Classes/ViewController.m

/*
     File: ViewController.m
 Abstract: View controller, the main view controller of the app
  Version: 1.2
 
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*/
 
#import "ViewController.h"
#import "TabularDataCell.h"
#import <AudioToolbox/AudioServices.h>
 
@implementation ViewController
 
- (void)updateGraphingView
{
    // set the consntant (alpha) value for the graph view
    CGFloat value = [valueField.text floatValue]; 
    
    if ( value < slider.minimumValue )
    {
        value = slider.minimumValue;
    }
    else if ( value > slider.maximumValue )
    {
        value = slider.maximumValue;
    }
    
    graphingView.formulaConstant = value;
}
 
- (void)viewDidLoad 
{
    // update the graph view
    [self updateGraphingView];
 
    // set the hint for the stop watch button
    [stopWatch setAccessibilityHint:@"Toggles animation."];    
 
    // allow updates of graph
    shouldUpdateGraph = YES;
    
    [super viewDidLoad];
}
 
- (void)updateLabel:(NSString *)text
{
    resultLabel.text = text;
}
 
- (IBAction)touchesEndedForGraphingView:(id)sender event:(UIEvent *)event
{
    // handle touches in the graph view
    CGPoint touchUp = [[[event allTouches] anyObject] locationInView:graphingView];
    if ( touchUp.x < 100 )
    {
        [self updateLabel:[NSString stringWithFormat:@"f(%.2f) = %.5f",-M_PI/2, graphingView.formulaConstant * -M_PI/2 * sin(-M_PI/2)]];
    }
    else if ( touchUp.x < 200 )
    {
        [self updateLabel:[NSString stringWithFormat:@"f(%.2f) = %.5f",0, graphingView.formulaConstant * 0 * sin(0)]];        
    }
    else if ( touchUp.x < 300 )
    {
        [self updateLabel:[NSString stringWithFormat:@"f(%.2f) = %.5f",M_PI/2, graphingView.formulaConstant * M_PI/2 * sin(M_PI/2)]];
    }
}
 
- (void)_countdownValue
{
    // update the text field and graph based on whether the stop watch is on or off
    if ( !stopWatchStateOn )
    {
        return;
    }
 
    CGFloat value = [valueField.text floatValue];
    
    if ( value > slider.maximumValue )
    {
        stopWatchDirectionUp = NO;
    }
    else if ( value < slider.minimumValue )
    {
        stopWatchDirectionUp = YES;        
    }
    
    CGFloat step = .005f;
    if ( stopWatchDirectionUp )
    {
        value += step;
    }
    else
    {
        value -= step;        
    }
    
    slider.value = value;
    
    valueField.text = [NSString stringWithFormat:@"%.5f", value];
    [self updateGraphingView];
 
    [self performSelector:@selector(_countdownValue) withObject:nil afterDelay:.02f];
}
 
- (IBAction)stopWatchButtonWasPressed:(id)sender
{
    if ( stopWatchStateOn )
    {
        stopWatchStateOn = NO;
        [stopWatch setImage:[UIImage imageNamed:@"countdown-off.png"] forState:UIControlStateNormal];
        
        // update the accessibility label to indicate what pressing the button now will do
        [stopWatch setAccessibilityLabel:@"Start animating graph"];
    }
    else
    {
        stopWatchStateOn = YES;
        [stopWatch setImage:[UIImage imageNamed:@"countdown-on.png"] forState:UIControlStateNormal];
        [self performSelector:@selector(_countdownValue) withObject:nil afterDelay:0.0f];
 
        // update the accessibility label to indicate what pressing the button now will do
        [stopWatch setAccessibilityLabel:@"Stop animating graph"];
    }
    
    // play sound when pressed
    static SystemSoundID soundId = 0;
    if ( soundId == 0 )
    {
        AudioServicesCreateSystemSoundID((CFURLRef)[NSURL fileURLWithPath:[[NSBundle mainBundle] pathForResource:@"Sound" ofType:@"aiff"]], &soundId);
    }
    
    AudioServicesPlaySystemSound(soundId);
}
 
- (IBAction)textFieldChanged:(id)sender
{
    // only allow the text field to update in this iteration
    if ( shouldUpdateGraph )
    {
        shouldUpdateGraph = NO;
        slider.value = [valueField.text floatValue];
        [self updateGraphingView];
        shouldUpdateGraph = YES;
    }
}
 
- (IBAction)sliderWasChanged:(id)sender
{
    CGFloat value = [slider value];
    
    // only allow the slider to update in this iteration
    if ( shouldUpdateGraph )
    {
        shouldUpdateGraph = NO;
        valueField.text = [NSString stringWithFormat:@"%0.5f",value];
        [self updateGraphingView];
        shouldUpdateGraph = YES;
    }
}
 
- (BOOL)textFieldShouldReturn:(UITextField *)textField
{
    [textField endEditing:NO];
    return YES;
}
 
#pragma mark -
#pragma mark Tabular Data View
 
- (IBAction)tableButtonWasPressed:(id)sender
{
    CGRect frame = tabularDataView.frame;
    frame.origin.y = frame.size.height;
    
    if ( [tabularDataView superview] == nil )
    {
        [self.view addSubview:tabularDataView];
    }
        
    tabularDataView.frame = frame;
    [tabularDataTableView reloadData];
    
    [UIView beginAnimations:nil context:NULL];
    [UIView setAnimationDuration:.5];
    frame.origin.y = 0;
    tabularDataView.frame = frame;
    [UIView commitAnimations];
 
    // when the table view slides in, its significant enough that a screen change notification should be posted
    UIAccessibilityPostNotification(UIAccessibilityScreenChangedNotification, nil);
}
 
- (NSInteger)tableView:(UITableView *)table numberOfRowsInSection:(NSInteger)section
{
    return 100;
}
 
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    TabularDataCell *cell = [[[TabularDataCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:nil] autorelease];
    cell.formulaConstant = [valueField.text floatValue];
    cell.row = indexPath.row;
    return cell;
}
 
- (IBAction)doneButtonPressed
{
    CGRect frame = tabularDataView.frame;
 
    [UIView beginAnimations:nil context:NULL];
    [UIView setAnimationDuration:.5];
    frame.origin.y = frame.size.height;
    tabularDataView.frame = frame;
    [UIView commitAnimations];
 
    // when the table view goes away, its significant enough that a screen change notification should be posted
    UIAccessibilityPostNotification(UIAccessibilityScreenChangedNotification, nil);
}
 
@end


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