i am trying to implement something that user can insert an number then program show me the row number but i little bit confusing , i would be grateful if you help me , here is my code :
for(int i = 0; i < myTextField.text; i++) {
[myScrollTable selectRowAtIndexPath:[NSIndexPath indexPathForRow:i inSection:0 ] animated:YES scrollPosition:UITableViewScrollPositionTop];
the compiler shows me a Warning and app crashes what can i do to equal my UtextField with indexPathForRow ?
warning alert: comparison between pointer and integer
You need to convert the textfield value to an int. That's what the compiler is warning you about.
for(int i = 0; i < [myTextField.text intValue]; i++) { ...
Not sure why you're using a loop if you only want to scroll to the row. Use scrollToRowAtIndexPath:atScrollPosition:animated: (Reference Doc)1
Related
I've 10 pan recognisers and want to assign to class property.
How can I increase numeric part of property name in for() loop?
for (int i=0; i < [_myArray count]; i++)
{
myClassInstance.recognizer = pangesture + i ?? // doesn't work of course. but how??
}
It's not fantastic form — definitely follow Caleb's comments wherever possible — but if you're really backed into a corner:
for(int i = 0; i < [_myArray count]; i++)
{
NSString *nameOfProperty = [NSString stringWithFormat:#"pangesture%d", i];
UIPanGestureRecognizer *recogniser = [self valueForKey:nameOfProperty];
}
That's using key-value coding; IBOutlets are necessarily KVC compliant or there'd be no way to load the NIB.
I've 10 pan recognisers and want to assign to class property. How can
I increase numeric part of property name in for() loop?
I'm not sure I understand your question fully, but assuming that you've got 10 gesture recognizers named g1 through g10 that you want to assign to 10 objects using a loop, a good approach would be to put those 10 gesture recognizers into an array and then make the assignment using the current index:
NSArray *recognizers = #[g1, g2, g3, g4, g5, g6, g7, g8, g9, g10];
if ([recognizers count < [_myArray count]) {
NSLog("Houston, we have a problem! Not enough gesture recognizers to go around.");
}
for (int i=0; i < [_myArray count]; i++)
{
myClassInstance.recognizer = recognizers[i]; // note the fancy "new" array access syntax!
}
If you're not allocating the gesture recognizers individually, then you can just create one each time though the loop:
for (MyClass *instance in _myArray) {
instance.recognizer = [[UIGestureRecognizer alloc] init...];
}
This code causes the app to crash! I'm looping through a dictionary and everything logs out fine. It works when i write -1 in the for loop but not otherwise,
-(void)updateProjectTimes {
for(int i = 0; i < [projectsTable numberOfRowsInSection:0]-1; i++) {
NSString *currentValue = [[[projects objectForKey:#"activeProjects"] objectAtIndex:i] objectForKey:#"timepassed"];
NSString *finishValue = [[[projects objectForKey:#"activeProjects"] objectAtIndex:i] objectForKey:#"timeleft"];
if([currentValue intValue] < [finishValue intValue]) {
[[[projects objectForKey:#"activeProjects"] objectAtIndex:i] setObject:[NSString stringWithFormat:#"%d", ([currentValue intValue] + 1)] forKey:#"timepassed"];
} else {
[(NSMutableArray *)[projects objectForKey:#"activeProjects"] removeObjectAtIndex:i];
if([[projects objectForKey:#"activeProjects"] count] == 0) {
[projectTimer invalidate];
projectTimer = nil;
}
}
//[projectsTable reloadData]; works if i put it here!
}
[projectsTable reloadData]; //<- But not here!! :(
}
I assume you are wokring with tableView. Apparently you are modifing the data source of your tableView. When you remove an object from the data source, you have to adjust your tableView as well. Meaning either call reloadData, or call [tableView deleteRowsAtIndexPaths:(NSArray *)indexPaths withRowAnimation:(UITableViewRowAnimation)animation].
The reason your app doesn't crash if you put -1, could be -- perhaps -- because there is only on item that matches the [currentValue intValue] < [finishValue intValue] condition, so that if you go through [projectsTable numberOfRowsInSection:0]-1, after removing that object, numberOfRowsInSection matches the count of projectsTable.
But it is good only for one cycle. When the next cycle happens, in the if...loop, you app crashes again, unless you include the [projectsTable reloadData] in the same if...loop.
While the reloadData method works just fine, but if you are simply removing a row, or adding a row to your table by adding or removing objects, its better to use deleteRowsAtIndexPaths or insertRowsAtIndexPaths methods. There will be less overhead and work for your app, and would make it smoother and faster.
