Android™

Get the Root of a JSON Document

See more JSON Examples

Demonstrates how to get back to the JSON root object from anywhere in the JSON document. This example uses the following JSON document:

{
  "flower": "tulip",
  "abc":
    {
    "x": [
       { "a" : 1 },
       { "b1" : 100, "b2" : 200 },
       { "c" : 3 }
    ],
    "y": 200,
    "z": 200
    }
}

Android™

// Important: Don't forget to include the call to System.loadLibrary
// as shown at the bottom of this code sample.
package com.test;

import android.app.Activity;
import com.chilkatsoft.*;

import android.widget.TextView;
import android.os.Bundle;

public class SimpleActivity extends Activity {

  private static final String TAG = "Chilkat";

  // Called when the activity is first created.
  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    boolean success = false;

    CkJsonObject json = new CkJsonObject();

    String jsonStr = "{\"flower\": \"tulip\",\"abc\":{\"x\": [{ \"a\" : 1 },{ \"b1\" : 100, \"b2\" : 200 },{ \"c\" : 3 }],\"y\": 200,\"z\": 200}}";

    success = json.Load(jsonStr);
    if (success == false) {
        Log.i(TAG, json.lastErrorText());
        return;
        }

    // Get the "abc" object.
    CkJsonObject abcObj = new CkJsonObject();
    success = json.ObjectOf2("abc",abcObj);
    if (success == false) {
        Log.i(TAG, json.lastErrorText());
        return;
        }

    // Side note: The JSON of a sub-part of the document can be emitted from any JSON object:
    abcObj.put_EmitCompact(false);
    Log.i(TAG, abcObj.emit());

    // Navigate to the "x" array
    CkJsonArray xArray = new CkJsonArray();
    abcObj.ArrayOf2("x",xArray);

    // Navigate to the 2nd object contained within the array.  This contains members b1 and b2
    CkJsonObject bObj = new CkJsonObject();
    xArray.ObjectAt2(1,bObj);

    // Show that we're at "b1/b2".
    // The value of "b1" should be "200"
    Log.i(TAG, "b2 = " + String.valueOf(bObj.IntOf("b2")));

    // Now go back to the JSON doc root:
    CkJsonObject docRoot = new CkJsonObject();
    bObj.GetDocRoot2(docRoot);

    // We'll skip the null check and assume it's non-null...

    // Pretty-print the JSON doc from the root to show that this is indeed the root.
    docRoot.put_EmitCompact(false);
    Log.i(TAG, docRoot.emit());

  }

  static {
      System.loadLibrary("chilkat");

      // Note: If the incorrect library name is passed to System.loadLibrary,
      // then you will see the following error message at application startup:
      //"The application <your-application-name> has stopped unexpectedly. Please try again."
  }
}