Android Open Source - FABulous Floating Action Button

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Back to project page FABulous.

License

The source code is released under:

MIT License

Java Source Code

package com.kemallette.fabulous;
//  ww  w  .  j a va 2s  .c  om

import android.R.anim;
import android.annotation.SuppressLint;
import android.content.Context;
import android.graphics.Point;
import android.os.Build;
import android.util.AttributeSet;
import android.view.Display;
import android.view.View;
import android.view.WindowManager;
import android.view.animation.AccelerateDecelerateInterpolator;
import android.view.animation.Interpolator;
import android.widget.AbsListView;
import android.widget.ImageView;

import com.nineoldandroids.animation.ObjectAnimator;
import com.nineoldandroids.view.ViewHelper;

@SuppressLint("NewApi")
public class FloatingActionButton extends ImageView{

  private static final int       ANIMATION_DURATION = 400; // in milliseconds
  
  
  private boolean             isHidden        = false;
  
  private float             displayedYPos  = -1, 
                 hiddenYPos     = -1;
  
  private final Interpolator  mInterpolator  = new AccelerateDecelerateInterpolator();


  public FloatingActionButton(Context context){

    this(context, null);
  }


  public FloatingActionButton(Context context, AttributeSet attributeSet){

    this(context, attributeSet, 0);
  }


  public FloatingActionButton(Context context, AttributeSet attrs, int defStyleAttr){

    super(context, attrs, defStyleAttr);


      final WindowManager windowManager = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);
    final Display display = windowManager.getDefaultDisplay();
    final Point displaySize = new Point();

    // If we have access to 3.2 SDK, use that display API, otherwise, fallback to old getHeight() 
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB_MR2){
      display.getSize(displaySize);
      hiddenYPos = displaySize.y;
    }else {
      hiddenYPos = display.getHeight();
    }
  }


  @Override
  protected void onLayout(boolean changed, int left, int top, int right, int bottom){

    super.onLayout(changed, left, top, right, bottom);

    if (displayedYPos == -1)
      displayedYPos = ViewHelper.getY(this);
  }


  public void toggleHide(boolean hide){

    ObjectAnimator animator;
    
    if (isHidden != hide){

      isHidden = hide;

      // Animate the FABs movement to the new y position
      animator = ObjectAnimator
               .ofFloat(this, "y", isHidden ? hiddenYPos : displayedYPos)
                            .setDuration(ANIMATION_DURATION);
      animator.setInterpolator(mInterpolator);
      animator.start();
    }
  }

  public void respondTo(AbsListView listView){
    if (listView != null )
      listView.setOnScrollListener(new ScrollDirectionListener(this));
  }


  protected class ScrollDirectionListener implements AbsListView.OnScrollListener{

    private static final int       DIRECTION_CHANGED_THRESH  = 2;
    
    private boolean                   isUpdated;
    private int                       lastVisibleChildPos, // Position in View parent
                       lastChildTopPos; // Position of child's top coordiante

    private final FloatingActionButton  mFab;
    

    ScrollDirectionListener(FloatingActionButton floatingActionButton){

      mFab = floatingActionButton;
    }


    public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount){

      final View firstViewChild = view.getChildAt(0);
      int firstChildTopPos = 0;
      boolean isMovingDown;
      boolean hasChangedDirection = true;

      if (firstViewChild != null)
        firstChildTopPos = firstViewChild.getTop();

      if (lastVisibleChildPos == firstVisibleItem){
        int topDelta = lastChildTopPos - firstChildTopPos;
        isMovingDown = firstChildTopPos < lastChildTopPos;
        hasChangedDirection = Math.abs(topDelta) > DIRECTION_CHANGED_THRESH;
      }else{
        isMovingDown = firstVisibleItem > lastVisibleChildPos;
      }
      if (hasChangedDirection && isUpdated){
        mFab.toggleHide(isMovingDown);
      }
      lastVisibleChildPos = firstVisibleItem;
      lastChildTopPos = firstChildTopPos;
      isUpdated = true;
    }


    public void onScrollStateChanged(AbsListView view, int scrollState){
      // Here you can implement your own functionality when the list scrolling
      // changes to/from scrollstates:  IDLE, TOUCH_SCROLL, FLING 
      
    }
  }

}

Java Source Code List

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