Android: How to do an if-else statement depending on user input by spinner & radio button

Question

I am trying to write an if-else statement depending on what the user clicks. This is my main.xml:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>

<TextView 
android:text="Food #1:" 
android:textSize="20dp" 
android:textStyle="bold"
android:layout_height="wrap_content" 
android:id="@+id/txt_comparing" 
android:layout_width="wrap_content"
android:layout_centerHorizontal="true">
</TextView>

<Spinner 
android:layout_height="wrap_content" 
android:layout_width="match_parent"
android:layout_below="@+id/txt_comparing"
android:id="@+id/spn_1">
</Spinner>

    <RadioGroup
android:id="@+id/canteen1"
android:orientation="horizontal"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:layout_below="@+id/spn_1" >

<RadioButton
    android:id="@+id/option_0"
    android:text="ITAS  "/>
<RadioButton
    android:id="@+id/option_1"
    android:text="Design "/>
<RadioButton
    android:id="@+id/option_2"
    android:text="Engineering "/>

</RadioGroup>

<TextView 
android:text="Food #2:" 
android:textSize="20dp" 
android:layout_centerHorizontal="true"
android:textStyle="bold"
android:layout_below="@+id/canteen1"
android:layout_height="wrap_content" 
android:id="@+id/txt_and" 
android:layout_width="wrap_content">
</TextView>

<Spinner 
android:layout_height="wrap_content" 
android:layout_width="match_parent" 
android:layout_below="@+id/txt_and"
android:id="@+id/spn_2">
</Spinner>

<RadioGroup
android:id="@+id/canteen2"
android:orientation="horizontal"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:layout_below="@+id/spn_2" >

<RadioButton
    android:id="@+id/option1_0"
    android:text="ITAS  "/>
<RadioButton
    android:id="@+id/option1_1"
    android:text="Design "/>
<RadioButton
    android:id="@+id/option1_2"
    android:text="Engineering "/>

</RadioGroup>

<Button 
android:id="@+id/btn_compare" 
android:text="   Compare   " 
android:textStyle="bold"
android:layout_alignParentBottom="true" 
android:layout_height="wrap_content" 
android:layout_width="wrap_content"
android:layout_alignParentRight="true">>
</Button>

<Button 
android:text="  Clear   " 
android:layout_height="wrap_content" 
android:id="@+id/clear" 
android:layout_toLeftOf="@+id/btn_compare" 
android:layout_alignTop="@+id/btn_compare" 
android:layout_alignBottom="@+id/btn_compare" 
android:layout_width="wrap_content">
</Button>

In my main java class, how do I create an if-else statement depending on what the user clicks? I have tried and researched many times but did not get the answer.

Thank you in advance!

Answer 1

You should assign OnClickListener to each clickable view (Button).
It could be either the same listener or new different instance for each button.

In case of single listener, you can implement button id switcher and got known which button is pressed.
I've spent a little time to prepare illustration:

OnClickListener listener = new OnClickListener() {

    @Override
    public void onClick(View view) {
    switch (view.getId()) {
            case R.id.button1:
                Toast.makeText(getApplicationContext(), "Button 1 pressed", Toast.LENGTH_SHORT).show();
            break;
            case R.id.button2:
                Toast.makeText(getApplicationContext(), "Button 2 pressed", Toast.LENGTH_SHORT).show();
            break;
        }

    }
};

((Button)findViewById(R.id.button1)).setOnClickListener(listener);
((Button)findViewById(R.id.button2)).setOnClickListener(listener);