[英]UItableView performance issue after scrolling for a while
我有一個UItableViewCell,它是在tableView:CellForRowAtIndexpath內以編程方式創建的,在滾動了一段時間后,性能下降。
我最初將它作為InterfaceBuilder中的自定義UITableViewCell使用,但是我沒有以編程方式創建此視圖,該視圖將性能提高了約40%,但是在滾動顯示40-100行后,它開始變得非常毛刺。出了如何緩存單元格UITableView的高度的方法,但是如果我的代碼中出現基本錯誤,我現在就很痛苦。 例如mybe我的雙端隊列不起作用? 我不確定如何檢查此問題,並希望在診斷我的問題時獲得幫助。
這就是我的tableview方法的樣子
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = @"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[UITableViewCell alloc]initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:CellIdentifier];
}
// Configure the cell...
cell.selectionStyle = UITableViewCellSelectionStyleNone;
if ([sortedItemsArray count] > 0) {
NSDictionary *currentInstallDictionary = [sortedItemsArray objectAtIndex:indexPath.row];
NSNumber *tempDUP = [currentInstallDictionary objectForKey:@"dup"];
NSInteger myInteger = [tempDUP integerValue];
if (myInteger == 0) {
//assign vals to labels
areaLabel = [[UILabel alloc] initWithFrame:CGRectMake(10.0, -2.0, 140.0, 35.0)];
NSString *areaString = [currentInstallDictionary objectForKey:@"area"];
if ((NSNull *) areaString != [NSNull null]) {
areaLabel.text = areaString;
} else {
areaLabel.text = @" ";
}
areaLabel.lineBreakMode = NSLineBreakByCharWrapping;
areaLabel.numberOfLines = 0;
[areaLabel sizeToFit];
[cell addSubview:areaLabel];
// removed other UIlabel that were here for readability
descriptionLabel = [[UILabel alloc] initWithFrame:CGRectMake(450.0, 5.0, 140.0, 35.0)];
NSString *descriptionString = [currentInstallDictionary objectForKey:@"partDesc"];
if ((NSNull *) descriptionString != [NSNull null]) {
descriptionLabel.text = descriptionString;
} else {
descriptionLabel.text = @" ";
}
descriptionLabel.lineBreakMode = NSLineBreakByCharWrapping;
descriptionLabel.numberOfLines = 0;
[descriptionLabel sizeToFit];
[cell addSubview:descriptionLabel];
shipmentLabel = [[UILabel alloc] initWithFrame:CGRectMake(605.0, 5.0, 140.0, 35.0)];
NSString *shipString = [currentInstallDictionary objectForKey:@"totShip"];
if ((NSNull *) shipString != [NSNull null]) {
shipmentLabel.text = shipString;
} else {
shipmentLabel.text = @" ";
}
shipmentLabel.lineBreakMode = NSLineBreakByCharWrapping;
shipmentLabel.numberOfLines = 0;
[shipmentLabel sizeToFit];
[cell addSubview:shipmentLabel];
quantityALabel = [[UILabel alloc] initWithFrame:CGRectMake(755.0, 5.0, 50.0, 35.0)];
NSString *totDryQtyString = [currentInstallDictionary objectForKey:@"totDryQty"];
if ((NSNull *) totDryQtyString != [NSNull null]) {
quantityALabel.text = totDryQtyString;
} else {
quantityALabel.text = @" ";
}
quantityALabel.lineBreakMode = NSLineBreakByCharWrapping;
quantityALabel.numberOfLines = 0;
[quantityALabel sizeToFit];
[cell addSubview:quantityALabel];
quantityBLabel = [[UILabel alloc] initWithFrame:CGRectMake(815.0, 5.0, 50.0, 35.0)];
NSString *totInsQtyString = [currentInstallDictionary objectForKey:@"totInsQty"];
if ((NSNull *) totInsQtyString != [NSNull null]) {
quantityBLabel.text = totInsQtyString;
} else {
quantityBLabel.text = @" ";
}
quantityBLabel.lineBreakMode = NSLineBreakByCharWrapping;
quantityBLabel.numberOfLines = 0;
[quantityBLabel sizeToFit];
[cell addSubview:quantityBLabel];
NSString *tDStateAString = [currentInstallDictionary objectForKey:@"totDryStateA"];
NSString *tDStateBString = [currentInstallDictionary objectForKey:@"totDryStateB"];
fitButtonImage = [UIButton buttonWithType:UIButtonTypeCustom];
fitButtonImage.frame = CGRectMake(888.0, 5.0, 35.0, 35.0);
if (([tDStateAString isEqualToString:@"T"]) && ([tDStateBString isEqualToString:@"W"])) {
UIImage *checkedOnImage = [UIImage imageNamed:@"CheckedOn.png"];
[fitButtonImage setImage:checkedOnImage forState:UIControlStateNormal];
[cell addSubview:fitButtonImage];
