iOS：表格重新加载改变布局

Posted 2023-03-24

【中文标题】iOS：表格重新加载改变布局

【英文标题】：iOS: Table reload altering layout

【发布时间】：2013-12-13 17:12:49

【问题描述】：

我的 UI 有一个 UITableView 和另一个视图。 UITableView 具有可折叠部分，如sample code 所示。加载后看起来像这样：

用户可以使用滑动手势来展开右侧的灰色视图。我只是改变灰色视图的原点并使用动画来实现这一点。那么它看起来像这样：

但是，当我关闭 UITableView 的一部分时，UI 似乎“重置”并恢复到原来的布局：

当我打开或关闭 UITableView 的一部分时，我希望灰色视图保持在原来的位置。我怎样才能做到这一点？

我的 ViewController 的代码如下：

#import "BooklistMaster.h"
#import "BooklistDetailViewController.h"
#import "Booklist.h"
#import "BooklistTitleCell.h"
#import "BooklistTitle.h"
#import "BooklistDetailHeaderView.h"
#import "BooklistDetailSectionInfo.h"
#import "BooklistDetailHandler.h"

static NSString *SectionHeaderViewIdentifier = @"SectionHeaderViewIdentifier";

@interface BooklistDetailViewController ()

@property (nonatomic) NSMutableArray *sectionInfoArray;
@property (nonatomic) NSIndexPath *pinchedIndexPath;
@property (nonatomic) NSInteger openSectionIndex;
@property (nonatomic) CGFloat initialPinchHeight;

@property (nonatomic) IBOutlet BooklistDetailHeaderView *sectionHeaderView;

// use the uniformRowHeight property if the pinch gesture should change all row heights simultaneously
@property (nonatomic) NSInteger uniformRowHeight;


@end

//#define DEFAULT_ROW_HEIGHT 88
#define HEADER_HEIGHT 48

@implementation BooklistDetailViewController

@synthesize listTitleLabel;
@synthesize backButton;
@synthesize booklistMaster;
@synthesize titleBarView;
@synthesize searchBar;
@synthesize tap;
@synthesize booklistId;
@synthesize booklistName;
@synthesize spinner;
@synthesize detailPaneFocused;
@synthesize detailView;
@synthesize swipeLeft;
@synthesize swipeRight;
@synthesize tableView;

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil

    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) 
        // Custom initialization
    
    return self;


- (void)viewDidLoad

    [super viewDidLoad];
    // Do any additional setup after loading the view.
    [self.view sendSubviewToBack:tableView];
    detailPaneFocused=NO;
    listTitleLabel.text = booklistName;
    [spinner startAnimating];
    [spinner setHidden:NO];
     [titleBarView setBackgroundColor:[UIColor colorWithRed:.77647 green:.77647 blue:.79607 alpha:1]];

    tap = [[UITapGestureRecognizer alloc]
           initWithTarget:self
           action:@selector(dismissKeyboard)];
    [tap setCancelsTouchesInView:YES];

    swipeLeft = [[UISwipeGestureRecognizer alloc]initWithTarget:self action:@selector(didSwipeLeft:)];
    [swipeLeft setDirection:UISwipeGestureRecognizerDirectionLeft];
    [detailView addGestureRecognizer:swipeLeft];

    swipeRight = [[UISwipeGestureRecognizer alloc]initWithTarget:self action:@selector(didSwipeRight:)];
    [swipeRight setDirection:UISwipeGestureRecognizerDirectionRight];
    [detailView addGestureRecognizer:swipeRight];


    // Set up default values.
    self.tableView.sectionHeaderHeight = HEADER_HEIGHT;
    /*
     The section info array is thrown away in viewWillUnload, so it's OK to set the default values here. If you keep the section information etc. then set the default values in the designated initializer.
     */
   // self.uniformRowHeight = DEFAULT_ROW_HEIGHT;
    self.openSectionIndex = NSNotFound;

    UINib *sectionHeaderNib = [UINib nibWithNibName:@"BooklistDetailSectionHeaderView" bundle:nil];
    [self.tableView registerNib:sectionHeaderNib forHeaderFooterViewReuseIdentifier:SectionHeaderViewIdentifier];

    self.tableView.tableFooterView = [[UIView alloc] initWithFrame:CGRectZero];

    BooklistDetailHandler *handler = [[BooklistDetailHandler alloc] initForController:self];
    [handler getBooklistForId:booklistId];



-(void)didSwipeRight:(UISwipeGestureRecognizer *)recognizer
    if (detailPaneFocused==YES) 
        detailPaneFocused=NO;
        [UIView animateWithDuration:.3
                         animations:^ 
                             CGRect newBounds = self.detailView.frame;
                             newBounds.origin.x += 200;
                             self.detailView.frame = newBounds;
                             [self.detailView layoutSubviews];


                         ];
    


-(void)didSwipeLeft:(UISwipeGestureRecognizer *)recognizer
    if (detailPaneFocused==NO) 
        detailPaneFocused=YES;
        [UIView animateWithDuration:.3
                         animations:^ 
                             CGRect newBounds = self.detailView.frame;
                             newBounds.origin.x -= 200;
                             self.detailView.frame = newBounds;
                             [self.detailView layoutSubviews];


                         ];
    


- (void)didReceiveMemoryWarning

    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.


