只是当你想解散对话框时要小心——使用dialog.dismiss()。在我的第一次尝试中，我使用了遣散dialog(0)(我可能从某个地方复制)，有时它可以工作。使用系统提供的对象听起来是更安全的选择。

您可以为此使用AlertDialog，并使用它的Builder类构造一个AlertDialog。下面的例子使用默认的构造函数，它只接受Context，因为对话框将从传入的Context继承适当的主题，但是如果你想这样做，还有一个构造函数允许你指定一个特定的主题资源作为第二个参数。

new AlertDialog.Builder(context)
    .setTitle("Delete entry")
    .setMessage("Are you sure you want to delete this entry?")

    // Specifying a listener allows you to take an action before dismissing the dialog.
    // The dialog is automatically dismissed when a dialog button is clicked.
    .setPositiveButton(android.R.string.yes, new DialogInterface.OnClickListener() {
        public void onClick(DialogInterface dialog, int which) { 
            // Continue with delete operation
        }
     })

    // A null listener allows the button to dismiss the dialog and take no further action.
    .setNegativeButton(android.R.string.no, null)
    .setIcon(android.R.drawable.ic_dialog_alert)
    .show();

public void showSimpleDialog(View view) {
    // Use the Builder class for convenient dialog construction
    AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);
    builder.setCancelable(false);
    builder.setTitle("AlertDialog Title");
    builder.setMessage("Simple Dialog Message");
    builder.setPositiveButton("OK!!!", new DialogInterface.OnClickListener() {
        @Override
        public void onClick(DialogInterface dialog, int id) {
            //
        }
    })
    .setNegativeButton("Cancel ", new DialogInterface.OnClickListener() {
        @Override
        public void onClick(DialogInterface dialog, int which) {

        }
    });

    // Create the AlertDialog object and return it
    builder.create().show();
}

也可以看看我的关于Android对话的博客，你会在这里找到所有的细节:http://www.fahmapps.com/2016/09/26/dialogs-in-android-part1/。

     new AlertDialog.Builder(loginregister.this)
            .setTitle("messege")
            .setPositiveButton("ok", null)
            .setMessage( "user name : " + username + "/n" +
                            "password :" + password + "/n"  )
    .show();

创建这个静态方法，并在任何需要的地方使用它。

public static void showAlertDialog(Context context, String title, String message, String posBtnMsg, String negBtnMsg) {
            AlertDialog.Builder builder = new AlertDialog.Builder(context);
            builder.setTitle(title);
            builder.setMessage(message);
            builder.setPositiveButton(posBtnMsg, new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialog, int which) {
                    dialog.cancel();
                }
            });
            builder.setNegativeButton(negBtnMsg, new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialog, int which) {
                    dialog.cancel();
                }
            });
            AlertDialog dialog = builder.create();
            dialog.show();

        }

为Kotln开发人员提供最简单的解决方案

val alertDialogBuilder: AlertDialog.Builder = AlertDialog.Builder(requireContext())
    alertDialogBuilder.setMessage(msg)
    alertDialogBuilder.setCancelable(true)

    alertDialogBuilder.setPositiveButton(
        getString(android.R.string.ok)
    ) { dialog, _ ->
        dialog.cancel()
    }

    val alertDialog: AlertDialog = alertDialogBuilder.create()
    alertDialog.show()