ios - 未在所有 uitableviewcells 上绘制线

Question

我有一个带有自定义单元格的表格 View (当然由自定义类管理)，它具有以下 drawRect:自定义类中的函数:

- (void)drawRect:(CGRect)rect
{
    [super drawRect:rect];
    CGRect busNumberFrame = busNumber.frame;

    NSLog(@"-----------------");
    NSLog(@"Line Origin X: %f", busNumberFrame.origin.x + busNumberFrame.size.width);
    NSLog(@"Line Origin Y: %f", self.frame.origin.y);
    NSLog(@"Line End X: %f", busNumberFrame.origin.x + busNumberFrame.size.width);
    NSLog(@"Line End Y: %f", self.frame.origin.y + self.frame.size.height);
    NSLog(@"-----------------");

    CGContextRef cgContext = UIGraphicsGetCurrentContext();
    CGContextSetRGBStrokeColor(cgContext, 0.0, 0.0, 0.0, 1.0);
    CGContextSetLineWidth(cgContext, 0.75);
    CGContextMoveToPoint(cgContext, busNumberFrame.origin.x + busNumberFrame.size.width, self.frame.origin.y);
    CGContextAddLineToPoint(cgContext, busNumberFrame.origin.x + busNumberFrame.size.width, self.frame.origin.y + self.frame.size.height);
    CGContextStrokePath(cgContext);
}

这会从单元格顶部到底部绘制一条线。这为第一个单元格成功绘制，但随后的单元格不显示应该绘制的线。这是 cellForRowAtIndexPath 的代码

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    BusInfoTableViewCell *cell = (BusInfoTableViewCell *)[tableView dequeueReusableCellWithIdentifier:@"Bus Route Cell"];

    Bus *bus = [self.fetchedResultsController objectAtIndexPath:indexPath];
    // Configure the cell...

    cell.busNumber.text = [bus.number stringValue];
    cell.firstStop.text = bus.departure;
    cell.lastStop.text = bus.arrival;
    [cell.contentView setNeedsDisplay];
    return cell;
}

这是 drawRect:的日志输出:

2012-02-21 19:35:08.840 ETA[2208:707] -----------------
2012-02-21 19:35:08.843 ETA[2208:707] Line Origin X: 79.000000
2012-02-21 19:35:08.843 ETA[2208:707] Line Origin Y: 0.000000
2012-02-21 19:35:08.844 ETA[2208:707] Line End X: 79.000000
2012-02-21 19:35:08.845 ETA[2208:707] Line End Y: 63.000000
2012-02-21 19:35:08.845 ETA[2208:707] -----------------
2012-02-21 19:35:08.850 ETA[2208:707] -----------------
2012-02-21 19:35:08.851 ETA[2208:707] Line Origin X: 79.000000
2012-02-21 19:35:08.852 ETA[2208:707] Line Origin Y: 63.000000
2012-02-21 19:35:08.852 ETA[2208:707] Line End X: 79.000000
2012-02-21 19:35:08.853 ETA[2208:707] Line End Y: 126.000000
2012-02-21 19:35:08.853 ETA[2208:707] -----------------
2012-02-21 19:35:08.857 ETA[2208:707] -----------------
2012-02-21 19:35:08.857 ETA[2208:707] Line Origin X: 79.000000
2012-02-21 19:35:08.858 ETA[2208:707] Line Origin Y: 126.000000
2012-02-21 19:35:08.859 ETA[2208:707] Line End X: 79.000000
2012-02-21 19:35:08.859 ETA[2208:707] Line End Y: 189.000000
2012-02-21 19:35:08.860 ETA[2208:707] -----------------

我可能做错了什么......

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提前致谢。

Answer 1

坐标是单元格的本地坐标，因此您应该使用以下坐标(self.frame 的所有实例都应该是 self.bounds ):

- (void)drawRect:(CGRect)rect {
    [super drawRect:rect];
    CGRect busNumberFrame = busNumber.frame;

    NSLog(@"-----------------");
    NSLog(@"Line Origin X: %f", busNumberFrame.origin.x + busNumberFrame.size.width);
    NSLog(@"Line Origin Y: %f", self.bounds.origin.y);
    NSLog(@"Line End X: %f", busNumberFrame.origin.x + busNumberFrame.size.width);
    NSLog(@"Line End Y: %f", self.bounds.origin.y + self.bounds.size.height);
    NSLog(@"-----------------");

    CGContextRef cgContext = UIGraphicsGetCurrentContext();
    CGContextSetRGBStrokeColor(cgContext, 0.0, 0.0, 0.0, 1.0);
    CGContextSetLineWidth(cgContext, 0.75);
    CGContextMoveToPoint(cgContext, busNumberFrame.origin.x + busNumberFrame.size.width, self.bounds.origin.y);
    CGContextAddLineToPoint(cgContext, busNumberFrame.origin.x + busNumberFrame.size.width, self.bounds.origin.y + self.bounds.size.height);
    CGContextStrokePath(cgContext);
}