NSDocumentDirectory和UIScrollView中的删除

Question

我的代码有问题，所以可以用缩略图预览UIScrollView中的图像。我的照片来自NSDocumentDirectory。不过，我可以从它中删除，但是当我从右到左位置开始时，我可以正确地从它中删除( VIEW & in NSDocumentDirectory)。

问题：现在，我可以删除无论如何，但我有一些问题。

• First，虽然我可以删除，但是视图没有排列，我的rearrangeItems:方法也没有被调用。
• 第二次，然后在第一次加载时，我可以删除我喜欢的任何内容，但是就像我说的那样，rearrangeItems:方法没有被调用，所以它们的名称不是renamed。
• 第三代，是在第一次加载，我可以删除在反正，但当我退出应用程序，我可以删除，但我的图像在NSDocu中并没有删除。

希望有人能帮我这个忙。下面是我的代码预览。

- (void)addImage:(UIImage *)imageToAdd {
    [_images addObject:imageToAdd];
    [_thumbs addObject:[imageToAdd imageByScalingAndCroppingForSize:CGSizeMake(60, 60)]];

    int row = floor(([_thumbs count] - 1) / 5);
    int column = (([_thumbs count] - 1) - (row * 5));

    UIImage *thumb = [_thumbs objectAtIndex:[_thumbs count]-1];
    UIButton *button = [UIButton buttonWithType:UIButtonTypeRoundedRect];
    button.frame = CGRectMake(column*60+10, row*60+10, 60, 60);
    [button setImage:thumb forState:UIControlStateNormal];
    [button addTarget:self action:@selector(deleteItem:) forControlEvents:UIControlEventTouchUpInside];
    button.tag = [_images count] - 1;
    // This is the title of where they were created, so we can see them move.s
    [button setTitle:[NSString stringWithFormat:@"%d, %d", row, column] forState:UIControlStateNormal];

    [_buttons addObject:button];
    [scrollView addSubview:button];
    // This will add 10px padding on the bottom as well as the top and left.
    [scrollView setContentSize:CGSizeMake(300, row*60+20+60)];
}

    - (void) deleteItem:(id)sender {
        _clickedButton = (UIButton *)sender;
        UIAlertView *saveMessage = [[UIAlertView alloc] initWithTitle:@""
                                                                  message:@"DELETE？"
                                                                 delegate:self
                                                        cancelButtonTitle:@"NO"
                                                        otherButtonTitles:@"YES", nil];
        [saveMessage show];  

    }



    - (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex
    {
        NSString *title = [alertView buttonTitleAtIndex:buttonIndex];
    if([title isEqualToString:@"YES"]) {
            NSLog(@"YES was selected.");
        UIButton *button = _clickedButton;
        [button removeFromSuperview];

        [_buttons removeObjectAtIndex:button.tag];

        NSFileManager *fileManager = [NSFileManager defaultManager];
        NSArray *paths = NSSearchPathForDirectoriesInDomains(NSCachesDirectory,NSUserDomainMask, YES);
        NSString *documentsDirectory = [paths objectAtIndex:0];
        NSString *fullPath = [documentsDirectory stringByAppendingPathComponent:[NSString stringWithFormat:@"oneSlotImages%lu.png", button.tag]];           
        [fileManager removeItemAtPath: fullPath error:NULL];

        [self rearrangeItems:button.tag];

        }
    }


    - (void)viewDidAppear:(BOOL)animated
    {
        [_thumbs removeAllObjects];

            for(int i = 0; i <= 100; i++) 
            { 
                NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
                NSString *documentsDir = [paths objectAtIndex:0];

                NSString *savedImagePath = [documentsDir stringByAppendingPathComponent:[NSString stringWithFormat:@"Images%d.png", i]]; 
                NSLog(@"savedImagePath=%@",savedImagePath);
                if([[NSFileManager defaultManager] fileExistsAtPath:savedImagePath]){ 
                    [self addImage:[UIImage imageWithContentsOfFile:savedImagePath]]; 
                    //NSLog(@"file exists");
                } 
            } 
            NSLog(@"Count : %d", [_images count]);
    }

更新:新的重排方法

- (void)rearrangeItems:(int)startIndex {

    for (UIButton *button in _buttons) {
        // Shift the tags down one
        if (button.tag > startIndex) {
             NSLog(@"called here");
            // Version 2 ****************************
            NSFileManager *fileManager = [NSFileManager defaultManager];
            NSArray *paths = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES);
            NSString *documentsDirectory = [paths objectAtIndex:0];
            NSString *fullPath = [documentsDirectory stringByAppendingPathComponent:[NSString stringWithFormat:@"oneSlotImages%lu.png", button.tag]];
            NSData *imageData = [NSData dataWithContentsOfFile:fullPath];
            [fileManager removeItemAtPath: fullPath error:NULL];
            // **************************************

            button.tag -= 1;

