Android Firebase:如何简单地获取某个键下的所有值? [英] Android Firebase: How to simply get all the values under a certain key?

问题描述

要解决这个问题，是的，SO上也有类似的问题，但是并不能完全解释我的情况对我的想法的要求.

To get it out of the way, yes there is a similar question on SO, but it doesn't explain exactly what my situation asks for I think.

在Firebase实时数据库中，我有一个看起来像这样的json树:

In the Firebase Realtime Database, I have a json tree that looks something like this:

users{
   userid{
       templates{
          templateName1{  // example name that the user saves their template as.
                          // each template is an ArrayList
                  //templateName1 ArrayList contents
            }
          templateName2{ 
                  //templateName1 ArrayList contents
            }
          templateName2{ 
                  //templateName1 ArrayList contents
            }
       }
   }
}

我需要能够在模板"中列出每个模板，而在其他时候，只需获取特定模板的ArrayList值即可.但是我似乎无法弄清楚如何做这个简单的事情.

I need to be able to list each template in "templates", and at other times simply get the ArrayList value of a specific template. However I can't seem to figure out how to do this simple thing.

根据我在Google中搜索/阅读的文档，我的代码应如下所示:

From what I've googled/read in the docs, my code should look something like this:

DatabaseReference mTemplateRef = mDatabase.child("users").child(uid).child("templates");

    mTemplateRef.addListenerForSingleValueEvent(
            new ValueEventListener() {
                @Override
                public void onDataChange(DataSnapshot dataSnapshot) {
                    dataSnapshot.getChildren();

                    // somehow get the values here

                }
    });

当我调试并输入表达式数据dataSnapshot.getChildren()时，我可以看到预期的内容，但似乎无法将这些数据导入我的应用程序.有任何想法吗?

When I debug, and enter the expression data dataSnapshot.getChildren() I can see the contents as expected, but I can't seem to get that data into my app. Any ideas?

推荐答案

这就是我想要的:

settingsRef.addListenerForSingleValueEvent(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {
            for(DataSnapshot dataSnapshot1 : dataSnapshot.getChildren()){
                // easy
                String value = dataSnapshot1.getValue(String.class);                    
            }
        }

        @Override
        public void onCancelled(DatabaseError databaseError) {

        }
    });

这篇关于Android Firebase:如何简单地获取某个键下的所有值?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！