Question

Hi I am trying to draw one line graph and for that I am using this code.

DrawGraph dg = new DrawGraph(this);
    pane.addView(dg);
    dg.setData(10, 10, 100, 100);   //cords. for Firs Line
    pane.invalidate();
    dg.setData(100, 100, 100, 300);  //cords. for second Line
    pane.invalidate();

and this my DrawGraph class is here.

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.view.View;

public class DrawGraph extends View{
Paint p;
int x1;
int y1;
int x2;
int y2;
Canvas fc;
int i = 0;

public DrawGraph(Context context) {
    super(context);
    p = new Paint();
    fc = new Canvas();
}

public void setData(int x1, int y1, int x2, int y2)
{
    this.x1 = x1;
    this.y1 = y1;
    this.x2 = x2;
    this.y2 = y2;
}

public void onDraw(Canvas c){
            c.drawLine(x1, y1, x2, y2, p);
   }
}

But the problem is there, I can see only one line in the graph (second line) and I need both Lines
I means all the Lines in graph at a time.
any solution please. Thanks.

Answer 1

You have called setData twice, so the second call will overwrite the first values you set.

If you are trying to draw graphs, you can use a library such as AndroidPlot to do the heavy lifting for you. (http://androidplot.com/wiki/Home) There are other libraries but I’ve personally used AndroidPlot and it worked well for me – I had to draw 2 lines on a graph as well.