Draw and delete polygon in google map

Question

I try to draw polygon on button click and delete polygon from another button, it's working fine first time but after delete I can't draw another polygon. Please guide me. Here is code snippet:

var polyOptions = {
        strokeWeight: 0,
        fillOpacity: 0.45,
        editable: true,
        fillColor: '#FF1493'
    };  
var selectedShape;

var drawingManager = new google.maps.drawing.DrawingManager({
        drawingMode: google.maps.drawing.OverlayType.POLYGON,
        drawingControl: false,
        markerOptions: {
            draggable: true
        },
        polygonOptions: polyOptions
  });

$('#enablePolygon').click(function(){
        drawingManager.setMap(map);
    });

$('#resetPolygon').click(function(){
        if (selectedShape) {
            selectedShape.setMap(null);
        }
        drawingManager.setMap(null);
        $('#showonPolygon').hide();
        $('#resetPolygon').hide();
    });

function clearSelection() {
        if (selectedShape) {
          selectedShape.setEditable(false);
          selectedShape = null;
        }
    }


    function setSelection(shape) {
        clearSelection();
        selectedShape = shape;
        shape.setEditable(true);
    }

google.maps.event.addListener(drawingManager, 'overlaycomplete', function(e) {
    all_overlays.push(e);
    if (e.type != google.maps.drawing.OverlayType.MARKER) {
      // Switch back to non-drawing mode after drawing a shape.
      drawingManager.setDrawingMode(null);

      // Add an event listener that selects the newly-drawn shape when the user
      // mouses down on it.
      var newShape = e.overlay;
      newShape.type = e.type;
      google.maps.event.addListener(newShape, 'click', function() {
        setSelection(newShape);
      });
      setSelection(newShape);
    }
  });

Here I show reset button on polygon complete event and try to find area of current polygon:

google.maps.event.addListener(drawingManager, 'polygoncomplete', function(polygon) {
//  var area = google.maps.geometry.spherical.computeArea(selectedShape.getPath());
//  $('#areaPolygon').html(area.toFixed(2)+' Sq meters');
    $('#resetPolygon').show();
});

Here is HTML:

<input type="button" id="enablePolygon" value="Calculate Area" />
<input type="button" id="resetPolygon" value="Reset" style="display: none;" />
<div id="showonPolygon" style="display:none;"><b>Area:</b> <span id="areaPolygon">&nbsp;</span></div>

Answer 1

You are setting the DrawingMode of the DrawingManager to null. When you re-enable the DrawingManager, you need to set it back to google.maps.drawing.OverlayType.POLYGON.

$('#enablePolygon').click(function() {
  drawingManager.setMap(map);
  drawingManager.setDrawingMode(google.maps.drawing.OverlayType.POLYGON);
});

proof of concept fiddle

code snippet:

var geocoder;
var map;
var all_overlays = [];

function initialize() {
  var map = new google.maps.Map(
    document.getElementById("map_canvas"), {
      center: new google.maps.LatLng(37.4419, -122.1419),
      zoom: 13,
      mapTypeId: google.maps.MapTypeId.ROADMAP
    });
  var polyOptions = {
    strokeWeight: 0,
    fillOpacity: 0.45,
    editable: true,
    fillColor: '#FF1493'
  };
  var selectedShape;

  var drawingManager = new google.maps.drawing.DrawingManager({
    drawingMode: google.maps.drawing.OverlayType.POLYGON,
    drawingControl: false,
    markerOptions: {
      draggable: true
    },
    polygonOptions: polyOptions
  });

  $('#enablePolygon').click(function() {
    drawingManager.setMap(map);
    drawingManager.setDrawingMode(google.maps.drawing.OverlayType.POLYGON);
  });

  $('#resetPolygon').click(function() {
    if (selectedShape) {
      selectedShape.setMap(null);
    }
    drawingManager.setMap(null);
    $('#showonPolygon').hide();
    $('#resetPolygon').hide();
  });
  google.maps.event.addListener(drawingManager, 'polygoncomplete', function(polygon) {
    //  var area = google.maps.geometry.spherical.computeArea(selectedShape.getPath());
    //  $('#areaPolygon').html(area.toFixed(2)+' Sq meters');
    $('#resetPolygon').show();
  });

  function clearSelection() {
    if (selectedShape) {
      selectedShape.setEditable(false);
      selectedShape = null;
    }
  }


  function setSelection(shape) {
    clearSelection();
    selectedShape = shape;
    shape.setEditable(true);
  }

  google.maps.event.addListener(drawingManager, 'overlaycomplete', function(e) {
    all_overlays.push(e);
    if (e.type != google.maps.drawing.OverlayType.MARKER) {
      // Switch back to non-drawing mode after drawing a shape.
      drawingManager.setDrawingMode(null);

      // Add an event listener that selects the newly-drawn shape when the user
      // mouses down on it.
      var newShape = e.overlay;
      newShape.type = e.type;
      google.maps.event.addListener(newShape, 'click', function() {
        setSelection(newShape);
      });
      setSelection(newShape);
    }
  });
}
google.maps.event.addDomListener(window, "load", initialize);

html,
body,
#map_canvas {
  height: 100%;
  width: 100%;
  margin: 0px;
  padding: 0px
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="https://maps.googleapis.com/maps/api/js?libraries=drawing&key=AIzaSyCkUOdZ5y7hMm0yrcCQoCvLwzdM6M8s5qk"></script>
<input type="button" id="enablePolygon" value="Calculate Area" />
<input type="button" id="resetPolygon" value="Reset" style="display: none;" />
<div id="showonPolygon" style="display:none;"><b>Area:</b>  <span id="areaPolygon">&nbsp;</span>
</div>
<div id="map_canvas"></div>