B4J Question How to convert JSON tree to a flat structured list of maps

Mashiane

Expert
Licensed User
Ola

Time flies and now I need code to flatten a json tree, the previous code to unflatten works well, now I kindly need an opposite effect.

Previous code: https://www.b4x.com/android/forum/threads/how-to-unflatten-list-to-a-json-tree.107189/#content

As an example, this is the JSON tree, each item can have child items, so I need something to return the parentid, name, child id children (plus attributes)

B4X:
<script>
        items: [
        {
          id: 1,
          name: 'Applications :',
          children: [
            { id: 2, name: 'Calendar : app' },
            { id: 3, name: 'Chrome : app' },
            { id: 4, name: 'Webstorm : app' },
          ],
        },
        {
          id: 5,
          name: 'Documents :',
          children: [
            {
              id: 6,
              name: 'vuetify :',
              children: [
                {
                  id: 7,
                  name: 'src :',
                  children: [
                    { id: 8, name: 'index : ts' },
                    { id: 9, name: 'bootstrap : ts' },
                  ],
                },
              ],
            },
            {
              id: 10,
              name: 'material2 :',
              children: [
                {
                  id: 11,
                  name: 'src :',
                  children: [
                    { id: 12, name: 'v-btn : ts' },
                    { id: 13, name: 'v-card : ts' },
                    { id: 14, name: 'v-window : ts' },
                  ],
                },
              ],
            },
          ],
        },
        {
          id: 15,
          name: 'Downloads :',
          children: [
            { id: 16, name: 'October : pdf' },
            { id: 17, name: 'November : pdf' },
            { id: 18, name: 'Tutorial : html' },
          ],
        },
        {
          id: 19,
          name: 'Videos :',
          children: [
            {
              id: 20,
              name: 'Tutorials :',
              children: [
                { id: 21, name: 'Basic layouts : mp4' },
                { id: 22, name: 'Advanced techniques : mp4' },
                { id: 23, name: 'All about app : dir' },
              ],
            },
            { id: 24, name: 'Intro : mov' },
            { id: 25, name: 'Conference introduction : avi' },
          ],
        },
      ],
    }),
  }
</script>

Thanks
 

DonManfred

Expert
Licensed User
Upvote 0

DonManfred

Expert
Licensed User
1. This is the corrected json (yours was not valid!)
B4X:
[
        {
          id: 1,
          name: 'Applications :',
          children: [
            { id: 2, name: 'Calendar : app' },
            { id: 3, name: 'Chrome : app' },
            { id: 4, name: 'Webstorm : app' }
          ]
        },
        {
          id: 5,
          name: 'Documents :',
          children: [
            {
              id: 6,
              name: 'vuetify :',
              children: [
                {
                  id: 7,
                  name: 'src :',
                  children: [
                    { id: 8, name: 'index : ts' },
                    { id: 9, name: 'bootstrap : ts' }
                  ]
                }
              ]
            },
            {
              id: 10,
              name: 'material2 :',
              children: [
                {
                  id: 11,
                  name: 'src :',
                  children: [
                    { id: 12, name: 'v-btn : ts' },
                    { id: 13, name: 'v-card : ts' },
                    { id: 14, name: 'v-window : ts' }
                  ]
                }
              ]
            }
          ]
        },
        {
          id: 15,
          name: 'Downloads :',
          children: [
            { id: 16, name: 'October : pdf' },
            { id: 17, name: 'November : pdf' },
            { id: 18, name: 'Tutorial : html' }
          ]
        },
        {
          id: 19,
          name: 'Videos :',
          children: [
            {
              id: 20,
              name: 'Tutorials :',
              children: [
                { id: 21, name: 'Basic layouts : mp4' },
                { id: 22, name: 'Advanced techniques : mp4' },
                { id: 23, name: 'All about app : dir' }
              ]
            },
            { id: 24, name: 'Intro : mov' },
            { id: 25, name: 'Conference introduction : avi' }
          ]
        }
      ]
    }
  }

B4X:
Dim parser As JSONParser
parser.Initialize(json)
Dim root As List = parser.NextArray
For Each colroot As Map In root
 Dim children As List = colroot.Get("children")
 For Each colchildren As Map In children
  Dim name As String = colchildren.Get("name")
  Dim id As Int = colchildren.Get("id")
 Next
 Dim name As String = colroot.Get("name")
 Dim id As Int = colroot.Get("id")
Next
 
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