public RadialGradient(float centerX, float centerY, float radius, int[] colors, float[] stops, TileMode tileMode) {

        throw new RuntimeException("Stub!");

    }

    public RadialGradient(float centerX, float centerY, float radius, int centerColor, int edgeColor, TileMode tileMode) {

        throw new RuntimeException("Stub!");

    }

package com.loaderman.customviewdemo;

import android.content.Context;

import android.graphics.Canvas;

import android.graphics.Paint;

import android.graphics.RadialGradient;

import android.graphics.Shader;

import android.util.AttributeSet;

import android.view.View;

public class RadialGradientView extends View {

    private Paint mPaint;

    private RadialGradient mRadialGradient;

    private int mRadius;

    public RadialGradientView(Context context, AttributeSet attrs) {

        super(context, attrs);

        setLayerType(LAYER_TYPE_SOFTWARE, null);

        mPaint = new Paint();

    }

    @Override

protected void onDraw(Canvas canvas) {

    super.onDraw(canvas);

    /**

     * 两色渐变

     */

    if (mRadialGradient == null){

        mRadius = getWidth()/6;

        mRadialGradient = new RadialGradient(getWidth()/2,getHeight()/2,mRadius,0xffff0000,0xff00ff00, Shader.TileMode.CLAMP);

        mPaint.setShader(mRadialGradient);

    }

    /**

     * 多色渐变

     */

//        if (mRadialGradient == null) {

//            mRadius = getWidth() / 2;

//            int[] colors = new int[]{0xffff0000, 0xff00ff00, 0xff0000ff, 0xffffff00};

//            float[] stops = new float[]{0f, 0.2f, 0.5f, 1f};

//            mRadialGradient = new RadialGradient(getWidth() / 2, getHeight() / 2, mRadius, colors, stops, Shader.TileMode.REPEAT);

//            mPaint.setShader(mRadialGradient);

//        }

    canvas.drawRect(0,0,getWidth(),getHeight(),mPaint);

}

}

package com.loaderman.customviewdemo;

import android.animation.Animator;

import android.animation.ObjectAnimator;

import android.content.Context;

import android.graphics.Canvas;

import android.graphics.Paint;

import android.graphics.RadialGradient;

import android.graphics.Shader;

import android.util.AttributeSet;

import android.view.MotionEvent;

import android.view.animation.AccelerateInterpolator;

import android.widget.Button;

public class RippleView extends Button {

    private int mX, mY;

    private ObjectAnimator mAnimator;

    private int DEFAULT_RADIUS = 50;

    private int mCurRadius = 0;

    private RadialGradient mRadialGradient;

    private Paint mPaint;

    public RippleView(Context context, AttributeSet attrs) {

        super(context, attrs);

        setLayerType(LAYER_TYPE_SOFTWARE,null);

        mPaint = new Paint();

    }

    @Override

    public boolean onTouchEvent(MotionEvent event) {

        if (mX != event.getX() || mY != mY) {

            mX = (int) event.getX();

            mY = (int) event.getY();

            setRadius(DEFAULT_RADIUS);

        }

        if (event.getAction() == MotionEvent.ACTION_DOWN) {

            return true;

        } else if (event.getAction() == MotionEvent.ACTION_UP) {

            if (mAnimator != null && mAnimator.isRunning()) {

                mAnimator.cancel();

            }

            if (mAnimator == null) {

                mAnimator = ObjectAnimator.ofInt(this,"radius",DEFAULT_RADIUS, getWidth());

            }

            mAnimator.setInterpolator(new AccelerateInterpolator());

            mAnimator.addListener(new Animator.AnimatorListener() {

                public void onAnimationStart(Animator animation) {

                }

                public void onAnimationEnd(Animator animation) {

                    setRadius(0);

                }

                public void onAnimationCancel(Animator animation) {

                }

                public void onAnimationRepeat(Animator animation) {

                }

            });

            mAnimator.start();

        }

        return super.onTouchEvent(event);

    }

    public void setRadius(final int radius) {

        mCurRadius = radius;

        if (mCurRadius > 0) {

            mRadialGradient = new RadialGradient(mX, mY, mCurRadius, 0x00FFFFFF, 0xFF58FAAC, Shader.TileMode.CLAMP);

            mPaint.setShader(mRadialGradient);

        }

        postInvalidate();

    }

    @Override

    protected void onDraw(Canvas canvas) {

        super.onDraw(canvas);

        canvas.drawCircle(mX, mY, mCurRadius, mPaint);

    }

}