//讀檔
- (NSString *)filePath:(NSString*)name
{
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,
                                        NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];
    return [documentsDirectory stringByAppendingPathComponent:name];
}
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    NSString *path = [self filePath:@"test.txt"];
    NSLog(@"%@",path);
    if ([[NSFileManager defaultManager] fileExistsAtPath:path])
    {
		NSLog(@"file exist");
		NSArray *array = [[NSArray alloc] initWithContentsOfFile: path];
		for(NSString *name in array)
		{
			NSLog(@"%@", name);
		}
    }
    return YES;
}
//存檔
- (void)applicationDidEnterBackground:(UIApplication *)application
{
    NSString *path = [self filePath:@"test.txt"];
	if ([[NSFileManager defaultManager] fileExistsAtPath:path])
	{
		NSLog(@"file exist");
	}
	else
	{
		NSLog(@"create file");
		NSArray *array = [[NSArray alloc] initWithObjects:@"andy", @"peter", @"kevin", nil];
		[array writeToFile:path atomically:YES];
	}
}