iOS加載啟動畫面Default.png的代碼

給iOS程序上加了一個啟動畫面Default.png，下面是啟動圖片的加載代碼：

self.connectionTimer=[NSTimer scheduledTimerWithTimeInterval:1.5 target:self selector:@selector(timerFired:) userInfo:nil repeats:NO];
    [[NSRunLoop currentRunLoop] addTimer:self.connectionTimer forMode:NSDefaultRunLoopMode];
    do{
        [[NSRunLoop currentRunLoop]runUntilDate:[NSDate dateWithTimeIntervalSinceNow:1.0]];
    }while (!done);

-(void)timerFired:(NSTimer *)timer{
    done = YES;
}