向导航栏添加刷新按钮

Question

Hi everyone Im having a pain in the ass time trying to get this Navigation bar to include a Refresh Button if you can look at the code below and then provide some help this is my original code along with the UIBarbutton snippet that i found for the refresh button from another users project on google. Which i am running into the following errors:

- (void)viewDidLoad
{
    [super viewDidLoad];
    [self.tableView setBackgroundView:nil];
    self.tableView.backgroundColor = [ColorHelper charcoalBackgroundImage];
    UIBarButtonItem *refresh = [[UIBarButtonItem alloc]initWithBarButtonSystemItem:UIBarButtonSystemItemRefresh target:self action:@selector(refresh:)];
    self.navigationItem.leftBarButtonItem = refresh;
    // [button release]; remove this line if you're using ARC
}
- (void) refresh
{

}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
}

Answer 1

- (void)viewDidLoad
{
    [super viewDidLoad];
    [self.tableView setBackgroundView:nil];
    self.tableView.backgroundColor = [ColorHelper charcoalBackgroundImage];

    UIBarButtonItem *button = [[UIBarButtonItem alloc]initWithBarButtonSystemItem:UIBarButtonSystemItemRefresh target:self action:@selector(refresh:)];
    self.navigationItem.rightBarButtonItem = button;
}

Write your method as this because you are passing UIBarButton object in call.

- (void) refresh:(id)sender
{

}

OR

UIBarButtonItem *button = [[UIBarButtonItem alloc]initWithBarButtonSystemItem:UIBarButtonSystemItemRefresh target:self action:@selector(refresh)];

Answer 2

May be this code will help you...

UIImage *reloadImage = [UIImage imageNamed:@"reload.png"];
UIButton *btnReload = [UIButton buttonWithType:UIButtonTypeCustom];
btnReload.bounds = CGRectMake( 10, 0, reloadImage.size.width, reloadImage.size.height );
[btnReload addTarget:self action:@selector(reloadData:) forControlEvents:UIControlEventTouchUpInside];
[btnReload setImage:reloadImage forState:UIControlStateNormal];
UIBarButtonItem *reloadButton = [[UIBarButtonItem alloc] initWithCustomView:btnReload];
self.navigationItem.leftBarButtonItem = reloadButton;

Answer 3

- (void)viewDidLoad
{
    [super viewDidLoad];
    [self.tableView setBackgroundView:nil];
    self.tableView.backgroundColor = [ColorHelper charcoalBackgroundImage];

    UIBarButtonItem *button = [[UIBarButtonItem alloc]initWithBarButtonSystemItem:UIBarButtonSystemItemRefresh target:self action:@selector(refresh:)];
    self.navigationItem.rightBarButtonItem = button;
    // [button release]; remove this line if you're using ARC
}

It seems that you are already use ARC. So you should remove [button release] . Your book is on the way to the history.

Answer 4

Your action selector and the actual method are not the same. One is refresh: and the other is refresh .

Change the selector to match the actual method.

@selector(refresh)

Answer 5

for swift 4

let refreshButton = UIBarButtonItem(barButtonSystemItem: .refresh, target: self, action: #selector(refresh))
self.navigationItem.rightBarButtonItem = refreshButton

@objc func refresh() {

}