我纠结了几天，之前也找过。
我在 UITableViewCell 中有用于最喜欢的单元格的按钮。
如何在应用程序关闭后保存按钮状态(选定按钮加载图像“fav.png”和普通按钮加载“unfav.png”)？
// BirdsTableViewController.m
// iranbirdtest2
//
// Created by Mehdi on 9/27/15.
// Copyright (c) 2015 Mehdi.n13. All rights reserved.
// after 15 azar-21 mehr
#import "BirdsTableViewController.h"
#import "Bird.h"
#import "GeneralViewController.h"
#import "FavoriteTableViewController.h"
#import "MyManager.h"
//NSMutableArray *favoritesArray;
@interface BirdsTableViewController (){
}
@property (strong, nonatomic) UITabBarController *myTabbarController;
@property (strong, nonatomic) GeneralViewController *myFirstViewController;
@end
@implementation BirdsTableViewController
{
}
- (IBAction)buttonTouchDown:(UIButton *)sender {
sender.selected = !sender.selected; //to switch from selected to unselected
//OR in IBaction we can use:
/*
if ([sender isSelected]) {
[sender setImage:[UIImage imageNamed:@"unfav.png"] forState:UIControlStateNormal];
[sender setSelected:NO];
} else {
[sender setImage:[UIImage imageNamed:@"fav.png"] forState:UIControlStateSelected];
[sender setSelected:YES];
[[NSUserDefaults standardUserDefaults] setBool:YES forKey: @"someKey"];
}
*/
}
- (void) viewDidLoad {
[super viewDidLoad];
for (NSIndexPath *indexPath in [[NSUserDefaults standardUserDefaults] mutableArrayValueForKey:@"mySavedMutableArray"]) {
[self.tableView selectRowAtIndexPath:indexPath animated:NO scrollPosition:UITableViewScrollPositionNone];
}
self.title=@"پرندگان ایران";
self.tableView.delegate = self;
self.tableView.dataSource = self;
//create array
birds=[[NSMutableArray alloc]init];
// UIButton* myButton;
Bird *bird=[[Bird alloc]init];
bird.name=@"زنبور خوار";
bird.filename=@"bird1";
bird.detail=@"این قسمت مربوط به توضیح می باشد";
[birds addObject:bird];
bird=[[Bird alloc]init]; //dont forget reuse
bird.name=@"زاغ";
bird.filename=@"bird2";
bird.detail=@"توضیحات مربوط به شماره ۲";
[birds addObject:bird];
bird=[[Bird alloc]init];
bird.name=@"طوطی";
bird.filename=@"bird3";
bird.detail=@"توضیحات مربوط به شماره سومی";
[birds addObject:bird];
//add more later
MyManager *sharedManager = [MyManager sharedManager];
// Uncomment the following line to preserve selection between presentations.
// self.clearsSelectionOnViewWillAppear = NO;
// Uncomment the following line to display an Edit button in the navigation bar for this view controller.
// self.navigationItem.rightBarButtonItem = self.editButtonItem;
//this is for page view controller:
self.parentViewController.view.backgroundColor = [UIColor colorWithPatternImage:[UIImage imageNamed:@"common_bg"]];
self.tableView.backgroundColor = [UIColor clearColor];
UIEdgeInsets inset = UIEdgeInsetsMake(5, 0, 0, 0);
self.tableView.contentInset = inset;
[self.tableView setSeparatorStyle:UITableViewCellSelectionStyleNone]; //delete sepreate line odf tables
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
- (void) viewWillDisappear:(BOOL)animated{
}
#pragma mark - Table view data source
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
// Return the number of sections.
return 1;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
// Return the number of rows in the section.
return birds.count;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"cell" forIndexPath:indexPath];
if (cell == nil) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:@"cell"];
}
// Configure the cell...
tableView.allowsSelection=YES;
Bird *current=[birds objectAtIndex:indexPath.row];
UIImageView *birdImageView = (UIImageView *)[cell.contentView viewWithTag:100];
birdImageView.image = [UIImage imageNamed:current.filename];
UILabel *name = (UILabel *)[cell.contentView viewWithTag:101];
name.text=[current name];
//button code in table view
UIButton *button=(UIButton *) [cell.contentView viewWithTag:103];//fav
[button setImage:[UIImage imageNamed:@"unfav.png"] forState:UIControlStateNormal];
[button setImage:[UIImage imageNamed:@"fav.png"] forState:UIControlStateSelected];
button.frame = CGRectMake(0,0, 50, 50);
button.tag = indexPath.row;
[button addTarget:self action:@selector(buttonPressed:) forControlEvents:UIControlEventTouchUpInside];
[cell.contentView addSubview:button]; // add the button to the cell
[cell.contentView bringSubviewToFront:button];
// Assign our own background image for the cell
UIImage *background = [self cellBackgroundForRowAtIndexPath:indexPath];
UIImageView *cellBackgroundView = [[UIImageView alloc] initWithImage:background];
cellBackgroundView.image = background;
cell.backgroundView = cellBackgroundView;
UIImageView *imgView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"sepratortable.png"]];
[imgView sizeToFit];
[cell.contentView addSubview:imgView];
return cell;
}
-(void)buttonPressed:(UIButton *)sender
{
NSLog(@"Button Pressed");
MyManager *sharedManager = [MyManager sharedManager];
NSIndexPath *indexPath = [self.tableView indexPathForCell:(UITableViewCell*)sender.superview.superview];
if([sharedManager.favoritesArray containsObject:[birds objectAtIndex:indexPath.row]])
{
[sharedManager.favoritesArray removeObject:[birds objectAtIndex:indexPath.row]];
[self.tableView reloadData];
}
else
{
[sharedManager.favoritesArray addObject:[birds objectAtIndex:indexPath.row]];
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Do you want to say hello?" message:@"More info..." delegate:self cancelButtonTitle:@"Cancel" otherButtonTitles:@"Say Hello",nil];
[alert show];
; //we can remove later
}
//save favorite array in plist.
