Question

以下代码应该在mapWindow NSView上绘制一个矩形。我的程序还有另一个使用NSView窗口的文件;因此我想要一个新窗口。但是，矩形不显示。任何帮助将不胜感激。

@interface mapWindow : NSView {@private NSView* theMapWindow;}

- (void)drawRect:(int)pointx: (int)pointy;

@property (assign) IBOutlet NSView* theMapWindow;

@end

@implementation mapWindow
@synthesize theMapWindow;
- (void)mouseDown:(NSEvent *)event 
{
    NSPoint point = [event locationInWindow];
    //NSLog( @"mouseDown location: (%f,%f)", (float) point.x, (float) point.y);
    [self drawRect:point.x:point.y];
}

- (void)drawRect:(int)pointx: (int)pointy
{
    NSLog(@"Drawing point at (%d, %d)",pointx, pointy);
    NSPoint origin = { pointx,pointy };

    NSRect rect;
    rect.origin = origin;
    rect.size.width  = 128;
    rect.size.height = 128;

    NSBezierPath * path;
    path = [NSBezierPath bezierPathWithRect:rect];

    [path setLineWidth:4];

    [[NSColor whiteColor] set];
    [path fill];

    [[NSColor grayColor] set]; 
    [path stroke];

    [theMapWindow setNeedsDisplayInRect:rect];
}

Answer 1

你做错了。你不应该自己打电话给drawRect，它会被你召唤。将drawRect的调用替换为setNeedsDisplayInRect，并从setNeedsDisplayInRect方法中删除drawRect。

Answer 2

你的drawRect ::是自定义方法，与drawRect：不同，当你将视图作为当前上下文时，它不会被调用，尝试在你的周围抛出[self lockFocus]，[self unlockFocus]绘图代码。

Answer 3

代表您调用

NSView的{{1}}方法;您应该将它用于您的绘图，如Drawing View Content中所述。

drawRect:

-

@interface mapWindow : NSView {

@private
   NSView* theMapWindow;
   NSPoint drawPoint;
}

// - (void)drawRect:(int)pointx: (int)pointy;

@property (assign) IBOutlet NSView* theMapWindow;
@property (assign) NSPoint drawPoint;

@end

Objective-C在单独的窗口上绘图

3 个答案: