我对Objective-C并不陌生，并且遇到了一些初学者问题。我有一个应用程序，该应用程序的行为应该像照相馆一样。用户从其相机胶卷中选择一张图片，然后这些图片将显示在UIImageViews中。我正在尝试保存他们选择的图像。我有9个UIImageView，问题是当我为每个UIImageView选择不同的照片时，关闭并重新启动该应用程序，其他8个UIImageViews将显示存储在第一个图像视图中的照片。这是我正在使用的代码：
- (NSString *)dataFilePath {
NSArray *paths = NSSearchPathForDirectoriesInDomains(
NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
return [documentsDirectory stringByAppendingPathComponent:kFilename9];
}
- (void)applicationDidEnterBackground:(UIApplication*)application {
NSLog(@"Image on didenterbackground: %@", imageView);
self.imageData = [NSData dataWithData:UIImagePNGRepresentation(imageView.image)];
self.imageData = [NSData dataWithData:UIImagePNGRepresentation(imageView2.image)];
self.imageData = [NSData dataWithData:UIImagePNGRepresentation(imageView3.image)];
self.imageData = [NSData dataWithData:UIImagePNGRepresentation(imageView4.image)];
self.imageData = [NSData dataWithData:UIImagePNGRepresentation(imageView5.image)];
self.imageData = [NSData dataWithData:UIImagePNGRepresentation(imageView6.image)];
self.imageData = [NSData dataWithData:UIImagePNGRepresentation(imageView7.image)];
self.imageData = [NSData dataWithData:UIImagePNGRepresentation(imageView8.image)];
self.imageData = [NSData dataWithData:UIImagePNGRepresentation(imageView9.image)];
[self.imageData writeToFile:[self dataFilePath] atomically:YES];
NSLog(@"The image is: %@", [[imageView image] description]);
NSLog(@"dataFilePath is: %@", [self dataFilePath]);
}
- (void)viewDidLoad
{
NSString *filePath = [self dataFilePath];
NSLog(@"FilePath: %@", filePath);
NSLog(@"Image: %@", imageView);
if ([[NSFileManager defaultManager] fileExistsAtPath:filePath]) {
NSData *vdlData = [[NSData alloc] initWithContentsOfFile:filePath];
imageView.image = [[UIImage alloc] initWithData:vdlData];
imageView2.image = [[UIImage alloc] initWithData:vdlData];
imageView3.image = [[UIImage alloc] initWithData:vdlData];
imageView4.image = [[UIImage alloc] initWithData:vdlData];
imageView5.image = [[UIImage alloc] initWithData:vdlData];
imageView6.image = [[UIImage alloc] initWithData:vdlData];
imageView7.image = [[UIImage alloc] initWithData:vdlData];
imageView8.image = [[UIImage alloc] initWithData:vdlData];
imageView9.image = [[UIImage alloc] initWithData:vdlData];
}
UIApplication *app = [UIApplication sharedApplication];
[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(applicationDidEnterBackground:)
name:UIApplicationDidEnterBackgroundNotification
object:app];
[super viewDidLoad];
}
我试图弄清楚我需要更改什么以使UIImageViews显示正确的图片，而不是全部显示相同的图片。这可能是一个简单的修复程序，但是任何帮助将不胜感激，谢谢！
最佳答案
好的，这是我的做法：
使用NSUserDefaults将图像保存为可变数组：
ViewController.h
@property(retain) NSUserDefaults *user;
ViewController.m
@synthesize user;
- (void)viewWillAppear:(BOOL)animated
{
self.user = [NSUserDefaults standardUserDefaults];
编辑
NSMutableArray* array = [[self.user objectForKey:@"images"]mutableCopy];
while(array == nil)
{
[self.user setObject:[NSMutableArray arrayWithObject:@""] forKey:@"images"]
array = [[self.user objectForKey:@"images"]mutableCopy];
NSLog(@"%@",@"attempting to create an array to store the images in");
}
结束编辑
}
- (void)applicationDidEnterBackground:(UIApplication*)application {
NSLog(@"Image on didenterbackground: %@", imageView);
NSMutableArray* array = [NSMutableArray arrayWithObject:[NSData dataWithData:UIImagePNGRepresentation(imageView.image)]];
[array addObject:[NSData dataWithData:UIImagePNGRepresentation(imageView2.image)];
[array addObject:[NSData dataWithData:UIImagePNGRepresentation(imageView3.image)];
[array addObject:[NSData dataWithData:UIImagePNGRepresentation(imageView4.image)];
[array addObject:[NSData dataWithData:UIImagePNGRepresentation(imageView5.image)];
[array addObject:[NSData dataWithData:UIImagePNGRepresentation(imageView6.image)];
[array addObject:[NSData dataWithData:UIImagePNGRepresentation(imageView7.image)];
[array addObject:[NSData dataWithData:UIImagePNGRepresentation(imageView8.image)];
[array addObject:[NSData dataWithData:UIImagePNGRepresentation(imageView9.image)];
[self.user setObject:array forKey:@"images"];
}
- (void)viewDidLoad
{
NSMutableArray* array = [[self.user objectForKey:@"images"]mutableCopy];
编辑
if(array.count == 9)
{
imageView.image = [[UIImage alloc] initWithData:[array objectAtIndex:0]];
imageView2.image = [[UIImage alloc] initWithData:[array objectAtIndex:1]];
imageView3.image = [[UIImage alloc] initWithData:[array objectAtIndex:2]];
imageView4.image = [[UIImage alloc] initWithData:[array objectAtIndex:3]];
imageView5.image = [[UIImage alloc] initWithData:[array objectAtIndex:4]];
imageView6.image = [[UIImage alloc] initWithData:[array objectAtIndex:5]];
imageView7.image = [[UIImage alloc] initWithData:[array objectAtIndex:6]];
imageView8.image = [[UIImage alloc] initWithData:[array objectAtIndex:7]];
imageView9.image = [[UIImage alloc] initWithData:[array objectAtIndex:8]];
}
结束编辑
UIApplication *app = [UIApplication sharedApplication];
[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(applicationDidEnterBackground:)
name:UIApplicationDidEnterBackgroundNotification
object:app];
[super viewDidLoad];
}
- (void)viewDidUnload
{
self.user = nil;
}
这样，您将不会丢失图像或数据，它们将被存储并易于访问，并且即使您更新应用程序也不会消失。
干杯!