如何创建自定义 UICollectionViewCell [英] how to create custom UICollectionViewCell
本文介绍了如何创建自定义 UICollectionViewCell的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我有一个 UICollectionView 并且我试图在 collectionViewCell 中设置一个 label 和一个 image.不幸的是，我似乎无法显示任何标签或其他任何内容.
I have a UICollectionView and Im trying to set a label and an image in the collectionViewCell. Unfortunately I cant seem to get any labels to display or anything else for that matter.
这是我的代码:
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath{
UICollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:@"cellIdentifier" forIndexPath:indexPath];
UILabel *issue = [[UILabel alloc] initWithFrame:CGRectMake(0,10,cell.bounds.size.width,40)];
if(indexPath.item %2 == 0){
cell.backgroundColor=[UIColor blueColor];
issue.text = @"Some Text";
issue.textColor = [UIColor greenColor];
issue.textAlignment = NSTextAlignmentCenter;
}
else {
cell.backgroundColor=[UIColor redColor];
issue.text = @"Some Text";
issue.textColor = [UIColor greenColor];
issue.textAlignment = NSTextAlignmentCenter;
}
}
不幸的是，没有显示标签，标签中的文本也没有显示.
Unfortunately no label is being displayed and neither is the text in the label.
更新:我已经添加了这个类文件中的其余代码.
Updated: I've added the rest of the code from this class file.
#import "ContainerListController.h"
#import "ContainerController.h"
#import "ContainerList.h"
@implementation ContainerListController
//Deallocate temp variables
- (void)dealloc {
[[NSNotificationCenter defaultCenter] removeObserver:self];
}
//Initiate objects
- (id)init {
if (self = [super initWithTitle:LocStr(@"CONTAINER_LIST_TITLE") navBarHidden:NO]) {
m_paths = [ContainerList shared].paths;
[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(onContainerListDidChange)
name:kSDKLauncherContainerListDidChange object:nil];
}
return self;
}
//Load all the views.
- (void)loadView {
//Allocate a UI view
self.view = [[UIView alloc] init];
//Create flow layout
UICollectionViewFlowLayout *layout = [[UICollectionViewFlowLayout alloc] init];
//Force Horizontal Scroll
[layout setScrollDirection:UICollectionViewScrollDirectionHorizontal];
layout.minimumInteritemSpacing =[[UIScreen mainScreen] bounds].size.width;
layout.minimumLineSpacing=0.0;
//Create Collection
UICollectionView *coll =[[UICollectionView alloc] initWithFrame:self.view.frame collectionViewLayout:layout];
//Allocations
m_coll = coll;
coll.dataSource =self;
coll.delegate =self;
coll.pagingEnabled = YES;
coll.collectionViewLayout = layout;
//Customize Cells
[coll registerClass:[UICollectionViewCell class] forCellWithReuseIdentifier:@"cellIdentifier"];
[coll setBackgroundColor:[UIColor orangeColor]];
[layout invalidateLayout];
//Create the subview
[self.view addSubview:coll];
//set minimum spacing
/*if(UIDeviceOrientationIsLandscape([UIDevice currentDevice].orientation)){
NSLog(@"Changed to landscape Spacing");
layout.minimumLineSpacing = 100.0f;
layout.minimumInteritemSpacing = 100.0f;
}
else{
layout.minimumLineSpacing = 40.0f;
layout.minimumInteritemSpacing = 40.0f;
}*/
//Old Layout
//UITableView *table = [[UITableView alloc] initWithFrame:CGRectZero style:UITableViewStylePlain];
//m_table = table;
//table.dataSource = self;
//table.delegate = self;
//[self.view addSubview:table];
}
- (void)onContainerListDidChange {
m_paths = [ContainerList shared].paths;
[m_table reloadData];
[m_coll reloadData];
}
//Debugging components function
/*-(void)printComps:(NSArray* ) components{
for (NSInteger i =0; i<16; i++) {
NSString * item;
item=components[i];
}
}*/
//old tableview cell
- (UITableViewCell *)
tableView:(UITableView *)tableView
cellForRowAtIndexPath:(NSIndexPath *)indexPath{
UITableViewCell *cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault
reuseIdentifier:nil];
cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;
NSString *path = [m_paths objectAtIndex:indexPath.row];
NSArray *components = path.pathComponents;
cell.textLabel.text = (components == nil || components.count == 0) ?
