Radio buttons case/switch command

Question

I apologise if an answer to this has already been posted, but I have looked for ages and can't find anything suitable.

I have four radio buttons and want to process a different calculation depending on which one has been selected from input data (from edit text). I also have a button to press to start the calculation.

The whole process works apart from the radio buttons. I know I need to use a switch/case command, but i am not sure ow to set it up.

I have tried the following in the main activity java class:

package com.minichanic.idealgas;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.RadioButton;
import android.widget.RadioGroup;


public class MainActivity extends Activity implements android.view.View.OnClickListener{
    Button add, subtract, multiply, divide, mod;
    EditText pressin, volin, molin, tempin;
    RadioButton radio0, radio1, radio2, radio3;
    RadioGroup RadioGroup1;
    private int variable;

    /** Called when the activity is first created  */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        RadioGroup1 = (RadioGroup) findViewById(R.id.radioGroup1);

        // Reference TextViews and Buttons 

        pressin = (EditText) findViewById(R.id.editText1);
        volin = (EditText) findViewById(R.id.editText2);
        molin = (EditText) findViewById(R.id.editText3);
        tempin = (EditText) findViewById(R.id.editText4);
        add = (Button) findViewById(R.id.button1);


        // Set listeners for when buttons are pressed 
        add.setOnClickListener(this);


    }

    /**
     * Switch statement to decide which button was pressed droidacid.com
     */
    public void onClick(View arg0) {
        // Get values from EditTexts
        double pressure = Double.parseDouble(pressin.getText().toString());
        double volume = Double.parseDouble(volin.getText().toString());
        double moles = Double.parseDouble(molin.getText().toString());
        double temperature = Double.parseDouble(tempin.getText().toString());


          // Perform relevant operations depending on radio button
          // Check which radio button was clicked


        switch(variable){
                 case R.id.radio0:
                pressure = ((moles * 8.31* temperature)/volume);
                break;
                 case R.id.radio1:
                        volume = ((moles * 8.31* temperature)/pressure);
                        break;
                 case R.id.radio2:
                    moles = ((pressure * volume) /  (temperature * 8.31));
                        break;
                 case R.id.radio3:
                    temperature = ((pressure * volume) /  (moles * 8.31));
                        break;



            }

        // Add result to Running total stored in output TextView 
        String tempresult = ""+temperature;
        TextView tresult = (EditText) findViewById(R.id.editText4);
        tresult.setText(tempresult);
        String pressresult = ""+pressure;
        TextView presult = (EditText) findViewById(R.id.editText1);
        presult.setText(pressresult);
        String molresult = ""+moles;
        TextView mresult = (EditText) findViewById(R.id.editText3);
        mresult.setText(molresult);
        String volresult = ""+volume;
        TextView vresult = (EditText) findViewById(R.id.editText2);
        vresult.setText(volresult);


    }

}

The xml layout contains:

    <RadioButton
        android:id="@+id/radio0"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:checked="true"
        android:text="@string/pressure" />

    <RadioButton
        android:id="@+id/radio1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/vol" />

    <RadioButton
        android:id="@+id/radio2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/mol" />

    <RadioButton
        android:id="@+id/radio3"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/temp" />
</RadioGroup>

It was working fine, until I started introduced the radio buttons and now it crashes. Many thanks for any ideas.

Answer 1

I'm posting this as another answer because it is too long for comment.

Set android:onClick="onRadioButtonClicked" to every radio button

<RadioButton
        android:id="@+id/radio0"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:checked="true"
        android:text="@string/pressure"

        android:onClick="onRadioButtonClicked"

 />
...

Create local variable where you store currently selected radio button and set it to default radio button

...
View selectedRadio;
...
public void onCreate(Bundle savedInstanceState) {
    ...
    selectedRadio = findViewById(R.id.radio0);
    ...
}
...

create method onRadioButtonClicked which will be called after clicking specified radio button and setting our variable selectedRadio to currently selected radio button

public void onRadioButtonClicked(View view) {
    selectedRadio = view;
}

then adjust your onClick method to perform calculations

public void onClick(View arg0) {
    ...
    switch(selectedRadio.getId()) {
        case R.id.radio0:
            // your code
            break;
        case R.id.radio1:
            // another code
            break;
        ...
    }
    ...
}

Hope this helps you. Did not tested this code but should work.

Answer 2

All radio button should be within radiogroup. Please see this example.

http://www.mkyong.com/android/android-radio-buttons-example/

Usage of switch is fine.