Question

I have a very simple question about menu control in Android. I’m writing a program that performs some simple numeric calculations and outputs an answer. My question is how do make the program move to second screen when a button is pressed, and how can I let the user move back to the original screen.
Here’s a quick example

Screen 1

"Add Numbers"

Input 1st # ____       
Input 2nd # ____      
(Add) 

Screen 2

The answer is "____"

The user inputs two integers. presses add, and then the program moves to the second screen which displays the answer. If they user wants they can return to the first screen and start over.

I know this has been covered but with so many resources I don’t know what to look for. Answers or links to resources would be most helpful. Thank you!

Answer 1

You can use the following layout for the screen to input numbers. Name the file first.xml.

  <TextView
        android:id="@+id/firstnumber"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Input Ist:"
        android:textSize="20px"
        android:textStyle="bold"
        />

 <EditText 
         android:id="@+id/first"
         android:layout_height="wrap_content"
         android:layout_width="250px"

   /> 

    <TextView 
         android:id="@+id/secondnumber"
         android:text = "Input 2nd"  
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:textSize="20px"
         android:textStyle="bold"
         />     

    <EditText 
              android:id="@+id/second"
                  android:layout_height="wrap_content"
                  android:layout_width="250px"

      /> 

     <Button 
          android:id="@+id/add_button"
              android:text="Add"
              android:layout_width="wrap_content"
              android:layout_height="wrap_content"
              android:textSize="15px"
              android:layout_centerHorizontal="true"

              /> 

</LinearLayout>

To add these numbers

public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.first);
         Button add = (Button) findViewById(R.id.add);
        add.setOnClickListener(this);
        EditText num1 = (EditText)findViewById(R.id.first);
        EditText num2 = (EditText)findViewById(R.id.second);
}

The click listener code

public void onClick(View v) {

                int n1 = Integer.parseInt(num1.getText().toString());
                int n2 = Integer.parseInt(num2.getText().toString());
                int result = n1 + n2;
                String res = Integer.toString(result);
                                Intent intent = new Intent(getApplicationContext(), Result.class);
                                intent.putExtra("result", result); //Passing the result to the second activity using intent
                startActivity(intent);
                }

In the Result.java class.

public class Result extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState){
        super.onCreate(savedInstanceState);
        setContentView(R.layout.result);
            Intent intent = getIntent();
                String result = intent.getStringExtra("result");
                TextView t1 = (TextView)findViewById(R.id.result);
                t1.setText(result);
    }
}

Hope this helps..