} else if (([tDStateAString isEqualToString:@"T"]) && ([tDStateBString isEqualToString:@"R"])) {
UIImage *checkedOnDisabledImage = [UIImage imageNamed:@"CheckedOnDisabled.png"];
[fitButtonImage setImage:checkedOnDisabledImage forState:UIControlStateNormal];
[cell addSubview:fitButtonImage];
} else {
if (![quantityALabel.text isEqualToString:@"0"]) {
UIImage *checkedOffImage = [UIImage imageNamed:@"CheckedOff.png"];
[fitButtonImage setImage:checkedOffImage forState:UIControlStateNormal];
fitButtonImage.userInteractionEnabled = YES;
} else {
fitButtonImage.userInteractionEnabled = NO;
}
}
NSString *tIStateAString = [currentInstallDictionary objectForKey:@"totInstStateA"];
NSString *tIStateBString = [currentInstallDictionary objectForKey:@"totInstStateB"];
insButtonImage = [UIButton buttonWithType:UIButtonTypeCustom];
insButtonImage.frame = CGRectMake(968.0, 5.0, 35.0, 35.0);
if (([tIStateAString isEqualToString:@"T"]) && ([tIStateBString isEqualToString:@"W"])) {
UIImage *checkedOnImage = [UIImage imageNamed:@"CheckedOn.png"];
[insButtonImage setImage:checkedOnImage forState:UIControlStateNormal];
[cell addSubview:insButtonImage];
} else if (([tIStateAString isEqualToString:@"T"]) && ([tIStateBString isEqualToString:@"R"])) {
UIImage *checkedOnDisabledImage = [UIImage imageNamed:@"CheckedOnDisabled.png"];
[insButtonImage setImage:checkedOnDisabledImage forState:UIControlStateNormal];
[cell addSubview:insButtonImage];
} else {
UIImage *checkedOffImage = [UIImage imageNamed:@"CheckedOff.png"];
[insButtonImage setImage:checkedOffImage forState:UIControlStateNormal];
[cell addSubview:insButtonImage];
}
//add lines to cell
lineBreakOneView = [[UIView alloc] initWithFrame:CGRectMake(140.0, 0.0, 0.5, 44.0)];
lineBreakOneView.backgroundColor = [UIColor lightGrayColor];
[cell addSubview:lineBreakOneView];
lineBreakTwoView = [[UIView alloc] initWithFrame:CGRectMake(290.0, 0.0, 0.5, 44.0)];
lineBreakTwoView.backgroundColor = [UIColor lightGrayColor];
[cell addSubview:lineBreakTwoView];
lineBreakThreeView = [[UIView alloc] initWithFrame:CGRectMake(440.0, 0.0, 0.5, 44.0)];
lineBreakThreeView.backgroundColor = [UIColor lightGrayColor];
[cell addSubview:lineBreakThreeView];
lineBreakFourView = [[UIView alloc] initWithFrame:CGRectMake(590.0, 0.0, 0.5, 44.0)];
lineBreakFourView.backgroundColor = [UIColor lightGrayColor];
[cell addSubview:lineBreakFourView];
lineBreakFiveView = [[UIView alloc] initWithFrame:CGRectMake(745.0, 0.0, 0.5, 44.0)];
lineBreakFiveView.backgroundColor = [UIColor lightGrayColor];
[cell addSubview:lineBreakFiveView];
lineBreakSixView = [[UIView alloc] initWithFrame:CGRectMake(805.0, 0.0, 0.5, 44.0)];
lineBreakSixView.backgroundColor = [UIColor lightGrayColor];
lineBreakSixView.alpha = 0.3;
[cell addSubview:lineBreakSixView];
lineBreakSevenView = [[UIView alloc] initWithFrame:CGRectMake(865.0, 0.0, 0.5, 44.0)];
lineBreakSevenView.backgroundColor = [UIColor lightGrayColor];
[cell addSubview:lineBreakSevenView];
lineBreakEightView = [[UIView alloc] initWithFrame:CGRectMake(945.0, 0.0, 0.5, 44.0)];
lineBreakEightView.backgroundColor = [UIColor lightGrayColor];
lineBreakEightView.alpha = 0.3;
[cell addSubview:lineBreakEightView];
return cell;
}
}
return cell; // this shouldnt happen if the data is correct
}
實際上那里還有更多的標簽..所以它是一個相當不錯的UITableViewCell,我也想添加一些圖像等等。但是在我這樣做之前,我需要幫助來解決性能問題。正在遭受。
任何想法或幫助解決UITableView的滾動性能將不勝感激。
像這樣的東西: [cell addSubview:areaLabel];
(其中areaLabel = [[UILabel alloc] init..
)在cellForRowAtIndexPath
內部cellForRowAtIndexPath
,除非您在if (cell == nil)
。 在您的情況下,您要連續創建標簽並將其添加到單元格,因此在滾動一會兒之后,您的實際單元格將包含大量標簽/子視圖(有些可能隱藏在其他標簽/子視圖之后)。
您只需要創建和添加這些子視圖一次,然后僅設置/刷新它們的內容。
正如@Fogmeister提到的,最好創建一個自定義單元格(在其中進行所有自定義的單獨類)。
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