Function and usage of numberpick

Numberpick The function and usage of
Value selector , It is used for users to enter values , You can enter values through the keyboard , You can also drag to select values
public class MainActivity extends Activity {
NumberPicker np1, np2;
// Define the minimum value , Initial value of maximum value
int minfraction = 140, maxfraction = 150;

@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.numberpicket);
    np1 = findViewById(R.id.numberpicket);

    np1.setMaxValue(150);
    np1.setMinValue(140);
    // Set up np1 The current value of the 
    np1.setValue(minfraction);
    // Add listener 
    np1.setOnValueChangedListener(new NumberPicker.OnValueChangeListener() {
        // When numberPICKET When things change , Will stimulate the method 

        @Override
        public void onValueChange(NumberPicker picker, int oldVal, int newVal) {
            minfraction = newVal;
            showSelectedPrice();
        }
    });
    np2 = findViewById(R.id.numberpicket01);

    np2.setMinValue(145);
    np2.setMaxValue(150);
    // set currency 
    np2.setValue(maxfraction);
    // Add listener 
    np2.setOnValueChangedListener(new NumberPicker.OnValueChangeListener() {
        @Override
        public void onValueChange(NumberPicker picker, int oldVal, int newVal) {
            minfraction = newVal;
            showSelectedPrice();
        }
    });
}

private void showSelectedPrice() {
    Toast.makeText(this, " Your lowest score in a single subject is " + minfraction + " Your highest score in a single subject is " + maxfraction, Toast.LENGTH_LONG).show();
}

}

<?xml version="1.0" encoding="utf-8"?>

<TableRow
    android:layout_width="match_parent"
    android:layout_height="wrap_content">

    <TextView
        android:layout_width="120dp"
        android:layout_height="wrap_content"
        android:text=" Minimum score of single subject " />

    <NumberPicker
        android:id="@+id/numberpicket"
        android:layout_width="match_parent"
        android:layout_height="150dp"
        android:focusable="true"
        android:focusableInTouchMode="true" />
</TableRow>

<TableRow
    android:layout_width="match_parent"
    android:layout_height="wrap_content">

    <TextView
        android:layout_width="120dp"
        android:layout_height="wrap_content"
        android:text=" The maximum score of a single subject "></TextView>

    <NumberPicker
        android:id="@+id/numberpicket01"
        android:layout_width="match_parent"
        android:layout_height="150dp"
        android:focusable="true"
        android:focusableInTouchMode="true" />
</TableRow>