如何自定义分组表视图单元格的背景/边框颜色？ [英] How to customize the background/border colors of a grouped table view cell?

问题描述

我想自定义分组样式UITableView的背景和边框颜色。

I would like to customize both the background and the border color of a grouped-style UITableView.

我可以使用以下方法自定义背景颜色：

I was able to customize the background color by using the following:

tableView.contentView.backgroundColor = [UIColor greenColor];

但边框颜色仍然是我不知道如何改变的。

But the border color is still something I don't know how to change.

如何自定义分组样式表视图的这两个方面？

How do I customize these two aspects of the grouped-style table view?

推荐答案

更新：在iPhone OS 3.0及更高版本 UITableViewCell 现在有一个 backgroundColor 属性真的很容易（特别是结合 [UIColor colorWithPatternImage：] 初始化）。但我会为任何需要它的人留下2.0版本的答案。

UPDATE: In iPhone OS 3.0 and later UITableViewCell now has a backgroundColor property that makes this really easy (especially in combination with the [UIColor colorWithPatternImage:] initializer). But I'll leave the 2.0 version of the answer here for anyone that needs it…

是。这是我做到这一点，当我不得不这样做：

It's harder than it really should be. Here's how I did this when I had to do it:

你需要设置UITableViewCell的backgroundView属性为一个自定义的UIView绘制边框和背景本身的相应的颜色。此视图需要能够以4种不同的模式绘制边框，在节的第一个单元格的顶部为圆形，在节的最后一个单元格的底部为圆形，在节的中间的单元格没有圆角，并在包含一个单元格的部分的四个角落四舍五入。

You need to set the UITableViewCell's backgroundView property to a custom UIView that draws the border and background itself in the appropriate colors. This view needs to be able to draw the borders in 4 different modes, rounded on the top for the first cell in a section, rounded on the bottom for the last cell in a section, no rounded corners for cells in the middle of a section, and rounded on all 4 corners for sections that contain one cell.

不幸的是我不知道如何自动设置此模式，所以我不得不设置在UITableViewDataSource的-cellForRowAtIndexPath方法。

Unfortunately I couldn't figure out how to have this mode set automatically, so I had to set it in the UITableViewDataSource's -cellForRowAtIndexPath method.

这是一个真正的PITA，但我已经确认与苹果工​​程师，这是目前的唯一方法。

It's a real PITA but I've confirmed with Apple engineers that this is currently the only way.

更新以下是该自定义bg视图的代码。有一个绘图错误，使圆角看起来有点滑稽，但我们转移到一个不同的设计和报废的自定义背景，我有机会解决之前。仍然可能对您非常有帮助：

Update Here's the code for that custom bg view. There's a drawing bug that makes the rounded corners look a little funny, but we moved to a different design and scrapped the custom backgrounds before I had a chance to fix it. Still this will probably be very helpful for you:

//
//  CustomCellBackgroundView.h
//
//  Created by Mike Akers on 11/21/08.
//  Copyright 2008 __MyCompanyName__. All rights reserved.
//

#import <UIKit/UIKit.h>

typedef enum  {
    CustomCellBackgroundViewPositionTop, 
    CustomCellBackgroundViewPositionMiddle, 
    CustomCellBackgroundViewPositionBottom,
    CustomCellBackgroundViewPositionSingle
} CustomCellBackgroundViewPosition;

@interface CustomCellBackgroundView : UIView {
    UIColor *borderColor;
    UIColor *fillColor;
    CustomCellBackgroundViewPosition position;
}

    @property(nonatomic, retain) UIColor *borderColor, *fillColor;
    @property(nonatomic) CustomCellBackgroundViewPosition position;
@end

//
//  CustomCellBackgroundView.m
//
//  Created by Mike Akers on 11/21/08.
//  Copyright 2008 __MyCompanyName__. All rights reserved.
//

#import "CustomCellBackgroundView.h"

static void addRoundedRectToPath(CGContextRef context, CGRect rect,
                                 float ovalWidth,float ovalHeight);

@implementation CustomCellBackgroundView
@synthesize borderColor, fillColor, position;

