[英]Persist view controller state in SWRevealViewConttoller in iOS?
我在SWRevealViewController
的導航抽屜中使用SWRevealViewController
。我有一個主屏幕,默認情況下會在應用啟動時顯示。我還有其他屏幕,例如SWRevealViewController
設置'',` SWRevealViewController
幫助'',``關於''。 因此,當用戶在屏幕之間切換時,第一視圖控制器的狀態將重置。
我正在使用下面的代碼在屏幕之間切換。
-(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
UITableViewCell *cell=[self.tableView cellForRowAtIndexPath:indexPath];
if(indexPath.row==0)
{
[self performSegueWithIdentifier:@"home" sender:cell];
[cell setSelected:YES];
}
else if(indexPath.row==1)
{
[self performSegueWithIdentifier:@"settings" sender:cell];
}
else if(indexPath.row==2)
{
[self performSegueWithIdentifier:@"help" sender:cell];
}
else if(indexPath.row==3)
{
[self performSegueWithIdentifier:@“about” sender:cell];
}
}
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
NSLog(@"Segue");
NSIndexPath *indexPath = [self.tableView indexPathForSelectedRow];
UINavigationController *destViewController = (UINavigationController*)segue.destinationViewController;
destViewController.title = [[titles objectAtIndex:indexPath.row] capitalizedString];
if([segue.identifier isEqualToString:@"settings"])
{
self.revealViewController.navigationItem.title = @"Settings";
}
else if([segue.identifier isEqualToString:@"help"])
{
self.revealViewController.navigationItem.title = @"help";
}
else if([segue.identifier isEqualToString:@"about"])
{
self.revealViewController.navigationItem.title = @"about";
}
if([segue isKindOfClass:[SWRevealViewControllerSegue class]])
{
SWRevealViewControllerSegue *swSegue = (SWRevealViewControllerSegue*) segue;
swSegue.performBlock = ^(SWRevealViewControllerSegue* rvc_segue, UIViewController* svc, UIViewController* dvc) {
UINavigationController* navController = (UINavigationController*)self.revealViewController.frontViewController;
[navController setViewControllers: @[dvc] animated: NO ];
[self.revealViewController setFrontViewPosition: FrontViewPositionLeft animated: YES];
};
}
}
我看到的一種解決方案是,將viewController保留在導航堆棧中,以使viewController不會被破壞,當用戶轉到“ home”時,它仍保留在堆棧中,然后從導航堆棧重新啟動,而不是再次初始化視圖控制器。
例如對於HelpVC,您將其屬性存儲在側面菜單控制器中:
@property (nonatomic, strong) HelpViewContoller* helpVC;
比行選擇而不是調用segue更為方便,您實例化了視圖控制器,但是在此之前,您檢查它是否已被實例化,您已經在使用它:
-(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
UITableViewCell *cell=[self.tableView cellForRowAtIndexPath:indexPath];
if(indexPath.row==0) {
if (helpVC == nil) {
helpVC = [self.storyboard instantiateViewControllerWithIdentifier:@"helpVCidentifier"];
[self changeFrontVCto:helpVC];
}
}
}
-(void) changeFrontVCto:(UIViewController*)vc {
UINavigationController* navController = (UINavigationController*)self.revealViewController.frontViewController;
[navController setViewControllers: @[vc] animated: NO ];
[self.revealViewController setFrontViewPosition: FrontViewPositionLeft animated: YES];
}
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