[全局水波纹 View] #Android #View

ClickRippleLayout.java

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.os.Build;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.widget.FrameLayout;

import java.util.List;
import java.util.concurrent.CopyOnWriteArrayList;

import androidx.annotation.NonNull;
import androidx.annotation.Nullable;

public class ClickRippleLayout extends FrameLayout {

    private static final float rippleWidth = 200;

    private List<Circle> circles = new CopyOnWriteArrayList<>();

    private Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);

    public ClickRippleLayout(@NonNull Context context) {
        super(context);
        init();
    }

    public ClickRippleLayout(@NonNull Context context, @Nullable AttributeSet attrs) {
        super(context, attrs);
        init();
    }

    public ClickRippleLayout(@NonNull Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        init();
    }

    private void init() {
        paint.setColor(Color.GRAY);
        paint.setStyle(Paint.Style.FILL);
        setBackgroundResource(android.R.color.transparent);
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
            setElevation(Integer.MAX_VALUE);
        }
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        for (final Circle circle : circles) {
            paint.setAlpha((int) (rippleWidth - circle.radius));
            canvas.drawCircle(circle.x, circle.y, circle.radius, paint);
            circle.radius += 1 + circle.radius / 20;
            if (circle.radius >= rippleWidth) {
                circles.remove(circle);
            }
            postInvalidateDelayed(1);
        }
    }

    @Override
    public boolean onInterceptTouchEvent(MotionEvent ev) {
        switch (ev.getAction()) {
            case MotionEvent.ACTION_DOWN:
                circles.add(new Circle(ev.getX(), ev.getY()));
                postInvalidate();
                return false;
        }
        return super.onInterceptTouchEvent(ev);
    }

    private static class Circle {
        final float x;
        final float y;
        float radius = 20;

        Circle(float x, float y) {
            this.x = x;
            this.y = y;
        }
    }
}

layout.xml

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <Button
        android:id="@+id/tv_text"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:text="@string/app_name" />

    <com.twiceyuan.globalclickeffect.ClickRippleLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

</FrameLayout>