滚动时，一个单元格的内容在下一个单元格中重复出现。单元格是自定义单元格。
static NSString *cellIdentifier1 = @"pollCell";
IXPollCustomCell *pollCell = (IXPollCustomCell *)[tableView dequeueReusableCellWithIdentifier:cellIdentifier1];
if (pollCell == nil) {
pollCell = [[[NSBundle mainBundle] loadNibNamed:@"IXPollCustomCell" owner:self options:nil] objectAtIndex:0];
pollCell.selectionStyle = UITableViewCellSelectionStyleNone;
}
[self configurePollCell:pollCell atIndexPath:indexPath];//custom cell configuration
如何防止子视图内容重复出现？
编辑:-
我在此处包括configurePollCell函数。
-(void)configurePollCell:(IXPollCustomCell*)cell atIndexPath:(NSIndexPath *)indexPath
{
ThreadInfo *info = [_fetchedResultsController objectAtIndexPath:indexPath];
if([info.pollType isEqualToString:@"Star"])
{
cell.multiChoiceView.hidden=YES;
cell.starView.hidden=NO;
UIImage *blackStarImage=[[UIImage alloc]initWithContentsOfFile:[[NSBundle mainBundle]pathForResource:@"star_orange" ofType:@"png"]];
UIImage *whiteStarImage=[[UIImage alloc]initWithContentsOfFile:[[NSBundle mainBundle]pathForResource:@"star_white" ofType:@"png"]];
cell.star1ImageView.image=whiteStarImage;
cell.star2ImageView.image=whiteStarImage;
cell.star3ImageView.image=whiteStarImage;
cell.star4ImageView.image=whiteStarImage;
cell.star5ImageView.image=whiteStarImage;
cell.selectedStar1ImageView.hidden=YES;
cell.selectedStar2ImageView.hidden=YES;
cell.selectedStar3ImageView.hidden=YES;
cell.selectedStar4ImageView.hidden=YES;
cell.selectedStar5ImageView.hidden=YES;
cell.averageLabel.text=@"";
//Coloring
BOOL isStarColoringRequired=NO;
if([info.isPollSender boolValue])
{
if ([info.pollScope isEqualToString:@"private"])
{
if([info.responseCount integerValue]>=2)
{
isStarColoringRequired=YES;
}
}
else
{
isStarColoringRequired=YES;
}
}
else
{
if ([info.pollScope isEqualToString:@"private"])
{
if([info.pollVisibility isEqualToString:@"public"])
{
if((info.selectedStar!=nil && [info.replied boolValue] )&&[info.responseCount integerValue]>=2)
{
isStarColoringRequired=YES;
}
}
}
else
{
if(info.selectedStar!=nil && [info.replied boolValue])
{
isStarColoringRequired=YES;
}
}
}
if(isStarColoringRequired)
{
if(ansDict!=nil)
{
double maxHeight= cell.star1ImageView.frame.size.height;
double maxWidth= cell.star1ImageView.frame.size.width;
int star1Value=[[ansDict valueForKey:@"star1"] intValue];
int star2Value=[[ansDict valueForKey:@"star2"] intValue];
int star3Value=[[ansDict valueForKey:@"star3"] intValue];
int star4Value=[[ansDict valueForKey:@"star4"] intValue];
int star5Value=[[ansDict valueForKey:@"star5"] intValue];
NSInteger total=[info.responseCount integerValue];
if(total!=0)
{
float star1Per=(float)star1Value/total;
float star2Per=(float)star2Value/total;
float star3Per=(float)star3Value/total;
float star4Per=(float)star4Value/total;
float star5Per=(float)star5Value/total;
float averageScore=(star1Value+star2Value*2+star3Value*3+star4Value*4+star5Value*5)/(float)total;
cell.averageLabel.text=[NSString stringWithFormat:@"Average Score - %.2f",averageScore];
CGFloat star1Y=maxHeight-(star1Per * maxHeight);
CGRect star1Rect = CGRectMake(0,star1Y,maxWidth,star1Per * maxHeight );
CGImageRef imageRef1 = CGImageCreateWithImageInRect([blackStarImage CGImage], star1Rect);
UIImage *croppedImage1 = [UIImage imageWithCGImage:imageRef1];
CGImageRelease(imageRef1);
cell.color1ImageView.frame=star1Rect;
cell.color1ImageView.image=nil;
cell.color1ImageView.image=croppedImage1;
CGFloat star2Y=maxHeight-(star2Per * maxHeight);
CGRect star2Rect = CGRectMake(0,star2Y,maxWidth,star2Per * maxHeight );
CGImageRef imageRef2 = CGImageCreateWithImageInRect([blackStarImage CGImage], star2Rect);
UIImage *croppedImage2 = [UIImage imageWithCGImage:imageRef2];
