I have a UIPickerView in my viewController. I can get the value of the row number of the selected value in the picker from the delegate method
- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component
But in my case, I need to get the row number of the selected component as soon as the view appears. Is there a way to get the row number/trigger the delegate method as soon as the view appears.
You just have to use selectedRowInComponent
selectedRowInComponent:
Returns the index of the selected row in a given component.
- (NSInteger)selectedRowInComponent:(NSInteger)component Parameters
component
A zero-indexed number identifying a component of the picker view.
Return Value
A zero-indexed number identifying the selected row, or -1 if no row is
selected. Availability
Available in iOS 2.0 and later.
See Also
– selectRow:inComponent:animated:
Related Sample Code
iPhoneCoreDataRecipes
Declared In UIPickerView.h
you use this for select in pickerview
- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component
{
NSString *str= [yardsArray objectAtIndex:row];
}
use this code when view will load
-(void)ViewDidLoad
{
NSString *str= [yardsArray count];
}
in viewDidLoad
travers the array of your objects and match object of which you want to find out the row
and tell me if this is the solution
Related
I have two pickers - country and region. I need to populate the region picker based on the row selected in the country picker. I have arrays to populate both the pickers. I need some help to change the rows of region picker based on the country picker's selection. Any help would be greatly appreciated. Thanks a lot in advance.
Ok You have two pickers lets say countryPicker and regionPicker.
in the delegate method for UIPickerView add one condition
- (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component
{
NSString *pickerTitle = #"";
if (pickerView == countryPicker)
{
pickerTitle = [countryFeeds objectAtindex:row];
//assigns the country title if pickerView is countryPicker
}
else if (pickerView == regionPicker)
{
pickerTitle = [regionFeeds objectAtindex:row];
//assigns the region title if pickerView is regionPicker
}
return pickerTitle;
}
- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component
{
if (pickerView == countryPicker)
{
//selects the region corresponding to the selected country.
//totalRegions is a NSDictionary having country names as keys and array of their regions as values
regionFeeds = [totalRegions objectForKey:[countryFeeds objectAtindex:row]];
//Now reloading the regionPicker with new values.
[regionPicker reloadAllComponents];
}
else if (pickerView == regionPicker)
{
// your code to select a region
}
}
I hope this solves your problem :)
BR, Hari
Are they separate picker views, or one picker view with two columns?
Either way, when you change the value in one picker, just call reloadAllComponents on the other picker (or reloadComponent: if you are using a split picker) and then when it reloads the data from it's data source you can use the value from the first picker to supply the correct region list.
My suggestion is please maintain the country and region in one picker with two components(country,region).If u do like this then we can change the one component values based on another component value.
NSUInteger selectedRow= [CountryPicker selectedRowInComponent:0];
NSString *userchoice =[self pickerView:CountryPicker titleForRow:selectedRow forComponent:0];
This will give you the title for the selected row by the user in country picker
then using the arrays you have to populate names of regions
You can use
- (void)selectRow:(NSInteger)row inComponent:(NSInteger)component animated:(BOOL)animated
on the RegionPicker
I am trying to pass my UItextfield value over to a UIPicker that I have loading in a alertview I'm just not sure what functions are available to me to get the values back into the picker?
At a guess I should be doing something in my
- (NSInteger)pickerView:(UIPickerView*)pv numberOfRowsInComponent:(NSInteger)component
{
if (pv == pickerViewA) {
return 10;
}
else
return 16;
}
but looking at the developers notes their is not much info about the UIPickerViewDataSource other than returning number of rows...
any help would be greatly appreciated.
There are other data source and delegates as-
//for title of a row in a component
- (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component
//for width of a componenet
- (CGFloat)pickerView:(UIPickerView *)pickerView widthForComponent:(NSInteger)component
//for row height of a component
-(CGFloat)pickerView:(UIPickerView *)pickerView rowHeightForComponent:(NSInteger)component
//for number of components
-(NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView
for more info look at documentation -
http://developer.apple.com/library/ios/#DOCUMENTATION/UIKit/Reference/UIPickerViewDelegate_Protocol/Reference/UIPickerViewDelegate.html
and
http://developer.apple.com/library/ios/#documentation/uikit/reference/UIPickerView_Class/Reference/UIPickerView.html
You can use either one of the following two delegates to add data content to UIPickerView
– pickerView:titleForRow:forComponent:
– pickerView:viewForRow:forComponent:reusingView:
For the first one u can return any NSString object and you cannot customize anything like font size or color for that.
But if you use the second one you can add the data content as a view to UIPickerView which can be achieved using a UILabel and here you can customize the view as you require.
Hope this might help you
Happy coding !
I need something with this
NSMutableArray *foodArray;
NSMutableArray *ingredientsArray;
[foodArray addObject:Pizza];
and when select Pizza in a PickerView show me in the second row ingredientsArray for the pizza
First, you'll need to make sure that you've implemented
- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component
once that is done you'll need to update the data that is driving your UIPickerView whenever a new row is selected in the first component, then call reloadComponent: on the picker view, passing in the component (in this case 1).
As soon as I scroll the PickerView (or) UIDatePicker, I need the value to get displayed on a TextField :
While Scrolling. Even when the picker is moving the text field should update itself. Is it possible ?
On the event that the Picker stops moving and comes to rest. Is there an event for the PickerView to come to rest so that I could update the textField (as soon as the pickerView comes to rest).
// I do not wish to use the TextFieldDidEndEditing
// I want the textField to update itself when the picker view comes to rest.
It would be helpful if anyone could solve 1) and 2)
(1) might not be possible. For (2), you can use the delegate method pickerView:didSelectRow:inComponent. Let me know if you need any help with this.
For UIPickerView
(1) Implement pickerView:titleForRow:forComponent,
- (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component {
// Every time the picker view is rotated, this method will be called to fetch the title.
NSInteger selectedRow = [pickerView selectedRowInComponent:0];
// Get selected row like above and process data and update text field.
[..] // Process the title
return the title.
}
(2) This is more obvious.
- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component {
// You have the selected row, update the text field.
}
For the first question, this isn't possible with the default control however there is nothing to stop you writing your own and simulate the effect using touchesMoved etc...
i am working on a project in which i have to perform following two work:
1.) Fetch value from CoreData and store it in an NSMutableArray.
2.) Take a UIPickerView and fill it with an Array value.
Problem is that size of array is dynamic and i canto fill an array value in UIPickerView. can someone help me.
in order for the UIPickerView to work correctly, you must supply the amount of components (columns) and the number of rows for each component whenever it reloads:
as mentioned, use [myPickerView reloadAllComponents]; to reload the view once the array is populated, but you MUST implement also these things after you declare the containing view controller class as <UIPickerViewDelegate> link the picker to the file owner as a delegate, and then:
- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView{
return 1;// or the number of vertical "columns" the picker will show...
}
- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component {
if (myLoadedArray!=nil) {
return [myLoadedArray count];//this will tell the picker how many rows it has - in this case, the size of your loaded array...
}
return 0;
}
- (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component {
//you can also write code here to descide what data to return depending on the component ("column")
if (myLoadedArray!=nil) {
return [myLoadedArray objectAtIndex:row];//assuming the array contains strings..
}
return #"";//or nil, depending how protective you are
}
After updating the value (Inserting or modifying existing) in your array.
Call reloadAllComponents on your UIPickerView instance.
- (void)reloadAllComponents
Use as below
[myPickerView reloadAllComponents];