call NSString whit multiple parameters - ios

Question

I am a beginner and maybe it is a trivial question.
I have this method:
-(NSString *)getInfoFormediaItem:(MPMediaItemCollection *)list {
NSString *trackCount;
if ([list count] > 0) {
trackCount = [NSString stringWithFormat:NSLocalizedString(#"%lu Songs", #""), (unsigned long)[list count]];
} else if([list count] == 1) {
trackCount = [NSString stringWithFormat:NSLocalizedString(#"1 Song", #"")];
} else {
trackCount = [NSString stringWithFormat:NSLocalizedString(#"0 Song", #"") ];
}
return [NSString stringWithFormat:#"%#", trackCount];
}
I would like to call it here with a MPMediaItemCollection:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:#"cell"];
if( cell == nil )
{
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:#"cell"];
}
MPMediaQuery *playlistsQuery = [MPMediaQuery playlistsQuery];
NSArray *playl = [playlistsQuery collections];
MPMediaItem *rowItem = [playl objectAtIndex:indexPath.row];
MPMediaItemCollection * collection = [[MPMediaItemCollection alloc] initWithItems:[NSArray arrayWithObject:rowItem]];
cell.detailTextLabel.text = [self getInfoFormediaItem:collection];
}
I would like to get the number of tracks in each playlist.
It doesn't work. How do I fix? Thanks in advance!

Answer 1

Why are you using performSelector:withObject:? Just call the method directly:
cell.detailTextLabel.text = [self getInfoFormediaItem:collection];
Why are you passing nil to the withObject: parameter? That's why your code goes to the else. list is nil so [list count] will always be 0. You need to pass an actual instance of a MPMediaItemCollection.
Why are you needlessly using stringWithFormat: for the 1 and 0 count checks? Just do:
-(NSString *)getInfoFormediaItem:(MPMediaItemCollection *)list {
NSString *trackCount;
if ([list count] > 1) {
trackCount = [NSString stringWithFormat:NSLocalizedString(#"%lu Songs", #""), (unsigned long)[list count]];
} else if([list count] == 1) {
trackCount = NSLocalizedString(#"1 Song", #"");
} else {
trackCount = NSLocalizedString(#"0 Song", #"");
}
return trackCount;
}
Based on your updated question, your cellForRowAtIndexPath code isn't correct for the getting the media collection. The collectionsmethod returns an array of MPMediaCollection objects, not MPMediaItem objects. You need:
MPMediaQuery *playlistsQuery = [MPMediaQuery playlistsQuery];
NSArray *playl = [playlistsQuery collections];
MPMediaItemCollection *collection = playl[indexPath.row];
Now you can use collection when you call getInfoFormediaItem:.

Answer 2

You simply don't need to call this statement:
cell.detailTextLabel.text = [self performSelector:#selector(getInfoFormediaItem:) withObject:nil];
in your "getInfoFormediaItem"method. You do that in your "cellforrowataIndexPath" method when you define the cell,just call like this:
cell.detailTextLabel.text = [self getInfoFormediaItem:This_Is_A_List_You_Wanna_Pass_To_The_Method];
and you should be good to go.

Answer 3

In addition to the problems pointed out by other posters, your if statement will not work as you want it to:
if ([list count] > 0) {
trackCount = [NSString stringWithFormat:NSLocalizedString(#"%lu Songs",
#""), (unsigned long)[list count]];
} else if([list count] == 1) {
trackCount = [NSString stringWithFormat:NSLocalizedString(#"1 Song", #"")];
} else {
trackCount = [NSString stringWithFormat:NSLocalizedString(#"0 Song", #"") ];
}
The "if ... >0" clause will match first, before checking for a value of 1, since 1 is > 0. Thus the "if ... == 1" will never evaluate as true. You need to reorder that if statement:
if ([list count] == 1) {
trackCount = NSLocalizedString(#"1 Song", #"");
else if ([list count] > 0) {
trackCount = [NSString stringWithFormat:NSLocalizedString(#"%lu Songs",
#""), (unsigned long)[list count]];
}
else
{
trackCount = NSLocalizedString(#"0 Songs", #"");
}