根据不同单元格上不同十六进制值的输入，为一个单元格生成几种彩色背景？

Question

In other words, when 00FF00 is typed in cell A1, cell B1's formula turns it into #00FF00 , which automatically highlights cell B1 with the corresponding color. The first time it works.

Yet, once cell A1's hexadecial value is manually changed to another color like FF0000 , cell B1 does automatically change the value to #FF0000 but not the background --> the previous background remains (in this case #00FF00 ).

Answer 1

Try the following script code:

function onEdit(e) {
  var ss = SpreadsheetApp.getActiveSpreadsheet();
  var s = ss.getActiveSheet();
  var c = ss.getActiveCell();
  if( s.getName() == 'Sheet1' && c.getA1Notation() == 'A1' )
  s.getRange('B1').setBackground( '#' + c.getValue() );
};

In the above code change the sheet name "Sheet1" and also cells "A1" & "B1" as per your requirement.

Answer 2

Here is a code that works but I need to input the Hex values manually to get the background color to appear automatically --> for the moment, a hex value in B1 resulting from a formula (with A1+A2+A3 cells in it) will only work one time (then, what ever Hex value be changed, the cell B1 keeps its previous background color even though the Hex value in the cell -B1, changes).

// regex for hex color codes
HEX_COLOR_REGEX = /(^#[0-9A-Fa-f]{3}$)|(#[0-9A-Fa-f]{6}$)/;

// column to watch for changes (i.e. column where hex color codes are to be entered)
HEX_CODE_COLUMN = 5; // i.e. column A

// column to change when above column is edited
HEX_COLOR_COLUMN = 5; // i.e. column B

// utility function to test whether a given string qualifies as a hex color code
function hexTest(testCase) {
  return HEX_COLOR_REGEX.test(testCase);
}

function onEdit(e) {
  var range = e.range;
  var row = range.getRow();
  var column = range.getColumn();
  if (column === HEX_CODE_COLUMN) {
    var values = range.getValues();
    values.forEach( function checkCode(rowValue, index) {
      var code = rowValue[0];
      if (hexTest(code)) {
        var cell = SpreadsheetApp.getActiveSheet().getRange(row + index, HEX_COLOR_COLUMN);
        cell.setBackground(code);
        SpreadsheetApp.flush();
      }
    });
  }
}