在NSTableView中實現拖放

Question

任何人都可以幫我在NSTableView中實現拖放操作嗎？ 我在下面使用了這段代碼，但這些方法在執行期間沒有被調用。

- (BOOL)tableView:(NSTableView *)tv writeRowsWithIndexes:(NSIndexSet *)rowIndexes toPasteboard:(NSPasteboard*)pboard
{
    // Copy the row numbers to the pasteboard.
    NSData *data = [NSKeyedArchiver archivedDataWithRootObject:rowIndexes];
    [pboard declareTypes:[NSArray arrayWithObject:@".gif"] owner:self];
    [pboard setData:data forType:@".gif"];
    return YES;
}

- (NSDragOperation)tableView:(NSTableView*)tv validateDrop:(id <NSDraggingInfo>)info proposedRow:(NSInteger)row proposedDropOperation:(NSTableViewDropOperation)op
{
    // Add code here to validate the drop

    if (row > [ m_imageArray count])
        return NSDragOperationNone;

    if (nil == [info draggingSource]) // From other application
    {
        return NSDragOperationNone;
    }
    else if (self == [info draggingSource]) // From self
    {
        return NSDragOperationNone;
    }
    else // From other documents 
    {
        [tv setDropRow: row dropOperation: NSTableViewDropAbove];
        return NSDragOperationCopy;
    }

    NSLog(@"validate Drop");
    return NSDragOperationCopy;
}


- (BOOL)tableView:(NSTableView *)aTableView acceptDrop:(id <NSDraggingInfo>)info
              row:(NSInteger)row dropOperation:(NSTableViewDropOperation)operation
{
    NSPasteboard* pboard = [info draggingPasteboard];
    NSData* rowData = [pboard dataForType:@".gif"];
    NSIndexSet* rowIndexes = [NSKeyedUnarchiver unarchiveObjectWithData:rowData];
    NSInteger dragRow = [rowIndexes firstIndex];

    // Move the specified row to its new location...
}

Answer 1

這是一個例子

#import "TableViewController.h"
#import "Person.h"

#define MyDataType @"MyDataType"

@implementation TableViewController {
    NSMutableArray *list;
    NSInteger sourceIndex;
}
@synthesize tableView;

-(void)awakeFromNib {
    [tableView registerForDraggedTypes:[NSArray arrayWithObjects:MyDataType, nil]];
    list = [[NSMutableArray alloc] init];
    Person *person = [[Person alloc] initWithName:@"Newton" age:64];
    [list addObject:person];
    person = [[Person alloc] initWithName:@"Archimedes" age:74];
    [list addObject:person];
    person = [[Person alloc] initWithName:@"Euler" age:44];
    [list addObject:person];
    person = [[Person alloc] initWithName:@"Poincare" age:24];
    [list addObject:person];
    person = [[Person alloc] initWithName:@"Gauss" age:34];
    [list addObject:person];
}

-(void)reArrange:(NSMutableArray *)array sourceNum:(NSInteger)sourceNum destNum:(NSInteger)destNum {
    Person *person = list[sourceNum];
    [list insertObject:person atIndex:destNum];

    if (sourceNum < destNum) {
        [list removeObjectAtIndex:sourceNum];
    } else {
        [list removeObjectAtIndex:sourceNum+1];
    }

    [tableView reloadData];
}


#pragma mark - Table

// how many rows are there in the table?
-(NSInteger)numberOfRowsInTableView:(NSTableView *)tv {
    return list.count;
}

// What object should I show in a particular cell?
-(id)tableView:(NSTableView *)tv objectValueForTableColumn:(NSTableColumn *)tableColumn row:(NSInteger)row {
    Person *person = list[row];
    NSString *identifier = [tableColumn identifier];
    return [person valueForKey:identifier];
}

// Should I accept the drag with the rows specified by rowIndexes? If YES then place the data on the provided paste board.
- (BOOL)tableView:(NSTableView *)tv writeRowsWithIndexes:(NSIndexSet *)rowIndexes toPasteboard:(NSPasteboard *)pboard {
    NSData *data = [NSKeyedArchiver archivedDataWithRootObject:rowIndexes];
    [pboard declareTypes:[NSArray arrayWithObject:MyDataType] owner:self];
    [pboard setData:data forType:MyDataType];
    sourceIndex = [rowIndexes firstIndex];
    return YES;
}

