OSX: Why my app needs click on it first to receive keydown event? - objective-c

Question

I currently developing a small dictionary app under OSX for my own use, I would like to have a feature that when I hit the return key, the focus would go to the nssearchfeild.
So I try to make the app to receive keyDown event using a NSView and NSViewController told by this tutorial.
But every time I start the app, it wouldn't receive the keyDown event. I have to click on the window once, then hit the keyboard, so that it can receive keyDown event.
What did I do wrong? Can anyone help me out with this problem? I have been stuck in this problem for days, and searching throught Google and API wouldn't help much.
Thanks in advance!
Here is my code for AppDelegate.m
#import "AppDelegate.h"
#import "MyDictViewController.h"
#interface AppDelegate()
#property (nonatomic,strong) IBOutlet MyDictViewController *viewController;
#end
#implementation AppDelegate
- (void)applicationDidFinishLaunching:(NSNotification *)aNotification
{
self.viewController = [[MyDictViewController alloc] initWithNibName:#"MyDictViewController" bundle:nil];
[self.window.contentView addSubview:self.viewController.view];
self.viewController.view.frame = ((NSView*)self.window.contentView).bounds;
[self.window makeKeyAndOrderFront:nil];
}
#end
And My ViewController.m
#import "MyDictViewController.h"
#import "FileHelper.h"
#import <Carbon/Carbon.h>
#interface MyDictViewController ()
#property (weak) IBOutlet NSTableView *wordsFilteredTable;
#end
#implementation MyDictViewController
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
self.IMAGE_FILE = [NSImage imageNamed:#"Document.png"];
self.wordlist = [FileHelper readLines];
self.filterWordlist = [[NSMutableArray alloc] init];
}
return self;
}
- (void)loadView
{
[super loadView];
[self.view becomeFirstResponder];
}
-(void)keyDown:(NSEvent*)theEvent
{
NSLog(#"Caught key event");
}
-(void)keyUp:(NSEvent *)theEvent
{
unsigned short keycode = [theEvent keyCode];
switch (keycode)
{
case kVK_Return:
[self.searchField becomeFirstResponder];
default:
break;
}
}
-(void)mouseDown:(NSEvent*)theEvent
{
NSLog(#"Caught mouse event");
}
- (NSView *)tableView:(NSTableView *)tableView viewForTableColumn:(NSTableColumn *)tableColumn row:(NSInteger)row {
self.wordsFilteredTable.rowHeight = 37;
NSTableCellView *cellView = [tableView makeViewWithIdentifier:tableColumn.identifier owner:self];
if( [tableColumn.identifier isEqualToString:#"WordColumn"] )
{
NSString *word = [self.filterWordlist objectAtIndex:row];
cellView.textField.stringValue = word;
cellView.imageView.image = self.IMAGE_FILE;
return cellView;
}
return cellView;
}
- (NSInteger)numberOfRowsInTableView:(NSTableView *)tableView {
return [self.filterWordlist count];
}
- (void)controlTextDidChange:(NSNotification *)obj
{
NSTextView* textView = [[obj userInfo] objectForKey:#"NSFieldEditor"];
self.currentWord = [textView string];
[self.filterWordlist removeAllObjects];
for(NSString* word in self.wordlist) {
if ([word hasPrefix:self.currentWord]) {
[self.filterWordlist addObject:word];
}
}
[self.wordsFilteredTable reloadData];
}
#end
And my AppView.m
#import "AppView.h"
#implementation AppView
- (void)setViewController:(NSViewController *)newController
{
if (viewController)
{
[super setNextResponder:[viewController nextResponder]];
[viewController setNextResponder:nil];
}
viewController = newController;
if (newController)
{
[super setNextResponder: viewController];
[viewController setNextResponder:[self nextResponder]];
}
}
- (void)setNextResponder:(NSResponder *)newNextResponder
{
if (viewController)
{
[viewController setNextResponder:newNextResponder];
return;
}
[super setNextResponder:newNextResponder];
}
#end