按后退按钮，在对话框上显示警告框

Question

我试图通过按后退按钮删除该对话框，在对话框上显示警告框。我在switch语句中创建了这个对话框。我通过使用每个可能的方面来尝试它，但它没有帮助 继承我的代码：

lv.setOnItemClickListener(new OnItemClickListener() {

            @Override
            public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,
                    long arg3) {
                // TODO Auto-generated method stub
                switch (arg2) {
                case 0:
                    AlertDialog.Builder dialog = new AlertDialog.Builder(
                            Listitem.this);
                    dialog.setTitle("kya h");
                    dialog.setMessage("kuch ni");
                    dialog.setCancelable(true);
                    dialog.create();
                    dialog.show();

                    dialog.setOnKeyListener(new OnKeyListener() {

                        @Override
                        public boolean onKey(DialogInterface dialog,
                                int keyCode, KeyEvent event) {
                            // TODO Auto-generated method stub

                            if (keyCode == KeyEvent.KEYCODE_BACK) {
                                // finish();
                                // dialog.dismiss();
                                exitByBackKey();
                            }
                            return false;
                        }

                        private void exitByBackKey() {
                            // TODO Auto-generated method stub
                            AlertDialog.Builder alertbox = new AlertDialog.Builder(Listitem.this);
                            alertbox.setMessage("Do u want to exit");
                            alertbox.setPositiveButton("Yes",
                                    new DialogInterface.OnClickListener() {

                                        @Override
                                        public void onClick(
                                                DialogInterface dialog,
                                                int which) {
                                            // TODO Auto-generated
                                            // method stub
                                            finish();
                                            dialog.cancel();

                                        }
                                    })
                                    .setNegativeButton(
                                            "No",
                                            new DialogInterface.OnClickListener() {

                                                @Override
                                                public void onClick(
                                                        DialogInterface dialog,
                                                        int which) {
                                                    // TODO Auto-generated
                                                    // method stub

                                                }
                                            }).show();

                        }
                    });
                    break;

                }
            }
        });
    }
}

Answer 1

要更改后退按钮的行为，您只需覆盖onBackPressed()方法。

@Override
public void onBackPressed() {
    new AlertDialog.Builder(this)
        .setMessage("Do u want to exit")
        .setNegativeButton("No")
        .setPositiveButton("Yes", new OnClickListener() {

            public void onClick(DialogInterface arg0, int arg1) {
                finish();
                dialog.cancel();
            }
        }).create().show();
}

确保dialog方法可以访问onBackPressed()。