java.lang.NullPointerException in textview inside asyncTask - android-asynctask

Question

If I use the following code, I will have no error, but there will be a freeze time.
#Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
StrictMode.setThreadPolicy(policy);
setContentView(R.layout.profilepic);
initialize();
Bundle bundle = getIntent().getExtras();
email = bundle.getString("Email");
ArrayList<NameValuePair> postParameters;
String response = null;
postParameters = new ArrayList<NameValuePair>();
postParameters.add(new BasicNameValuePair("emaillog", email));
try {
response = CustomHttpClient.executeHttpPost("http://whatstherex.info/checkU.php", postParameters);
res = response.toString();
res = res.replaceAll("null", "");
username = res.toString();
tvProfilePic.setText("Hi " + username + ", you are encourage to add a profile picture.");
}catch(Exception e){
res = e.toString();
tvProfilePic.setText(res);
}
}
But if I use this code with asyncTask and progressDialog like this:
#Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
StrictMode.setThreadPolicy(policy);
setContentView(R.layout.profilepic);
initialize();
getUsername();
}
private AsyncTask<String, Void, String> task;
public void getUsername(){
Bundle bundle = getIntent().getExtras();
email = bundle.getString("Email");
task = new AsyncTask<String, Void, String>() {
ProgressDialog dialog;
ArrayList<NameValuePair> postParameters;
String response = null;
#Override
protected void onPreExecute() {
//
ArrayList<NameValuePair> postParameters = new ArrayList<NameValuePair>();
postParameters.add(new BasicNameValuePair("emaillog", email));
dialog = new ProgressDialog(Profilepic.this, ProgressDialog.STYLE_SPINNER);
dialog.setMessage("Loading Data...");
dialog.show();
}
#Override
protected String doInBackground(String... params) {
//
try {
response = CustomHttpClient.executeHttpPost("http://whatstherex.info/checkU.php", postParameters);
res = response.toString();
res = res.replaceAll("null", "");
username = res.toString();
return username;
}catch(Exception e){
res = e.toString();
return res;
}
}
#Override
protected void onPostExecute(String result) {
if(result.length()< 25){
username = result;
tvProfilePic.setText("Hi " + result + ", you are encourage to add a profile picture.");
dialog.dismiss();
}else{
tvProfilePic.setText(result);
dialog.dismiss();
}
}
};
task.execute();
}
I get java.lang.NullPointerException in the textview.
What's the problem? Can anyone help me how to resolve this issue with NullPointerException appearing?

Answer 1

I see that you use tvProfilePic but I don't see where you define it.
In case you are not defining it, it should be done in a similar way as
tvProfilePic = findViewById(R.id.profile_pic)
Are you doing this?
Note that 'profile_pic' is the name in the layout XML document.

Answer 2

You are using tvProfilePic as a textview but i can't see where you defined it.
if you are not defining it then define it using something like
tvProfilePic = findViewById(R.id.profile_pic)
You are getting nullpointerexception because your tvProfilePic is null