Getting an nullPointerException while changing layout in CountDownTimer 's finish() method

Question

I am Getting an nullPointerException at "button.setOnClickListener(this);"....while changing layout in CountDownTimer 's finish() method. here is code...Please help me to solve this....... thanks in advance

package com.example.vikrant.countdowntimer;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.AsyncTask;
import android.os.CountDownTimer;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.text.Layout;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;

import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.concurrent.ExecutionException;

public class MainActivity extends AppCompatActivity implements View.OnClickListener {

    Button button;
    ImageView image;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        final Context c = getApplicationContext();
         new CountDownTimer(10000,5000){

             @Override
             public void onTick(long millisUntilFinished) {
                 setContentView(R.layout.timer);
             }

             @Override
             public void onFinish() {
                 setContentView(R.layout.activity_main);
             }
         }.start();

        button = (Button) findViewById(R.id.button);
        button.setOnClickListener(this);

    }

    @Override
    public void onClick(View v) {
        String url="https://firebasestorage.googleapis.com/v0/b/fir-assignment-34e5b.appspot.com/o/rangoliA%2Frangolinew.jpg?alt=media&token=4a376937-7fec-420a-a18c-8c9ec7da95af";
        image = (ImageView) findViewById(R.id.imageView);
        DownloadImage downloadImage = new DownloadImage();
        Bitmap bitmap;
        try {
            bitmap = downloadImage.execute(url).get();
            image.setImageBitmap(bitmap);
        } catch (InterruptedException e) {
            e.printStackTrace();
        } catch (ExecutionException e) {
            e.printStackTrace();
        }

    }

    public class DownloadImage extends AsyncTask<String,Void,Bitmap>{

        @Override
        protected Bitmap doInBackground(String... params) {
            URL url;
            HttpURLConnection httpURLConnection;
            try {
                url = new URL(params[0]);
                httpURLConnection = (HttpURLConnection) url.openConnection();
                httpURLConnection.connect();
                InputStream inputStream = httpURLConnection.getInputStream();
                Bitmap bitmap = BitmapFactory.decodeStream(inputStream);
                return bitmap;

            } catch (Exception e) {
                e.printStackTrace();
                return null;
            }

        }
    }
}

is this button available at timer layout / activity_main layout ? Just check the condition before finishing the timer. — King of Masses, Jul 21 '17 at 08:09
are you trying to make a splsh screen in android ? https://stackoverflow.com/questions/5486789/how-do-i-make-a-splash-screen — King of Masses, Jul 21 '17 at 08:23

score 0 · Answer 1 · answered Jul 21 '17 at 08:09

0

Your button is probably defined in your "R.layout.activity_main". When you set another content, the "findViewById(R.id.button)" will return null (because its not defined in the other layout).

Why do you change the layouts after all?

answered Jul 21 '17 at 08:09

Prexx

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Yes the button is defined in activity_main.xml....I want to change the layout automatically when my app start...is there any way by which i will not get this exception and do what i want?? – Vikrant Tyagi Jul 21 '17 at 08:12
are you talking about splsh screen in android ? https://stackoverflow.com/questions/5486789/how-do-i-make-a-splash-screen – King of Masses Jul 21 '17 at 08:18

Getting an nullPointerException while changing layout in CountDownTimer 's finish() method

1 Answers1