我正在编写一个 Cocoa 应用程序。我写了一个可以拖放一个图像的代码。但现在我需要通过双击绘制几个图像并对其进行 D&D。每次双击-新图像，每次单击现有图像-启动 D&D。问题在于实现。我无法想象一种简单的实现方式。有人可以提出解决方案吗？
谢谢。
#import "DotView.h"
@implementation DotView
- (id)initWithFrame:(NSRect)frame
{
self = [super initWithFrame:frame];
if (self)
{
center.x = center.y = 100.0;
}
return self;
}
- (void)drawRect:(NSRect)rect {
NSRect bounds = [self bounds];
[[NSColor whiteColor] set];
NSRectFill(bounds);
[[NSGraphicsContext currentContext]
setImageInterpolation: NSImageInterpolationHigh];
NSSize viewSize = [self bounds].size;
NSSize imageSize = { 50, 40 };
NSPoint imageOrigin = center;
imageOrigin.x -= imageSize.width * 0.50;
imageOrigin.y -= imageSize.height * 0.50;
NSRect destRect;
destRect.origin = imageOrigin;
destRect.size = imageSize;
NSString * file = @"/Users/classuser/Desktop/ded.jpg";
NSImage * image = [[NSImage alloc] initWithContentsOfFile:file];
[image setFlipped:NO];
[image drawInRect: destRect
fromRect: NSZeroRect
operation: NSCompositeSourceOver
fraction: 1.0];
NSBezierPath * path = [NSBezierPath bezierPathWithRect:destRect];
}
-(void)mouseDown:(NSEvent*)event
{
NSPoint point = [event locationInWindow];
if(center.x<point.x+25 && center.x>point.x-25)
if(center.y<point.y+20 && center.y>point.y-20)
center = [self convertPoint:point fromView:nil];
}
- (void) mouseDragged:(NSEvent*)event {
[self mouseDown:event];
[self setNeedsDisplay:YES];
}
@end