MultiChoice AlertDialog，Android中的限制选择

Question

我有一个MultiChoice AlertDialog，在那里我有25个选择。

我想让用户只选择任何5个中的25个。

当她选择第六种选择时，我想对它进行检查，并显示一条祝酒词，上面说她只能做出5种选择。

有可能用MultiChoice AlertDialog吗？请帮帮我！

Answer 1

创建一个静态变量"count“，并在选中的选项上增加它，并在复选框的onclick事件上取消其选中时递减。详情如下：

import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.os.Bundle;
import android.view.View;
import android.widget.TextView;
import android.widget.Toast;

public class AlertWithCheckBoxActivity extends Activity {
    /** Called when the activity is first created. */
    static int count = 0;
    final CharSequence[] items={".NET","J2EE","PHP"};
    boolean[] itemsChecked = new boolean[items.length];
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
    }
    public void showDialog(View v)
    {

        count = 0;
        AlertDialog.Builder builder=new AlertDialog.Builder(this);
        builder.setTitle("Pick a Choice");
        builder.setPositiveButton("OK", new DialogInterface.OnClickListener() {

            @Override
            public void onClick(DialogInterface dialog, int which) {
                String selectedTech="Selected Tech - ";
                for (int i = 0; i < items.length; i++) {
                    if (itemsChecked[i]) {

                        selectedTech=selectedTech+items[i]+" ";
                        itemsChecked[i]=false;
                    }
                }
            }
        });

        builder.setMultiChoiceItems(items, new boolean[]{false,false,false}, new DialogInterface.OnMultiChoiceClickListener() {

            @Override
            public void onClick(DialogInterface dialog, int which, boolean isChecked) {
                if(isChecked) {
                    if(count < 5) {
                        itemsChecked[which] = isChecked;
                        count++;
                    }else{
                        //Display your toast here
                    }
                }else{
                    count--;
                }
            }
        });
        builder.show();
    }
}

Answer 2

OP的确切解决方案是：

final boolean[] selected = new boolean[25];

builder.setMultiChoiceItems(R.array.values, selected, new DialogInterface.OnMultiChoiceClickListener() {

    int count = 0;

    @Override
    public void onClick(DialogInterface dialog, int which, boolean isChecked) {
        count += isChecked ? 1 : -1;
        selected[which] = isChecked;

        if (count > 5) {
            Toast.makeText(getActivity(), "You selected too many.", Toast.LENGTH_SHORT).show();
            selected[which] = false;
            count--;
            ((AlertDialog) dialog).getListView().setItemChecked(which, false);
        }
    }

});

Answer 3

我用的不是LunaVulpo的解决方案

if (((AlertDialog) dialog).getListView().getCheckedItemCount() > 2) {
...
}

因为当用户再次打开opens对话框以编辑他的选择时，计数重置，而选中的项仍然保留。