-(void)setRefreshWindow{
    CGRect frame = CGRectMake(0.0, 0.0, 320.0, 20.0);
    statusbarWindow = [[UIWindow alloc] initWithFrame:frame];
    [statusbarWindow setBackgroundColor:[UIColor clearColor]];
    [statusbarWindow setWindowLevel:UIWindowLevelStatusBar+1.0f];
   
    // 添加自定義子視圖
    UIImageView *customView = [[UIImageView alloc] initWithFrame:CGRectMake(100, 0, 120, 18)];
    customView.image=[UIImage imageNamed:@"數據刷新欄.png"];
   
//    UILabel *label=[[UILabel alloc] initWithFrame:CGRectMake(100, 0, 100, 20)];
//    //    label.backgroundColor=[UIColor clearColor];
//    label.text=@"數據正在刷新";
//    [customView addSubview:label];
    [statusbarWindow addSubview:customView];
    [statusbarWindow makeKeyAndVisible];
} 


摘自  shijiucdy的專欄