- (BOOL) isOpaque {
    return NO;
}

- (id)initWithFrame:(CGRect)frame {
    if (self = [super initWithFrame:frame]) {
        // Initialization code
    }
    return self;
}

- (void)drawRect:(CGRect)rect {
    // Drawing code
    CGContextRef c = UIGraphicsGetCurrentContext();
    CGContextSetFillColorWithColor(c, [fillColor CGColor]);
    CGContextSetStrokeColorWithColor(c, [borderColor CGColor]);

    if (position == CustomCellBackgroundViewPositionTop) {
        CGContextFillRect(c, CGRectMake(0.0f, rect.size.height - 10.0f, rect.size.width, 10.0f));
        CGContextBeginPath(c);
        CGContextMoveToPoint(c, 0.0f, rect.size.height - 10.0f);
        CGContextAddLineToPoint(c, 0.0f, rect.size.height);
        CGContextAddLineToPoint(c, rect.size.width, rect.size.height);
        CGContextAddLineToPoint(c, rect.size.width, rect.size.height - 10.0f);
        CGContextStrokePath(c);
        CGContextClipToRect(c, CGRectMake(0.0f, 0.0f, rect.size.width, rect.size.height - 10.0f));
    } else if (position == CustomCellBackgroundViewPositionBottom) {
        CGContextFillRect(c, CGRectMake(0.0f, 0.0f, rect.size.width, 10.0f));
        CGContextBeginPath(c);
        CGContextMoveToPoint(c, 0.0f, 10.0f);
        CGContextAddLineToPoint(c, 0.0f, 0.0f);
        CGContextStrokePath(c);
        CGContextBeginPath(c);
        CGContextMoveToPoint(c, rect.size.width, 0.0f);
        CGContextAddLineToPoint(c, rect.size.width, 10.0f);
        CGContextStrokePath(c);
        CGContextClipToRect(c, CGRectMake(0.0f, 10.0f, rect.size.width, rect.size.height));
    } else if (position == CustomCellBackgroundViewPositionMiddle) {
        CGContextFillRect(c, rect);
        CGContextBeginPath(c);
        CGContextMoveToPoint(c, 0.0f, 0.0f);
        CGContextAddLineToPoint(c, 0.0f, rect.size.height);
        CGContextAddLineToPoint(c, rect.size.width, rect.size.height);
        CGContextAddLineToPoint(c, rect.size.width, 0.0f);
        CGContextStrokePath(c);
        return; // no need to bother drawing rounded corners, so we return
    }

    // At this point the clip rect is set to only draw the appropriate
    // corners, so we fill and stroke a rounded rect taking the entire rect

    CGContextBeginPath(c);
    addRoundedRectToPath(c, rect, 10.0f, 10.0f);
    CGContextFillPath(c);  

    CGContextSetLineWidth(c, 1);  
    CGContextBeginPath(c);
    addRoundedRectToPath(c, rect, 10.0f, 10.0f);  
    CGContextStrokePath(c); 
}


- (void)dealloc {
    [borderColor release];
    [fillColor release];
    [super dealloc];
}


@end

static void addRoundedRectToPath(CGContextRef context, CGRect rect,
                                float ovalWidth,float ovalHeight)

{
    float fw, fh;

    if (ovalWidth == 0 || ovalHeight == 0) {// 1
        CGContextAddRect(context, rect);
        return;
    }

    CGContextSaveGState(context);// 2

    CGContextTranslateCTM (context, CGRectGetMinX(rect),// 3
                           CGRectGetMinY(rect));
    CGContextScaleCTM (context, ovalWidth, ovalHeight);// 4
    fw = CGRectGetWidth (rect) / ovalWidth;// 5
    fh = CGRectGetHeight (rect) / ovalHeight;// 6

    CGContextMoveToPoint(context, fw, fh/2); // 7
    CGContextAddArcToPoint(context, fw, fh, fw/2, fh, 1);// 8
    CGContextAddArcToPoint(context, 0, fh, 0, fh/2, 1);// 9
    CGContextAddArcToPoint(context, 0, 0, fw/2, 0, 1);// 10
    CGContextAddArcToPoint(context, fw, 0, fw, fh/2, 1); // 11
    CGContextClosePath(context);// 12

    CGContextRestoreGState(context);// 13
}

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