动态隐藏TableView节标题
问题描述：
我试图隐藏并显示节标题时有或没有数据填充tableview。我现在的代码偶尔会按预期工作，但大多数情况下，一个或两个节标题将保持显示，（但是，如果我在没有数据时将标题拖出屏幕，它将按预期消失）。动态隐藏TableView节标题
这是我用来隐藏/取消隐藏部分的代码。
-(UIView *)tableView:(UITableView *)tableView viewForHeaderInSection:(NSInteger)section {
//Create custom header titles for desired header spacing
if (section == 0) {
UIView *headerView;
if (self.searchUsers.count || self.searchTracks.count)
{
headerView = [[UIView alloc]initWithFrame:CGRectMake(0, 0, 320, 40)];
}
else{
headerView = [[UIView alloc]initWithFrame:CGRectMake(0, 0, 0, 0)];
}
HeaderTitleLabel *headerTitle = [[HeaderTitleLabel alloc] initWithFrame:CGRectMake(17, 10, 150, 20) headerText:@"USERS"];
[headerView addSubview:headerTitle];
return headerView;
}
else if (section == 1){
UIView *headerView;
if (self.searchUsers.count || self.searchTracks.count)
{
headerView = [[UIView alloc]initWithFrame:CGRectMake(0, 0, 320, 40)];
}
else{
headerView = [[UIView alloc]initWithFrame:CGRectMake(0, 0, 0, 0)];
}
HeaderTitleLabel *headerTitle = [[HeaderTitleLabel alloc] initWithFrame:CGRectMake(17, 0, 150, 20) headerText:@"SONGS"];
[headerView addSubview:headerTitle];
return headerView;
}
else
return nil;
}
-(CGFloat)tableView:(UITableView *)tableView heightForHeaderInSection:(NSInteger)section
{
//custom header spacing
if (section == 0) {
if (self.searchUsers.count || self.searchTracks.count)
{
return 40;
}
else
return 0;
}
else if (section == 1) {
if (self.searchUsers.count || self.searchTracks.count)
{
return 50;
}
else
return 0;
}
else
return 0;
}
检查我的数组对象，如果没有则设置帧的高度为0，这似乎并没有被工作虽然。任何想法我应该怎么做呢？谢谢。
答
您正在使用错误的表格视图方法。你能澄清你到底想做什么吗？我可以帮你。而不是UIView使用UITableView单元格。
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
if (self.searchUsers.count || self.searchTracks.count)
{
if (indexPath.section ==0) {
static NSString *simpleTableIdentifier = @"CategoryCell";
CategoryCell *cell = (CategoryCell *)[tableView dequeueReusableCellWithIdentifier:simpleTableIdentifier];
if (cell == nil)
{
NSArray *nib = [[NSBundle mainBundle] loadNibNamed:@"CategoryCell" owner:self options:nil];
cell = [nib objectAtIndex:0];
}
cell.lbl_CatName.text = [[self.CategoryArray objectAtIndex:indexPath.row] objectForKey:kNAME];
return cell;}
else if (indexPath.section ==1){
static NSString *EarnPointIdentifier = @"EarnPointTableCell";
EarnPointTableCell *EarnPointcell = (EarnPointTableCell *)[tableView dequeueReusableCellWithIdentifier:EarnPointIdentifier];
if (EarnPointcell == nil)
{
NSArray *nib = [[NSBundle mainBundle] loadNibNamed:@"EarnPointTableCell" owner:self options:nil];
EarnPointcell = [nib objectAtIndex:0];
}
return EarnPointcell ;
}
else{
//it will have transparent background and every thing will be transparent
static NSString *RewardIdentifier = @"RewardTableCell";
RewardTableCell *RewardCell = (RewardTableCell *)[tableView dequeueReusableCellWithIdentifier:RewardIdentifier];
if (RewardCell == nil)
{
NSArray *nib = [[NSBundle mainBundle] loadNibNamed:@"RewardTableCell" owner:self options:nil];
RewardCell = [nib objectAtIndex:0];
}
return RewardCell ;
}
}
}
+0
我有两个自定义标题部分。一个标题为“用户”，一个标题为“歌曲”。我有一个搜索来填充表视图。简单地说，我希望当没有数据填充tableview（坏搜索，初始加载）时隐藏部分标题。 – Andy 2015-04-04 17:05:28
+0
为什么不使用UITableViewCell。而不是检查是否（self.searchUsers.count || self.searchTracks.count） {}两次尝试使用它一次，当它为空尝试使用具有透明背景的单元格 – 2015-04-04 17:19:16
