objective-c - NSKeyedArchiver 为 UIView 的 subview 返回 nil

Question

我有一个 ViewController，我在其中添加了一个名为 DrawingView 的自定义 UIView。我想在此 DrawingView 中添加 UITextView 的动态数量，因此我将 UITextView 子类化为 CustomTextView。在 ViewController 中，我有以下代码将 textview 添加到 DrawingView。

- (void)viewDidLoad
{
    [super viewDidLoad];
    DrawingView * newDrawingView = [[DrawingView alloc]init];
    self.drawingView = newDrawingView ;
}

-(void)setDrawingView:(DrawingView *)_drawingView
{  
    if (drawingView != _drawingView)
    {        
        [drawingView removeFromSuperview];
        drawingView = _drawingView;
        drawingView.customDelegate = self;
        drawingView.frame = scrollView.bounds;    
        drawingView.layer.cornerRadius = 8;
        drawingView.backgroundColor = [UIColor whiteColor];
        drawingView.clipsToBounds = YES;

        [self.view addSubview:drawingView];
    }
}

在按钮操作上，我在绘图 View 中添加了 CustomTextView。

currentText = [[TextViewContainer alloc]init];
[drawingView currentText];

现在我想存档此 DrawingView 及其 subview ，即 CustomTextView。所以在 CustomTextView 中我添加了 NSCoding Protocol 并在其中添加了属性

- (id)initWithCoder:(NSCoder *)aDecoder
{
     if ((self  =  [super initWithCoder:aDecoder]))
     {
         self.layer.borderWidth  =  [aDecoder decodeFloatForKey: @"borderWidth"] ;
     }
}

- (void)encodeWithCoder:(NSCoder *)aCoder
{
    [aCoder encodeFloat:self.layer.borderWidth forKey:@"borderWidth"];
}

上述方法中还有其他自定义属性。对于存档，我使用以下方法。

- (NSData *)dataForView:(UIView *)view:(NSString *)fileName
{

    NSMutableData *data = [NSMutableData data];
    NSKeyedArchiver  *archiver = [[NSKeyedArchiver alloc] initForWritingWithMutableData:data];
    [archiver encodeObject:view forKey:fileName];
    [archiver finishEncoding];

    return (id)data;
}


-(void)saveChangesInFile :(NSString *)fileName
{
    NSData *data = [self dataForView:drawingView:fileName];

    NSString *docsDirectory  =  [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];

    NSString *dataPath  =  [docsDirectory stringByAppendingPathComponent:@"/.hidden"];

    if (![[NSFileManager defaultManager] fileExistsAtPath:dataPath])
    {
        [[NSFileManager defaultManager] createDirectoryAtPath:dataPath withIntermediateDirectories:NO attributes:nil error:nil];
    }

    NSString *pathes  =  [dataPath stringByAppendingPathComponent:fileName];

    [data writeToFile:pathes atomically:YES];
}


- (UIView *)viewForData:(NSData *)data:(NSString*)key
{
    NSKeyedUnarchiver  *unarchiver = [[NSKeyedUnarchiver alloc] initForReadingWithData:data];

    UIView *view = [unarchiver decodeObjectForKey:key];

    [unarchiver finishDecoding];

    return view;
}

-(void)openSavedFileWithName:(NSString*)fileName{

    NSString *docsDirectory  =  [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];

    NSString *dataPath  =  [docsDirectory stringByAppendingPathComponent:@"/.hidden"];
    NSString *filepath = [dataPath stringByAppendingFormat:@"/%@",fileName];
    NSData *data = [NSData dataWithContentsOfFile:filepath];

    if (data)
    {    
        UIView *newDrawView = [self viewForData:data:fileName];
    }
    NSLog(@"neew :%@",newDrawView.subviews);
    self.drawingView = (DrawingView *)newDrawView ;
    NSLog(@"self.drawingView :%@",self.drawingView.subviews);
}

但是我得到的 subview 数组为零。谁能帮帮我。

Answer 1

认为您正在尝试归档 View 本身。

[archiver encodeObject:view forKey:fileName];

我觉得不对。您不能存档任何 UI 组件，但只能存档模型。例如，您可以将模型(包括特定 View 的大小、颜色和背景图像)保存到数据库中，但不能将 View 本身保存到数据库中。同样对于归档，您需要归档其数据(即数组、图像等)而不是 UI 组件本身。

看看the NSKeyedArchiver ClassReference了解更多详情。另外，请看the link详细解释。谢谢。