Android error แบบนี้ Host name may not be null แก้อย่างไรดีค่ะ

StrictMode.setThreadPolicy(new StrictMode.ThreadPolicy.Builder().permitAll().build());
		Toast.makeText(MyCalendarActivity.this,DMYnow, Toast.LENGTH_SHORT).show();   
		date = DMYnow;
	
		HttpClient hc = new DefaultHttpClient();
		HttpPost hp = new HttpPost("http://"+IP+"/promotion/ListV.php?date="+date);
		HttpResponse hr = null;
		BufferedReader br = null;
		  
			try {
				hr = hc.execute(hp);
								
				br = new BufferedReader(new InputStreamReader(hr.getEntity().getContent()));
				String Data = "";		
				StringBuffer sb = new StringBuffer("");
					while( (Data = br.readLine()) != null)
					{	
						sb.append(Data);   
						Toast.makeText(MyCalendarActivity.this, ""+Data, Toast.LENGTH_LONG).show();
						
						if(Data.equals("null"))
						{
							Check = 0 ;
							Toast.makeText(MyCalendarActivity.this, "Null", Toast.LENGTH_LONG).show();
						}
						else{	
						Check = 1 ;
						  			
						try {
							 JSONArray jArray = new JSONArray(sb.toString());				 
							for(int g =0;g<jArray.length();g++)
							{	//JSONObject json_data = null;   
								JSONObject  json_data = jArray.getJSONObject(g);									
									ListV[0] = json_data.getString("date");
									ListV[1] = json_data.getString("time");
									ListV[2] = json_data.getString("title");
						Toast.makeText(MyCalendarActivity.this, " "+ListV[0]+" "+ListV[1]+" "+ListV[2], Toast.LENGTH_LONG).show();   } 
						} 
						catch (JSONException e1) {
							Toast.makeText(MyCalendarActivity.this, "IOException e1", Toast.LENGTH_LONG).show();
							e1.printStackTrace();   }
						}}}
			
				catch (IOException e2) {
					Toast.makeText(MyCalendarActivity.this, "IOException e2", Toast.LENGTH_LONG).show();
					e2.printStackTrace();   }