java(android) - unexpected error

Question

My application shut down unexpectedly, I don't really know what the problem is. I'm new to programming java. I tried the 'try', 'catch' and 'finally' methods. Here is the code:

package com.eqsec.csaba;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
public class EqsecActivity extends Activity {
/** Called when the activity is first created. */
Button solve;
EditText vA, vB, vC;
TextView solution;
int discriminant, iA, iB, iC;
@Override
public void onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 setContentView(R.layout.main);
 solve = (Button) findViewById(R.id.bSolve);
 vA = (EditText) findViewById(R.id.etA);
 vB = (EditText) findViewById(R.id.etB);
 vC = (EditText) findViewById(R.id.etC);
 solve.setOnClickListener(new View.OnClickListener() {
 public void onClick(View v) {
 // TODO Auto-generated method stub
 try{
 String A = vA.getText().toString();
 iA = Integer.parseInt(A);
 String B = vB.getText().toString();
 iB = Integer.parseInt(B);
 String C = vC.getText().toString();
 iC = Integer.parseInt(C);
 solution.setText("Yout total is " + iA);
 }catch (ArithmeticException e) {
 e.printStackTrace();
 }
 }
 });
 }
 }

Please help me, i want to write an android application, which can solve some math problems.

• Mohamed_AbdAllah: What do you receive in Logcat?
• KV Prajapati: Please use Log.i() method and see what happen at Logcat.
• Konstantin Pribluda: Problem is described in detail in your logcat. Usually carefull reading of stacktrace solves 90% of problems

Answer 1

You have to catch NumberFormatException instead of ArithmeticException.

And initialize solution variable before. Like:

solution = (TextView) findViewById(R.id.solution);

Full code will be:

package com.eqsec.csaba;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
public class EqsecActivity extends Activity {
/** Called when the activity is first created. */
Button solve;
EditText vA, vB, vC;
TextView solution;
int discriminant, iA, iB, iC;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
solve = (Button) findViewById(R.id.bSolve);
vA = (EditText) findViewById(R.id.etA);
vB = (EditText) findViewById(R.id.etB);
vC = (EditText) findViewById(R.id.etC);
solution = (TextView) findViewById(R.id.solution);
solve.setOnClickListener(new View.OnClickListener() {
 public void onClick(View v) {
 // TODO Auto-generated method stub
 try{
 String A = vA.getText().toString();
 iA = Integer.parseInt(A);
 String B = vB.getText().toString();
 iB = Integer.parseInt(B);
 String C = vC.getText().toString();
 iC = Integer.parseInt(C);
 solution.setText("Yout total is " + iA);
 }catch (NumberFormatException e) {
 e.printStackTrace();
 }
 }
 });
 }
 }

• njzk2: Also, "solution" is not initialized.
• WarrenFaith: @user1121334 Provide the error message you got in your LogCat! Please do not ignore comments that request detailed information from you...
• RalphChapin: Just catching "Exception" is often the quickest way to figure out a problem like this. Refine it once you get it working.

Answer 2

Try this:

 solve.setOnClickListener(new View.OnClickListener() {
 public void onClick(View v) {
 // TODO Auto-generated method stub
 String A = vA.getText().toString();
 iA = Integer.ValueOf(A);
 String B = vB.getText().toString();
 iB = Integer.ValueOf(B);
 String C = vC.getText().toString();
 iC = Integer.ValueOf(C);
 // intialize solution
 solution.setText("Yout total is " + String.ValueOf(iA));
 //This is not the total yet
 }
 });

• Mohamed_AbdAllah: You must tell us what do you receive in LogCat to be able to help you