Android: Collapsing Linearlayout instead of Collapsing Toolbar

Question

I\'m trying to create a Master/Detail transaction in a single fragment. I thought of using LinearLayout as the container of my edittext for my header. Then a RecyclerView fo

Answer 1

You can use a timer and gradually shrink the height/margin of the topbar's LinearLayout (Edit: flaws in Anton Maiorov's answer is fixed here)

See below snippet (tested on devices)

Approach I: Anton Maiorov's answer, flaws fixed, this is much simpler than the 2nd implementation below

public class MainActivity extends AppCompatActivity {

    LinearLayout toolbar;
    int mOriginalHeight;
    boolean initialSizeObtained = false;    
    boolean isShrink = false;

    Animation _hideAnimation = new Animation() {
        @Override
        protected void applyTransformation(float interpolatedTime, Transformation t) {
            LinearLayout.LayoutParams params = (LinearLayout.LayoutParams) toolbar.getLayoutParams();
            params.topMargin = -(int) (mOriginalHeight * interpolatedTime);
            toolbar.setLayoutParams(params);
        }
    };

    Animation _showAnimation = new Animation() {
        @Override
        protected void applyTransformation(float interpolatedTime, Transformation t) {
            LinearLayout.LayoutParams params = (LinearLayout.LayoutParams) toolbar.getLayoutParams();
            params.topMargin = (int) (mOriginalHeight * (interpolatedTime - 1));
            toolbar.setLayoutParams(params);
        }
    };

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

        toolbar = (LinearLayout) findViewById(R.id.toolbar);
        //Get the original height, which is measured according to WRAP_CONTENT
        toolbar.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
            @Override
            public void onGlobalLayout() {
                if (initialSizeObtained)
                    return;
                initialSizeObtained = true;
                mOriginalHeight = toolbar.getMeasuredHeight();
            }
        });
        _hideAnimation.setDuration(2000);
        _showAnimation.setDuration(2000);
    }

    //Click on the Olimpic image --> Toggles the top toolbar
    public void ToggleTopBar(View view) {
        isShrink = !isShrink;

        toolbar.clearAnimation();  //Important            
        toolbar.startAnimation(isShrink? _hideAnimation : _showAnimation);
    }
}

Approach II: my original answer by changing the toolbar's height, and also using timer manually, which is more involved:

public class MainActivity extends AppCompatActivity {

    LinearLayout toolbar;
    int mOriginalHeight;
    boolean initialSizeObtained = false;
    int currentHeight;
    boolean isShrink = false;
    Timer timer;

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

        toolbar = (LinearLayout) findViewById(R.id.toolbar);
        toolbar.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
            @Override
            public void onGlobalLayout() {
                if (initialSizeObtained)
                    return;
                initialSizeObtained = true;
                mOriginalHeight = toolbar.getMeasuredHeight();
                currentHeight = mOriginalHeight;
                Log.d("Demo", "Original height is " + mOriginalHeight);
            }
        });
    }

    //Click on the Olimpic image --> Toggles the top toolbar
    public void ToggleTopBar(View view) {
        isShrink = !isShrink;
        Resize(isShrink, toolbar, 250);
    }


    void Resize(final boolean isShrink, final LinearLayout layout, final int minHeight) {
        final int H0 = mOriginalHeight;
        timer = runTimerAction(10, new Runnable() {
                    public void run() {
                        Log.d("demo", "Current Height= " + currentHeight);
                        if (isShrink && currentHeight > minHeight) {
                            currentHeight -= 10;
                            layout.getLayoutParams().height = currentHeight;
                            refreshToolbar();
                        } else if (!isShrink && currentHeight < H0) {
                            currentHeight += 10;
                            layout.getLayoutParams().height = currentHeight;
                            refreshToolbar();
                        } else {
                            layout.getLayoutParams().height = isShrink ? minHeight : H0;
                            refreshToolbar();
                            if (timer != null)
                                timer.cancel();
                        }
                    }
                }
        );
    }

    public void refreshToolbar() {
        runOnUiThread(new Runnable() {
            @Override
            public void run() {
                toolbar.requestLayout();
            }
        });
    }