[NSKeyedArchiver archiveRootObject:sharedManager.favoritesArray toFile:@"/Users/Mehdi/Desktop/Project/Backup/21 mehr/fav.plist"];
NSLog(@"Favoritearray : %d",sharedManager.favoritesArray.count);
/*
NSUserDefaults *userDefaults = [NSUserDefaults standardUserDefaults];
[userDefaults setValue:birds forKey:@"key"];
[[NSUserDefaults standardUserDefaults] synchronize];
*/
}
- (void)tableView:(UITableView *)tableView didDeselectRowAtIndexPath:(NSIndexPath *)indexPath
{
}
- (UIImage *)cellBackgroundForRowAtIndexPath:(NSIndexPath *)indexPath
{
NSInteger rowCount = [self tableView:[self tableView] numberOfRowsInSection:0];
NSInteger rowIndex = indexPath.row;
UIImage *background = nil;
if (rowIndex == 0) {
background = [UIImage imageNamed:@"cell_top.png"];
} else if (rowIndex == rowCount - 1) {
background = [UIImage imageNamed:@"cell_bottom.png"];
} else {
background = [UIImage imageNamed:@"cell_middle.png"];
}
return background;
}
/*
// Override to support conditional editing of the table view.
- (BOOL)tableView:(UITableView *)tableView canEditRowAtIndexPath:(NSIndexPath *)indexPath {
// Return NO if you do not want the specified item to be editable.
return YES;
}
*/
/*
// Override to support editing the table view.
- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath {
if (editingStyle == UITableViewCellEditingStyleDelete) {
// Delete the row from the data source
[tableView deleteRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationFade];
} else if (editingStyle == UITableViewCellEditingStyleInsert) {
// Create a new instance of the appropriate class, insert it into the array, and add a new row to the table view
}
}
*/
/*
// Override to support rearranging the table view.
- (void)tableView:(UITableView *)tableView moveRowAtIndexPath:(NSIndexPath *)fromIndexPath toIndexPath:(NSIndexPath *)toIndexPath {
}
*/
/*
// Override to support conditional rearranging of the table view.
- (BOOL)tableView:(UITableView *)tableView canMoveRowAtIndexPath:(NSIndexPath *)indexPath {
// Return NO if you do not want the item to be re-orderable.
return YES;
}
*/
#pragma mark - Navigation
/*
In a storyboard-based application, you will often want to do a little preparation before navigation
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
// Get the new view controller using [segue destinationViewController].
UITabBarController *pvc=[segue destinationViewController];
// Pass the selected object to the new view controller.
//what row selected?
NSIndexPath *path=[self.tableView indexPathForSelectedRow];
Bird *c =birds[path.row];
}
*/
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
/* if ([segue.identifier isEqualToString:@"ShowGeneralView"]) {
NSIndexPath *indexPath = [self.tableView indexPathForSelectedRow];
GeneralViewController *destViewController = segue.destinationViewController;
destViewController.currentbird = [birds objectAtIndex:indexPath.row];
}
*/
self.myTabbarController = (UITabBarController*) [segue destinationViewController];
self.myFirstViewController = [self.myTabbarController.viewControllers objectAtIndex:0];
NSIndexPath *path=[self.tableView indexPathForSelectedRow];
Bird *c =birds[path.row];
_myFirstViewController.currentbird=c;
}
@end
我在应用程序关闭后保存最喜欢的行没问题。 问题在于无法保存和检索的按钮状态。
我知道我必须使用 NSUserDefaults，但是如何呢？
最佳答案
您的收藏夹按钮似乎位于一个单元格中，当按下该按钮时，您可以在鸟类数组中添加或删除收藏夹。您甚至似乎正在存储一个文件的 plist，以便在应用程序启动之间进行持久存储。除非我遗漏了什么，否则您需要在构建行时在 cellForRowAtIndexPath 中设置按钮的状态。只需检查您正在构建的单元格的收藏夹数组，如果它在其中，则将图像设置为正确的状态。
需要注意的一件事是，无论您认为图像的默认状态是什么，您都需要设置它。这是因为单元被重复使用(为了提高内存效率)。因此，假设您使用灰色单元格的默认图像状态构建单元格。用户点击最喜欢的图标，然后您将其设置为红心。然后当用户将单元格滚动到屏幕外时，iOS 将重用该单元格并且图像仍将设置为红色图像。如果该行不在您的收藏夹中，您没有明确将其设置为灰色，它将保持红色。
此外，正如您在问题中提到的，您可以使用 NSUserDefaults 来存储您的收藏夹数组，而不是文件(而且它可能会更简单)。它还允许您使用 iCloud 跨设备同步用户收藏夹(需要做更多工作来处理合并冲突)。关于如何在 NSUserDefaults 中存储数据，有很多资源。
在您的 cellForRowAtIndexPath 中，您可能想要执行以下操作:
if([sharedManager.favoritesArray containsObject:[birds objectAtIndex:indexPath.row]])
{
[button setSelected:NO];
} else {
[button setSelected:YES];
}
此外，在您的 buttonPressed 方法中，您应该使用
sender.selected = !sender.selected;
我将摆脱 (IBAction)buttonTouchDown: 方法，并将所有按钮处理逻辑放在 buttonPressed 方法中。在两个地方使用该逻辑会导致困惑。
关于ios-应用程序关闭后如何保存按钮状态？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/34297143/