Friday, July 8, 2011

Get array elements in JSON

Further works on the former exercise "Parse JSON with JSONObject", array elements are added in the dummy JSON.

Get array elements in JSON

Modify res/values/strings.xml to add array in dummy JSON string.
<?xml version="1.0" encoding="utf-8"?>
<resources>
<string name="hello">Hello World, AndroidJSONActivity!</string>
<string name="app_name">AndroidJSON</string>
<string name="dummy_json">"{\"results\":{\"myblog\":\"android-er\", \"myurl\":"\""http://android-er.blogspot.com/\",\"array\":[{\"element\":\"Element 1\"}, {\"element\":\"Element 2\"}, {\"element\":\"Element 3\"}]"}}"</string>
</resources>


Modify main.xml to add a TextView "json_myarray" to display the array elements.
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="@string/hello"
/>
<TextView
android:id="@+id/json_src"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
/>
<TextView
android:id="@+id/json_object"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
/>
<TextView
android:id="@+id/json_result"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
/>
<TextView
android:id="@+id/json_myblog"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
/>
<TextView
android:id="@+id/json_myurl"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
/>
<TextView
android:id="@+id/json_myarray"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
/>
</LinearLayout>


Modify the code, to retrieve array elements from JSON.
package com.exercise.AndroidJSON;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;
import android.widget.Toast;

public class AndroidJSONActivity extends Activity {

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

TextView JsonSrc = (TextView)findViewById(R.id.json_src);
TextView JsonObject = (TextView)findViewById(R.id.json_object);
TextView JsonResult = (TextView)findViewById(R.id.json_result);
TextView JsonMyBlog = (TextView)findViewById(R.id.json_myblog);
TextView JsonMyUrl = (TextView)findViewById(R.id.json_myurl);
TextView JsonMyArray = (TextView)findViewById(R.id.json_myarray);

String json_source = getString(R.string.dummy_json);
JsonSrc.setText(json_source);

try {
JSONObject jsonObject = new JSONObject(json_source);
JSONObject results = jsonObject.getJSONObject("results");
String myBlog = results.getString("myblog");
String myUrl = results.getString("myurl");

JsonObject.setText("\njsonObject:\n" + jsonObject.toString());
JsonResult.setText("\nresults:\n" + results.toString());
JsonMyBlog.setText("\nmyBlog:\n" + myBlog);
JsonMyUrl.setText("\nmyUrl:\n" + myUrl);

//Retrieve Array Elements in JSON
String stringArrayElement = "\n";
JSONArray jsonArray = results.getJSONArray("array");
for (int i = 0; i < jsonArray.length(); i++) {
JSONObject arrayElement = jsonArray.getJSONObject(i);
stringArrayElement += arrayElement.getString("element") + "\n";
}

JsonMyArray.setText(stringArrayElement);

} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
Toast.makeText(AndroidJSONActivity.this,
e.toString(),
Toast.LENGTH_LONG).show();
}
}
}


Download the files.

Related article:
- Another example to parse JSON

1 comment:

SunaryoPro said...

wow... googd article man... very much