《30天精通iPhone手机编程》－Day17

本文介绍了一个使用UIPickerView控件实现的老虎机游戏案例。通过加载不同的图像资源，演示了如何配置UIPickerView并使其在点击按钮后随机滚动。文章详细展示了创建图像视图、设置UIPickerView的数据源及委托方法的过程。

这一章的demo主要涉及的是UIPickerView控件

- (void)viewDidLoad {
    [super viewDidLoad];
	//创建图像变量对象，获取图像类型数据
	UIImage *seven = [UIImage imageNamed:@"seven.png"];
	UIImage *bar = [UIImage imageNamed:@"bar.png"];
	UIImage *crown = [UIImage imageNamed:@"crown.png"];
	UIImage *cherry = [UIImage imageNamed:@"cherry.png"];
	UIImage *lemon = [UIImage imageNamed:@"lemon.png"];
	UIImage *apple = [UIImage imageNamed:@"apple.png"];
	for(int i =1; i<=5; i++)
	{
        //创建图像视图变量对象，获取图像视图类型数据
		UIImageView *sevenView = [[UIImageView alloc] initWithImage:seven];
		UIImageView *barView = [[UIImageView alloc] initWithImage:bar];
		UIImageView *crownView = [[UIImageView alloc] initWithImage:crown];
		UIImageView *cherryView = [[UIImageView alloc] initWithImage:cherry];
		UIImageView *lemonView = [[UIImageView alloc] initWithImage:lemon];
		UIImageView *appleView = [[UIImageView alloc] initWithImage:apple];
		NSArray *imageViewArray = [[NSArray alloc] initWithObjects:
								   sevenView,barView, crownView,cherryView,lemonView,appleView,nil];
        //定义选择器中每一列的数据字符类型字符串
		NSString *fieldName = [[NSString alloc] initWithFormat:@"column%d",i];
		//在选取器中调用imageViewArray数组的值定义到关键字为fieldName字符变量
		[self setValue:imageViewArray forKey:fieldName];
		[fieldName release];
		[imageViewArray release];
		[sevenView release];
		[barView release];
		[crownView release];
		[cherryView release];
		[lemonView release];
		[appleView release];
	}
	//srandom为随机数生成的起源，设定时间值为空
	srandom(time(NULL));
}
//按钮方法，构建老虎机游戏转动
-(IBAction)spin{
    //创建判定变量win，定义判定变量为否
	BOOL win = NO;
    //定义选取器同一行的数值为1
	int numInRow = 1;
    //定义选取器的最后一行数值为－1
	int lastVal = -1;
	for(int i = 0; i<5 ;i++)
	{
		int newValue = random() % [self.column1 count];
        //当newValue的值等于最后一行的数值时
		if(newValue == lastVal)
            //选取器的行数加1,添加下一行数值
			numInRow++;
		else
			numInRow =1;
		lastVal = newValue;
        //定义选取器中所选行的数值是newValue，所在部分为循环语句的数值i
		[picker selectRow:newValue inComponent:i animated:YES];
        //读取数值为i的部分
		[picker reloadComponent:i];
		if(numInRow >= 3)
			win = YES;
	}
	
	if(win)
		winLabel.text = @"WIN!!!";
	else
		winLabel.text = @"~LOSE~";
}
//定义列数
-(NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView
{
	return 5;
}
//行数
-(NSInteger)pickerView:(UIPickerView *)pickerView
numberOfRowsInComponent:(NSInteger)component
{
	return [self.column1 count];
}
//显示选取器的行与列
-(UIView *)pickerView:(UIPickerView *)pickerView
		   viewForRow:(NSInteger)row
		 forComponent:(NSInteger)component reusingView:(UIView *)view
{
    //创建字符变量对象，定义选取器中每一列的数据字符类型字符串
	NSString *arrayName = [[NSString alloc] initWithFormat:@"column%d",component+1];
    //valueForKey制定其值为arrayName
	NSArray *array = [self valueForKey:arrayName];
    //返回数组对应的图片
	return [array objectAtIndex:row];
}