+0
我正在制作表格视图标题..标题需要UIViews我没有问题显示每个部分的单元格。 – Andy 2015-04-04 17:55:38
答
您的模型应该驱动您的表格视图。不要仅仅从模型中返回“行数”值，而是返回“段数”值。请考虑一个包含两个数组作为模型的数组。
答
它现在似乎工作正常。我所做的是创建布尔值来跟踪我的数据，当我的数据源为零。像这样;
[SoundCloudAPI getTracksWithSearch:userInput userID:nil withCompletion:^(NSMutableArray *tracks) {
self.searchTracks = tracks;
[self.tableView beginUpdates];
if (tracks.count) {
self.songsHeaderIsHidden = NO;
}
else
self.songsHeaderIsHidden = YES;
[self.tableView reloadSections:[NSIndexSet indexSetWithIndex:1] withRowAnimation:UITableViewRowAnimationFade];
[[self.tableView headerViewForSection:1] setNeedsLayout];
[[self.tableView headerViewForSection:1] setNeedsDisplay];
[self.tableView endUpdates];
}];
然后设置相应的头..
-(UIView *)tableView:(UITableView *)tableView viewForHeaderInSection:(NSInteger)section {
//Create custom header titles for desired header spacing
if (section == 0) {
if (self.userHeaderIsHidden) {
return nil;
}
else {
UIView *userHeaderView = [[UIView alloc]initWithFrame:CGRectMake(0, 0, 320, 40)];
HeaderTitleLabel *usersHeaderTitle = [[HeaderTitleLabel alloc] initWithFrame:CGRectMake(17, 10, 150, 20) headerText:@"USERS"];
[userHeaderView addSubview:usersHeaderTitle];
return userHeaderView;
}
}
else if (section == 1){
if (self.songsHeaderIsHidden) {
return nil;
}
else {
UIView *songsHeaderView = [[UIView alloc]initWithFrame:CGRectMake(0, 0, 320, 40)];
songsHeaderView = [[UIView alloc]initWithFrame:CGRectMake(0, 0, 320, 40)];
HeaderTitleLabel *songsHeaderTitle = [[HeaderTitleLabel alloc] initWithFrame:CGRectMake(17, 0, 150, 20) headerText:@"SONGS"];
[songsHeaderView addSubview:songsHeaderTitle];
return songsHeaderView;
}
}
else
return nil;
}
答
就个人而言，我会用UICollectionView，写自己的布局。这样，您可以明确地布置节标题的位置。最好的办法是可能继承UICollectionViewFlowLayout，因为你所有的超类属性自由（如itemSize，headerReferenceSize等）
下面是我写的有粘性的头，像Instagram的应用程序的实现。
请注意，在prepareLayout，我只是计算每个元素的正常位置。然后在layoutAttributesForElementInRect我通过并找出在哪里放置标题。这是您可以查看是否应该显示标题的位置。
import UIKit
class BoardLayout: UICollectionViewFlowLayout {
private var sectionFrames: [CGRect] = []
private var headerFrames: [CGRect] = []
private var footerFrames: [CGRect] = []
private var layoutAttributes: [UICollectionViewLayoutAttributes] = []
private var contentSize: CGSize = CGSizeZero
override func prepareLayout() {
super.prepareLayout()
self.sectionFrames.removeAll(keepCapacity: false)
self.headerFrames.removeAll(keepCapacity: false)
self.footerFrames.removeAll(keepCapacity: false)
self.layoutAttributes.removeAll(keepCapacity: false)
let sections = self.collectionView?.numberOfSections()
var yOffset: CGFloat = 0.0
for var i: Int = 0; i < sections; i++ {
let indexPath = NSIndexPath(forItem: 0, inSection: i)
var itemSize: CGSize = self.itemSize
if let d = self.collectionView?.delegate as? UICollectionViewDelegateFlowLayout {
if let collection = self.collectionView {
if let size = d.collectionView?(collection, layout: self, sizeForItemAtIndexPath: NSIndexPath(forItem: 0, inSection: i)) {
itemSize = size
}
}
}
let headerFrame = CGRect(x: 0, y: yOffset, width: self.headerReferenceSize.width, height: self.headerReferenceSize.height)
self.headerFrames.append(headerFrame)
var headerAttribute = UICollectionViewLayoutAttributes(forSupplementaryViewOfKind: UICollectionElementKindSectionHeader, withIndexPath: indexPath)
