I created a custom button on a custom object that launches a Visualforce page to capture the signature of a user. The Visualforce page has two buttons: Capture Signature and Exit. Upon clicking Capture Signature, the canvas is captured and attached in the Notes and Attachments related list of the record. The problem I am facing is that my code is only working through desktop browsers and the Salesforce1 simulator (i.e. /one/one.app), but the attachment isn't getting attached when testing with my iPhone. On my iPhone, I am able to get to the Visualforce page, draw a signature, and click the buttons, however, the attachment isn't appearing in the Notes and Attachments related list. Here is my code:
Visualforce Page:
<apex:page docType="html-5.0" standardController="EHS_Procedure__c" extensions="ehsSignatureExtensionController">
<script>var $j = jQuery.noConflict();</script>
<apex:stylesheet value="{!URLFOR($Resource.jquerymobile,'/jquerymobile/jquery.mobile-1.3.2.min.css')}"/>
<apex:includeScript value="{!URLFOR($Resource.jquery)}" />
<apex:includeScript value="{!URLFOR($Resource.jquerymobile,'/jquerymobile/jquery.mobile-1.3.2.min.js')}"/>
<canvas id="signatureCanvas" width="315" height="400" style="border: 1px solid white;"/>
<apex:includeScript value="/soap/ajax/28.0/connection.js"/>
<script>
sforce.connection.sessionId = "{!$Api.Session_Id}";
var canvas = document.getElementById("signatureCanvas");
var context = canvas.getContext("2d");
var mouseButton = 0;
var lastX = lastY = null;
var ehsId = '{!EHS_Procedure__c.Id}';
function saveSignature() {
var image = canvas.toDataURL().split(',')[1];
ehsSignatureExtensionController.saveSignature(ehsId,image,handleResult);
}
function handleResult(result,event) {
if(result.success) {
window.top.location.href='/'+ehsId;
} else {
alert('Error: '+result.errorMessage);
}
}
function handleEvent(event) {
if(event.type==="mousedown"||event.type==="touchstart") {
mouseButton = event.which || 1;
lastX = lastY = null;
}
if(event.type==="touchcancel" || event.type==="touchcancel" || event.type==="mouseup") {
mouseButton = 0;
lastX = lastY = null;
}
if((event.type==="touchmove" || event.type==="mousemove") && mouseButton) {
var newX, newY;
var canvasX = 0, canvasY = 0, obj = event.srcElement || event.target;
do {
canvasX += obj.offsetLeft;
canvasY += obj.offsetTop;
} while(obj = obj.offsetParent);
if(event.targetTouches && event.targetTouches.length) {
newX = event.targetTouches[0].clientX - (canvasX/2);
newY = event.targetTouches[0].clientY - (canvasY/2);
} else {
newX = event.offsetX;
newY = event.offsetY;
}
if(!lastX && !lastY) {
lastX = newX;
lastY = newY;
context.beginPath();
context.moveTo(lastX,lastY);
context.lineTo(lastX,lastY,lastX,lastY);
context.stroke();
} else {
context.beginPath();
context.moveTo(lastX,lastY);
context.lineTo(newX,newY);
context.stroke();
lastX = newX;
lastY = newY;
}
}
if(event.type=="touchmove" || event.type==="mousedrag" || (event.type==="selectstart" && (event.srcElement||event.target)===canvas)) {
event.returnValue=false;
event.stopPropagation();
event.preventDefault();
return false;
}
}
canvas.addEventListener("mousedrag",handleEvent,true);
canvas.addEventListener("mousemove",handleEvent,true);
canvas.addEventListener("mousedown",handleEvent,true);
window.addEventListener("mouseup",handleEvent,true);
canvas.addEventListener("touchstart",handleEvent,true);
canvas.addEventListener("touchmove",handleEvent,true);
window.addEventListener("touchend",handleEvent,true);
window.addEventListener("selectstart",handleEvent,true);
</script>
<apex:form >
<button onclick="saveSignature()">Capture Signature</button>
<apex:commandButton action="{!cancel}" value="Exit"/>
</apex:form>
</apex:page>
Apex Class:
public with sharing class ehsSignatureExtensionController {
private final EHS_Procedure__c ehs;
public ehsSignatureExtensionController(ApexPages.StandardController controller) {
ehs = (EHS_Procedure__c)controller.getRecord();
}
@RemoteAction public static RemoteSaveResult saveSignature(Id ehsId, String signatureBody) {
Attachment a = new Attachment(ParentId=ehsId, name='Signature.png', ContentType='image/png', Body=EncodingUtil.base64Decode(signatureBody));
Database.saveResult result = Database.insert(a,false);
RemoteSaveResult newResult = new RemoteSaveResult();
newResult.success = result.isSuccess();
newResult.attachmentId = a.Id;
newResult.errorMessage = result.isSuccess()?'':result.getErrors()[0].getMessage();
return newResult;
}
public class RemoteSaveResult {
public Boolean success;
public Id attachmentId;
public String errorMessage;
}
public pageReference cancel(){
pageReference page = new PageReference('/'+ehs.id);
page.setRedirect(true);
return page;
}
}
Do you have any recommendations on getting this to work on the Salesforce1 app?
Best Answer
Take a look at the below url for salesforce1:
http://corycowgill.blogspot.in/2013/12/capturing-signatures-with-html5-canvas.html
The gist of it is to use an HTML 5 canvas with Javascript drawing, and then base64 encode the cavnas data so it can be sent as a string back to a custom controller. The controller then decodes the string and stores the resulting blob in the body of a document for example.