Dynamic protection based on cell value

Question

In my Google spreadsheet, I want to protect all cells below a checkbox if it's value is true and unprotect if it's value is false. Every cell in row 3 is a checkbox that this has to work for.

Example Sheet:

    +------------+------------+------------+------------+------------+-----
    |  Column A  |  Column B  |  Column C  |  Column D  |  Column E  | ...
+---+------------+------------+------------+------------+------------+-----
| 1 |            |            |            |            |            |  
+---+------------+------------+------------+------------+------------+-----
| 2 |            |            |            |            |            |  
+---+------------+------------+------------+------------+------------+-----
| 3 | checkbox1  | checkbox2  | checkbox3  | checkbox4  | checkbox5  | ...
+---+------------+------------+------------+------------+------------+-----
| 4 | value1.1   | value2.1   | ...        | ...        | ...        | ...
+---+------------+------------+------------+------------+------------+-----
| 5 | value1.2   | value2.2   | ...        | ...        | ...        | ... 
+---+------------+------------+------------+------------+------------+-----
| 6 |            |            |            |            |            |  
+---+------------+------------+------------+------------+------------+-----
|   |            |            |            |            |            |  

So if I set checkbox1 to true, A3:A50 should be protected and unprotected if I set it to false
...same for checkbox2 -> B3:B50 ...checkbox3 -> C3:C50 ...

This should also only work in one specific sheet (let's call it 'sheet1'). I know how I can set protection using a script but I don't know how to create the dynamic ranges.

I hope you can help me with this.

Answer 1

I expect you have already solved this, but still wanted to post my solution for others who might have the same issue. I edited user0's answer to allow for dynamic criteria

function onEdit(event){
  var ss = SpreadsheetApp.getActiveSpreadsheet();
  var sh = ss.getSheets()[0]; // 0 == first sheet.
  var cellRange = SpreadsheetApp.getActiveSpreadsheet().getActiveRange();

  if (isWatched(cellRange)) { // Check if edited cell is the one we're watching.
    if (event.value == "TRUE"){ // If the new value is true, protect the data
      setProtected(cellRange)
    } else { // If the new value isn't true we remove the protection (this allows you to remove the protection by unchecking the checkbox)
      var protections = sh.getProtections(SpreadsheetApp.ProtectionType.RANGE);
      for (var i = 0; i < protections.length; i++) {
        if (protections[i].getRange().getColumn() == cellRange.getColumn()) { // We only check if the column of a protection is the same
          protections[i].remove(); // remove protection.
        }
      }
    }
  }
}

function setProtected(cellRange){
  // Sets the desired range to protected
  var ss = SpreadsheetApp.getActiveSpreadsheet();
  var sh = ss.getSheets()[0];
  var protectedRows = sh.getRange(cellRange.getRow() + 1, cellRange.getColumn(), 7); // We protect the 7 rows underneath the checkbox

  protectedRows.protect().setDescription("Protected cell");
}

function isWatched(cellRange) {
  // Check if cell is watched
  if (cellRange.getRow() == 3){
    return true
  } else {
    return false
  }
}

Answer 2

for A column:

function onEdit(event){

  var ss = SpreadsheetApp.getActiveSpreadsheet();
  var sh = ss.getSheets()[0]; // 0 == first sheet.
  var ee = SpreadsheetApp.getActiveSpreadsheet().getActiveRange().getA1Notation();
  if (ee == "A3") { // Check if edited cell is the one we're watching.
    if (SpreadsheetApp.value == "true"){ // If the value == "true", do stuff.
      var protections = sh.getProtections(SpreadsheetApp.ProtectionType.RANGE);
      for (var i = 0; i < protections.length; i++) {
        if (protections[i].getDescription() == 'Test1') { // If protect. descript. == "Test1"
          protections[i].remove(); // then remove protection.
        }
      }
    } 
  }  
}

function setProtected(){
  // Sets the desired range to protected with "Test1" description for demonstration.
  var ss = SpreadsheetApp.getActiveSpreadsheet();
  var sh = ss.getSheets()[0];
  var protectedRows = sh.getRange("A4:A50");
  protectedRows.protect().setDescription("Test1");
}