headerAttribute.frame = headerFrame
headerAttribute.zIndex = 1000
self.layoutAttributes.append(headerAttribute)
yOffset += self.headerReferenceSize.height - 1 // - 1 so that the bottom border of the header and top border of the cell line up
let sectionFrame = CGRect(x: 0, y: yOffset, width: itemSize.width, height: itemSize.height)
self.sectionFrames.append(sectionFrame)
var sectionAttribute = UICollectionViewLayoutAttributes(forCellWithIndexPath: indexPath)
sectionAttribute.frame = sectionFrame
self.layoutAttributes.append(sectionAttribute)
yOffset += itemSize.height
let footerFrame = CGRect(x: 0, y: yOffset, width: self.footerReferenceSize.width, height: self.footerReferenceSize.height)
self.footerFrames.append(footerFrame)
var footerAttribute = UICollectionViewLayoutAttributes(forSupplementaryViewOfKind: UICollectionElementKindSectionFooter, withIndexPath: indexPath)
footerAttribute.frame = footerFrame
self.layoutAttributes.append(footerAttribute)
yOffset += self.minimumLineSpacing + self.footerReferenceSize.height
}
self.contentSize = CGSize(width: self.collectionView!.width, height: yOffset)
}
override func layoutAttributesForElementsInRect(rect: CGRect) -> [AnyObject]? {
var newAttributes: [UICollectionViewLayoutAttributes] = []
for attributes in self.layoutAttributes {
let frame = attributes.frame
if !CGRectIntersectsRect(frame, CGRect(x: 0, y: rect.origin.y, width: rect.size.width, height: rect.size.height)) {
continue
}
let indexPath = attributes.indexPath
let section = indexPath.section
if let kind = attributes.representedElementKind {
if kind == UICollectionElementKindSectionHeader {
var headerFrame = attributes.frame
let footerFrame = self.footerFrames[section]
if CGRectGetMinY(headerFrame) <= self.collectionView!.contentOffset.y {
headerFrame.origin.y = self.collectionView!.contentOffset.y
}
if CGRectGetMinY(headerFrame) >= CGRectGetMinY(footerFrame) {
headerFrame.origin.y = footerFrame.origin.y
}
attributes.frame = headerFrame
self.headerFrames[section] = headerFrame
} else if kind == UICollectionElementKindSectionFooter {
attributes.frame = self.footerFrames[section]
}
} else {
attributes.frame = self.sectionFrames[section]
}
newAttributes.append(attributes)
}
return newAttributes
}
override func layoutAttributesForItemAtIndexPath(indexPath: NSIndexPath) -> UICollectionViewLayoutAttributes! {
let frame = self.sectionFrames[indexPath.item]
let attributes = super.layoutAttributesForItemAtIndexPath(indexPath)
attributes.frame = frame
return attributes
}
override func layoutAttributesForSupplementaryViewOfKind(elementKind: String, atIndexPath indexPath: NSIndexPath) -> UICollectionViewLayoutAttributes! {
let attributes = super.layoutAttributesForSupplementaryViewOfKind(elementKind, atIndexPath: indexPath)
if elementKind == UICollectionElementKindSectionHeader {
attributes.frame = self.headerFrames[indexPath.section]
} else if elementKind == UICollectionElementKindSectionFooter {
attributes.frame = self.footerFrames[indexPath.section]
}
return attributes
}
override func collectionViewContentSize() -> CGSize {
return self.contentSize
}
override func shouldInvalidateLayoutForBoundsChange(newBounds: CGRect) -> Bool {
return true
}
}
我建议使用UICollectionViewDelegateFlowLayout方法，这样你就可以动态地确定头部的参考尺寸。
我有投票urs希望能回到我的回答 – 2015-06-20 14:34:06