When I press a button and the EditTexts are empty it crashes

Question

I am making a simple calculator as my first made by me app and I have two EditTexts and if I press any of the 4 calculation buttons the app crashes, I have set a toast message to display if EditText1 & EditText2 are empty and if not do calculation according to button pressed...how can I prevent it from crashing? Here's my MainActivity.java :

public class MainActivity extends Activity {
    EditText number1text;
    EditText number2text;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        number1text = (EditText) findViewById(R.id.num1text);
        number2text = (EditText) findViewById(R.id.num2text);
    }

    public void calcadd(View v) { // here
        if (number1text.getText().toString().isEmpty() || number2text.getText().toString().isEmpty()) {
            Toast msg = Toast.makeText(getBaseContext(),
            "You Should Put Numbers To Do Calculation",
            Toast.LENGTH_LONG);
            msg.show();
        }
        else{

        }
        Integer num1text = Integer.parseInt(number1text.getText().toString());
        Integer num2text = Integer.parseInt(number2text.getText().toString());
        Integer ans = num1text + num2text;

        TextView answer = (TextView) findViewById(R.id.ans);
        answer.setText("Answer:" + ans.toString());
    }

    public void calcminus(View v) { // here 
        if (number1text.getText().toString().isEmpty() || number2text.getText().toString().isEmpty()) {
            Toast msg = Toast.makeText(getBaseContext(),
            "You Should Put Numbers To Do Calculation",
            Toast.LENGTH_LONG);
            msg.show();
        }
        else{

        }
        Integer num1text = Integer.parseInt(number1text.getText().toString());
        Integer num2text = Integer.parseInt(number2text.getText().toString());
        Integer ans = num1text - num2text;

        TextView answer = (TextView) findViewById(R.id.ans);
        answer.setText("Answer:" + ans.toString());
    }

    public void calcdivide(View v) { // here
        if (number1text.getText().toString().isEmpty() || number2text.getText().toString().isEmpty()) {
            Toast msg = Toast.makeText(getBaseContext(),
            "You Should Put Numbers To Do Calculation",
            Toast.LENGTH_LONG);
            msg.show();
        }
        else{

        }
        Integer num1text = Integer.parseInt(number1text.getText().toString());
        Integer num2text = Integer.parseInt(number2text.getText().toString());
        Integer ans = num1text / num2text;

        TextView answer = (TextView) findViewById(R.id.ans);
        answer.setText("Answer:" + ans.toString());
    }

    public void calcmultiply(View v) { // here
        if (number1text.getText().toString().isEmpty() || number2text.getText().toString().isEmpty()) {
            Toast msg = Toast.makeText(getBaseContext(),
            "You Should Put Numbers To Do Calculation",
            Toast.LENGTH_LONG);
            msg.show();
        }
        else{

        }
        Integer num1text = Integer.parseInt(number1text.getText().toString());
        Integer num2text = Integer.parseInt(number2text.getText().toString());
        Integer ans = num1text * num2text;

        TextView answer = (TextView) findViewById(R.id.ans);
        answer.setText("Answer:" + ans.toString());
     }  




    @Override
    public boolean onCreateOptionsMenu(Menu menu) { // here
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }
}

and this is my activity_main.xml:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" >

    <TextView
        android:id="@+id/num1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:text="@string/num1"
        android:textAppearance="?android:attr/textAppearanceMedium" 
        />

    <EditText
        android:id="@+id/num1text"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/num1"
        android:layout_below="@+id/num1"
        android:ems="10"
        android:inputType="number" 
        >

        <requestFocus />
    </EditText>

    <TextView
        android:id="@+id/num2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/num1text"
        android:layout_below="@+id/num1text"
        android:text="@string/num2"
        android:textAppearance="?android:attr/textAppearanceMedium" 
        />

    <EditText
        android:id="@+id/num2text"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/num2"
        android:layout_below="@+id/num2"
        android:ems="10"
        android:inputType="number" 
        />