- (void)viewWillAppear:(BOOL)animated 

    [super viewWillAppear:animated];



- (IBAction)buttonPressed:(id)sender 

    [[self navigationController]  popViewControllerAnimated:YES];


-(void)dismissKeyboard 
    [searchBar resignFirstResponder];


- (void)searchBarSearchButtonClicked:(UISearchBar *)searchBar

    [self dismissKeyboard];


-(void)searchBarTextDidBeginEditing:(UISearchBar *)searchBar
    [self.view addGestureRecognizer:tap];

    [UIView animateWithDuration:.3
                     animations:^ 
                         CGRect newBounds = self.searchBar.frame;
                         newBounds.size.width += 200; //newBounds.size.width -= 215; to contract
                         newBounds.origin.x -= 200;
                         self.searchBar.frame = newBounds;
                         [self.searchBar layoutSubviews];
                     ];



-(void)searchBarTextDidEndEditing:(UISearchBar *)searchBar
    [self.view removeGestureRecognizer:tap];
    [UIView animateWithDuration:.3
                     animations:^ 
                         CGRect newBounds = self.searchBar.frame;
                         newBounds.size.width -= 200; //newBounds.size.width -= 215; to contract
                         newBounds.origin.x += 200;
                         self.searchBar.frame = newBounds;
                         [self.searchBar layoutSubviews];
                     ];


- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
    return booklistMaster.subLists.count;


- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
//    Booklist *list = [booklistMaster.subLists objectAtIndex:section];
//    return list.booklistTitles.count;

    BooklistDetailSectionInfo *sectionInfo = (self.sectionInfoArray)[section];
    NSInteger numStoriesInSection = sectionInfo.booklist.booklistTitles.count;

    return sectionInfo.open ? numStoriesInSection : 0;


//- (NSArray *)sectionIndexTitlesForTableView:(UITableView *)tableView
//    
//    NSMutableArray *array = [[NSMutableArray alloc] init];
//    for (Booklist *list in booklistMaster.subLists) 
//        [array addObject:@"a"];
//    
//    
//    return array;
//    
//
- (UIView *)tableView:(UITableView *)tableView viewForHeaderInSection:(NSInteger)section
    BooklistDetailHeaderView *sectionHeaderView = [self.tableView dequeueReusableHeaderFooterViewWithIdentifier:SectionHeaderViewIdentifier];

    BooklistDetailSectionInfo *sectionInfo = (self.sectionInfoArray)[section];
    sectionInfo.headerView = sectionHeaderView;

    sectionHeaderView.titleLabel.text = sectionInfo.booklist.listName;
    sectionHeaderView.section = section;
    sectionHeaderView.delegate = self;

    return sectionHeaderView;



//- (CGFloat)tableView:(UITableView *)tableView heightForHeaderInSection:(NSInteger)section
//    
//
//- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath 
//    
//  BooklistDetailSectionInfo *sectionInfo = (self.sectionInfoArray)[indexPath.section];
//    return [[sectionInfo objectInRowHeightsAtIndex:indexPath.row] floatValue];
//    // Alternatively, return rowHeight.
//

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath



    BooklistTitleCell *cell = [tableView dequeueReusableCellWithIdentifier:@"BooklistTitleCell" forIndexPath:indexPath];

    Booklist *booklist = [booklistMaster.subLists objectAtIndex:indexPath.section];
    BooklistTitle *booklistTitle = [booklist.booklistTitles objectAtIndex:indexPath.row];
    cell.titleLabel.text=booklistTitle.title;

    return cell;


- (void)sectionHeaderView:(BooklistDetailHeaderView *)sectionHeaderView sectionOpened:(NSInteger)sectionOpened 

    BooklistDetailSectionInfo *sectionInfo = (self.sectionInfoArray)[sectionOpened];

    sectionInfo.open = YES;

    /*
     Create an array containing the index paths of the rows to insert: These correspond to the rows for each quotation in the current section.
     */
    NSInteger countOfRowsToInsert = sectionInfo.booklist.booklistTitles.count;
    NSMutableArray *indexPathsToInsert = [[NSMutableArray alloc] init];
    for (NSInteger i = 0; i < countOfRowsToInsert; i++) 
        [indexPathsToInsert addObject:[NSIndexPath indexPathForRow:i inSection:sectionOpened]];
    

    /*
     Create an array containing the index paths of the rows to delete: These correspond to the rows for each quotation in the previously-open section, if there was one.
     */
    NSMutableArray *indexPathsToDelete = [[NSMutableArray alloc] init];

    NSInteger previousOpenSectionIndex = self.openSectionIndex;
    if (previousOpenSectionIndex != NSNotFound) 

