objective-c - NSOutlineView 没有做它在它的子类中应该做的事情

Question

我创建了 NSOutlineView 的子类，并使用以下代码使行颜色交替。

头文件。

#import <Cocoa/Cocoa.h>


@interface MyOutlineView : NSOutlineView {
}

- (void) drawStripesInRect:(NSRect)clipRect;

@end

实现文件。

#import "MyOutlineView.h"

// RGB values for stripe color (light blue)
#define STRIPE_RED   (237.0 / 255.0)
#define STRIPE_GREEN (243.0 / 255.0)
#define STRIPE_BLUE  (254.0 / 255.0)
static NSColor *sStripeColor = nil;

@implementation MyOutlineView

// This is called after the table background is filled in,
// but before the cell contents are drawn.
// We override it so we can do our own light-blue row stripes a la iTunes.
- (void) highlightSelectionInClipRect:(NSRect)rect {
    [self drawStripesInRect:rect];
    [super highlightSelectionInClipRect:rect];
}

// This routine does the actual blue stripe drawing,
// filling in every other row of the table with a blue background
// so you can follow the rows easier with your eyes.
- (void) drawStripesInRect:(NSRect)clipRect {
    NSRect stripeRect;
    float fullRowHeight = [self rowHeight] + [self intercellSpacing].height;
    float clipBottom = NSMaxY(clipRect);
    int firstStripe = clipRect.origin.y / fullRowHeight;
    if (firstStripe % 2 == 0)
        firstStripe++;   // we're only interested in drawing the stripes
    // set up first rect
    stripeRect.origin.x = clipRect.origin.x;
    stripeRect.origin.y = firstStripe * fullRowHeight;
    stripeRect.size.width = clipRect.size.width;
    stripeRect.size.height = fullRowHeight;
    // set the color
    if (sStripeColor == nil)
        sStripeColor = [[NSColor colorWithCalibratedRed:STRIPE_RED
                                                  green:STRIPE_GREEN
                                                   blue:STRIPE_BLUE
                                                  alpha:1.0] retain];
    [sStripeColor set];
    // and draw the stripes
    while (stripeRect.origin.y < clipBottom) {
        NSRectFill(stripeRect);
        stripeRect.origin.y += fullRowHeight * 2.0;
    }
}

@end

但问题是代码应该做的事情并没有发生在大纲 View 上，代码是正确的，但我是否需要通过某种方式将大纲 View 连接到代码？

Answer 1

如果您在IB中实例化大纲 View ，则需要在身份检查器中将大纲 View 的类名称设置为“MyOutlineView”。请记住双击该控件，以便选择内部矩形，并且检查器窗口标题为“Outline View Identity”；单击该控件只会选择 ScrollView ( ScrollView 中嵌入了轮廓 View )。

如果您以编程方式创建大纲 View ，请确保实例化 MyOutlineView 而不是 NSOutlineView:

MyOutlineView *outlineView = [[MyOutlineView alloc] initWithFrame:rect];

其中 rect 是大纲 View 的框架。