@"" : components.lastObject;
return cell;
}
//Old tableView
- (void)
tableView:(UITableView *)tableView
didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
[tableView deselectRowAtIndexPath:indexPath animated:YES];
NSString *path = [m_paths objectAtIndex:indexPath.row];
ContainerController *c = [[ContainerController alloc] initWithPath:path];
if (c != nil) {
[self.navigationController pushViewController:c animated:YES];
}
NSLog(@"Selected an item");
}
//old TableView count for epubs
- (NSInteger)
tableView:(UITableView *)tableView
numberOfRowsInSection:(NSInteger)section{
return m_paths.count;
}
- (void)viewDidLayoutSubviews {
//m_table.frame = self.view.bounds;
m_coll.frame = self.view.bounds;
}
//Collection View Cell Data Allocation
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView
cellForItemAtIndexPath:(NSIndexPath *)indexPath{
UICollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:@"cellIdentifier" forIndexPath:indexPath];
UILabel *issue = [[UILabel alloc] initWithFrame:CGRectMake(0,10,cell.bounds.size.width,40)];
//UICollectionViewCell *content = [[UICollectionViewCell alloc] init];
if(indexPath.item %2 == 0){
cell.backgroundColor=[UIColor blueColor];
issue.text = @"Some Text";
issue.textColor = [UIColor greenColor];
issue.textAlignment = NSTextAlignmentCenter;
}
else {
cell.backgroundColor=[UIColor redColor];
issue.text = @"Some Text";
issue.textColor = [UIColor greenColor];
issue.textAlignment = NSTextAlignmentCenter;
}
NSString *path = [m_paths objectAtIndex:indexPath.row];
NSArray *components = path.pathComponents;
NSString *Title = components.lastObject;
NSLog(@"Title: %@",Title);
NSString *Titletest = components.lastObject;
NSInteger comp1 = components.count;
NSString *comps = @"components";
NSLog(@"There are: %ld %@", (long)comp1,comps);
NSLog(@"Title: %@",Titletest);
for (NSInteger i =0; i<15; i++) {
NSString * item;
item=components[i];
NSLog(@"Component:%ld %@",(long)i,components[i]);
}
return cell;
}
//Collection View Cell Data De-Allocation
- (void)
collectionView:(UICollectionView *)collectionView
numberofItemsInSection:(NSIndexPath *)indexPath{
[collectionView deselectItemAtIndexPath:indexPath animated:YES];
NSString *path = [m_paths objectAtIndex:indexPath.row];
ContainerController *c = [[ContainerController alloc] initWithPath:path];
if(c !=nil){
[self.navigationController pushViewController:c animated:YES];
}
}
//Collection
-(NSInteger)
collectionView:(UICollectionView *)collectionView
numberOfItemsInSection:(NSInteger)section{
return m_paths.count;
}
//Set Collection View Cell Size
-(CGSize)
collectionView:(UICollectionView *) collectionView
layout:(UICollectionViewLayout*)collectionViewLayout
sizeForItemAtIndexPath:(NSIndexPath *)indexPath{
//Set Landscape size of cells
/*if(UIDeviceOrientationIsLandscape([UIDevice currentDevice].orientation)){
CGFloat cellWidth = [[UIScreen mainScreen] bounds].size.width-360;
CGFloat cellHeigt = [[UIScreen mainScreen] bounds].size.height-60;
NSLog(@"Is Landscape");
return CGSizeMake(cellWidth, cellHeigt);
}
//Set Potrait size of cells
else{
CGFloat cellWidth = [[UIScreen mainScreen] bounds].size.width-60;
CGFloat cellHeigt = [[UIScreen mainScreen] bounds].size.height-160;
NSLog(@"Is Portrait");
return CGSizeMake(cellWidth, cellHeigt);
}*/
return CGSizeMake(collectionView.bounds.size.width, collectionView.bounds.size.height);
}
//Collection View Cell Position
- (UIEdgeInsets)collectionView:
(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout insetForSectionAtIndex:(NSInteger)section {
if(UIDeviceOrientationIsPortrait([UIDevice currentDevice].orientation)){
return UIEdgeInsetsMake(150.0,0.0,150.0,0.0); // top, left, bottom, right
}
else{
return UIEdgeInsetsMake(20.0,0.0,0.0,0.0); // top, left, bottom, right
}
}
- (void)didRotateFromInterfaceOrientation:(UIInterfaceOrientation)fromInterfaceOrientation{
[m_coll performBatchUpdates:nil completion:nil];
}
-(void)viewWillTransitionToSize:withTransitionCoordinator{
[m_coll performBatchUpdates:nil completion:nil];
}
/*-(CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)
collectionViewLayout minimumLineSpacingForSectionAtIndex:(NSInteger)section{
CGFloat cellSpacing = ((UICollectionViewFlowLayout *) collectionViewLayout).minimumLineSpacing;
CGFloat cellWidth = ((UICollectionViewFlowLayout *) collectionViewLayout).itemSize.width;
NSInteger cellCount = [collectionView numberOfItemsInSection:section];
CGFloat inset = (collectionView.bounds.size.width - ((cellCount-1) * (cellWidth + cellSpacing))) * 0.5;
inset = MAX(inset, 0.0);
if(UIDeviceOrientationIsLandscape([UIDevice currentDevice].orientation)){
NSLog(@"Changed to landscape Spacing");
return inset;
}
else{
return inset;
}
}*/
@end
推荐答案
使用自定义 collectionViewCell 的清晰示例.
