常用的功能总结

http://www.cocoachina.com/ios/20170626/19616.html

[self.tableview respondsToSelector:@selector(setSectionIndexColor:)这个可以叫做动态拦截吧

这个链接是我无意中遇到的，觉得博主很辛苦另外有些代码确实有用，就存了下来

1.去除数组中重复的数据   NSArray *newArr = [oldArr valueForKeyPath:@“@distinctUnionOfObjects.self"];

2.判断图片类型                                     //通过图片Data数据第一个字节 来获取图片扩展名
- (NSString *)contentTypeForImageData:(NSData *)data
{
    uint8_t c;
    [data getBytes:&c length:1];
    switch (c)
    {
        case 0xFF:
            return @"jpeg";
 
        case 0x89:
            return @"png";
 
        case 0x47:
            return @"gif";
 
        case 0x49:
        case 0x4D:
            return @"tiff";
 
        case 0x52:
        if ([data length] < 12) {
            return nil;
        }
 
        NSString *testString = [[NSString alloc] initWithData:[data subdataWithRange:NSMakeRange(0, 12)] encoding:NSASCIIStringEncoding];
        if ([testString hasPrefix:@"RIFF"]
            && [testString hasSuffix:@"WEBP"])
        {
            return @"webp";
        }
 
        return nil;
    }
 
    return nil;
}

3.身份证验证正则表达式

- (BOOL)validateIdentityCard {
    BOOL flag;
    if (self.length <= 0) {
        flag = NO;
        return flag;
    }
    NSString *regex2 = @"^(\\d{14}|\\d{17})(\\d|[xX])$";
    NSPredicate *identityCardPredicate = [NSPredicate predicateWithFormat:@"SELF MATCHES %@",regex2];
    return [identityCardPredicate evaluateWithObject:self];
}

4.合并两个图片

+ (UIImage*)mergeImage:(UIImage*)firstImage withImage:(UIImage*)secondImage {

    CGImageRef firstImageRef = firstImage.CGImage;

    CGFloat firstWidth = CGImageGetWidth(firstImageRef);

    CGFloat firstHeight = CGImageGetHeight(firstImageRef);

    CGImageRef secondImageRef = secondImage.CGImage;

    CGFloat secondWidth = CGImageGetWidth(secondImageRef);

    CGFloat secondHeight = CGImageGetHeight(secondImageRef);

    CGSize mergedSize = CGSizeMake(MAX(firstWidth, secondWidth), MAX(firstHeight, secondHeight));

    UIGraphicsBeginImageContext(mergedSize);

    [firstImage drawInRect:CGRectMake(0, 0, firstWidth, firstHeight)];

    [secondImage drawInRect:CGRectMake(0, 0, secondWidth, secondHeight)];

    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

    return image;

}

// 画水印

- (void) setImage:(UIImage *)image withWaterMark:(UIImage *)mark inRect:(CGRect)rect

{

    if ([[[UIDevice currentDevice] systemVersion] floatValue] >= 4.0)

    {

        UIGraphicsBeginImageContextWithOptions(self.frame.size, NO, 0.0);

    }

    //原图

    [image drawInRect:self.bounds];

    //水印图

    [mark drawInRect:rect];

    UIImage *newPic = UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

    self.image = newPic;

}