UIView使用CALayer添加单独一边

最新推荐文章于 2018-05-22 09:23:20 发布

jade07

最新推荐文章于 2018-05-22 09:23:20 发布

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CC 4.0 BY-SA版权

本文链接：https://blog.youkuaiyun.com/jade07/article/details/49737261

本文介绍了一种使用CAGradientLayer为UIView添加自定义方向阴影的方法。通过将方向参数转换为CAGradientLayer的起点和终点坐标，可以轻松地为视图的顶部、底部、左侧或右侧添加渐变阴影。

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#define kValidDirections [NSArray arrayWithObjects: @"top", @"bottom", @"left", @"right",nil]

- (void) insertLayertoView:(UIView*)sourceView WithRadius:(float)radius Color:(UIColor *)color Directions:(NSArray *)directions

{

    // Ignore duplicate direction
    NSMutableDictionary *directionDict = [[NSMutableDictionary alloc] init];
    for (NSString *direction in directions) [directionDict setObject:@"1" forKey:direction];

    for (NSString *direction in directionDict) {
        // Ignore invalid direction
        if ([kValidDirections containsObject:direction])
        {
            CAGradientLayer *shadow = [CAGradientLayer layer];

            if ([direction isEqualToString:@"top"]) {
                [shadow setStartPoint:CGPointMake(0.5, 0.0)];
                [shadow setEndPoint:CGPointMake(0.5, 1.0)];
                shadow.frame = CGRectMake(0, 0, sourceView.bounds.size.width, radius);
            }
            else if ([direction isEqualToString:@"bottom"])
            {
                [shadow setStartPoint:CGPointMake(0.5, 1.0)];
                [shadow setEndPoint:CGPointMake(0.5, 0.0)];
                shadow.frame = CGRectMake(0, sourceView.bounds.size.height - radius, sourceView.bounds.size.width, radius);
            } else if ([direction isEqualToString:@"left"])
            {
                shadow.frame = CGRectMake(0, 0, radius, sourceView.bounds.size.height);
                [shadow setStartPoint:CGPointMake(0.0, 0.5)];
                [shadow setEndPoint:CGPointMake(1.0, 0.5)];
            } else if ([direction isEqualToString:@"right"])
            {
                shadow.frame = CGRectMake(sourceView.bounds.size.width - radius, 0, radius, sourceView.bounds.size.height);
                [shadow setStartPoint:CGPointMake(1.0, 0.5)];
                [shadow setEndPoint:CGPointMake(0.0, 0.5)];
            }

            shadow.colors = [NSArray arrayWithObjects:(id)[color CGColor], (id)[[UIColor clearColor] CGColor], nil];
            [sourceView.layer insertSublayer:shadow atIndex:0];
        }
    }

}