Android Competency Center

Let’s look at how to parse JSON objects in android

1> First we’ll need an example :

Lets look at a standard example from the json site http://json.org/example.html

     {"menu": {
				  "id": "file",
				  "value": "File",
				  "popup": {
				    "menuitem": [
				      {"value": "New", "onclick": "CreateNewDoc()"},
				      {"value": "Open", "onclick": "OpenDoc()"},
				      {"value": "Close", "onclick": "CloseDoc()"}
				    ]
				  }
				}}

you could either save this in a file or save it in a string…..like I’ve done

2> Android already contains the required JSON libraries

Lets create a JSON Object;

private JSONObject jObject;

and lets our example be a String ,

private String jString = "{\"menu\":	{\"id\": \"file\", \"value\": \"File\", \"popup\": { \"menuitem\": 	[ {\"value\": \"New\", \"onclick\": \"CreateNewDoc()\"}, 	{\"value\": \"Open\", \"onclick\": \"OpenDoc()\"}, 	 	{\"value\": \"Close\", \"onclick\": \"CloseDoc()\"}]}}}";

now we have to convert jString to the jObject ,

jObject = new JSONObject(jString); 

Now we have to start extracting the content from jObject ,

Lets extract the menu object by creating a new menu object,

JSONObject menuObject = jObject.getJSONObject("menu");

Now lets extract its atrtibutes ,

String attributeId = menuObject.getString("id");
String attributeValue = menuObject.getString("value");
JSONObject popupObject = menuObject.getJSONObject("popup");

since “popup” is not plainly a String lets extract it to an object ,

3> Now popup contains an array of “menuitem”

So, we’ll have to extract it to a JSONArray,

 JSONArray menuitemArray = popupObject.getJSONArray("menuitem"); 

Since it contains 3 items lets put it in a for loop.

for (int i = 0; i < 3; i++) {
			System.out.println(menuitemArray.getJSONObject(i)
					.getString("value").toString());
			System.out.println(menuitemArray.getJSONObject(i).getString(
					"onclick").toString());
		}

Basically thats it , u should see the output in the DDMS

4> The full code is as below,

import org.json.JSONArray;
import org.json.JSONObject;
import android.app.Activity;
import android.os.Bundle;

public class JsonParser extends Activity {
	private JSONObject jObject;
	private String jString = "{\"menu\": {\"id\": \"file\", \"value\": \"File\", \"popup\": { \"menuitem\": [ {\"value\": \"New\",   \"onclick\": \"CreateNewDoc()\"}, {\"value\": \"Open\", \"onclick\": \"OpenDoc()\"}, {\"value\": \"Close\", \"onclick\": \"CloseDoc()\"}]}}}";

	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);
		try {
			parse();
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
	private void parse() throws Exception {
		jObject = new JSONObject(jString);

		JSONObject menuObject = jObject.getJSONObject("menu");
		String attributeId = menuObject.getString("id");
		System.out.println(attributeId);

		String attributeValue = menuObject.getString("value");
		System.out.println(attributeValue);

		JSONObject popupObject = menuObject.getJSONObject("popup");
		JSONArray menuitemArray = popupObject.getJSONArray("menuitem");

		for (int i = 0; i < 3; i++) {
			System.out.println(menuitemArray.getJSONObject(i)
					.getString("value").toString());
			System.out.println(menuitemArray.getJSONObject(i).getString(
					"onclick").toString());
		}
	}
}

Android, Android API, Mobile Market -1, Android, how, JSON, parse, parsing, simple, to

Hello coders,

Lets look at a fairly simple example of creating a transparent theme and how to apply it to a Dialog……

Step 1> Create a colors.xml file in the ‘values’ folder under ‘res’ and add the following line..

<drawable name="transparent">#00000000</drawable>

Step 2> Create a styles.xml file in the ‘values’ folder under ‘res’ and the following lines…

<style name="Transparent">
<item name="android:windowIsTranslucent">true</item>
<item name="android:windowAnimationStyle">
@android:style/Animation.Translucent
</item>
<item name="android:windowBackground">@drawable/transparent</item>
<item name="android:windowNoTitle">true</item>
<item name="android:colorForeground">#fff</item>
</style>

( I guess the tags and attributes are self explanatory …. )

Step 3> Actually thats it……………………

Let’s add this to a dialog…..

Step 4> Create a class with the following lines……

public class DialogBox extends Dialog {

    public DialogBox(Context context, int theme) {
        super(context, theme);
        setContentView(R.layout.dialog);
        okButton = (Button) findViewById(R.id.dialog_OkButton);
        setListeners();
    }
}

(Make sure you create a layout for the dialog )

Step 5> Next create an activity class as follows….

public class T_Temp extends Activity {

    private DialogBox dialog;

    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        dialog = new DialogBox(this, R.style.Transparent);
        dialog.show();
    }
}

When creating the dialog just add the transparent theme ……

Step 6> That’s it …

( don’t forget to add the activity in the android manifest file..)

When you add the widgets and background it will look something like this..

Before

After

Step 7> Another trick is you can make the background blurred ….

just add the following line in the dialog box…

   getWindow().setFlags(WindowManager.LayoutParams.FLAG_BLUR_BEHIND, WindowManager.LayoutParams.FLAG_BLUR_BEHIND);

Output looks somthing like this…….

So the final code is:

public class DialogBox extends Dialog {

    public DialogBox(Context context, int theme) {
        super(context, theme);
        getWindow().setFlags(WindowManager.LayoutParams.FLAG_BLUR_BEHIND, WindowManager.LayoutParams.FLAG_BLUR_BEHIND);
        setContentView(R.layout.dialog);
        okButton = (Button) findViewById(R.id.dialog_OkButton);
        setListeners();
    }
}

Android, Mobile Market Android, blur, blurred, dialog, image, images, no title, notitle, style, styles, theme, themes, transparent