Implementing Dialog box with checkboxes

问题

Here is my Dialog box

public class CustomDialogClass extends Dialog implements
 android.view.View.OnClickListener {

     public Activity c;
     public Dialog d;
     public Button no;
     CheckBox yes;
     boolean p;
     public CustomDialogClass(Activity a) {
         super(a);
         // TODO Auto-generated constructor stub
         this.c = a;
     }

     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         requestWindowFeature(Window.FEATURE_NO_TITLE);
         setContentView(R.layout.custom_dialog);
         yes = (CheckBox) findViewById(R.id.checkBox1);
         no = (Button) findViewById(R.id.btn_no);
         no.setOnClickListener(this);
         yes.setChecked(false);
         yes.setOnClickListener(this);
     }

     @Override
     public void onClick(View v) {
         switch (v.getId()) {
         case R.id.checkBox1:
             yes.setChecked(true);
             break;
         case R.id.btn_no:
             dismiss();
             break;
         default:
             break;
         }
     }
 }

Now, I open the dialog and check the checkbox, click on button and dismiss the dialog. But When I open it again, the checkbox is again unchecked. what should i do?

回答1:

The way you are using your dialog is not recommended anymore! You should consider using a DialogFragment.

The problem why you are loosing your checked state is because the dialog is recreated when you open it again.

See this example of the DialogFragment approach http://developer.android.com/reference/android/app/DialogFragment.html. You will see that you can pass arguments to the dialog.

For a solution I recommend that when you close the dialog you pass the selected value back to the hosting activity... when the dialog should be reopenned you just pass the arguments to the dialog so that the dialog sets its default selection.

Edit:

Since you would like to display checkboxes I will take and adapt the example code from http://developer.android.com/guide/topics/ui/dialogs.html#AddingAList for checkboxes. It's still convenient to use the AlertDialog.Builder.

Wrap the Builder into a DialogFragment by overwriting the onCreateDialog-method. You can pass the list of selected items via the Bundle as boolean array and then use is for setMultiChoiceItems.

public class CheckBoxAlertDialogFragment extends DialogFragment {
    public static CheckBoxAlertDialogFragment newInstance(boolean[] checkedItems) {
        CheckBoxAlertDialogFragment frag = new CheckBoxAlertDialogFragment();
        Bundle args = new Bundle();
        args.putBooleanArray("checkedItems", checkedItems);
        frag.setArguments(args);
        return frag;
}

@Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
    final boolean[] checkedItems = getArguments().getBooleanArray("checkedItems");

    AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
    // Set the dialog title
    builder.setTitle(R.string.pick_toppings)
            // Specify the list array, the items to be selected by default (null for none),
            // and the listener through which to receive callbacks when items are selected
            .setMultiChoiceItems(R.array.toppings, checkedItems,
                    new DialogInterface.OnMultiChoiceClickListener() {
                        @Override
                        public void onClick(DialogInterface dialog, int which,
                                            boolean isChecked) {
                            checkedItems[which] = isChecked;
                        }
                    })
            // Set the action buttons
            .setPositiveButton(R.string.ok, new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialog, int id) {
                    // User clicked OK, so save the checkedItems results somewhere
                    // or return them to the component that opened the dialog
                    //...
                }
            })
            .setNegativeButton(R.string.cancel, new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialog, int id) {
                    //...
                }
            });

    return builder.create();
}
}

In your activity you should have a variable, e.g. named checkedItems, of type boolean[] somewhere which saves the checkbox states. You can open the dialog then with:

void showDialog() {
        DialogFragment newFragment = CheckBoxAlertDialogFragment.newInstance(checkedItems);
        newFragment.show(getFragmentManager(), "dialog tag");
    }

回答2:

Your check box is going to be unchecked each time you show/create the dialog because in its onCreate method you have yes.setChecked(false);. Instead of just dismissing the dialog you should save the checkbox's value before dismissing and get that value to reset the check box each time the dialog is created. You could use SharedPreferences for this which will retain the value even if your Activity is destroyed or pass the value back and forth as needed with your main activity.

Thanks to @andd, I had forgotten that Dialog is deprecated and he is right that you should be using the DialogFragment in which case the SharedPreferences wouldn't be necessary.

来源：https://stackoverflow.com/questions/17859514/implementing-dialog-box-with-checkboxes

标签

android

checkbox

dialog