set values after sending mail - email

Question

I want the script to send an email to those mail addresses where unchecked boxes are in the row - This works fine. But I want the value of the checkbox to be set “True” after the mails were sent.
My Problem is that I need the last for-loop to stop after all checkboxes are checked. In other words: The last loop has to stop when an empty cell appears.
First of all I manually trigger the script - later I will start it with the help of a button in the menu (function onOpen...)
Appreciate any help – thanks a lot!
Check out the sheet and the code below:
function sendmail() {
var ui = SpreadsheetApp.getUi();
var ss = SpreadsheetApp.getActiveSpreadsheet();
var s = ss.getSheetByName('Sheet1');
var r = s.getRange('C:C'); //Checkboxes
var v = r.getValues();
for(var i=v.length-1;i>=0;i--)
if(v[0,i]=='false') {
var range = ss.getRange("A1:D4");
var UserData = range.getValues();
var UserData = range.getValues();
var row = UserData[i];
var name = row[0];
var email = row[1];
MailApp.sendEmail(row[1], "Test", "Hello " + name + ", This is an email");
var response = ui.alert("mail was send to ", ui.ButtonSet.OK);
}
for (k=1; k < 20; k++) { //loop which has to stop
s.getRange(k, 3).setValue("True");
}
}

Answer 1

A couple of major changes in your script.
The condition for the loop is wrong. Change to:
for(var i=v.length-1;i>0;i--)
The UI response is missing the recipient name. Change to:
var response = ui.alert("mail was send to "+name, ui.ButtonSet.OK);
var UserData = range.getValues(); is declared twice: delete one row
Immediately after the UI alert (and still within the IF loop), add a line to update the checkbox: UserData[i][2] = true;
Simplify the updating of checkboxes.
Delete the existing lines:
for (k=1; k < 20; k++) {
s.getRange(k, 3).setValue("True");
}
Substitute:
range.setValues(UserData)
Revised Script
function sosendmail() {
var ui = SpreadsheetApp.getUi();
var ss = SpreadsheetApp.getActiveSpreadsheet();
var s = ss.getSheetByName('Sheet1');
var r = s.getRange('C:C'); //Checkboxes
var v = r.getValues();
for(var i=v.length-1;i>0;i--)
if(v[0,i]=='false') {
var range = ss.getRange("A1:D4");
var UserData = range.getValues();
var row = UserData[i];
var name = row[0];
var email = row[1];
// MailApp.sendEmail(row[1], "Test", "Hello " + name + ", This is an email");
Logger.log("mail sent")
var response = ui.alert("mail was send to "+name, ui.ButtonSet.OK);
UserData[i][2] = true;
}
range.setValues(UserData)
}
Alternative Script
The following script is offered as an alternative. It avoids multiple getRange()/getValue statements and uses a more conventional top-down loop.
function sosendmail01() {
var ui = SpreadsheetApp.getUi();
var ss = SpreadsheetApp.getActiveSpreadsheet();
var s = ss.getSheetByName('Sheet1');
// get the number of rows (Alast)
var Avals = ss.getRange("A2:A").getValues();
var AlastRow = Avals.filter(String).length;
// Logger.log("DEBUG: number of rows = "+AlastRow)
// get the data range
var r = s.getRange(2, 1, AlastRow, 3);// get all the data
// Logger.log("DEBUG: the data range = "+r.getA1Notation())
var v = r.getValues(); // get the data
// loop through the rows of data
for (var i = 0;i<AlastRow;i++){
if (v[i][2] != false) {
// the checkbox is ticked Don't sent an email
// Logger.log("DEBUG: i:"+i+", name = "+v[i][0]+" - the checkbox is ticked");
} else{
// the checkbox IS NOT ticked - send an email
//Logger.log("DEBUG: i:"+i+", name = "+v[i][0]+" checkbox = "+v[i][2]+" - the checkbox is NOT ticked");
var name = v[i][0];
var email = v[i][1];
//MailApp.sendEmail(email, "Test", "Hello " + name + ", This is an email");
Logger.log("DEBUG: mail sent to "+name+" at "+email)
var response = ui.alert("mail was send to "+name, ui.ButtonSet.OK);
v[i][2] = true;
}
}
r.setValues(v);
}