android - 在网格中添加OxyPlot View

我有一个类，它继承contentpage

public class MainPage : ContentPage
{

    public Label lblTime { get; set; }

    public Grid grid { get; set; }

    public MainPage ()
    {

        //some code which doesn't matter

        lblTime = new Label {
            VerticalOptions = LayoutOptions.CenterAndExpand,
            HorizontalOptions = LayoutOptions.CenterAndExpand,
            Text = currentTime
        };

        Grid grid = new Grid
        {
            VerticalOptions = LayoutOptions.FillAndExpand,
            RowDefinitions =
            {
                new RowDefinition { Height = new GridLength(40, GridUnitType.Auto) },
                new RowDefinition { Height = new GridLength() }
            },
            ColumnDefinitions =
            {
                new ColumnDefinition { Width = new GridLength(50, GridUnitType.Auto) },
                new ColumnDefinition { Width = new GridLength(50, GridUnitType.Star) }
            }
        };

        grid.Children.Add (lblTime, 0, 1, 0, 1);

        Content = new StackLayout {
            Children = {
                grid
            }
        };
    }
}

我还有一个类，它绘制图形：

public class DrawGraph
{
    public PlotModel MyModel { get; set; }

    public DrawGraph ()
    {

        var plotModel = new PlotModel {};

        plotModel.Title = "Test";

        var xaxis = new LinearAxis {
            Position = AxisPosition.Bottom
        };

        var yaxis = new LinearAxis {
            Position = AxisPosition.Left
        };

        yaxis.TickStyle = OxyPlot.Axes.TickStyle.Inside;
        xaxis.MinorTickSize = 20;
        yaxis.TicklineColor = OxyColors.Blue;

        plotModel.Axes.Add (xaxis);
        plotModel.Axes.Add (yaxis);

        var series1 = new LineSeries {
            StrokeThickness = 3,
            MarkerType = MarkerType.Circle,
            MarkerSize = 4,
            MarkerStroke = OxyColors.LimeGreen,
            MarkerStrokeThickness = 1
        };

        double[,] chartValues = new double[,] {{1437041279684.0156,1.0897299999999999},{1437041339421.4324,1.0896},{1437041397111.7322,1.0897100000000002},{1437041458595.2488,1.0898599999999998},{1437041519510.7329,1.08992},{1437041578914.1306,1.08983},{1437041639357.5877,1.0895100000000002},{1437041699721.0405,1.0895299999999999},{1437041758381.3958,1.0895000000000001},{1437041818605.84,1.08954},{1437041879932.3479,1.0894400000000002},{1437041939531.7568,1.08902}};

        for (int i = 0; i < chartValues.GetLength(0)/2; i++) {
            series1.Points.Add (new DataPoint (chartValues[i,0],chartValues[i,1]));
        }

        plotModel.Series.Add (series1);

        this.MyModel = plotModel;
    }
}

我的问题是，如何调用DrawGraph类并将其生成的视图放在网格单元中？我想应该是从drawgraph类调用生成的plotview，比如grid.children.add（plotview，0，1，1，2）；但是我想不出来。

最佳答案

嗨，最好的方法是使用绑定将视图挂接到视图模型。绘图视图
在这种情况下，您需要做以下更改：
在您的内容页中，我们必须创建一个plotview并将其添加到网格中，这就是图表将要呈现的地方，

var graph = new PlotView ();
grid.Children.Add (graph, 0, 0, 1, 0);

接下来，我们必须告诉图形我们绑定到了什么，在这种情况下，我们在viewmodel（我们的drawgraph类）上将modelproperty绑定到mymodel，我们还需要将页面的bindingContext设置为一个新的drawgraph实例。

graph.SetBinding(PlotView.ModelProperty, new Binding ("MyModel"));
this.BindingContext = new DrawGraph ();

我们的drawgraph类需要做一些更改，以便他能够正确地更新ui，我们需要实现inpc接口。所以我们加上：

public class DrawGraph : INotifyPropertyChanged
    {
       public event PropertyChangedEventHandler PropertyChanged;

       public void OnPropertyChaged([CallerMemberName]string caller = null){
            var handler = PropertyChanged;
            if (handler != null) {
                handler(this, new PropertyChangedEventArgs(caller));
            }
       }

我们需要更改属性设置器，以便在更改时通知：

PlotModel myModel;
public PlotModel MyModel {
    get{ return myModel; }
    set {
        myModel = value;
        OnPropertyChaged ();
    }
}

这应该是你需要得到的图表渲染。
每次设置新的mymodel属性时，它都会更新ui。

关于android - 在网格中添加OxyPlot View ，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/31540841/