本方法在打开对话框后,如果没有选中项则禁用Positive Button,选中了选项后则使Positive Button可用.
import android.app.Activity; import android.app.AlertDialog; import android.app.Dialog; import android.content.DialogInterface; import android.os.Bundle; import android.view.View; import android.view.View.OnClickListener; import android.widget.Button; import android.widget.Toast; public class MainActivity extends Activity { private Button btnOpenDialog; private String[] books = null; private Activity activity; private int selectedBookIndex = -1; private AlertDialog alertDialog; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); initBooks(); setContentView(R.layout.activity_main); activity = this; btnOpenDialog = (Button) findViewById(R.id.btnOpenDialog); btnOpenDialog.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { alertDialog = new AlertDialog.Builder(activity).setTitle(R.string.hello_world).setSingleChoiceItems(books, selectedBookIndex, new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { selectedBookIndex = which; allowCloseDialogByTapPositiveButton(); } }).setNegativeButton("取消", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { selectedBookIndex = -1; // distoryDialog(dialog); return; } }).setPositiveButton("确定", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { if(selectedBookIndex == -1){ alertDialog.getButton(Dialog.BUTTON_POSITIVE).setEnabled(false); Toast.makeText(activity, "对不起,你不买书,不能走购物通道啊!", Toast.LENGTH_LONG).show(); // keepDialog(dialog); return; }else{ Toast.makeText(activity, "您选择了图书:" + books[selectedBookIndex] + ".", Toast.LENGTH_LONG).show(); } } }).show(); alertDialog.setCancelable(false); alertDialog.setCanceledOnTouchOutside(false); allowCloseDialogByTapPositiveButton(); } }); } private void allowCloseDialogByTapPositiveButton() { if(selectedBookIndex > -1) { alertDialog.getButton(Dialog.BUTTON_POSITIVE).setEnabled(true); }else{ alertDialog.getButton(Dialog.BUTTON_POSITIVE).setEnabled(false); } } void initBooks() { books = new String[] { "飞狐外传", "雪山飞狐", "连城诀", "天龙八部", "射雕英雄传", "白马啸西风", "鹿鼎记", "笑傲江湖", "书剑恩仇录", "神雕侠侣", "侠客行", "倚天屠龙记", "碧血剑", "鸳鸯刀", "越女剑" }; } }