问题
Im getting a memory warning when Im using the camera on an iPhone. Im also using ARC.
When you take a photo and press the 'use Photo' button on the camera view controller I get a memory warning. The intention is once the 'use Photo' button is pressed that it changes the contents of the an ImageView.
I thought the memory issue might be due to the fact that the image that is captured is full screen, and the ImageView is 250h 250w. But I tried scaling down the size of the image taken by the camera and then assign it to the ImageView. However this still did not work, even when I resized it to 100 x 100.
Secondly, I then did not assign the photo taken by the camera to the ImageView but it still has the memory warning.
I looked at other answers here and attempted the two above but it is still there. I will show my code below. Will this affect my submission to the app store? Surely if it is such a common occurence that it is a bug or there is a work around? It would be great if one could look at the code provided and spot the error or suggest how to handle this memory warning?
My app is 95+% finished apart from this memory warning so it is getting close to submission time.
My code:
- (IBAction)takePhoto:(id)sender {
self.imagePicker = [[UIImagePickerController alloc] init];
self.imagePicker.delegate = self;
self.imagePicker.allowsEditing=NO;
if ([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]) {
[self.imagePicker setSourceType:UIImagePickerControllerSourceTypeCamera];
[self presentViewController:self.imagePicker animated:YES completion:NULL];
}
else{
[self.imagePicker setSourceType:UIImagePickerControllerSourceTypePhotoLibrary];
[self presentViewController:self.imagePicker animated:YES completion:NULL];
}
}
- (IBAction)choosePhoto:(id)sender {
self.imagePicker2 = [[UIImagePickerController alloc] init];
self.imagePicker2.delegate = self;
self.imagePicker2.allowsEditing=NO;
[self.imagePicker2 setSourceType:UIImagePickerControllerSourceTypePhotoLibrary];
[self presentViewController:self.imagePicker2 animated:YES completion:NULL];
}
-(void) imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info{
self.image = [info objectForKey:UIImagePickerControllerOriginalImage];
CGRect rect = CGRectMake(0,0,100,100);
UIGraphicsBeginImageContext( rect.size );
[self.image drawInRect:rect];
UIImage *picture1 = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
[self.snapImage setImage:picture1];
[self.uploadImageBtn setHidden:NO];
[self dismissViewControllerAnimated:YES completion:NULL];
}
-(void)imagePickerControllerDidCancel:(UIImagePickerController *)picker{
[self dismissViewControllerAnimated:YES completion:NULL];
}
回答1:
I didnt find a good solution but I would not store the raw image in a property because the raw image takes up roughly 30MB of memory. So instead of:
self.image = [info objectForKey:UIImagePickerControllerOriginalImage];
I changed it to:
UIImage * image = [info objectForKey:UIImagePickerControllerOriginalImage];
This way the image is destroyed when it is no longer in use. Note: I've test this new method on iPhone 4 series and 5. The memory warning only appears on the 4 series not the 5.
From looking around the web there have been many bug reports submitted to Apple in regards to the Camera and iOS7. For instance, irregularly when you launch the Camera it will give a black preview - this is linked to iOS7, and more so the iPhone 4 series not 5. This is probably the difference in the processor power - but I am not sure. My app got approved for the app store so the memory warning will not be an issue –
回答2:
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
[[NSURLCache sharedURLCache] removeAllCachedResponses];
}
Clearing the Cache in the class i was using the "UIImagePickerController", worked for me !!!
来源：https://stackoverflow.com/questions/20119918/memory-warning-when-using-uiimagepickercontroller