cocoa - 如何先保存粘贴板内容，然后再恢复？

Question

我有一个不露面的 Mac OS X 应用程序，它需要从其他应用程序中复制选择。我通过模拟 CMD+C 击键来实现这一点。它完美地工作。但是有一个，我认为它很关键，副作用。未经用户许可，它将覆盖用户的粘贴板。所以在我复制选择之前我在想我应该保存粘贴板内容然后恢复它。有人可以给我一些提示，也许是示例代码？

Answer 1

NSPasteboard这是我为此写的一个类别。它似乎工作得很好。

@implementation NSPasteboard (SaveAndRestore)

// save current contents as an array of pasteboard items
- (NSArray *)save
{
    NSMutableArray *archive=[NSMutableArray array];
    for (NSPasteboardItem *item in [self pasteboardItems]) 
    {
        NSPasteboardItem *archivedItem=[[NSPasteboardItem alloc] init];
        for (NSString *type in [item types])
        {
            /* The mutableCopy performs a deep copy of the data. This avoids
               memory leak issues (bug in Cocoa?), which you might run into if
               you don't copy the data. */
            NSData *data=[[item dataForType:type] mutableCopy];
            if (data) { // nil safety check
                [archivedItem setData:data forType:type];
            }
        }
        [archive addObject:archivedItem];
    }
    return archive;
}

// restore previously saved data
- (void)restore:(NSArray *)archive
{
    [self clearContents];
    [self writeObjects:archive];
}

@end

Answer 2

使用对象关联的替代自包含实现：

#import <objc/runtime.h>

static void * kArchiveKey = &kArchiveKey;

@implementation NSPasteboard (SaveRestore)

- (void)setArchive:(NSArray *)newArchive
{
    objc_setAssociatedObject(self, kArchiveKey, newArchive, OBJC_ASSOCIATION_RETAIN);
}

- (NSArray *)archive
{
    return objc_getAssociatedObject(self, kArchiveKey);
}

- (void)save
{
    NSMutableArray *archive = [NSMutableArray array];
    for (NSPasteboardItem *item in [self pasteboardItems]) {
        NSPasteboardItem *archivedItem = [[NSPasteboardItem alloc] init];
        for (NSString *type in [item types]) {
            NSData *data = [item dataForType:type];
            if (data) {
                [archivedItem setData:data forType:type];
            }
        }
        [archive addObject:archivedItem];
    }
    [self setArchive:archive];
}

- (void)restore
{
    [self clearContents];
    [self writeObjects:[self archive]];
}

@end

Answer 3

看NSPasteboard。

+[NSPasteboard generalPasteboard]将为您提供共享的粘贴板，您可以使用该类来获取和设置内容。