CGImageRelease(imageRef2);
cell.color2ImageView.frame=star2Rect;
cell.color2ImageView.image=nil;
cell.color2ImageView.image=croppedImage2;
CGFloat star3Y=maxHeight-(star3Per * maxHeight);
CGRect star3Rect = CGRectMake(0,star3Y,maxWidth,star3Per * maxHeight );
CGImageRef imageRef3 = CGImageCreateWithImageInRect([blackStarImage CGImage], star3Rect);
UIImage *croppedImage3 = [UIImage imageWithCGImage:imageRef3];
CGImageRelease(imageRef3);
cell.color3ImageView.frame=star3Rect;
cell.color3ImageView.image=nil;
cell.color3ImageView.image=croppedImage3;
CGFloat star4Y=maxHeight-(star4Per * maxHeight);
CGRect star4Rect = CGRectMake(0,star4Y,maxWidth,star4Per * maxHeight );
CGImageRef imageRef4 = CGImageCreateWithImageInRect([blackStarImage CGImage], star4Rect);
UIImage *croppedImage4 = [UIImage imageWithCGImage:imageRef4];
CGImageRelease(imageRef4);
cell.color4ImageView.frame=star4Rect;
cell.color4ImageView.image=nil;
cell.color4ImageView.image=croppedImage4;
CGFloat star5Y=maxHeight-(star5Per * maxHeight);
CGRect star5Rect = CGRectMake(0,star5Y,maxWidth,star5Per * maxHeight );
CGImageRef imageRef5 = CGImageCreateWithImageInRect([blackStarImage CGImage], star5Rect);
UIImage *croppedImage5 = [UIImage imageWithCGImage:imageRef5];
CGImageRelease(imageRef5);
cell.color5ImageView.frame=star5Rect;
cell.color5ImageView.image=nil;
cell.color5ImageView.image=croppedImage5;
}
}
}
int selectedStarCount=[info.selectedStar intValue];
if([info.pollVisibility isEqualToString:@"private"])
{
switch (selectedStarCount) {
case 1:
cell.selectedStar1ImageView.hidden=NO;
break;
case 2:
cell.selectedStar2ImageView.hidden=NO;
break;
case 3:
cell.selectedStar3ImageView.hidden=NO;
break;
case 4:
cell.selectedStar4ImageView.hidden=NO;
break;
case 5:
cell.selectedStar5ImageView.hidden=NO;
break;
default:
break;
}
}
else
{
if(info.selectedStar!=nil)
{
switch (selectedStarCount) {
case 1:
cell.selectedStar1ImageView.hidden=NO;
break;
case 2:
cell.selectedStar2ImageView.hidden=NO;
break;
case 3:
cell.selectedStar3ImageView.hidden=NO;
break;
case 4:
cell.selectedStar4ImageView.hidden=NO;
break;
case 5:
cell.selectedStar5ImageView.hidden=NO;
break;
default:
break;
}
}
}
if(info.image !=nil)
{
CGRect addFrame = cell.starView.frame;
if (info.threadMessage.length > 100){
addFrame.origin.y = 178 + 240;
} else {
addFrame.origin.y = 178 + 220;
}
cell.starView.frame = addFrame;
} else {
CGRect addFrame = cell.starView.frame;
cell.starView.frame = CGRectMake(0, ((0.8* self.view.frame.size.height)-10) / 2 +40, addFrame.size.width, 73);
}
}
}
最佳答案
您可以在子类中实现prepareForReuse方法，并在那里进行清理。当您将子视图添加到单元格时，它将保留在那里，直到您更改/删除它。dequeueReusableCell仅在可能的情况下为您提供一个单元，它不会对单元本身进行任何清理。
所以，如果我有例如:
MyCustomCell *cell = [tableView dequeueReusableCellWithIdentifier:cellIdentifier];
if (!cell)
{
cell = [[MyCustomCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier: dequeueReusableCellWithIdentifier:cellIdentifier];
static dispatch_once_t onceToken = 0;
dispatch_once(&onceToken, ^{
UIView *testView = [[UIView alloc] initWithFrame:CGRectMake(20, 20, 20, 20);
testView.tag = 20;
testView.backgroundColor = UIColor.redColor;
[cell.contentView addSubview:testView];
});
}
cell.textLabel.text = @(indexPath.row).stringValue;
return cell;
当我向下滚动时，该红色子视图将出现在每个第n个单元格中。如果标记视图并实现
prepareForReuse，则可以删除该视图。- (void)prepareForReuse
{
[[self.contentView viewWithTag:20] removeFromSuperview]; //Does not crash if the view is nil. It's okay to send messages to nil in ObjC
}
在这种情况下，当我向下滚动时，我的红色视图将消失。因此，解决问题的方法是，您需要为每个单元格初始化添加一次子视图，然后在单元出队时对其进行管理。我希望这可以解决。
关于ios - 使用dequeueReusableCellWithIdentifier时不会清除UITableView自定义单元格的 subview 内容，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/29745482/