Set checkboxes status in Multichoice AlertDialog in Android

Question

Following is my code for my AlertDialog.Builder

    final String[] values = new String[] {"Select All", "Android", "ios", "windows", "Blackberry"};
    final ArrayList<String> selecteditems = new ArrayList<String>();
    AlertDialog.Builder builder = new AlertDialog.Builder(this);
    builder.setTitle("Select your favorite OS");
      builder.setMultiChoiceItems(values, null , new DialogInterface.OnMultiChoiceClickListener() {

        @Override
        public void onClick(DialogInterface dialog, int which, boolean isChecked) {

            if (isChecked) {
                selecteditems.add(String.valueOf(which));

            } else {

                selecteditems.remove(Integer.valueOf(which));
            }
        }
    })
    .setPositiveButton("OK", new DialogInterface.OnClickListener() {

        @Override
        public void onClick(DialogInterface dialog, int which) {
            dialog.dismiss();

        }
    })
    .setNegativeButton("Cancel", new DialogInterface.OnClickListener() {

        @Override
        public void onClick(DialogInterface dialog, int which) {
           dialog.dismiss();

        }
    });

    AlertDialog dialog = builder.create();
    dialog.show();

What I want to do is to be able to detect when 'Select All' is checked, which I can from the isChecked loop. But I want to be able to set all the options to checked when the user checks 'Select All' and remove the checks when user unchecks 'Select All'.

Answer 1

It should be something like the following code. The key point is to provide a boolean[] array of checkedItems and update it later when you try to select all.

• checkedItems array should be updated (because the Dialog still has reference to it.)

• And dialog.getListView().setItemChecked(i, true); should be called for every item.

  items.add(0, "Select All");
  
  boolean[] checkedItems = new boolean[items.size()];
  
  AlertDialog.Builder builder = new AlertDialog.Builder(getContext());
  builder.setTitle(dialogTitle)
          .setMultiChoiceItems(items.toArray(new String[items.size()]), checkedItems, new DialogInterface.OnMultiChoiceClickListener() {
  
              @Override
              public void onClick(DialogInterface dialog, int which, boolean isChecked) {
  
                  if(which == 0) {
                      if(isChecked) {
                          multichoiceDialog.getListView().setItemChecked(0, true);
                          checkedItems[0] = true;
                          for(int i=1; i< checkedItems.length; i++) {
                              checkedItems[i] = true;
                              multichoiceDialog.getListView().setItemChecked(i, true);
                          }
  
                      }
                  }
              }
          })
          .setPositiveButton(R.string.ok, new DialogInterface.OnClickListener() {
  
              @Override
              public void onClick(DialogInterface dialog, int which) {
  
              }
          });
  
  multichoiceDialog = builder.create();
  multichoiceDialog.show();