打开openPanel的代码

- (IBAction)openPDFFile:(id)sender {

NSOpenPanel *panel = [NSOpenPanel openPanel];

[panel setAllowsMultipleSelection:YES];

NSArray* fileArray = [NSArray arrayWithObjects:@"pdf", nil];

[panel setAllowedFileTypes:fileArray];

[panel beginSheetModalForWindow:self.window completionHandler:^(NSInteger result) {

if (result == NSOKButton)

{

[panel close];

NSWindow *keyWindow = [NSApplication sharedApplication].keyWindow;

if (self.window == keyWindow) {

[[self homeViewCtrl].collectionView addItemsWithURLs:[panel URLs]];

}

}

}];

}