App crashes if no data available in mysql database - php

Question

my application crashes when Serialno and city is not available in database, sometimes it shows "No Data is Available", and some times it crashes, All i need is to display toast when ever Serial number and city is not present in database.
public String getvalues()
{
String uri = "http://www.lorryguru.com/retusno.php?city="+Citys+"&serialno="+SerialNo;
HttpGet httpGet = new HttpGet(uri);
HttpClient client = new DefaultHttpClient();
HttpResponse response;
StringBuilder stringBuilder = new StringBuilder();
try {
response = client.execute(httpGet);
HttpEntity entity = response.getEntity();
InputStream stream = entity.getContent();
int b;
while ((b = stream.read()) != -1)
{
stringBuilder.append((char) b);
}
}
catch (ClientProtocolException e)
{
e.printStackTrace();
}
catch (IOException e)
{
e.printStackTrace();
}
try
{
JSONArray arr = new JSONArray(stringBuilder.toString());
//result = jsonObj.getJSONArray(TAG_RESULT);
JSONObject c = arr.getJSONObject(0);
id = c.getString(TAG_ID);
district = c.getString(TAG_DISTRICT);
cit = c.getString(TAG_CITY);
serial_no = c.getString(TAG_SERIALNO);
gende = c.getString(TAG_GENDER);
wareno = c.getString(TAG_WARENO);
befor = c.getString(TAG_BEFORE);
afte = c.getString(TAG_AFTER);
latitude = c.getString(TAG_LATITUDE);
longitude = c.getString(TAG_LONGITUDE);
return "success";
}
catch (JSONException e)
{
return "No Data is Available";
//e.printStackTrace();
}
}
my php script is
<?php
require "init.php";
$serialno = $_REQUEST["serialno"];
$city = $_REQUEST["city"];
$sql = "SELECT * FROM dogs_details WHERE serial_no='".$serialno."' &&city='".$city."' ";
$res = $con->query($sql);
$result = array();
while($row = mysqli_fetch_array($res)){
if($row['after_dog']=="")
{
$afterimage="No Image";
}
else
{
$afterimage=$row['after_dog'];
}
array_push($result,
array('id'=>$row['id'],
'district'=>$row['district'],
'city'=>$row['city'],
'serialno'=>$row['serial_no'],
'gender'=>$row['gender'],
'wareno'=>$row['ware_no'],
'before'=>$row['before_dog'],
'after'=>$afterimage,
'latitude'=>$row['latitude'],
'longitude'=>$row['longitude']
));
}
echo json_encode($result);
mysqli_close($con);
?>
My postExecute is below
protected void onPostExecute(String s) {
InputMethodManager imm = (InputMethodManager) getSystemService(Activity.INPUT_METHOD_SERVICE);
imm.toggleSoftInput(InputMethodManager.HIDE_IMPLICIT_ONLY, 0);
dialog.hide();
Toast.makeText(getApplicationContext(), s, Toast.LENGTH_SHORT).show();
dis.setText("District " + district);
city.setText("City " + cit);
serialno.setText("Serial No. " + serial_no);
gender.setText("Gender " + gende);
Picasso.with(Serialno.this).load(befor).into(before);
if (afte.equals("No Image")) {
after.setImageDrawable(getResources().getDrawable(R.drawable.load));
} else {
Picasso.with(Serialno.this).load(afte).into(after);
}
// loction.setText("Latitude "+latitude+" "+"Longitude "+longitude);
Showing_Map();
}

Answer 1

Check nullity of all fields of JsonObject and then try to use them. For example:
try
{
JSONArray arr = new JSONArray(stringBuilder.toString());
//result = jsonObj.getJSONArray(TAG_RESULT);
JSONObject c = arr.getJSONObject(0);
if(c.isNull(TAG_ID)
id="";
else
id = c.getString(TAG_ID);
if(c.isNull(TAG_DISTRICT)
district="";
else
district = c.getString(TAG_DISTRICT);
..........................
...............................
return "success";
}
catch (JSONException e)
{
return "No Data is Available";
//e.printStackTrace();
}
And in onPostExecute show Toast:
protected void onPostExecute(String s) {
InputMethodManager imm = (InputMethodManager) getSystemService(Activity.INPUT_METHOD_SERVICE);
imm.toggleSoftInput(InputMethodManager.HIDE_IMPLICIT_ONLY, 0);
dialog.hide();
Toast.makeText(getApplicationContext(), s, Toast.LENGTH_SHORT).show();
dis.setText("District " + district);
//Toast when city is null
if(cit.equals(""))
Toast.makeText(getApplicationContext(), YOUR_MESSSAGE, Toast.LENGTH_SHORT).show();
//Toast when serail_no is null
if(serail_no .equals(""))
Toast.makeText(getApplicationContext(), YOUR_MESSSAGE, Toast.LENGTH_SHORT).show();
city.setText("City " + cit);
serialno.setText("Serial No. " + serial_no);
gender.setText("Gender " + gende);
Picasso.with(Serialno.this).load(befor).into(before);
if (afte.equals("No Image")) {
after.setImageDrawable(getResources().getDrawable(R.drawable.load));
} else {
Picasso.with(Serialno.this).load(afte).into(after);
}
// loction.setText("Latitude "+latitude+" "+"Longitude "+longitude);
Showing_Map();
}