            // Version 2 ****************************
            fullPath = [documentsDirectory stringByAppendingPathComponent:[NSString stringWithFormat:@"oneSlotImages%lu.png", button.tag]];
            [imageData writeToFile:fullPath atomically:YES];
            // **************************************

            // Recalculate Position
            int row = floor(button.tag / 5);
            int column = (button.tag - (row * 5));
            // Move
            button.frame = CGRectMake(column*61+8, row*61+8, 60, 60);
            if (button.tag == [_buttons count] - 1) {
                [scrollView setContentSize:CGSizeMake(300, row*61+16+60)];
            }

        }
    }
}

Answer 1

您显示的是"rearrangeButtons“，但永远不要使用它--我认为上面的代码已经过时了。在任何情况下，这里都有一些小问题：

[_images objectAtIndex:button.tag];
[_images removeObjectAtIndex:button.tag];
[_images removeObject:button];

第一个和最后一个语句是没有意义的，您应该使用的是：

[_images removeObjectAtIndex:button.tag];
[self rearrangeButtons:button.tag];

若要向应用程序添加是否正确的检查，请尝试将以下代码添加到rearrangeButtons的末尾：

int idx = 0;
for (UIButton *button in _buttons) {
  NSLog(@"Going to query button at index %d", idx);
  NSLog(@"Button at index %d is of type %@", idx, NSStringFromClass([button class]);
  // if the button is not a UIView subclass, it won't have tag. If its a dealloced 
  // object then it probably will crash when you ask it its class...
  if(button.tag != idx) NSLog(@"INDEX PROBLEM AT BUTTON ARRAY INDEC %d", idx);
  ++idx;
}

编辑:在循环中编辑的代码，用于打印对象类。

EDIT2:所以我把你的代码放到一个新的项目中，ButtonManager。本质上是可以的，但是你有一些问题。首先，即使不存在文件，也可以对文件名进行索引，这样索引就可能不同步。其次，对button.tag使用%lu格式，但这是一个整数，所以应该使用"%d“。最后，从数组中删除按钮，但不删除图像或缩略图。

如果您下载该项目，您将在所有需要更改的地方看到警告，以使其正常工作。我不知道为什么按钮索引会损坏--也许是其他代码。无论如何，在代码中添加了一个数据一致性测试--在代码中对其进行零星调用--如果它曾经失败过，那么您就知道您的问题在最后一个好的测试和最新的失败测试之间。

该项目在启动时启动一条"deleteItem:“消息，只要您点击”是“，就会继续删除数组中间的项。

Answer 2

用以下方法替换您的功能

- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex
{
    NSString *title = [alertView buttonTitleAtIndex:buttonIndex];
    if([title isEqualToString:@"YES"]) {
        NSLog(@"YES was selected.");
        UIButton *button = _clickedButton;
        [self rearrangeItems:button.tag];

    }
}


- (void)rearrangeItems:(int)startIndex {

       for (UIButton *button in _buttons) {
       // Shift the tags down one
        if (button.tag > startIndex) {
         NSLog(@"called here");
        [button removeFromSuperview];//remove the button from the scrollview
        [_buttons removeObjectAtIndex:button.tag];//remove the button object from _buttons array

        NSFileManager *fileManager = [NSFileManager defaultManager];
        NSArray *paths = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES);
        NSString *documentsDirectory = [paths objectAtIndex:0];
        NSString *fullPath = [documentsDirectory stringByAppendingPathComponent:[NSString stringWithFormat:@"oneSlotImages%lu.png", button.tag]];
        NSData *imageData = [NSData dataWithContentsOfFile:fullPath];
        [fileManager removeItemAtPath: fullPath error:NULL];

        button.tag -= 1;

        fullPath = [documentsDirectory stringByAppendingPathComponent:[NSString stringWithFormat:@"oneSlotImages%lu.png", button.tag]];
        [imageData writeToFile:fullPath atomically:YES];

        // Recalculate Position
        int row = floor(button.tag / 5);
        int column = (button.tag - (row * 5));
        // Move
        button.frame = CGRectMake(column*61+8, row*61+8, 60, 60);
        if (button.tag == [_buttons count] - 1) {
            [scrollView setContentSize:CGSizeMake(300, row*61+16+60)];
        }
        [scrollView setNeedsDisplay];
    }
}

希望这能有所帮助。