iphone - 如何将按钮添加到 QLPreviewController

Question

是否可以将新按钮添加到工具栏或 QLpreviewController 右上角的 actionButton 中？

如果是，我该如何编写代码？

Answer 1

尽管 QLPreviewController 是 UIViewController 的子类，但更改导航项没有任何效果。例如，这段代码理论上应该可以工作，但实际上并没有:

QLPreviewController *previewController = [[QLPreviewController alloc] init];
previewController.navigationItem.rightBarButtonItem = 
   [[[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemAction 
                             target:self action:@selector(share)] 

但是，您可以将工具栏添加到 QLPreviewController。首先设置工具栏以在加载 View 时显示:

- (void)viewWillAppear:(BOOL)animated
{
    [super viewWillAppear:animated];
    self.navigationController.toolbarHidden = NO;
}

- (void)viewWillDisappear:(BOOL)animated
{
    [super viewWillDisappear:animated];
    self.navigationController.toolbarHidden = YES;
}

接下来，从 QLPreviewController 委托(delegate)中设置您的 toolbarItems:

- (id)previewController:(QLPreviewController *)previewController 
                 previewItemAtIndex:(NSInteger)idx {

UIBarButtonItem *testButtonItem = [[UIBarButtonItem alloc] initWithTitle:@"Test"
                                                 style:UIBarButtonItemStylePlain
                                                 target:self
                                                 action:@selector(testButtonTapped:)];

NSArray *myToolbarItems = [NSArray arrayWithObjects:testButtonItem, nil];
previewController.toolbarItems = myToolbarItems;
[testButtonItem release];
}