按下后退按钮时如何显示警报消息？

Question

我需要在用户按下 Back Button 时向他显示一个 Alert Message。我写了下面的代码，它显示 Alert Box 一秒钟然后重定向。我在 Alert Box 中指定了 Button，如果用户 click 在 yes 上，那么我创建 Intent，否则我希望用户留在当前 [=26] =].

现在它向我显示以下错误消息。

android.view.WindowLeaked: Activity checkout.Checkout has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView{100e8093 V.E..... R.....I. 0,0-1080,476} that was originally added here
             at android.view.ViewRootImpl.<init>(ViewRootImpl.java:363)
             at android.view.WindowManagerGlobal.addView(WindowManagerGlobal.java:271)
             at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:85)
             at android.app.Dialog.show(Dialog.java:298)
             at android.support.v7.app.AlertDialog$Builder.show(AlertDialog.java:953)

代码。

@Override
public void onBackPressed() {
    super.onBackPressed();

    AlertDialog.Builder alertDialog2 = new AlertDialog.Builder(this);
    alertDialog2.setTitle("Delete Data");
    alertDialog2.setMessage("Are you sure you want to go back?.");
    // Add the buttons
    alertDialog2.setPositiveButton("OK", new DialogInterface.OnClickListener() {
        public void onClick(DialogInterface dialog, int id) {
            // User clicked OK button
            //Here i am doing JSON Stuff
            JSONObject commandData = new JSONObject(); 

        }
    });
    alertDialog2.show();

Answer 1

评论这一行：

super.onBackPressed();

Answer 2

@Override
public void onBackPressed() {

    AlertDialog.Builder alertDialog2 = new AlertDialog.Builder(this);
    alertDialog2.setTitle("Delete Data");
    alertDialog2.setMessage("Are you sure you want to go back?.");
    // Add the buttons
    alertDialog2.setPositiveButton("OK", new DialogInterface.OnClickListener() {
        public void onClick(DialogInterface dialog, int id) {
            // User clicked OK button
            //Here i am doing JSON Stuff
            JSONObject commandData = new JSONObject(); 

        }
    });

   alertDialog2.setNegativeButton("No",new DialogInterface.OnClickListener() {
        public void onClick(DialogInterface dialog, int id) {
          YourClass.super.onBackPressed();

        }
    };
    alertDialog2.show();

按下后退按钮时如何显示警报消息？

How to display Alert Message when back button is Pressed?

android

android-layout

android-fragments

android-alertdialog