Drag Drop delegate for NSView could not set an attribute - cocoa

Question

I am using NSView delegate to read the dragged excel values. For this I have subclassed NSView. My code is like-
#interface SSDragDropView : NSView
{
NSString *textToDisplay;
}
#property(nonatomic,retain) NSString *textToDisplay; // setters/getters
#synthesize textToDisplay;// setters/getters
#implementation SSDragDropView
- (NSDragOperation)draggingEntered:(id <NSDraggingInfo>)sender{
[self setNeedsDisplay: YES];
return NSDragOperationGeneric;
}
- (void)draggingExited:(id <NSDraggingInfo>)sender{
[self setNeedsDisplay: YES];
}
- (BOOL)prepareForDragOperation:(id <NSDraggingInfo>)sender {
[self setNeedsDisplay: YES];
return YES;
}
- (BOOL)performDragOperation:(id < NSDraggingInfo >)sender {
NSArray *draggedFilenames = [[sender draggingPasteboard] propertyListForType:NSFilenamesPboardType];
if ([[[draggedFilenames objectAtIndex:0] pathExtension] isEqual:#"xls"]){
return YES;
} else {
return NO;
}
}
- (void)concludeDragOperation:(id <NSDraggingInfo>)sender{
NSArray *draggedFilenames = [[sender draggingPasteboard] propertyListForType:NSFilenamesPboardType];
NSURL *url = [NSURL fileURLWithPath:[draggedFilenames objectAtIndex:0]];
NSString *textDataFile = [NSString stringWithContentsOfURL:url usedEncoding:nil error:nil]; //This text is the original excel text and its getting displayed.
[self setTextToDisplay:textDataFile];
}
I am setting the textDataFile value to a string attribute of that class. Now I am using SSDragDropView attribute value in some other class like-
SSDragDropView *dragView = [SSDragDropView new];
NSLog(#"DragView Value is %#",[dragView textToDisplay]);
But I am getting null each time. Is it like I can not set an attribute value in those delegate methods?

Answer 1

The above problem can be resolved just by declaring a global variable in your SSDragDropView.h class.
#import <Cocoa/Cocoa.h>
NSString *myTextToDisplay;
#interface SSDragDropView : NSView
{
The same can be set inside the desired delegate method
- (void)concludeDragOperation:(id <NSDraggingInfo>)sender {
// .... //Your Code
NSString *textDataFile = [NSString stringWithContentsOfURL:url usedEncoding:nil error:nil];
myTextToDisplay = textDataFile;
// .... //Your Code
}
:)

Answer 2

Add
[dragView registerForDraggedTypes:[NSArray arrayWithObjects:NSFilenamesPboardType, nil]];
- (NSDragOperation)draggingEntered:(id <NSDraggingInfo>)sender{
NSPasteboard *pboard = [sender draggingPasteboard];
NSArray *paths = [pboard propertyListForType:NSFilenamesPboardType];
NSLog(#"%#",paths);
[self setNeedsDisplay: YES];
return NSDragOperationGeneric;
}
Below code will print nil because you are not dragging anything on NSView.
SSDragDropView *dragView = [SSDragDropView new];
NSLog(#"DragView Value is %#",[dragView textToDisplay]);