DOM access in onPageDidEnter

@aumar wrote:

Hi,

I'm having problems accessing a Canvas element in onPageDidEnter().

Trying to create a chart with http://chartjs.org/ it onPageDidEnter() fails and I suspect that is because DOM is not fully created.

onPageDidEnter()
  {

  // setTimeout( this.drawGraph(null) ,2000 );
    let canvasElement =  document.getElementById("myChart2") ;
    console.log(canvasElement);
    var canvas : HTMLCanvasElement = <HTMLCanvasElement> canvasElement;
    console.log("canvas " + canvas.height);
    var ctx : CanvasRenderingContext2D   =  canvas.getContext("2d");
    console.log("ctx null? " + (ctx == null ));

    let data = [
        {
            value:  50 ,
            color:"#46BFBD",
            highlight: "#5AD3D1",
            label: "Value 1",
          },
          {
              value:  50 ,
              color:"#F7464A",
              highlight: "#FF5A5E",
              label: "Value 2",
            }
        ];

        let myDoughnutChart = new Chart(ctx).Doughnut(data,{});
  }

Uncaught IndexSizeError: Failed to execute 'arc' on 'CanvasRenderingContext2D': The radius provided (-0.5) is negative.

Doing this after a button push generates 0 errors.

Anyone knows what the problem is?

Posts: 3

Participants: 2

Read full topic