navigation manager for fragments

android fragment navigation manager

import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentTransaction;
import android.text.TextUtils;

import your.package.R;

public class NavigationManager {
    private FragmentManager mFragmentManager;

    public NavigationManager(FragmentManager fragmentManager){
        mFragmentManager = fragmentManager;
    }

    /**
     * Displays the next fragment
     *
     * @param fragment
     */
    public void attach(Fragment fragment, boolean isAnimated, String tag) {
        if (mFragmentManager != null && !isAtTheTopOnBackStack(tag)) {
            FragmentTransaction ft = mFragmentManager.beginTransaction();

            if (isAnimated)
                ft.setCustomAnimations(R.anim.abc_fade_in, R.anim.abc_fade_out, R.anim.abc_fade_in, R.anim.abc_fade_out);
            if (!TextUtils.isEmpty(tag))
                ft.addToBackStack(tag);
            ft.replace(R.id.content_frame, fragment);
            ft.commit();
        }
    }

    public void attach(Fragment fragment, int containerId, boolean isAnimated, String tag) {
        if (mFragmentManager != null && !isAtTheTopOnBackStack(tag)) {
            FragmentTransaction ft = mFragmentManager.beginTransaction();

            if (isAnimated)
                ft.setCustomAnimations(R.anim.abc_fade_in, R.anim.abc_fade_out, R.anim.abc_fade_in, R.anim.abc_fade_out);
            if (!TextUtils.isEmpty(tag))
                ft.addToBackStack(tag);
            ft.add(containerId, fragment, tag);
            ft.commit();
        }
    }

    public void attachAsRoot(Fragment fragment, boolean isAnimated, String tag) {
        if (mFragmentManager != null && !isAtTheTopOnBackStack(tag)) {
            for (int i = 0; i < mFragmentManager.getBackStackEntryCount(); i++)
                mFragmentManager.popBackStackImmediate();
            attach(fragment, isAnimated, tag);
        }
    }

    /**
     * @return true if stack has been popped succesfully, false if the stack has one element
     */
    public boolean popBackStackImmediate() {
        if (mFragmentManager == null) return false;
        if (mFragmentManager.getBackStackEntryCount() == 0) {
            return false;
        } else {
            mFragmentManager.popBackStackImmediate();
            return true;
        }
    }

    private boolean isAtTheTopOnBackStack(String tag) {
        if (mFragmentManager.getBackStackEntryCount() == 0) return false;
        return TextUtils.equals(mFragmentManager.getBackStackEntryAt(mFragmentManager.getBackStackEntryCount() - 1).getName(), tag);
    }

    public boolean isBackstackEmpty(){
        return mFragmentManager.getBackStackEntryCount() == 0;
    }

    public int getBackstackEntryCount(){
        return mFragmentManager.getBackStackEntryCount();
    }
}