (x < width && !colorPixelFound) {

            NSUInteger byteIndex = (bytesPerRow * y) + x * bytesPerPixel;

            CGFloat red = (CGFloat)rawData[byteIndex];
            CGFloat green = (CGFloat)rawData[byteIndex+1];
            CGFloat blue = (CGFloat)rawData[byteIndex+2];

            CGFloat h, s, b, a;
            UIColor *c = [UIColor colorWithRed:red green:green blue:blue alpha:1.0f];
            [c getHue:&h saturation:&s brightness:&b alpha:&a];

            b /= 255.0f;

            if (b > 0) {
                colorPixelFound = YES;
            }

            x++;
        }
        x=0;
        y++;
    }

    return colorPixelFound;

}