Progress bar for counting checkboxes

I need every click on the checkbox to increase the percentage in progressBar.

Example: I have two checkboxes, each corresponding to 50% within the progressBar.

I tried several codes, but none worked, I'm a beginner in java

Can someone help me? Please.

public class MainActivity extends AppCompatActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    final ProgressBar progressBar = (ProgressBar) findViewById(R.id.progressBar);
    final CheckBox checkBox = (CheckBox) findViewById(R.id.checkBox);
    final CheckBox checkBox2 = (CheckBox) findViewById(R.id.checkBox2);


    SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(this);
    final SharedPreferences.Editor editor = preferences.edit();
    if (preferences.contains("checkbox1") && preferences.getBoolean("checkbox1", false) == true) {
        checkBox.setChecked(true);
    } else {
        checkBox.setChecked(false);

    }
    checkBox.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
        @Override
        public void onCheckedChanged(CompoundButton compoundButton, boolean b) {
            if (checkBox.isChecked()) {
                editor.putBoolean("checkbox1", true);
                editor.apply();
            } else {
                editor.putBoolean("checkbox1", false);
                editor.apply();
            }
        }
    });


    if (preferences.contains("checkbox2") && preferences.getBoolean("checkbox2", false) == true) {
        checkBox2.setChecked(true);
    } else {
        checkBox2.setChecked(false);

    }
    checkBox2.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
        @Override
        public void onCheckedChanged(CompoundButton compoundButton, boolean b) {
            if (checkBox2.isChecked()) {
                editor.putBoolean("checkbox2", true);
                editor.apply();
            } else {
                editor.putBoolean("checkbox2", false);
                editor.apply();
            }
        }
    });

}

}