        BooklistDetailSectionInfo *previousOpenSection = (self.sectionInfoArray)[previousOpenSectionIndex];
        previousOpenSection.open = NO;
        [previousOpenSection.headerView toggleOpenWithUserAction:NO];
        NSInteger countOfRowsToDelete = previousOpenSection.booklist.booklistTitles.count;
        for (NSInteger i = 0; i < countOfRowsToDelete; i++) 
            [indexPathsToDelete addObject:[NSIndexPath indexPathForRow:i inSection:previousOpenSectionIndex]];
        
    

    // style the animation so that there's a smooth flow in either direction
    UITableViewRowAnimation insertAnimation;
    UITableViewRowAnimation deleteAnimation;
    if (previousOpenSectionIndex == NSNotFound || sectionOpened < previousOpenSectionIndex) 
        insertAnimation = UITableViewRowAnimationTop;
        deleteAnimation = UITableViewRowAnimationBottom;
    
    else 
        insertAnimation = UITableViewRowAnimationBottom;
        deleteAnimation = UITableViewRowAnimationTop;
    

    // apply the updates
    [self.tableView beginUpdates];
    [self.tableView insertRowsAtIndexPaths:indexPathsToInsert withRowAnimation:insertAnimation];
    [self.tableView deleteRowsAtIndexPaths:indexPathsToDelete withRowAnimation:deleteAnimation];
    [self.tableView endUpdates];

    self.openSectionIndex = sectionOpened;


- (void)sectionHeaderView:(BooklistDetailHeaderView *)sectionHeaderView sectionClosed:(NSInteger)sectionClosed 

    /*
     Create an array of the index paths of the rows in the section that was closed, then delete those rows from the table view.
     */
    BooklistDetailSectionInfo *sectionInfo = (self.sectionInfoArray)[sectionClosed];

    sectionInfo.open = NO;
    NSInteger countOfRowsToDelete = [self.tableView numberOfRowsInSection:sectionClosed];

    if (countOfRowsToDelete > 0) 
        NSMutableArray *indexPathsToDelete = [[NSMutableArray alloc] init];
        for (NSInteger i = 0; i < countOfRowsToDelete; i++) 
            [indexPathsToDelete addObject:[NSIndexPath indexPathForRow:i inSection:sectionClosed]];
        
        [self.tableView deleteRowsAtIndexPaths:indexPathsToDelete withRowAnimation:UITableViewRowAnimationTop];
    
    self.openSectionIndex = NSNotFound;


-(void)setMasterBooklist:(BooklistMaster *)list
    booklistMaster=list;
    /*
     Check whether the section info array has been created, and if so whether the section count still matches the current section count. In general, you need to keep the section info synchronized with the rows and section. If you support editing in the table view, you need to appropriately update the section info during editing operations.
     */
    if ((self.sectionInfoArray == nil) ||
        ([self.sectionInfoArray count] != [self numberOfSectionsInTableView:self.tableView])) 

        // For each play, set up a corresponding SectionInfo object to contain the default height for each row.
        NSMutableArray *infoArray = [[NSMutableArray alloc] init];

        for (Booklist *list in self.booklistMaster.subLists) 

            BooklistDetailSectionInfo *sectionInfo = [[BooklistDetailSectionInfo alloc] init];
            sectionInfo.booklist = list;
            sectionInfo.open = NO;

            // NSNumber *defaultRowHeight = @(DEFAULT_ROW_HEIGHT);
            NSInteger countOfTitles = sectionInfo.booklist.booklistTitles.count;
            for (NSInteger i = 0; i < countOfTitles; i++) 
                //[sectionInfo insertObject:defaultRowHeight inRowHeightsAtIndex:i];
            

            [infoArray addObject:sectionInfo];
        

        self.sectionInfoArray = infoArray;
    
    [spinner stopAnimating];
    [spinner setHidden:YES];
    [self.tableView reloadData];


- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
//    if (detailPaneFocused==NO)
//        [self focusDetailPane];
//    

- (NSIndexPath *)tableView:(UITableView *)tableView willSelectRowAtIndexPath:(NSIndexPath *)indexPath
    if (detailPaneFocused==NO&&![indexPath isEqual:[tableView indexPathForSelectedRow]])
        [self focusDetailPane];
    
    return indexPath;


- (void)focusDetailPane
    detailPaneFocused=YES;
    [UIView animateWithDuration:.3
                     animations:^ 
                         CGRect newBounds = self.detailView.frame;
                         newBounds.origin.x -= 200;
                         self.detailView.frame = newBounds;
                         [self.detailView layoutSubviews];

                     ];



@end

【参考方案1】：

这是由于自动布局。如果您在启用自动布局的情况下直接更改任何框架，则视图将在视图必须自行更新时立即恢复到其约束定义的位置。您应该通过为您想要更改的任何约束创建一个 IBOutlet 来制作动画，并在代码中调整它们的常量值（或者关闭自动布局）。

【讨论】：

实际上，我遇到了这个问题。如果我在我的 animateWithDuration 方法中更改约束的常量值，视图会立即捕捉到它们的新位置，不会发生动画。对此有何想法？

没关系，想通了。只需要 [self.view layoutIfNeeded];行也。再次感谢！