小编nis*_*sar的帖子

我们将在ios中开发一个项目,所以我正在学习一个带有scrollview的自动布局,当我添加一个图像时工作正常,当我试图添加多个图像时,我得到了非常奇怪的事情,第一个图像是拉长并与下一张图像重叠.这是我的代码

UIScrollView *scrollView = [[UIScrollView alloc] init];
UIImageView *imageView = [[UIImageView alloc] init];
[imageView setImage:[UIImage imageNamed:@"2.png"]];

UIImageView *imageView1 = [[UIImageView alloc] init];
[imageView1 setImage:[UIImage imageNamed:@"01.png"]];
[self.view addSubview:scrollView];

[scrollView addSubview:imageView1];
[scrollView addSubview:imageView];

scrollView.translatesAutoresizingMaskIntoConstraints = NO;
imageView.translatesAutoresizingMaskIntoConstraints = NO;
 imageView1.translatesAutoresizingMaskIntoConstraints = NO;

self.imageViewPointer = imageView;
self.imageViewPointer = imageView1;
scrollView.maximumZoomScale = 2;
scrollView.minimumZoomScale = .5;
scrollView.delegate = self;

NSDictionary *viewsDictionary = NSDictionaryOfVariableBindings(scrollView,imageView,imageView1);
NSLog(@"Current views dictionary: %@", viewsDictionary);
[self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|[scrollView]|" options:0 metrics: 0 views:viewsDictionary]];
[self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:|[scrollView]|" options:0 metrics: 0 views:viewsDictionary]];
[scrollView addConstraints:[NSLayoutConstraint …

我正在使用 notepad++ 编写服务器端 dart 代码，我已经使用 dart 编辑器成功编写了服务器端 dart 代码。但我同样认为我用 notepad++ 完成的地方在浏览器中的 dart 中出现了 net::ERR_UNSAFE_PORT 错误，通过命令提示符初始化的 Dart 服务器端已完成，当我尝试访问 172....190 时，Bowser(dartium) 说上面那个错误！！！

服务器端代码

main() {
  HttpServer.bind("172...", 4045).then((server) {
    server.listen((res) {
      res.response.headers.add("Access-Control-Allow-Origin", "172.25.10.181");
      res.response.headers
          .add("Access-Control-Allow-Methods", "POST,GET,DELETE,PUT,OPTIONS");
      res.response.headers.add('Access-Control-Allow-Headers',
          'Origin, X-Requested-With, Content-Type, Accept,application/x-www-form-urlencoded');
      print('I am writing server side code');
    });
  });
}

客户端代码

req = new HttpRequest();

  req.open('get', 'http://172...:4045');

  req.send(data);

  req.onReadyStateChange.listen((_) {
    if (req.readyState == HttpRequest.DONE &&
        (req.status == 200 || req.status == 0)) {
     print(req.responseText);
    }
  });

我正在将java脚本移动到dart,在java脚本中我创建了动态变量

window["text" + pageNumber] = 123;
alert(window["text" + pageNumber]);

我怎么能用飞镖做到这一点？

我正在尝试使用抛物线方程(y=x*x)创建图形.但我有点困惑,计算控制点的值.我该如何计算控制点值.

我的JavaScript功能:

function drawParabola()
{
    ctx.beginPath();
    for(i=-2;i<=2;i++)
    {                     
        //formual y= x * x;
        y = i * i;
        x = i;
        if (i == -2) {
            ctx.moveTo((5 + x) * 30, Math.abs((-5 + y)) * 30);      
        }
        else {
            //ctx.lineTo((5 + x) * 30, Math.abs((-5 + y)) * 30);
            context.quadraticCurveTo(**?**, **?**, (5 + x) * 30, Math.abs((-5 + y)) * 30);
        }
        ctx.strokeStyle = 'orange';
        ctx.stroke();
    }
}