Taking and saving a screenshot

[ChrisW]

I'm trying to save off a picture of the mapView...

UIGraphicsBeginImageContext(mapView.frame.size);
[self.window.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *mapImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

NSData *mapData = [NSData dataWithData:UIImagePNGRepresentation(mapImage)];
[mapData writeToFile:[self myFilePath:@"MyMap.png"] atomically:YES];

Then I later try and overwrite a button image with MyMap.png...

UIImage *image = [UIImage imageNamed:@"MyMap.png"];
[btnMap setImage:image forState:UIControlStateNormal];

I'm not sure why this isn't working. If anyone can help me out it would be greatly appreciated.
Thanks,
Chris

[iSDK]

Firstly the UIGraphicsGetImageFromCurrentImageContext() needs to be retained if I remember correctly and secondly if I am correct I think that you are trying to take a picture of the current window 'self.window.layer'. Try mapView.layer.

Originally Posted by ChrisW

I'm trying to save off a picture of the mapView...

UIGraphicsBeginImageContext(mapView.frame.size);
[self.window.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *mapImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

NSData *mapData = [NSData dataWithData:UIImagePNGRepresentation(mapImage)];
[mapData writeToFile:[self myFilePath:@"MyMap.png"] atomically:YES];

Then I later try and overwrite a button image with MyMap.png...

UIImage *image = [UIImage imageNamed:@"MyMap.png"];
[btnMap setImage:image forState:UIControlStateNormal];

I'm not sure why this isn't working. If anyone can help me out it would be greatly appreciated.
Thanks,
Chris

[ChrisW]

Thanks for the quick response!

Using the mapView layer makes more sense, so I fixed that part. Isn't the UIGraphicsGetImageFromCurrentImageContext() retained in the mapImage?

Here's the adjusted code...

UIGraphicsBeginImageContext(mapView.frame.size);
[[mapView layer] renderInContext:UIGraphicsGetCurrentContext()]; //also tried mapView.layer
UIImage *mapImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

NSData *mapData = UIImagePNGRepresentation(mapImage);
[mapData writeToFile:[self myFilePath:@"MyMap.png"] atomically:YES];

Edit:
Wanted to add that XCode says that renderInContext: method cannot be found.

[iSDK]

You need to import QuartzCore. Do you want to NSLog your 'myFilePath' to check that you are placing and retrieving the image from the correct place?

Originally Posted by ChrisW

Thanks for the quick response!

Using the mapView layer makes more sense, so I fixed that part. Isn't the UIGraphicsGetImageFromCurrentImageContext() retained in the mapImage?

Here's the adjusted code...

UIGraphicsBeginImageContext(mapView.frame.size);
[[mapView layer] renderInContext:UIGraphicsGetCurrentContext()]; //also tried mapView.layer
UIImage *mapImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

NSData *mapData = UIImagePNGRepresentation(mapImage);
[mapData writeToFile:[self myFilePath:@"MyMap.png"] atomically:YES];

Edit:
Wanted to add that XCode says that renderInContext: method cannot be found.