Validate a minimum of Checkbox on android

I have an activity with a checkbox list and they ask me to validate that you have at least 4 selected check in order to enter a detail. Is there any way to do it? I have researched a lot but I can not find a solution that serves me correctly

    <CheckBox
        android:id="@+id/ing_2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@id/ing_1"
        android:layout_marginLeft="70dp"
        android:text="Piña" />

    <CheckBox
        android:id="@+id/ing_3"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@id/ing_2"
        android:layout_marginLeft="70dp"
        android:text="Cilantro" />

    <CheckBox
        android:id="@+id/ing_4"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@id/ing_3"
        android:layout_marginLeft="70dp"
        android:text="Extra Oregano" />

    <CheckBox
        android:id="@+id/ing_5"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@id/txtIngredientes"
        android:layout_marginLeft="150dp"
        android:layout_toRightOf="@id/ing_1"
        android:text="Queso" />

    <CheckBox
        android:id="@+id/ing_6"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@id/ing_5"
        android:layout_marginLeft="150dp"
        android:layout_toRightOf="@id/ing_1"
        android:text="Carne" />

    <CheckBox
        android:id="@+id/ing_7"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@id/ing_6"
        android:layout_marginLeft="150dp"
        android:layout_toRightOf="@id/ing_1"
        android:text="Mozzarella" />

    <CheckBox
        android:id="@+id/ing_8"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@id/ing_7"
        android:layout_marginLeft="150dp"
        android:layout_toRightOf="@id/ing_1"
        android:text="Albaca" />

public void CrearPizzitax(View view) {
        int maza = 2500, total, i1 = 0,
                i2 = 0, i3 = 0, i4 = 0,
                i5 = 0, i6 = 0, i7 = 0,
                i8 = 0;

        if (ing1.isChecked()) {
            i1 = 700;
        }
        if (ing2.isChecked()) {
            i2 = 400;
        }
        if (ing3.isChecked()) {
            i3 = 1500;
        }
        if (ing4.isChecked()) {
            i4 = 600;
        }
        if (ing5.isChecked()) {
            i5 = 1000;
        }
        if (ing6.isChecked()) {
            i6 = 2000;
        }
        if (ing7.isChecked()) {
            i7 = 300;
        }
        if (ing8.isChecked()) {
            i8 = 100;
        }
        total = (maza + i1 + i2 + i3 + i4 + i5 + i6 + i7 + i8);
        String detalle = "Detalle:" + "\n";
        detalle += "Maza $:" + maza + "\n";
        detalle += ing1.getText() + " $:" + i1 + "\n";
        detalle += ing2.getText() + " $:" + i2 + "\n";
        detalle += ing3.getText() + " $:" + i3 + "\n";
        detalle += ing4.getText() + " $:" + i4 + "\n";
        detalle += ing5.getText() + " $:" + i5 + "\n";
        detalle += ing6.getText() + " $:" + i6 + "\n";
        detalle += ing7.getText() + " $:" + i7 + "\n";
        detalle += ing8.getText() + " $:" + i8 + "\n";
        detalle += "Total $:" + total + "\n";

        txtSalida.setText(detalle);
        InputMethodManager imn = (InputMethodManager) getSystemService(Context.INPUT_METHOD_SERVICE);
        imn.hideSoftInputFromWindow(txtSalida.getWindowToken(), 0);


    }