MainActivity.java

package com.alexstyl.searchtransition.mainscreen;

import android.content.Intent;
import android.os.Bundle;
import android.transition.Transition;
import android.transition.Transition.TransitionListener;
import android.transition.TransitionManager;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.FrameLayout;

import com.alexstyl.searchtransition.boilerplate.BoilerplateActivity;
import com.alexstyl.searchtransition.R;
import com.alexstyl.searchtransition.searchscreen.SearchActivity;
import com.alexstyl.searchtransition.transition.FadeInTransition;
import com.alexstyl.searchtransition.transition.FadeOutTransition;
import com.alexstyl.searchtransition.transition.SimpleTransitionListener;

public class MainActivity extends BoilerplateActivity {

    private SimpleToolbar toolbar;
    private int toolbarMargin;

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

        // setup your Toolbar as you would normally would
        // For simplicity, I am wrapping the styling of it into its a separate class
        toolbar = (SimpleToolbar) findViewById(R.id.main_toolbar);
        setSupportActionBar(toolbar);

        toolbarMargin = getResources().getDimensionPixelSize(R.dimen.toolbarMargin);
        toolbar.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // Prepare the keyboard as soon as the user touches the Toolbar
                // This will make the transition look faster
                showKeyboard();
                transitionToSearch();
            }
        });
    }

    private void transitionToSearch() {
        // create a transition that navigates to search when complete
        Transition transition = FadeOutTransition.withAction(navigateToSearchWhenDone());

        // let the TransitionManager do the heavy work for us!
        // all we have to do is change the attributes of the toolbar and the TransitionManager animates the changes
        // in this case I am removing the bounds of the toolbar (to hide the blue padding on the screen) and
        // I am hiding the contents of the Toolbar (Navigation icon, Title and Option Items)
        TransitionManager.beginDelayedTransition(toolbar, transition);
        FrameLayout.LayoutParams frameLP = (FrameLayout.LayoutParams) toolbar.getLayoutParams();
        frameLP.setMargins(0, 0, 0, 0);
        toolbar.setLayoutParams(frameLP);
        toolbar.hideContent();
    }

    private TransitionListener navigateToSearchWhenDone() {
        return new SimpleTransitionListener() {
            @Override
            public void onTransitionEnd(Transition transition) {
                Intent intent = new Intent(MainActivity.this, SearchActivity.class);
                startActivity(intent);

                // we are handing the enter transitions ourselves
                // this line overrides that
                overridePendingTransition(0, 0);

                // by this point of execution we have animated the 'expansion' of the Toolbar and hidden its contents.
                // We are half way there. Continue to the SearchActivity to finish the animation
            }
        };
    }

    @Override
    protected void onResume() {
        super.onResume();

        // when you are back from the SearchActivity animate the 'shrinking' of the Toolbar and
        // fade its contents back in
        fadeToolbarIn();

        // in case we are not coming here from the SearchActivity the Toolbar would have been already visible
        // so the above method has no effect
    }

    private void fadeToolbarIn() {
        TransitionManager.beginDelayedTransition(toolbar, FadeInTransition.createTransition());
        FrameLayout.LayoutParams layoutParams = (FrameLayout.LayoutParams) toolbar.getLayoutParams();
        layoutParams.setMargins(toolbarMargin, toolbarMargin, toolbarMargin, toolbarMargin);
        toolbar.showContent();
        toolbar.setLayoutParams(layoutParams);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        if (item.getItemId() == R.id.main_action_share) {
            shareDemo();
            return true;
        }
        return super.onOptionsItemSelected(item);
    }

}