我如何检测第三次应用程序启动

Question

我想在我的应用程序第三次启动时显示alertview。我到处都找遍了，就是找不到解决的办法。我怎么知道我的应用程序已经启动了第三次?

Thanks in Advance

Answer 1

您可以使用这些方法轻松地读写文件

+ (void) setSetting: (NSString *)key value: (NSString *)value {
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
[defaults setObject:value forKey:[NSString stringWithFormat:@"%@", key]]; 
[defaults synchronize];
}
+ (NSString *) getSetting: (NSString *)key defaultVal: (NSString *)defaultVal {
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
NSString *setting = [defaults stringForKey:[NSString stringWithFormat:@"%@", key]];
if (setting == nil) {
    setting = defaultVal;
}
return setting;
}

你可以在appDelegate中的didFinishLaunchingWithOptions:每次被触发时更新你存储在用户默认值中的值

Answer 2

这很简单。在你的NSUserDefaults中保存一个NSNumber并在每次启动应用时增加它。当它达到3时，显示一个警告

Answer 3

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)options {
// ...
if ([self plusPlusLaunchCount] == 3) {
    [self showRateUsAlert];
}
return YES;
}
- (void)showRateUsAlert {
// show the Rate Us alert view
}
- (NSInteger)plusPlusLaunchCount {
static NSString *Key = @"launchCount";
NSInteger count = 1 + [[NSUserDefaults standardUserDefaults] integerForKey:Key];
[[NSUserDefaults standardUserDefaults] setInteger:count forKey:Key];
return count;
}