How to remove Specific activity/activities from activity stack based on some action?

Issue

I am working on an application where i need to navigate to specific activity based on some actions. Here is a image

Here my first activity is the ReadingActivity. Based on some actions user will be taken to the NewProjectReadingActivity. There the user will have Two options.

Option One
Option Two

Based on the options chosen by the user he/she will be taken to the ReadingInputActivity. After taking the input from the ReadingInputActivity the user will be forwarded to the ReadingConfirmationActivity. There will be three options

Option One
Option Two
Option Three

If the user selects the Option One then he/she will be taken to the ReadingActivity which is very easy. I will clear the stack and start the ReadingActivity again and there if he/she presses the back button the app will be minimized which is totally fine. But if the user selects Option Two then he/she will be taken to the NewProjectReadingActivity.If i clear the activity stack and start NewProjectReadingActivity again then it will start the NewProjectReadingActivity but the problem is that if the user presses the back button it will minimize my app as it is the only Activity present in the activity stack.

What i want is that if the user selects Option Two on the ReadingConfirmationActivity then the user will be taken to the NewReadingActivity that means i want to remove ReadingConfirmationActivity (which is easy just call the finish()) and the activity started before that activity i,e ReadingInputActivity.

Every Activity mentioned above is hosting a fragment. I am providing the activity code below.

ReadingActivity

public class ReadingActivity extends BaseAppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        if( savedInstanceState == null ) {
            getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container, ReadingFragment.getInstance(), ReadingFragment.TAG).commit();
        }
        setDisplayHomeAsUpEnabled(true);
        setActionBarText(getString(R.string.new_project_reading));
    }

    @Override
    protected void setupContentView() {
        setContentView(R.layout.activity_reading);
    }

    public static Intent newIntent(Context context) {
        Intent intent = new Intent(context, ReadingActivity.class);
        return  intent;
    }
}

NewProjectReadingActivity

public class NewProjectReadingActivity extends BaseAppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        if( savedInstanceState == null ) {
            getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container, NewProjectReadingFragment.getInstance(), NewProjectReadingFragment.TAG).commit();
        }
        setDisplayHomeAsUpEnabled(true);
        setActionBarText(getString(R.string.new_project_reading));
    }

    @Override
    protected void setupContentView() {
        setContentView(R.layout.activity_new_project_reading);
    }

    public static Intent newIntent(Context context) {
        Intent intent = new Intent(context, NewProjectReadingActivity.class);
        return  intent;
    }
}

ReadingInputActivity

public class ReadingInputActivity extends BaseAppCompatActivity {

    private static final String EXTRA_VALUE_TYPE = "value_type";
    private int valueType = 0;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        valueType = getIntent().getIntExtra(EXTRA_VALUE_TYPE, 0);
        if( savedInstanceState == null ) {
            getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container, ReadingInputFragment.getInstance(valueType), ReadingInputFragment.TAG).commit();
        }
        setDisplayHomeAsUpEnabled(true);
        setActionBarText(getString(R.string.reading_input));
    }

    @Override
    protected void setupContentView() {
        setContentView(R.layout.activity_reading_input);
    }

    public static Intent newIntent(Context context, int valueType) {
        Intent intent = new Intent(context, ReadingInputActivity.class);
        intent.putExtra(EXTRA_VALUE_TYPE, valueType);
        return  intent;
    }
}

ReadingConfirmationActivity

public class ReadingConfirmationActivity   extends BaseAppCompatActivity {

    private static final String EXTRA_VALUE_TYPE = "value_type";
    private static final String EXTRA_READING_VALUE = "reading_value";
    private int valueType = 0;
    private double readingValue = 0;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        valueType = getIntent().getIntExtra(EXTRA_VALUE_TYPE, 0);
        readingValue = getIntent().getDoubleExtra(EXTRA_READING_VALUE, 0);
        if( savedInstanceState == null ) {
            getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container, ReadingConfirmationFragment.getInstance(valueType, readingValue), ReadingConfirmationFragment.TAG).commit();
        }
        setDisplayHomeAsUpEnabled(true);
        setActionBarText(getString(R.string.reading_input));
    }

    @Override
    protected void setupContentView() {
        setContentView(R.layout.activity_reading_confirmation);
    }

    public static Intent newIntent(Context context, int valueType, double readingValue) {
        Intent intent = new Intent(context, ReadingConfirmationActivity.class);
        intent.putExtra(EXTRA_VALUE_TYPE, valueType);
        intent.putExtra(EXTRA_READING_VALUE, readingValue);
        return  intent;
    }
}

Solution

You wrote:

What i want is that if the user selects Option Two on the ReadingConfirmationActivity then the user will be taken to the NewReadingActivity that means i want to remove ReadingConfirmationActivity (which is easy just call the finish()) and the activity started before that activity i,e ReadingInputActivity.

To do this you will do the following when the user selects Option Two in ReadingConfirmationActivity:

Intent intent = new Intent(this, NewReadingActivity.class);
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(intent);

This will cause all of the activities on top (and including) NewReadingActivity to be finished. A new instance of NewReadingActivity will be created and shown to the user. If you wish to return to the existing instance of NewReadingActivity, you can also do that by also adding Intent.FLAG_ACTIVITY_SINGLE_TOP to the Intent.

Answered By - David Wasser