خطا در تبدیل استرینگ به جیسون

سلام دوستان

استرینگ به راحتی و کاملا تمیز از سایت گرفته میشه ولی وقتی میخوام تبدیلش کنم خطا میده : 

اینم جیسون

[{"id":"1","value":"cygjk"},{"id":"2","value":"bylfkyt"}]

اینم کد

String result = WebService.read_url("http://192.168.1.108/mysite/");
		if (result != null);
		try {
			JSONArray tasks =new JSONArray(result);
			for (int i = 0 ; i < tasks.length() ; i ++ ){
				
				
				JSONObject task = tasks.getJSONObject(i);
			
			}
			
		} catch (JSONException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		

خطا

 08-28 08:42:17.994: W/System.err(809): org.json.JSONException: Value http of type java.lang.String cannot be converted to JSONArray
08-28 08:42:18.024: W/System.err(809): 	at org.json.JSON.typeMismatch(JSON.java:111)
08-28 08:42:18.024: W/System.err(809): 	at org.json.JSONArray.(JSONArray.java:91)
08-28 08:42:18.024: W/System.err(809): 	at org.json.JSONArray.(JSONArray.java:103)
08-28 08:42:18.034: W/System.err(809): 	at com.example.note.ActivityMain.onCreate(ActivityMain.java:22)
08-28 08:42:18.034: W/System.err(809): 	at android.app.Activity.performCreate(Activity.java:5133)
08-28 08:42:18.054: W/System.err(809): 	at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
08-28 08:42:18.054: W/System.err(809): 	at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2175)
08-28 08:42:18.054: W/System.err(809): 	at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261)
08-28 08:42:18.064: W/System.err(809): 	at android.app.ActivityThread.access$600(ActivityThread.java:141)
08-28 08:42:18.064: W/System.err(809): 	at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)
08-28 08:42:18.064: W/System.err(809): 	at android.os.Handler.dispatchMessage(Handler.java:99)
08-28 08:42:18.064: W/System.err(809): 	at android.os.Looper.loop(Looper.java:137)
08-28 08:42:18.094: W/System.err(809): 	at android.app.ActivityThread.main(ActivityThread.java:5103)
08-28 08:42:18.094: W/System.err(809): 	at java.lang.reflect.Method.invokeNative(Native Method)
08-28 08:42:18.104: W/System.err(809): 	at java.lang.reflect.Method.invoke(Method.java:525)
08-28 08:42:18.104: W/System.err(809): 	at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
08-28 08:42:18.114: W/System.err(809): 	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
08-28 08:42:18.114: W/System.err(809): 	at dalvik.system.NativeStart.main(Native Method)
08-28 08:42:18.274: I/Choreographer(809): Skipped 39 frames!  The application may be doing too much work on its main thread.
08-28 08:42:18.584: D/gralloc_goldfish(809): Emulator without GPU emulation detected.
08-28 08:42:19.484: I/Log(809): [{"id":"1","value":"cygjk"},{"id":"2","value":"bylfkyt"}]