java - How to draw a rectangle in android when a user moves finger? -

i want draw rectangle. first corner should point user first touches screen. when user moves finger, should draw rectangle. here's a link shows video want do. don't understand , maybe can me. want draw rectangle on white background not on image.

my code :

package com.example.androiddrawing;  import java.util.arraylist; import java.util.list;  import android.content.context; import android.graphics.canvas; import android.graphics.color; import android.graphics.paint; import android.graphics.path; import android.graphics.point; import android.util.attributeset; import android.view.motionevent; import android.view.view;  public class canvasview extends view {      private canvas canvas;     private paint paint = new paint();     private paint paint2 = new paint();     private paint paint3 = new paint();     private path path = new path();     private point point = new point();     private static list<path> lines = new arraylist<path>();     private static list<point> points = new arraylist<point>();     private float x, x2, xc, xd, x3, x4;     private float y, y2, yc, yd, y3, y4;     private boolean touchstarted = false;      public enum drawmode {         freedrawmode, rectdrawmode     };      public static drawmode currentdrawmode;      public void setdrawmode(drawmode newdrawmode) {         this.currentdrawmode = newdrawmode;     }      public canvasview(context context, attributeset attrs) {         super(context, attrs);          paint.setantialias(true);         paint.setstrokewidth(5);         paint.setcolor(color.black);         paint.setstyle(paint.style.stroke);         paint.setstrokejoin(paint.join.round);          paint2.setantialias(true);         paint2.setstrokewidth(5);         paint2.setcolor(color.red);         paint2.setstyle(paint.style.stroke);         paint2.setstrokejoin(paint.join.round);          paint3.setantialias(true);         paint3.setcolor(color.black);         paint3.setstrokewidth(10);         paint3.setstyle(paint.style.stroke);     }      @override     protected void ondraw(canvas canvas) {          (path p : lines)             canvas.drawpath(p, paint);         canvas.drawpath(path, paint2);          (point point : points)             canvas.drawcircle(point.x, point.y, 0, paint);      }      @override     public boolean ontouchevent(motionevent event) {         x = event.getx();         y = event.gety();          system.out.println(currentdrawmode);         if (currentdrawmode == drawmode.freedrawmode) {             switch (event.getaction()) {             case motionevent.action_down:                 // set new starting point                 paint2.setcolor(color.red);                 path = new path();                 path.moveto(x, y);                 touchstarted = true;                   break;             // return true;             case motionevent.action_move:                 // connect points                 touchstarted = false;                 path.lineto(x, y);                  break;             case motionevent.action_up:                 if (touchstarted) {                     point = new point();                     point.x = (int) x;                     point.y = (int) y;                     paint2.setcolor(color.black);                     points.add(point);                     touchstarted = false;                     system.out.println("siin");                 } else {                     system.out.println("seal");                     paint2.setcolor(color.black);                     lines.add(path);                 }                 break;             default:                 return false;             }         } else if (currentdrawmode == drawmode.rectdrawmode) {             switch (event.getaction()) {             case motionevent.action_down:                 // set new starting point                 paint3.setcolor(color.red);             //code here                  break;             // return true;             case motionevent.action_move:                  //code here                   break;             case motionevent.action_up:                      //code here                   break;             default:                 return false;             }         }         // makes our view repaint , call ondraw         invalidate();         return true;     }  } 

i should write code put comments //code here, don't understand, how have draw rectangle.

you can use below code. hope helps you.

public class drawsample extends view {  int mstartx; int mstarty; int mendx; int mendy;  paint mpaint = new paint();  int mselectedcolor = color.black;  public drawsample(context context, attributeset attrs, int defstyle) {      super(context, attrs, defstyle);      mpaint.setcolor(mselectedcolor);     mpaint.setstrokewidth(5);     mpaint.setstyle(paint.style.stroke);      setfocusable(true); }  public drawsample(context context, attributeset attrs) {     this(context, attrs, 0); }  @override public boolean ontouchevent(motionevent event) {      switch (event.getactionmasked()) {          case motionevent.action_down:              mstartx = (int) event.getx();             mstarty = (int) event.gety();              break;          case motionevent.action_move:              mendx = (int) event.getx();             mendy = (int) event.gety();              invalidate();              break;          case motionevent.action_up:               mendx = (int) event.getx();             mendy = (int) event.gety();              invalidate();              break;          default:              super.ontouchevent(event);              break;     }      return true; }  @override protected void ondraw(canvas canvas) {      super.ondraw(canvas);      canvas.drawrect(mstartx, mstarty, mendx, mendy, mpaint); } }