    <TextView
        android:id="@+id/ans"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/num2text"
        android:layout_below="@+id/num2text"
        android:layout_marginTop="52dp"
        android:text="@string/anstxt"
        android:textAppearance="?android:attr/textAppearanceMedium" 
        />

    <Button
        android:id="@+id/button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/num2text"
        android:layout_below="@+id/num2text"
        android:text="@string/btnadd" 
        android:onClick="calcadd"/>

    <Button
        android:id="@+id/Button01"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignBaseline="@+id/button1"
        android:layout_alignBottom="@+id/button1"
        android:layout_toRightOf="@+id/button1"
        android:text="@string/btnminus" 
        android:onClick="calcminus"/>

    <Button
        android:id="@+id/button2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignBaseline="@+id/Button01"
        android:layout_alignBottom="@+id/Button01"
        android:layout_toRightOf="@+id/Button01"
        android:text="@string/btnmultiply" 
        android:onClick="calcmultiply"/>

    <Button
        android:id="@+id/Button02"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignBaseline="@+id/button2"
        android:layout_alignBottom="@+id/button2"
        android:layout_toRightOf="@+id/button2"
        android:text="@string/btndivide" 
        android:onClick="calcdivide"/>

</RelativeLayout>

Answer 1

else{

    }
    Integer num1text = Integer.parseInt(number1text.getText().toString());
    Integer num2text = Integer.parseInt(number2text.getText().toString());
    Integer ans = num1text + num2text;

    TextView answer = (TextView) findViewById(R.id.ans);
    answer.setText("Answer:" + ans.toString());

You do your work outside of the else{} statement, you are checking if they are empty which is good, but then if they are empty " ", you still try to do the calculations by doing them outside of the else brackets. You should change to what I have shown below...

else{
       Integer num1text = Integer.parseInt(number1text.getText().toString());
       Integer num2text = Integer.parseInt(number2text.getText().toString());
       Integer ans = num1text + num2text;

       TextView answer = (TextView) findViewById(R.id.ans);
       answer.setText("Answer:" + ans.toString());

      }

Answer 2

Even if this is not your current problem

1. Also make sure that you check that you are not dividing by 0 in your division function:
   Integer ans = num1text / num2text;
2. you can simplify your code creating a function that does the things that are currently repeated in every function (DRY; don't repeat yourself)

@1: eg by adding another if/else in your division function:

    public void calcdivide(View v) { // here
        if (number1text.getText().toString().isEmpty() || number2text.getText().toString().isEmpty()) {
            Toast msg = Toast.makeText(getBaseContext(),
            "You Should Put Numbers To Do Calculation",
            Toast.LENGTH_LONG);
            msg.show();
        }
        else{
            Integer num1text = Integer.parseInt(number1text.getText().toString());
            Integer num2text = Integer.parseInt(number2text.getText().toString());
            if (num2text>0)
            {
             //only do the division if divisor > 0
             Integer ans = num1text / num2text;
             TextView answer = (TextView) findViewById(R.id.ans);
             answer.setText("Answer:" + ans.toString());
            }
            else
            {
             //e.g. show a toastmessage here
            }
        }
    }

Answer 3

In all four of your if structures where you test for the EditTexts being empty, change this:

else{

}
Integer num1text = Integer.parseInt(number1text.getText().toString());
Integer num2text = Integer.parseInt(number2text.getText().toString());
Integer ans = num1text + num2text; // +, -, * or / depending

TextView answer = (TextView) findViewById(R.id.ans);
answer.setText("Answer:" + ans.toString());

to this (the code needs to be in the else block):

else{
    Integer num1text = Integer.parseInt(number1text.getText().toString());
    Integer num2text = Integer.parseInt(number2text.getText().toString());
    Integer ans = num1text + num2text;

    TextView answer = (TextView) findViewById(R.id.ans);
    answer.setText("Answer:" + ans.toString());
}

also, in each of your Toasts, change getBaseContext() to getApplicationContext() .