The bottom line, to make your code work, right after [(NSMutableArray *)[projects objectForKey:#"activeProjects"] removeObjectAtIndex:i]; remove the corresponding object from your tableView by calling deleteRowsAtIndexPaths.
Alternatively, you can also use beginUpdates and endUpdates. For a complete reference, refer to http://developer.apple.com/library/ios/#documentation/uikit/reference/UITableView_Class/Reference/Reference.html
Hope it helps.
I have custom object and I have stored my values in Array. but I am bit stuck to show objects values form array. My code definition is here.
for (int i = 0; i < 20; i++)
{
Person *myPerson = [[Person alloc] init];
myPerson.name = #"Brian";
myPerson.age = [NSNumber numberWithInteger:23];
[myArray addObject:myPerson];
[myPerson release];
}
Now I want to show all 20 values which is stored in Array (name and age of person).
How will I show that values?
There are many different ways of showing the customers depending on what you want.
1. Print to the console
If you just want to print them out to the console, you can use:
for (int i = 0; i < 20; i++)
{
Person *thisPerson = [myArray objectAtIndex:i];
NSLog(#"%# has an age of %d", thisPerson.name, thisPerson.age);
}
additionally, you can use Fast Enumerators to neaten things up:
for (Person *thisPerson in myArray)
{
NSLog(#"%# has an age of %d", thisPerson.name, thisPerson.age);
}
2. Showing in a table view
You'll need a UITableView with an instance of UITableViewController that conforms to the UITableViewDataSource protocol.
This tutorial gives you an excellent walkthrough:
http://www.icodeblog.com/2008/08/08/iphone-programming-tutorial-populating-uitableview-with-an-nsarray/
If neither of these solutions suits, please provide more information about what you're trying to achieve.
I've got this code to erase an annotations (pins) in my mkmapview without erasing my blue dot (userLocation). The problem is that it erasing the pins I've added in seemingly random numbers. when it's called through an IBAction it removes the first 5 then click again it removes the next 3, then the next 2, then the last one.
When pressed I need it to remove that latest pin...etc. etc.
for (int i = 0;
i < [mapView.annotations count];
i++
)
{ if ([[mapView.annotations objectAtIndex:i] isKindOfClass:[MyAnnotation class]])
{
[mapView removeAnnotation:[mapView.annotations objectAtIndex:i]];
}
}
The problem is that you are modifying the annotation collection while iterating over it. At every execution of the loop, the loop's termination condition [mapView.annotations count] changes its value. This will lead to unforeseen behavior. You should
either put all annotations you want to remove into an empty mutable array inside the loop an then call removeAnnotations: with this array as a parameter after you exit the loop,
or count down from the annotation with the highest index to 0.
Use this code
NSInteger *counter = [mapView.annotations count];
for (int i = 0; i < counter; i++ )
{
if ([[mapView.annotations objectAtIndex:i] isKindOfClass:[MyAnnotation class]])
{
[mapView removeAnnotation:[mapView.annotations objectAtIndex:i]];
}
}
Just trying to create a simple method that counts up 1 on the tally when the button is pressed. My knowledge is extremely limited and I am pretty sure that my problem is somewhere in the method implementation:
-(IBAction) updateTally:(id) sender {
NSString *text;
int total = 0;
total = total + 1;
text=[[NSString alloc] initWithFormat: #"%i", total];
lblTally.text = text;
}
I have done the necessary interface declarations for the lblTally UILabel and the updateTally method. I suspect that there is some sort of an NSString/int/%i/%# mixup that I am making but I'm not sure how to fix it. When I run the program as it currently is it displays a 0 in the lblTally label field on the iphone. When I press the button it then displays a 1 in that field. However, if I continue to press the button - nothing happens, it just remains a 1. How do I make it count up as I continually press the button over and over?
The problem is that you are reinitializing the total in each updateTally. You need to either store the tally in a member variable or extract the existing tally from the string, update it, then write it back to the string.
- (IBAction) updateTally:(id) sender
{
int oldtally = [lblTally.text integerValue];
int newtally = oldtally + 1;
lblTally.text = [NSString stringWithFormat:"%d",newtally];
}
I should also point out that your current code has a memory leak (you invoke alloc/init, but then you don't invoke release after you have assigned the result to the lblTally.text variable). You should either invoke [text release] after lblTally.text = text, or you should use stringWithFormat like I have used above, which uses autorelease so that the string does not need to be explicitly released (since it will be automatically released).
You are re-initialising the total variable each time the method runs.
int total = 0;
Move than line of code outside of the method. I dont do apple development but it'll be something like:
int total = 0;
-(IBAction) updateTally:(id) sender {
NSString *text;
total = total + 1;
text=[[NSString alloc] initWithFormat: #"%i", total];
lblTally.text = text;
}