Clear example to use custom collectionViewCell.
为UICollectionViewCell创建一个单独的类子类，见下面的代码:
Create a separate class subclass ofUICollectionViewCell see below code:
.h 文件:
#import <UIKit/UIKit.h>
@interface CollectionViewCell : UICollectionViewCell
@property (weak, nonatomic) IBOutlet UILabel *customLabel;
@end
.m 文件:
#import "CollectionViewCell.h"
@implementation CollectionViewCell
@end
现在使用 storyboard 将 collectionView 拖放到 viewController 内，然后为其选择单元集自定义类并连接其 IBOutlet标签见下图.
Now drag and drop the collectionView inside viewController using storyboard then by selecting cell set custom class for it and connect its IBOutlet of label see below image.
设置自定义类:
连接label的outlet: 如果从storyboard中添加label和其他ui组件
注意:在连接IBOutlet之前，将uilabel拖入单元格内.
Note: Drag uilabel inside cell before you connect its IBOutlet.
现在在 viewController 类中配置单元格.并通过连接delegate、dataSuorce和IBOutlet正确配置collectionView.
Now configure cell inside your viewController class. And configure collectionView correctly by connecting its delegate, dataSuorce and IBOutlet.
#import "ViewController.h"
#import "CollectionViewCell.h"
@interface ViewController (){
// instance variable deceleration part
NSMutableArray *yourArray;
}
@end
@implementation ViewController
- (void)viewDidLoad{
[super viewDidLoad];
_yourCollView.delegate = self;
_yourCollView.dataSource = self;
yourArray = [[NSMutableArray alloc] initWithObjects:@"1st cell",@"2nd cell",@"3rd cell",@"4th cell", nil];
// Do any additional setup after loading the view, typically from a nib.
}
// collection view delegate methods
- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section{
return [yourArray count];
}
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath{
CollectionViewCell *cell = (CollectionViewCell *)[collectionView dequeueReusableCellWithReuseIdentifier:@"MyCustomCell" forIndexPath:indexPath];
// configuring cell
// cell.customLabel.text = [yourArray objectAtIndex:indexPath.row]; // comment this line if you do not want add label from storyboard
// if you need to add label and other ui component programmatically
UILabel *label = [[UILabel alloc]initWithFrame:CGRectMake(0, 0, cell.bounds.size.width, cell.bounds.size.height)];
label.tag = 200;
label.text = [yourArray objectAtIndex:indexPath.row];
// this adds the label inside cell
[cell.contentView addSubview:label];
return cell;
}
//Note: Above two "numberOfItemsInSection" & "cellForItemAtIndexPath" methods are required.
// this method overrides the changes you have made to inc or dec the size of cell using storyboard.
- (CGSize)collectionView:(UICollectionView *)collectionView layout: (UICollectionViewLayout*)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath{
return CGSizeMake(100, 100);
}
} // class ends
设置单元格标识符(通过选择一个单元格)MyCustomCell 你在使用之前在 cellForItemAtIndexPath 方法中给出的，见下图:
Setup the cell identifier (by selecting a cell) MyCustomCell you have given inside cellForItemAtIndexPath method before use see below image:
注意:之前将uilabel的文字颜色改为白色，因为collectionView默认显示为黑色.
Note: Change the text color of uilabel to white before because by default collectionView appears black.
希望你明白.
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