[SNIPPET][View] Floating Action Button [FAB]

Vi lascio qui sotto il gist relativo al Floating Action Button che ho implementato in una mia app e basato sulla classe creata da un ragazzo su Google+
per chi non lo sapesse FAB è il nuovo pulsante rotondo introdotto con il Material Design. Questo non è un backport ma una View creata per simularlo.
Ho aggiunto tutte le features mancanti quali la profondità del bottone, la dimensione dell'ombra e gli attributi XML mancanti nella classe originale :)

Happy coding :)

	<?xml version="1.0" encoding="utf-8"?>
	<resources>
	<declare-styleable name="Fab">
	<attr name="fabDrawable" format="reference"/>
	<attr name="fabColor" format="color"/>
	<attr name="fabDepth" format="integer"/>
	<attr name="fabShadowRadius" format="float"/>
	</declare-styleable>
	</resources>

view raw attrs.xml hosted with ❤ by GitHub

	import android.animation.ObjectAnimator;
	import android.content.Context;
	import android.content.res.TypedArray;
	import android.graphics.Bitmap;
	import android.graphics.Canvas;
	import android.graphics.Color;
	import android.graphics.Paint;
	import android.graphics.Point;
	import android.graphics.drawable.BitmapDrawable;
	import android.graphics.drawable.Drawable;
	import android.util.AttributeSet;
	import android.util.DisplayMetrics;
	import android.view.Display;
	import android.view.MotionEvent;
	import android.view.View;
	import android.view.WindowManager;
	import android.view.animation.AccelerateInterpolator;
	import android.view.animation.DecelerateInterpolator;
	public class Fab extends View {
	Context _context;
	Paint mButtonPaint, mDrawablePaint;
	Bitmap mBitmap;
	int mScreenHeight;
	int mScreenWidth;
	float currentY;
	float currentX;
	float shadowRadius = 10.0f;
	int distance = 2;
	float pressedAlpha = 0.6f;
	boolean mHidden = false;
	int fabColor = Color.WHITE;
	float DEPTH_1 = 1.0f;
	float DEPTH_2 = 3.0f;
	float DEPTH_3 = 10.0f;
	float DEPTH_4 = 14.0f;
	float DEPTH_5 = 19.0f;
	private float mDepth = 3.0f;
	Drawable myDrawable;
	public static final int MODE_FROM_BOTTOM = 0;
	public static final int MODE_FROM_TOP = 1;
	public static final int MODE_FROM_LEFT = 2;
	public static final int MODE_FROM_RIGHT = 3;
	private int mMode = 0;
	public Fab(Context context, AttributeSet attributeSet)
	{
	super(context, attributeSet);
	_context = context;
	parseAttrs(attributeSet,0);
	init(fabColor);
	}
	public Fab(Context context, AttributeSet attributeSet, int defStyle)
	{
	super(context, attributeSet, defStyle);
	_context = context;
	parseAttrs(attributeSet, defStyle);
	init(fabColor);
	}
	public Fab(Context context)
	{
	super(context);
	_context = context;
	init(fabColor);
	}
	private void parseAttrs(AttributeSet attrs, int defStyle) {
	TypedArray a = _context.obtainStyledAttributes(attrs, R.styleable.Fab, defStyle, 0);
	myDrawable = a.getDrawable(R.styleable.Fab_fabDrawable);
	mBitmap = ((BitmapDrawable) myDrawable).getBitmap();
	fabColor = a.getColor(R.styleable.Fab_fabColor, Color.WHITE);
	distance = a.getInt(R.styleable.Fab_fabDepth, distance);
	shadowRadius = a.getFloat(R.styleable.Fab_fabShadowRadius, 10.0f);
	switch(distance) {
	case 0:
	mDepth = DEPTH_1;
	break;
	case 1:
	mDepth = DEPTH_2;
	break;
	case 2:
	mDepth = DEPTH_3;
	break;
	case 3:
	mDepth = DEPTH_4;
	break;
	case 4:
	mDepth = DEPTH_5;
	break;
	default:
	mDepth = DEPTH_2;
	}
	a.recycle();
	}
	public void setFabColor(int color)
	{
	this.fabColor = color;
	invalidate();
	}
	public void setFabDrawable(Drawable fabDrawable)
	{
	myDrawable = fabDrawable;
	mBitmap = ((BitmapDrawable) myDrawable).getBitmap();
	invalidate();
	}
	public void setFabShadowRadius(float radius) {
	this.shadowRadius = radius;
	invalidate();
	}
