ios - 如何在 viewWillDisappear 上清除/清空粘贴板

Question

我用来UIPasteboard在两个UITextView.

代码如下所示：

- (void)viewDidLoad {
   [super viewDidLoad];
   pasteBoard = [UIPasteboard generalPasteboard]; //it is declared in .h as UIPasteboard *pasteBoard;
}

-(IBAction)doCopyBtn {
    if (![toCopyTextView.text isEqualToString:@""]){
        pasteBoard.string = toCopyTextView.text;
        NSLog(@"pasteb1 %@", pasteBoard.string);
    } else {
        NSLog (@"error! enter smth");
    }
}

-(IBAction)doPasteBtn {
    if (![pasteBoard.string isEqualToString:@""]){ 
        toPasteTextView.text = pasteBoard.string;
        NSLog(@"pasteb2 %@", pasteBoard.string);
    } else {
        NSLog (@"error! enter smth");
    }
}

甚至这也无济于事（NSLog 返回pasteb2 (null)：）

-(void) viewWillDisappear:(BOOL)animated{
    [super viewWillDisappear:animated];
    [pasteBoard setString:@""]; 
}

Answer 1

iOS –UIPasteboard

尝试以下操作：

    UIPasteboard *pb = [UIPasteboard generalPasteboard];
    [pb setValue:@"" forPasteboardType:UIPasteboardNameGeneral];

Arab_Geek 的回答是正确的，但可用于 Cocoa（我怀疑您正在寻找 iOS 解决方案）

Answer 2

操作系统 -NSPasteboard

干得好 ..

NSPasteboard *pb = [NSPasteboard generalPasteboard];
[pb declareTypes: [NSArray arrayWithObject:NSStringPboardType] owner: self];
[pb setString: @"" forType: NSStringPboardType];

Answer 3

将值设置为""将返回nil用于所有预期目的。但是，它会使粘贴板处于与粘贴操作之前略有不同的状态。

迅速

let pb = self.pasteBoard()
pb.setValue("", forPasteboardType: UIPasteboardNameGeneral)

...不等于UIPasteboard.removePasteboardWithName(). 如果需要恢复UIPasteboard状态（1），您可以使用以下块：

迅速

let pb = self.pasteBoard()

let items:NSMutableArray = NSMutableArray(array: pb.items)
for object in pb.items {
    if let aDictionary = object as? NSDictionary {
        items.removeObject(aDictionary)
    }
}
pb.items = items as [AnyObject]

(1) 恢复状态。