保存UIBezierPaths

Question

是否可以节省大量的UIBezierPaths？如果是这样，怎么办呢？我已经尝试将它们全部放入NSMutableArray（和NSMutableDictionary），然后将该数组/字典保存到NSUserDefaults但是我得到了这个警告：

*** -[NSUserDefaults setObject:forKey:]: Attempt to insert non-property value '(
"<UIBezierPath: 0x20b9ca10>",
"<UIBezierPath: 0x20a1dbf0>",
"<UIBezierPath: 0x20b9e550>",
)' of class '__NSArrayM'.  Note that dictionaries and arrays in property lists must also contain only property values.

Answer 1

尝试使用此代码

-(void)saveData :(NSMutableArray *)dataArray;
{
    NSFileManager *filemgr;
    NSString *docsDir;
    NSArray *dirPaths;

    filemgr = [NSFileManager defaultManager];

    // Get the documents directory
    dirPaths = NSSearchPathForDirectoriesInDomains(
                                                   NSDocumentDirectory, NSUserDomainMask, YES);

    docsDir = [dirPaths objectAtIndex:0];

    // Build the path to the data file
    NSString *dataFilePath = [[NSString alloc] initWithString: [docsDir
                                                                stringByAppendingPathComponent: @"data.archive"]];

    [NSKeyedArchiver archiveRootObject:
     dataArray toFile:dataFilePath];
}

-(NSMutableArray *)loadData;
{
    NSFileManager *filemgr;
    NSString *docsDir;
    NSArray *dirPaths;

    filemgr = [NSFileManager defaultManager];

    // Get the documents directory
    dirPaths = NSSearchPathForDirectoriesInDomains(
                                                   NSDocumentDirectory, NSUserDomainMask, YES);

    docsDir = [dirPaths objectAtIndex:0];

    // Build the path to the data file
    NSString *dataFilePath = [[NSString alloc] initWithString: [docsDir
                                                                stringByAppendingPathComponent: @"data.archive"]];

    // Check if the file already exists
    if ([filemgr fileExistsAtPath: dataFilePath])
    {
        NSMutableArray *dataArray;

        dataArray = [NSKeyedUnarchiver
                     unarchiveObjectWithFile: dataFilePath];

        return dataArray;
    }
    return NULL;
}

应该工作正常，我测试了这个保存BezierPath并且似乎工作正常。我创建了一个名为archiving的类，它处理从手机中保存和加载数组和字典。

Answer 2

这是另一个直接归档/取消归档UIBezierPath的解决方案：

- (NSURL *)documentsDirectory
{
    return [[[NSFileManager defaultManager] URLsForDirectory:NSDocumentDirectory inDomains:NSUserDomainMask] lastObject];
}

- (void)archivePath:(UIBezierPath*)bPath withName:(NSString *)archiveName
{
    NSString *savePath = [[[self documentsDirectory] URLByAppendingPathComponent:archiveName] path];
    [NSKeyedArchiver archiveRootObject:bPath toFile:savePath];
}

- (UIBezierPath *)unarchivePathWithName:(NSString *)archiveName
{
    return (UIBezierPath *)[NSKeyedUnarchiver unarchiveObjectWithFile:[[[self documentsDirectory] URLByAppendingPathComponent:archiveName] path]];
}

我没有进行任何错误检查或验证文件是否存在，但如果您确定那里有文件，则可以正常工作。以下是如何使用它的示例：

UIBezierPath *bez = [UIBezierPath bezierPathWithRect:CGRectMake(0, 0, 500, 100)];
[bez appendPath:[UIBezierPath bezierPathWithOvalInRect:CGRectMake(0, 0, 200, 200)]];
[self archivePath:bez withName:@"path.archive"];
UIBezierPath *bez2 = [self unarchivePathWithName:@"path.archive"];