【发布时间】：2011-10-15 11:42:27
【问题描述】：
我有一个 APP (SDK 4.3)，可以将图像保存为谷歌地图上的航路点的附件。 文件保存是非常标准的（afaik）UIImagePickerController 代码。 我没有保存到相机胶卷，而是保存图像，然后将缩略图保存到子文件夹。我需要它。 在看似随机的点，完全没有错误被捕获和记录，图像不会保存到文件夹中，而是覆盖以前保存的图像文件！ 它像 FIFO 流行一样寻找整个世界。 这很奇怪，我什至构建了一个小型测试应用程序，并在幽灵出现时立即启动它......将一系列相机图像保存到相同的文件夹但看到相同的效果。一旦达到随机魔术文件编号，图像就会被覆盖！ 从某种意义上说是随机的，即在保存 7 张图像后，覆盖开始……即使在重新启动手机以确保内存泄漏不是问题之后也是如此。擦一下APP再试... 这次将在保存 16 或 23 个图像文件后发生。 我已经走到了各种极端，找不到问题的根源。 在小测试APP中，我也用同样的方法保存到相机胶卷中。它将保存在那里，但会覆盖在文件夹中。文件名是 10 个字符随机生成的字母数字。
我现在倾向于将其理解为一个错误。我总是可以重现错误，但无法预测。它是随机出现的。
当我正在扯头发时，我将不胜感激。
这里是代码...
//tester.h
#import <UIKit/UIKit.h>
@interface tester : UIViewController <UINavigationControllerDelegate, UIImagePickerControllerDelegate>
{
UIImagePickerController *imgPicker;
IBOutlet UIButton *pressit;
IBOutlet UIButton *seeya;
UIActivityIndicatorView *activity;
}
@property (retain )UIImagePickerController *imgPicker;
@property (nonatomic,retain)IBOutlet UIButton *pressit;
@property (nonatomic,retain)IBOutlet UIButton *seeya;
@property (nonatomic,retain)UIActivityIndicatorView *activity;
-(NSString *) genRandStringLength:(int) len ;
-(void)saveImagesFromPickerInTheBackgroundUsingImage:(UIImage *)img;
-(NSArray *)buildFilePaths;
- (IBAction)snapShots:(UIButton *)button;
-(IBAction)byebye:(id)sender;
@end
//=====================
//tester.m
#import "tester.h"
#import "MultiMediaUtilities.h"
@implementation tester
@synthesize imgPicker;
@synthesize pressit,seeya,activity;
//Image size constants
#define MAX_THUMBNAIL_RES_SIZE 103
#define MAX_IMAGE_RES_SIZE 640
- (IBAction)snapShots:(UIButton *)button
{
if (!imgPicker) imgPicker = [[UIImagePickerController alloc]init];
imgPicker.sourceType = UIImagePickerControllerSourceTypeCamera;
imgPicker.delegate = self;
[self presentModalViewController:imgPicker animated:YES];
}
- (void) imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
{
UIImage *memoImage = [[MultiMediaUtilities scaleAndRotateImage:[info objectForKey:@"UIImagePickerControllerOriginalImage"] toResolution:MAX_IMAGE_RES_SIZE ]retain];
UIImageWriteToSavedPhotosAlbum(memoImage, self, @selector(image:didFinishSavingWithError:contextInfo:), nil);
[self saveImagesFromPickerInTheBackgroundUsingImage:memoImage];
// Dismiss the camera
[self dismissModalViewControllerAnimated:YES];
}
//builds paths to files in system with components
-(NSArray *)buildFilePaths
{
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *docsPath = [documentsDirectory stringByAppendingPathComponent:@"imagesfolder"];
NSString *fullDocsPath = [docsPath stringByAppendingPathComponent:@"assets"];
NSString *fullThumbsPath = [fullDocsPath stringByAppendingPathComponent:@"thumbs"];
NSArray * retArray = [NSArray arrayWithObjects:fullDocsPath,fullThumbsPath,nil];
return retArray;
}
-(void)saveImagesFromPickerInTheBackgroundUsingImage:(UIImage *)img
{
@try
{
NSFileManager *NSFm = [NSFileManager defaultManager];
NSArray *pathsArray = [NSArray arrayWithArray:[self buildFilePaths]];
NSString *fullDocsPath = [NSString stringWithFormat:@"%@", (NSString *)[pathsArray objectAtIndex:0]];
NSString *fullThumbsPath = [NSString stringWithFormat:@"%@", (NSString *)[pathsArray objectAtIndex:1]];
//Ensure Folders exist
BOOL isDir=YES;
NSError *error;
if(![NSFm fileExistsAtPath:fullDocsPath isDirectory:&isDir])
if(![NSFm createDirectoryAtPath:fullDocsPath withIntermediateDirectories:YES attributes:nil error:&error])
NSLog(@"Error: Create Images folder failed");
//create thumbs folder too
if(![NSFm fileExistsAtPath:fullThumbsPath isDirectory:&isDir])
if(![NSFm createDirectoryAtPath:fullThumbsPath withIntermediateDirectories:YES attributes:nil error:&error])
NSLog(@"Error: Create Thumbs folder failed");
//build the filenames & paths
NSString *newImageName= [NSString stringWithFormat:@"%@.png", [self genRandStringLength:10]];
NSString *imagePath = [[fullDocsPath stringByAppendingPathComponent:newImageName]retain];
NSLog(@"SavingIMage ImagePath = %@",imagePath);
NSString *thumbPath = [[fullThumbsPath stringByAppendingPathComponent:newImageName]retain];
NSLog(@"SavingIMage thumbPAth = %@",thumbPath);
//Write the files out
NSData *imgData = UIImagePNGRepresentation(img);
[imgData writeToFile:imagePath options:NSDataWritingAtomic error:&error];
if (!error) {
NSLog(@"Error writing image %@",error.description);
}
NSData *thumbData = UIImagePNGRepresentation(img);
[thumbData writeToFile:thumbPath options:NSDataWritingAtomic error:&error];
if (!error) {
NSLog(@"Error writing thumb %@",error.description);
}
}
@catch (NSException * e)
{
NSLog(@"Exception: %@", e);
}
}
-(NSString *) genRandStringLength:(int) len
{
NSString *letters = @"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
NSMutableString *randomString = [NSMutableString stringWithCapacity: len];
for (int i=0; i<len; i++)
{
[randomString appendFormat: @"%c", [letters characterAtIndex: rand()%[letters length]]];
}
return randomString;
}
- (void)image:(UIImage*)image didFinishSavingWithError:(NSError *)error contextInfo:(NSDictionary*)info {
NSString *message;
NSString *title;
if (!error)
{
title = @"Camera...";
message = @"Image saved!...Just as well.";
}
else
{
title = @"Error";
message = [error description];
}
UIAlertView *alert = [[UIAlertView alloc]
initWithTitle:title
message:message
delegate:self
cancelButtonTitle:@"OK"
otherButtonTitles:nil];
[alert show];
[alert release];
if (image !=NULL){
[image release];
image=nil;
}
if(info !=NULL)
{
[info release];
info=nil;
}
}
- (void)viewDidUnload
{
[super viewDidUnload];
// Release any retained subviews of the main view.
// e.g. self.myOutlet = nil;
}
-(void)dealloc
{
[imgPicker release];
[pressit release];
[seeya release];
[activity release];
[super dealloc];
}
@end
【问题讨论】：
-
你为什么用
rand()而不是random()？你如何设置种子？
标签： objective-c xcode file-io ios4