点击按钮的动画，点击出现阴影，松开后逐渐扩散到整个按钮

直接继承View实现，属性全部自定义

<?xml version="1.0" encoding="utf-8"?><resources>    <!-- 按钮的背景色 -->    <attr name="back_ground_color" format="color" />    <!-- 点击的阴影颜色 -->    <attr name="click_color" format="color" />    <!-- 文本 -->    <attr name="text" format="string" />    <!-- 文本的位置 -->    <attr name="text_position" format="enum">        <enum name="left" value="0" />        <enum name="center" value="1" />        <enum name="right" value="2" />    </attr>    <!-- 文字的大小 -->    <attr name="text_size" format="dimension" />    <!-- 文字的颜色 -->    <attr name="text_color" format="color" />    <declare-styleable name="click_view">        <attr name="back_ground_color" />        <attr name="click_color" />        <attr name="text" />        <attr name="text_position" />        <attr name="text_size" />        <attr name="text_color" />    </declare-styleable></resources>

具体实现类

package com.sunrui.mysport.widget;import android.content.Context;import android.content.res.TypedArray;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Paint;import android.graphics.Rect;import android.graphics.RectF;import android.util.AttributeSet;import android.util.Log;import android.view.MotionEvent;import android.view.View;import com.sunrui.mysport.R;/** * Created by sunrui on 15/9/9. * 点击扩散效果的View */public class ClickView extends View {    /**     * 背景颜色     */    private int background_color;    /**     * 点击时的颜色     */    private int click_color;    /**     * 显示的文本     */    private String text;    /**     * 文本颜色     */    private int text_color;    /**     * 文本位置     * 0 左侧     * 1 居中     * 2 右侧     */    private int text_position;    /**     * 文本大小     */    private float text_size;    /**     * 控件的宽     */    private int width;    /**     * 控件的高     */    private int height;    /**     * 文本区域大小     */    private Rect text_area;    /**     * 文本画笔     */    private Paint text_p;    /**     * 背景画笔     */    private Paint background_p;    /**     * 点击效果的画笔     */    private Paint click_p;    /**     * 点击阴影的半径     */    private float radius;    /**     * 阴影部分区域     */    private RectF shadow_area;    public ClickView(Context context) {        super(context);    }    public ClickView(Context context, AttributeSet attrs) {        super(context, attrs);        init(context, attrs);    }    public ClickView(Context context, AttributeSet attrs, int defStyleAttr) {        super(context, attrs, defStyleAttr);        init(context, attrs);    }    private void init(Context context, AttributeSet attrs) {        TypedArray typedArray = context.getTheme().obtainStyledAttributes(attrs, R.styleable.click_view, 0, 0);        int n = typedArray.getIndexCount();        for (int i = 0; i < n; i++) {            int attr = typedArray.getIndex(i);            switch (attr) {                case R.styleable.click_view_back_ground_color:                    background_color = typedArray.getColor(attr, Color.WHITE);                    break;                case R.styleable.click_view_click_color:                    click_color = typedArray.getColor(attr, Color.GRAY);                    break;                case R.styleable.click_view_text:                    text_area = new Rect();                    text = typedArray.getString(attr);                    break;                case R.styleable.click_view_text_color:                    text_color = typedArray.getColor(attr, Color.BLACK);                    break;                case R.styleable.click_view_text_position:                    text_position = typedArray.getInt(attr, 1);                    break;                case R.styleable.click_view_text_size:                    text_size = typedArray.getDimension(attr, 32.0f);                    break;                default:                    break;            }        }        background_p = new Paint();        text_p = new Paint();        click_p = new Paint();        shadow_area = new RectF(0, 0, 0, 0);    }    @Override    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {        width = 0;        height = 0;        int specMode = MeasureSpec.getMode(widthMeasureSpec);        int specSize = MeasureSpec.getSize(widthMeasureSpec);        switch (specMode) {            case MeasureSpec.EXACTLY:                width = getPaddingLeft() + getPaddingRight() + specSize;                break;            case MeasureSpec.AT_MOST:                if (text_area != null) {                    width = getPaddingLeft() + getPaddingRight() + text_area.width();                } else {                    width = getPaddingLeft() + getPaddingRight();                }                break;            default:                break;        }        specMode = MeasureSpec.getMode(heightMeasureSpec);        specSize = MeasureSpec.getSize(heightMeasureSpec);        switch (specMode) {            case MeasureSpec.EXACTLY:                height = getPaddingTop() + getPaddingBottom() + specSize;                break;            case MeasureSpec.AT_MOST:                if (text_area != null) {                    height = getPaddingTop() + getPaddingBottom() + text_area.height();                } else {                    height = getPaddingTop() + getPaddingBottom();                }                break;            default:                break;        }        setMeasuredDimension(width, height);    }    @Override    protected void onDraw(Canvas canvas) {        //绘制背景        background_p.setColor(background_color);        canvas.drawRect(0, 0, width, height, background_p);        //绘制文字        text_p.setColor(text_color);        text_p.setTextSize(text_size);        float text_x = 0f;        text_p.getTextBounds(text, 0, text.length(), text_area);        float text_y = (height + text_area.height()) / 2;        Log.v("sss", text_y + "===" + height + "===" + text_area.height());        if (text_position == 0) {            text_x = 0f;        } else if (text_position == 1) {            text_x = (width - text_area.width()) / 2;            Log.v("sss", width + "===" + text_area.width() + text_area.height());        } else if (text_position == 2) {            text_x = width - text_area.width();        }        canvas.drawText(text, text_x, text_y, text_p);        //绘制阴影        click_p.setColor(click_color);        canvas.drawArc(shadow_area, 0, 360, false, click_p);    }    @Override    public boolean onTouchEvent(MotionEvent event) {        int action = event.getAction();        final float click_x = event.getX();        switch (action) {            case MotionEvent.ACTION_DOWN:                radius = height * 1.5f;                shadow_area = new RectF(click_x - radius / 2, (height - radius) / 2, click_x + radius / 2, (height + radius) / 2);                postInvalidate();                break;            case MotionEvent.ACTION_UP:                new Thread() {                    @Override                    public void run() {                        while (true) {                            if (radius > width * 2.0f) {                                break;                            }                            radius += width / 18;                            shadow_area = new RectF(click_x - radius / 2, (height - radius) / 2, click_x + radius / 2, (height + radius) / 2);                            try {                                Thread.sleep(300/18);                            } catch (InterruptedException e) {                                e.printStackTrace();                            }                            postInvalidate();                        }                        shadow_area = new RectF(0, 0, 0, 0);                    }                }.start();                break;            default:                break;        }        return true;    }}

布局文件

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:custom="http://schemas.android.com/apk/res-auto"    xmlns:tools="http://schemas.android.com/tools"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:paddingBottom="@dimen/activity_vertical_margin"    android:paddingLeft="@dimen/activity_horizontal_margin"    android:paddingRight="@dimen/activity_horizontal_margin"    android:paddingTop="@dimen/activity_vertical_margin"    tools:context="com.sunrui.mysport.ui.AddSportItemActivity">    <com.sunrui.mysport.widget.ClickView        android:layout_width="match_parent"        android:layout_height="48dp"        custom:back_ground_color="#ffffff"        custom:click_color="#33000000"        custom:text="点击测试"        custom:text_position="center"        custom:text_size="32px"        custom:text_color="#00ff00"/></RelativeLayout>

如果不是在Android studio中，将第二行的res-auto改成包名