How can Google Spreadsheet use "onedit" to change cells with if statements? - if-statement

Question

I'm new to Google script and hoping someone here could answer this.
I have 7 columns and each one has a drop down box so we can select a status "Ready", "Approved", "Waiting" etc.
There will soon be over 500 rows of statuses so ideally I would like to have a function on each column to automatically set the status of the column after it.
Example Cells:
Ready|Waiting|Waiting|Waiting|Waiting|Waiting|Waiting
When the first task is Approved, the cells should look like this:
Approved|Ready|Waiting|Waiting|Waiting|Waiting|Waiting
In the above example, the first cell should be clicked "Approved" by the user from the drop down list. Then the script should read the cell edit, and switch the next cell from "Waiting" to "Ready"
I am looking at the script route as I need to have the drop down cells clickable. If I put a function onto the cell itself, I lose the drop down options.
Any help with this would be really awesome!
Thanks in advance!

Answer 1

You may want to check this YouTube video and this transcribed code can be tweaked to suit your needs:
function setDataValid_(range, sourceRange) {
var rule = SpreadsheetApp.newDataValidation().requireValueInRange(sourceRange, true).build();
range.setDataValidation(rule);
}
function onEdit() {
var aSheet = SpreadsheetApp.getActiveSheet();
var aCell = aSheet.getActiveCell();
var aColumn = aCell.getColumn();
if (aColumn == 1 && aSheet.getName() == 'Worksheet') {
var range = aSheet.getRange(aCell.getRow(), aColumn + 1);
var sourceRange = SpreadsheetApp.getActiveSpreadsheet().getRangeByName(aCell.getValue());
setDataValid_(range, sourceRange)
}
}
And for additional insights, you may want to also see this thread.