UIImageView not resizing when bounds or frame is changed?

问题

So I have a custom view (its a custom textview that sits on top of keyboard); however it can resize so I would like the background image (UIImageView with UIImage inside of it) to scale with it. The following code does nothing:

//size of entire custom view
CGRect bFrame = self.keyboard.frame;
bFrame.origin.y += heightDifference;
bFrame.size.height += heightDifference;

//lets set frame and bounds for the uiimageview
self.keyboard.background.frame = bFrame;
self.keyboard.background.bounds = bFrame;

//I thought the lines above would work, but they didn't, trying to reset the image and change its content mode as a hack.. .still no beans.
self.keyboard.background.image = [UIImage imageNamed:@"keyboard_backgroundv1_5.png"];
self.keyboard.background.contentMode = UIViewContentModeScaleToFill;

回答1:

This function may help you

CGSize targetSize = CGSizeMake(self.keyboard.frame.size.width, self.keyboard.frame.size.height);

self.keyboard.background.image = [self imageByScalingProportionallyToSize:targetSize ImageForConvert:[UIImage imageNamed:@"keyboard_backgroundv1_5.png"]];


-(UIImage *)imageByScalingProportionallyToSize:(CGSize)targetSize ImageForConvert:(UIImage *)sourceImage
{
    UIImage *newImage = nil;

    CGSize imageSize = sourceImage.size;
    CGFloat width = imageSize.width;
    CGFloat height = imageSize.height;

    CGFloat targetWidth = targetSize.width;
    CGFloat targetHeight = targetSize.height;

    CGFloat scaleFactor = 0.0;
    CGFloat scaledWidth = targetWidth;
    CGFloat scaledHeight = targetHeight;

    CGPoint thumbnailPoint = CGPointMake(0.0,0.0);

    if (CGSizeEqualToSize(imageSize, targetSize) == NO) 
    {

        CGFloat widthFactor = targetWidth / width;
        CGFloat heightFactor = targetHeight / height;

        if (widthFactor < heightFactor) 
            scaleFactor = widthFactor;
        else
            scaleFactor = heightFactor;

        scaledWidth  = width * scaleFactor*1;
        scaledHeight = height * scaleFactor;

        // center the image

        if (widthFactor < heightFactor)
        {
            thumbnailPoint.y = (targetHeight - scaledHeight) * 0.5; 
        } else if (widthFactor > heightFactor) {
            thumbnailPoint.x = (targetWidth - scaledWidth) * 0.5;
        }
    }


    UIGraphicsBeginImageContext(targetSize);

    CGRect thumbnailRect = CGRectZero;
    thumbnailRect.origin = thumbnailPoint;
    thumbnailRect.size.width  = scaledWidth;
    thumbnailRect.size.height = scaledHeight;

    [sourceImage drawInRect:thumbnailRect];

    newImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return newImage ;
}

来源：https://stackoverflow.com/questions/11748198/uiimageview-not-resizing-when-bounds-or-frame-is-changed

标签

iphone

ios

uiimageview

resize

scaling