iOS尝试将图像保存到相机胶卷但未成功

Question

I have an image in an UIImageView and want to save it to the device's photos so that it can be ultimately saved as a wallpaper. Although the code compiles without an error the image does not save and I fear that I am doing something wrong when it comes to using 'UIImage' vs 'UIImageView' or something else all together. The name of the image is "Q115birdsfull~iphone.png" and my code thus far is below. What am I doing wrong???

Q115birdsViewController.h

#import <UIKit/UIKit.h>

@interface Q115birdsViewController : UIViewController 
{
    UIImage *Q115birdsfull;
}

@property (nonatomic, strong) UIImage *Q115birdsfull;

- (IBAction)onClickSavePhoto:(id)sender;

@end

Q115birdsViewController.m

#import "Q115birdsViewController.h"

@interface Q115birdsViewController ()
@end

@implementation Q115birdsViewController

@synthesize Q115birdsfull;

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
     self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
    // Custom initialization
}
return self;
}

- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view.
}

- (IBAction)onClickSavePhoto:(id)sender{
    UIImageWriteToSavedPhotosAlbum(Q115birdsfull, nil, nil, nil);
}

` Thank you in advance!

Answer 1

What you're attempting to save is a UIImage kept as a property and an ivar. What I don't see in your code is where you actually set that image to anything. That may be the step you are missing.

Try doing this:

- (IBAction)onClickSavePhoto:(id)sender{

    if(Q115birdsfull == NULL)
    {
        NSLog( @"there is no Q115birdsfull image set");
        Q115birdsfull = [UIImage imageNamed: @"Q115birdsfull"];

        // if it's STILL null, we'll try a much more specific name
        if(Q115birdsfull == NULL)
        {
            Q115birdsfull = [UIImage imageNamed: @"Q115birdsfull~iphone"];
        }
    }

    if(Q115birdsfull){
        // by the way, variable names should *always* start with lower case letters
        UIImageWriteToSavedPhotosAlbum(Q115birdsfull, nil, nil, nil);
    }
    else {
        NSLog( @"never found the Q115birdsfull png file... is it really being copied into your built app?");
    }
}