Question

I made just one activity that opens another activity. Everything was working right until i setted up onClickListener. Now my app force closes when it launch. Without these two lines application launches correctly:

BUeasycounter.setOnClickListener(this);
BUrps.setOnClickListener(this);

Here is my full source:

package com.dano.learning;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

public class Menu extends Activity implements View.OnClickListener{

    Button BUeasycounter;
    Button BUrps;
    @Override
    protected void onCreate(Bundle MyBundle) {
        super.onCreate(MyBundle);
        setContentView(R.layout.activity_main);
        initializeVars();
// next 2 lines cause the problem
        BUeasycounter.setOnClickListener(this);
        BUrps.setOnClickListener(this);
    }
    public void initializeVars(){
        Button BUeasycounter= (Button) findViewById(R.id.BUeasycounter);
        Button BUrps = (Button) findViewById(R.id.BUrps);
    }

    public void onClick(View v) {
        switch (v.getId()){
            case R.id.BUeasycounter:
                Intent openEasyCounter = new Intent("com.dano.learning.EASYCOUNTER");
                startActivity(openEasyCounter);
                break;
            case R.id.BUrps:
                Intent openRPS = new Intent("com.dano.learning.EASYCOUNTER");
                startActivity(openRPS);
                break;
        };

    }
}

Maybe i just typed something wrong but I cant find mistake in my source for more than two days. Thank you for your help.

Answer 1

There is no exception stack in question, but based on code I see one issue is:

    Button BUeasycounter;
    Button BUrps;

Both are pointing to null which could be throwing NullPointerException when you do

    BUeasycounter.setOnClickListener(this);
    BUrps.setOnClickListener(this);

Remove new variable in initializeVars method.

Example:

public void initializeVars(){
          BUeasycounter= (Button) findViewById(R.id.BUeasycounter);
          BUrps = (Button) findViewById(R.id.BUrps);
    }

Note: Java naming convention suggest that use small letter as first letter for variable name.