// What kind of drag operation should I perform?
- (NSDragOperation)tableView:(NSTableView*)tv validateDrop:(id )info proposedRow:(NSInteger)row proposedDropOperation:(NSTableViewDropOperation)op {
    return op == NSTableViewDropAbove; // Specifies that the drop should occur above the specified row.
}

// The mouse button was released over a row in the table view, should I accept the drop?
- (BOOL)tableView:(NSTableView*)tv acceptDrop:(id )info row:(NSInteger)row dropOperation:(NSTableViewDropOperation)op {
    [self reArrange:list sourceNum:sourceIndex destNum:row]; // let the source array reflect the change
    return YES;
}

@end

Answer 2

您需要為表視圖聲明自定義拖動類型，然后使用您的自定義類型調用registerForDraggedTypes: . 否則，正如您所注意到的，這些方法都不會被調用。

Answer 3

當我忘記將dataSource到IB中的NSTabeView時，我通常會觀察到這種錯誤，即實現tableView:writeRowsWithIndexes:toPasteboard:的類tableView:writeRowsWithIndexes:toPasteboard: NSTableViewDataSource的方法。

Answer 4

使用核心數據拖放NSTableview

1. 注冊用於拖放的表視圖對象： -

    [tblCategory registerForDraggedTypes:[NSArray arrayWithObject:@"public.text"]]; 

拖放委托方法： -

 - (id <NSPasteboardWriting>)tableView:(NSTableView *)tableView pasteboardWriterForRow:(NSInteger)row
 {

 Category *category = (Category *)[self.arrCategoryList objectAtIndex:row];
 NSString *identifier = category.categoryname;

 NSPasteboardItem *pboardItem = [[NSPasteboardItem alloc] init];
 [pboardItem setString:identifier forType: @"public.text"];
 return pboardItem;
 }

 - (NSDragOperation)tableView:(NSTableView *)tableView validateDrop:(id <NSDraggingInfo>)info proposedRow:(NSInteger)row proposedDropOperation:(NSTableViewDropOperation)dropOperation
{


if(dropOperation == NSTableViewDropOn)
{
NSPasteboard *p = [info draggingPasteboard];
NSString *title = [p stringForType:@"public.text"];
Category* category ;
NSInteger srcIndex;
for (srcIndex = 0; srcIndex < [_arrCategoryList count]; srcIndex++)
{
  category = [_arrCategoryList objectAtIndex:srcIndex];
if ([category.categoryname isEqualToString:title])
{
        break;
}
    category = nil;
}
if(!category)
{
     // Not found
     return NO;
 }

 [_arrCategoryList removeObjectAtIndex:srcIndex];
 [_arrCategoryList insertObject:category atIndex:row];
 [tblCategory reloadData];
 return NSDragOperationMove;
}
  return NSDragOperationNone;
}

 - (BOOL)tableView:(NSTableView *)tableView acceptDrop:(id <NSDraggingInfo>)info row:(NSInteger)row dropOperation:(NSTableViewDropOperation)dropOperation
 {
   return YES;
}

Answer 5

您可以為NSMutableArray或NSMutableDictionary或任何其他對象注冊draggedTypes。以下代碼片段用於NSMutableArray。

[tableView registerForDraggedTypes:[NSArray arrayWithObject:@"NSMutableArray"] ];

Answer 6

您需要在awakFromnib聲明registerForDraggedTypes方法

像這樣。

[table_view registerForDraggedTypes:[NSArray arrayWithObjects:BasicTableViewDragAndDropDataType, nil]];

Answer 7

我必須推薦這個優秀的紅毛衣博客文章

http://www.red-sweater.com/blog/274/a-moveable-beast

它提供了一個NSArrayController子類，它將支持對表項進行拖放重新排序，如果你想支持在tableview外部拖動你的對象，我們只需要為該類編寫一個簡潔的簡單添加：

http://www.rwe-uk.com/blog/comments/nstableview_drag_and_drop_with_bindings_and_nsarraycontroller

它建立在原始帖子的基礎上