	public void setFabDepth(int depth) {
	this.distance = depth;
	invalidate();
	}
	public void setPressedAlpha(float alpha) {
	this.pressedAlpha = alpha;
	invalidate();
	}
	public void setAnimationMode(int mode) {
	this.mMode = mode;
	}
	public void init(int fabColor)
	{
	setWillNotDraw(false);
	this.setLayerType(View.LAYER_TYPE_SOFTWARE, null);
	mButtonPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
	mButtonPaint.setColor(fabColor);
	mButtonPaint.setStyle(Paint.Style.FILL);
	mButtonPaint.setShadowLayer(shadowRadius, 0.0f, mDepth, Color.argb(100, 0, 0, 0));
	mDrawablePaint = new Paint(Paint.ANTI_ALIAS_FLAG);
	invalidate();
	WindowManager mWindowManager = (WindowManager) _context.getSystemService(Context.WINDOW_SERVICE);
	Display display = mWindowManager.getDefaultDisplay();
	Point size = new Point();
	display.getSize(size);
	mScreenHeight = size.y;
	mScreenWidth = size.x;
	}
	@Override
	protected void onDraw(Canvas canvas)
	{
	setClickable(true);
	canvas.drawCircle(getWidth()/2, getHeight()/2,(float) (getWidth()/2.6), mButtonPaint);
	canvas.drawBitmap(mBitmap, (getWidth() - mBitmap.getWidth()) / 2, (getHeight() - mBitmap.getHeight()) / 2, mDrawablePaint);
	}
	@Override
	public boolean onTouchEvent(MotionEvent event)
	{
	if(event.getAction() == MotionEvent.ACTION_UP)
	{
	setAlpha(1.0f);
	}
	else if(event.getAction() == MotionEvent.ACTION_DOWN)
	{
	setAlpha(pressedAlpha);
	}
	return super.onTouchEvent(event);
	}
	public int dpToPx(int dp)
	{
	DisplayMetrics displayMetrics = getContext().getResources().getDisplayMetrics();
	int px = Math.round(dp * (displayMetrics.xdpi / DisplayMetrics.DENSITY_DEFAULT));
	return px;
	}
	public boolean isHidden() {
	return this.mHidden;
	}
	public void hideFab() {
	if(mHidden == false) {
	currentY = getY();
	currentX = getX();
	ObjectAnimator mHideAnimation = null;
	switch(mMode) {
	case MODE_FROM_BOTTOM:
	mHideAnimation = ObjectAnimator.ofFloat(this, "Y", mScreenHeight);
	break;
	case MODE_FROM_TOP:
	mHideAnimation = ObjectAnimator.ofFloat(this, "Y", -mScreenHeight);
	break;
	case MODE_FROM_LEFT:
	mHideAnimation = ObjectAnimator.ofFloat(this, "X", -mScreenWidth);
	break;
	case MODE_FROM_RIGHT:
	mHideAnimation = ObjectAnimator.ofFloat(this, "X", mScreenWidth);
	break;
	default:
	mHideAnimation = ObjectAnimator.ofFloat(this, "Y", mScreenHeight);
	break;
	}
	mHideAnimation.setInterpolator(new AccelerateInterpolator());
	mHideAnimation.start();
	mHidden = true;
	}
	}
	public void showFab()
	{
	if(mHidden == true)
	{
	ObjectAnimator mShowAnimation = null;
	switch(mMode) {
	case MODE_FROM_BOTTOM:
	mShowAnimation = ObjectAnimator.ofFloat(this, "Y", currentY);
	break;
	case MODE_FROM_TOP:
	mShowAnimation = ObjectAnimator.ofFloat(this, "Y", -currentY);
	break;
	case MODE_FROM_LEFT:
	mShowAnimation = ObjectAnimator.ofFloat(this, "X", currentX);
	break;
	case MODE_FROM_RIGHT:
	mShowAnimation = ObjectAnimator.ofFloat(this, "X", currentX);
	break;
	default:
	mShowAnimation = ObjectAnimator.ofFloat(this, "Y", currentY);
	break;
	}
	mShowAnimation.setInterpolator(new DecelerateInterpolator());
	mShowAnimation.start();
	mHidden = false;
	}
	}
	}

view raw Fab.java hosted with ❤ by GitHub

	<com.your.package.Fab
	android:id="@+id/fabbutton"
	android:layout_width="72dp"
	android:layout_height="72dp"
	android:layout_margin="16dp"
	app:fabColor="@android:color/white"
	app:fabDepth="1"
	app:fabDrawable="@drawable/ic_content_new"
	app:fabShadowRadius="12" />

view raw layout_sample.xml hosted with ❤ by GitHub

	//***Your code***
	mFab = (Fab) rootView.findViewById(R.id.fabbutton);
	mFab.setAnimationMode(Fab.MODE_FROM_RIGHT);
	//***Your code***

view raw Sample.java hosted with ❤ by GitHub

Ottimo, dovrò testarlo :-)