AlertDialog + MultiChoiceItems

1.MainActivity.java

import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.content.DialogInterface.OnClickListener;
import android.content.DialogInterface.OnMultiChoiceClickListener;
import android.content.res.Resources;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
public class MainActivity extends Activity
{
    private Button mShowAlertDialog;
    private TextView mShowSelectedItemsOfAlertDialog;
    private String[] mItemsOfAlertDialog;
    private boolean[] mSelectedItems;
    @Override
    public void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        mItemsOfAlertDialog = getResources().getStringArray(R.array.dialog_items);
        mSelectedItems = new boolean[mItemsOfAlertDialog.length];
        mShowAlertDialog = (Button) findViewById(R.id.show_alert_dialog);
        mShowSelectedItemsOfAlertDialog = (TextView) findViewById(R.id.show_selected_items);
        mShowAlertDialog.setOnClickListener(new Button.OnClickListener() {
            @Override
            public void onClick(View v)
            {
                showAlertDialog();
            }
        });
    }
    private void showAlertDialog()
    {
        Resources resources = getResources();
        AlertDialog.Builder ab = new AlertDialog.Builder(this);
        ab.setTitle(resources.getString(R.string.alert_dialog_name));
        ab.setMultiChoiceItems(R.array.dialog_items, mSelectedItems,
                new MultiChoiceClickListener());
        ab.setPositiveButton(resources.getString(R.string.ok),
                new ClickListenerForPositiveButton());
        ab.setNegativeButton(resources.getString(R.string.exit),
                new ClickListenerForNegativeButton());
        ab.show();
    }
    private final class ClickListenerForNegativeButton implements OnClickListener
    {
        @Override
        public void onClick(DialogInterface dialog, int which)
        {
            dialog.dismiss();
        }
    }
    private final class ClickListenerForPositiveButton implements OnClickListener
    {
        @Override
        public void onClick(DialogInterface dialog, int which)
        {
            String selectedItems = "";
            for (int i = 0; i < mSelectedItems.length; ++i) {
                if (mSelectedItems[i]) {
                    selectedItems = selectedItems + mItemsOfAlertDialog[i] + "\n";
                }
            }
            mShowSelectedItemsOfAlertDialog.setText(getResources().getString(
                    R.string.selected_items)
                    + "\n" + selectedItems);
            dialog.dismiss();
        }
    }
    private final class MultiChoiceClickListener implements OnMultiChoiceClickListener
    {
        @Override
        public void onClick(DialogInterface dialog, int which, boolean isChecked)
        {
            mSelectedItems[which] = isChecked;
        }
    }
}

Note:
showAlertDialog(), 其中setMultiChoiceItems()就是設定為Multi choice的重點, 第一個參數mItemsOfAlertDialog為soft coding帶入dialog item, dialog item定義在xml  中 如下
/res/values/arrays.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <string-array
        name="dialog_items">
        <item>item1</item>
        <item>item2</item>
        <item>item3</item>
        <item>item4</item>
        <item>item5</item>
    </string-array>
</resources>

第2個參數 mSelectedItems 則是代表dialog item是否被選中
MultiChoiceClickListener類別則為監聽alertdialog中item被選中的事件,其實比較方便的寫法是直接建立匿名類別,但如此一來showAlertDialog()長度會被大幅增加, 可讀性降低
ClickListenerForNegativeButton類別則為監聽alertdialog中Negative Button被點擊的事件, 可以看到事件啟動之後僅把dialog dismiss,沒有作其他事情
ClickListenerForPositiveButton類別則為監聽alertdialog中Positive Button被點擊的事件, 事件啟動後檢查mSelectedItems的element,如果是true代表在dialog是被勾選的
 
2.main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >
    <Button
        android:id="@+id/show_alert_dialog"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="@string/show_alert_dialog" />
    <TextView
        android:id="@+id/show_selected_items"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="@string/selected_items" />
</LinearLayout>