Question

我有以下问题：我有一个包含5个对象的NSArray。我想使用NSTimer显示每个项目2秒钟，并在显示数组中的最后一项后释放计时器。

Country = [NSArray arrayWithObjects:@"Aus",@"India",@"Pak",@"China",@"Japan", nil];

cntcount = [Country count];
NSLog(@"concount=%i", cntcount);

[NSTimer scheduledTimerWithTimeInterval:2.0 target:self selector:@selector(startTime) userInfo:nil repeats:YES];

但我没有再迈出一步。我应该在starttime()函数中做什么？请帮忙！

//
//  AppViewController.m
//  NSTimerExample
//

#import "AppViewController.h"

@interface AppViewController ()

@end

@implementation AppViewController

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.

    Country = [NSArray arrayWithObjects:
                  @"Aus", @"India", @"Pak", @"China", @"Japan", nil];

    tempValue = 0; 
    NSTimer *popupTimer = [NSTimer scheduledTimerWithTimeInterval:2.0
                                                           target:self
                                                         selector:@selector(startTime:)
                                                         userInfo:nil
                                                          repeats:YES];
    NSRunLoop *runner = [NSRunLoop currentRunLoop];
    [runner addTimer:popupTimer forMode:NSDefaultRunLoopMode];

}

- (void)startTime:(NSTimer *)theTimer {
    int cntcount = [Country count];
    if(tempValue < cntcount) {

        NSString *objectName = [Country objectAtIndex:tempValue];
        NSLog(@"objectName=%@", objectName);

        tempValue++;
    } else {
        [theTimer invalidate];
        theTimer = nil;
        // or you can reset tempValue to 0.

    }
}

显示我想要释放计时器的最后一项，因为它不再需要，但我得到了EXC_BAD_ACCESS例外。

Answer 1

这样做，

在.h

int tempValue;

在.m

tempValue=0;     
NSTimer *popupTimer = [NSTimer scheduledTimerWithTimeInterval:2.0 target:self selector:@selector(startTime:) userInfo:nil repeats:YES];;
NSRunLoop *runner = [NSRunLoop currentRunLoop];
[runner addTimer:popupTimer forMode: NSDefaultRunLoopMode];

在计时器操作方法中：

-(void)startTime:(NSTimer*)theTimer {
    if(tempValue< Country.count) {

         // Display array object eg: label.text=[Country objectAtIndex:tempValue];

         tempValue++;
    } else {
        [theTimer invalidate];
        theTimer=nil;
        // or you can reset the tempValue into 0.

    }
}

Answer 2

#import "AppViewController.h"

@interface AppViewController ()

@end

@implementation AppViewController

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.

    Country=[[NSArray alloc]initWithObjects:@"Aus",@"India",@"Pak",@"China",@"Japan", nil];
    tempValue=0; 
    NSTimer *popupTimer = [NSTimer scheduledTimerWithTimeInterval:2.0 target:self selector:@selector(startTime:) userInfo:nil repeats:YES];;
    NSRunLoop *runner = [NSRunLoop currentRunLoop];
    [runner addTimer:popupTimer forMode: NSDefaultRunLoopMode];

}

- (void)startTime:(NSTimer*)theTimer {
    if(tempValue< Country.count) {

        NSString *objectname=[Country objectAtIndex:tempValue];
        NSLog(@"objectname is %@",objectname);       
        tempValue++;
    } else {
        [theTimer invalidate];
        theTimer=nil;
        // or you can reset the tempValue into 0.

    }
}

- (void)viewDidUnload {
    [super viewDidUnload];
    // Release any retained subviews of the main view.
}

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
    return (interfaceOrientation != UIInterfaceOrientationPortraitUpsideDown);
}

@end

感谢Tony并且此代码正常运行

在NSArray中显示每个对象2秒钟

2 个答案: