Ho fatto una classe semplice che crea pulsanti a catena, alla fine non ne ho mai avuto bisogno, quindi non è il migliore, ma eccolo qui:
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.os.Handler;
import android.support.annotation.NonNull;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.widget.Button;
public class RippleView extends Button
{
private float duration = 250;
private float speed = 1;
private float radius = 0;
private Paint paint = new Paint();
private float endRadius = 0;
private float rippleX = 0;
private float rippleY = 0;
private int width = 0;
private int height = 0;
private OnClickListener clickListener = null;
private Handler handler;
private int touchAction;
private RippleView thisRippleView = this;
public RippleView(Context context)
{
this(context, null, 0);
}
public RippleView(Context context, AttributeSet attrs)
{
this(context, attrs, 0);
}
public RippleView(Context context, AttributeSet attrs, int defStyleAttr)
{
super(context, attrs, defStyleAttr);
init();
}
private void init()
{
if (isInEditMode())
return;
handler = new Handler();
paint.setStyle(Paint.Style.FILL);
paint.setColor(Color.WHITE);
paint.setAntiAlias(true);
}
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh)
{
super.onSizeChanged(w, h, oldw, oldh);
width = w;
height = h;
}
@Override
protected void onDraw(@NonNull Canvas canvas)
{
super.onDraw(canvas);
if(radius > 0 && radius < endRadius)
{
canvas.drawCircle(rippleX, rippleY, radius, paint);
if(touchAction == MotionEvent.ACTION_UP)
invalidate();
}
}
@Override
public boolean onTouchEvent(@NonNull MotionEvent event)
{
rippleX = event.getX();
rippleY = event.getY();
switch(event.getAction())
{
case MotionEvent.ACTION_UP:
{
getParent().requestDisallowInterceptTouchEvent(false);
touchAction = MotionEvent.ACTION_UP;
radius = 1;
endRadius = Math.max(Math.max(Math.max(width - rippleX, rippleX), rippleY), height - rippleY);
speed = endRadius / duration * 10;
handler.postDelayed(new Runnable()
{
@Override
public void run()
{
if(radius < endRadius)
{
radius += speed;
paint.setAlpha(90 - (int) (radius / endRadius * 90));
handler.postDelayed(this, 1);
}
else
{
clickListener.onClick(thisRippleView);
}
}
}, 10);
invalidate();
break;
}
case MotionEvent.ACTION_CANCEL:
{
getParent().requestDisallowInterceptTouchEvent(false);
touchAction = MotionEvent.ACTION_CANCEL;
radius = 0;
invalidate();
break;
}
case MotionEvent.ACTION_DOWN:
{
getParent().requestDisallowInterceptTouchEvent(true);
touchAction = MotionEvent.ACTION_UP;
endRadius = Math.max(Math.max(Math.max(width - rippleX, rippleX), rippleY), height - rippleY);
paint.setAlpha(90);
radius = endRadius/4;
invalidate();
return true;
}
case MotionEvent.ACTION_MOVE:
{
if(rippleX < 0 || rippleX > width || rippleY < 0 || rippleY > height)
{
getParent().requestDisallowInterceptTouchEvent(false);
touchAction = MotionEvent.ACTION_CANCEL;
radius = 0;
invalidate();
break;
}
else
{
touchAction = MotionEvent.ACTION_MOVE;
invalidate();
return true;
}
}
}
return false;
}
@Override
public void setOnClickListener(OnClickListener l)
{
clickListener = l;
}
}
MODIFICARE
Dato che molte persone sono alla ricerca di qualcosa del genere, ho creato una classe che può far sì che altre viste abbiano l'effetto a catena:
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.os.Handler;
import android.support.annotation.NonNull;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewGroup;
import android.widget.FrameLayout;
public class RippleViewCreator extends FrameLayout
{
private float duration = 150;
private int frameRate = 15;
private float speed = 1;
private float radius = 0;
private Paint paint = new Paint();
private float endRadius = 0;
private float rippleX = 0;
private float rippleY = 0;
private int width = 0;
private int height = 0;
private Handler handler = new Handler();
private int touchAction;
public RippleViewCreator(Context context)
{
this(context, null, 0);
}
public RippleViewCreator(Context context, AttributeSet attrs)
{
this(context, attrs, 0);
}
public RippleViewCreator(Context context, AttributeSet attrs, int defStyleAttr)
{
super(context, attrs, defStyleAttr);
init();
}
private void init()
{
if (isInEditMode())
return;
paint.setStyle(Paint.Style.FILL);
paint.setColor(getResources().getColor(R.color.control_highlight_color));
paint.setAntiAlias(true);
setWillNotDraw(true);
setDrawingCacheEnabled(true);
setClickable(true);
}
public static void addRippleToView(View v)
{
ViewGroup parent = (ViewGroup)v.getParent();
int index = -1;
if(parent != null)
{
index = parent.indexOfChild(v);
parent.removeView(v);
}
RippleViewCreator rippleViewCreator = new RippleViewCreator(v.getContext());
rippleViewCreator.setLayoutParams(v.getLayoutParams());
if(index == -1)
parent.addView(rippleViewCreator, index);
else
parent.addView(rippleViewCreator);
rippleViewCreator.addView(v);
}
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh)
{
super.onSizeChanged(w, h, oldw, oldh);
width = w;
height = h;
}
@Override
protected void dispatchDraw(@NonNull Canvas canvas)
{
super.dispatchDraw(canvas);
if(radius > 0 && radius < endRadius)
{
canvas.drawCircle(rippleX, rippleY, radius, paint);
if(touchAction == MotionEvent.ACTION_UP)
invalidate();
}
}
@Override
public boolean onInterceptTouchEvent(MotionEvent event)
{
return true;
}
@Override
public boolean onTouchEvent(@NonNull MotionEvent event)
{
rippleX = event.getX();
rippleY = event.getY();
touchAction = event.getAction();
switch(event.getAction())
{
case MotionEvent.ACTION_UP:
{
getParent().requestDisallowInterceptTouchEvent(false);
radius = 1;
endRadius = Math.max(Math.max(Math.max(width - rippleX, rippleX), rippleY), height - rippleY);
speed = endRadius / duration * frameRate;
handler.postDelayed(new Runnable()
{
@Override
public void run()
{
if(radius < endRadius)
{
radius += speed;
paint.setAlpha(90 - (int) (radius / endRadius * 90));
handler.postDelayed(this, frameRate);
}
else if(getChildAt(0) != null)
{
getChildAt(0).performClick();
}
}
}, frameRate);
break;
}
case MotionEvent.ACTION_CANCEL:
{
getParent().requestDisallowInterceptTouchEvent(false);
break;
}
case MotionEvent.ACTION_DOWN:
{
getParent().requestDisallowInterceptTouchEvent(true);
endRadius = Math.max(Math.max(Math.max(width - rippleX, rippleX), rippleY), height - rippleY);
paint.setAlpha(90);
radius = endRadius/3;
invalidate();
return true;
}
case MotionEvent.ACTION_MOVE:
{
if(rippleX < 0 || rippleX > width || rippleY < 0 || rippleY > height)
{
getParent().requestDisallowInterceptTouchEvent(false);
touchAction = MotionEvent.ACTION_CANCEL;
break;
}
else
{
invalidate();
return true;
}
}
}
invalidate();
return false;
}
@Override
public final void addView(@NonNull View child, int index, ViewGroup.LayoutParams params)
{
//limit one view
if (getChildCount() > 0)
{
throw new IllegalStateException(this.getClass().toString()+" can only have one child.");
}
super.addView(child, index, params);
}
}