btn.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            // Build an AlertDialog
            AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);
 
            // String array for alert dialog multi choice items
            String[] colors = new String[]{
                    "Red","Green","Blue","Purple","Olive"
            };
 
            // Boolean array for initial selected items
            final boolean[] checkedColors = new boolean[]{
                    false,// Red
                    false,// Green
                    false,// Blue
                    false,// Purple
                    false // Olive
 
            };
 
            // Convert the color array to list
            final List<String> colorsList = Arrays.asList(colors);
 
            // Set multiple choice items for alert dialog
 
            builder.setMultiChoiceItems(colors,checkedColors,new DialogInterface.OnMultiChoiceClickListener() {
                @Override
                public void onClick(DialogInterface dialog,int which,boolean isChecked) {
 
                    // Update the current focused item's checked status
                    checkedColors[which] = isChecked;
 
                    // Get the current focused item
                    String currentItem = colorsList.get(which);
 
                    // Notify the current action
                    Toast.makeText(getApplicationContext(),currentItem + " " + isChecked,Toast.LENGTH_SHORT).show();
                }
            });
 
            // Specify the dialog is not cancelable
            builder.setCancelable(false);
 
            // Set a title for alert dialog
            builder.setTitle("Your preferred colors?");
 
            // Set the positive/yes button click listener
            builder.setPositiveButton("OK",new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialog,int which) {
                    // Do something when click positive button
                    tv.setText("Your preferred colors..... \n");
                    for (int i = 0; i<checkedColors.length; i++){
                        boolean checked = checkedColors[i];
                        if (checked) {
                            tv.setText(tv.getText() + colorsList.get(i) + ",");
                        }
                    }
                }
            });
 
            // Set the negative/no button click listener
            builder.setNegativeButton("No",int which) {
                    // Do something when click the negative button
                }
            });
 
            // Set the neutral/cancel button click listener
            builder.setNeutralButton("Cancel",int which) {
                    // Do something when click the neutral button
                }
            });
 
            AlertDialog dialog = builder.create();
            // Display the alert dialog on interface
            dialog.show();
        }
    });

我有两个问题：

>就像我选择了红色和紫色

(然后在TextView中得到如下输出：红色,紫色,)

首先,我想删除逗号(获取最后一个值)
>我已经选择了红色和紫色,当我再次打开对话框时,默认情况下没有选择红色和紫色(我如何保存状态)在这里输入代码,结果,当我再次选择这些(红色和紫色)​​时两个项目,在TextView中获取每个项目两次