【移动应用开发技术】怎么在Android中通过自定义控件实现水波纹效果

【移动应用开发技术】怎么在Android中通过自定义控件实现水波纹效果

今天就跟大家聊聊有关怎么在Android中通过自定义控件实现水波纹效果，可能很多人都不太了解，为了让大家更加了解，在下给大家总结了以下内容，希望大家根据这篇文章可以有所收获。MainActivity.javapackage

com.example.mhy.shuibowen;

import

android.support.v7.app.AppCompatActivity;

import

android.os.Bundle;

public

class

MainActivity

extends

AppCompatActivity

{

@Override

protected

void

onCreate(Bundle

savedInstanceState)

{

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

}

}activity_main.xml<?xml

version="1.0"

encoding="utf-8"?>

<RelativeLayout

xmlns:android="/apk/res/android"

xmlns:tools="/tools"

android:layout_width="match_parent"

android:layout_height="match_parent"

tools:context="com.example.mhy.shuibowen.MainActivity">

<com.example.mhy.shuibowen.MyRingWave

android:layout_width="match_parent"

android:layout_height="match_parent"

/>

</RelativeLayout>MyRingWave.javapackage

com.example.mhy.shuibowen;

import

android.content.Context;

import

android.graphics.Canvas;

import

android.graphics.Color;

import

android.graphics.Paint;

import

android.os.Handler;

import

android.util.AttributeSet;

import

android.view.MotionEvent;

import

android.view.View;

import

java.util.ArrayList;

/**

*

水波纹效果

*

Created

by

mhy

on

2016/6/16.

*/

public

class

MyRingWave

extends

View

{

/**

*

二个相临波浪中心点的最小距离

*/

private

static

final

int

DIS_SOLP

=

13;

protected

boolean

isRunning

=

false;

private

ArrayList<Wave>

wList;

public

MyRingWave(Context

context,AttributeSet

attrs)

{

super(context,

attrs);

wList

=

new

ArrayList<MyRingWave.Wave>();

}

@Override

protected

void

onDraw(Canvas

canvas)

{

for(int

i=0;

i<wList.size();

i++)

{

Wave

wave

=

wList.get(i);

canvas.drawCircle(wave.cx,

wave.cy,

wave.r,

wave.p);

}

}

@Override

public

boolean

onTouchEvent(MotionEvent

event)

{

super.onTouchEvent(event);

switch(event.getAction())

{

case

MotionEvent.ACTION_DOWN:

case

MotionEvent.ACTION_MOVE:

int

x

=

(int)

event.getX();

int

y

=

(int)

event.getY();

addPoint(x,

y);

break;

default:

break;

}

return

true;

}

private

Handler

handler

=

new

Handler(){

public

void

handleMessage(android.os.Message

msg)

{

//刷新数据

flushData();

//刷新页面

invalidate();

//循环动画

if

(isRunning)

{

handler.sendEmptyMessageDelayed(0,

50);

}

}

};

/**

*

刷新数据

*/

private

void

flushData()

{

for

(int

i

=

0;

i

<

wList.size();

i++)

{

Wave

w

=

wList.get(i);

//如果透明度为

0

从集合中删除

int

alpha

=

w.p.getAlpha();

if(alpha

==

0){

wList.remove(i);

//删除i

以后，i的值应该再减1

否则会漏掉一个对象，不过，在此处影响不大，效果上看不出来。

continue;

}

alpha-=5;

if(alpha<5){

alpha

=0;

}

//降低透明度

w.p.setAlpha(alpha);

//扩大半径

w.r

=

w.r+3;

//设置半径厚度

w.p.setStrokeWidth(w.r/3);

}

/*

*

如果集合被清空，就停止刷新动画

*/

if(wList.size()

==

0){

isRunning

=

false;

}

}

/**

*

添加新的波浪中心点

*

@param

x

*

@param

y

*/

private

void

addPoint(int

x,

int

y)

{

if(wList.size()

==

0)

{

addPoint2List(x,

y);

isRunning

=

true;

handler.sendEmptyMessage(0);

}else{

Wave

w

=

wList.get(wList.size()-1);

if(Math.abs(w.cx

-

x)>DIS_SOLP

||

Math.abs(w.cy-y)>DIS_SOLP){

addPoint2List(x,y);

}

};

}

/**

*

添加新的波浪

*

@param

x

*

@param

y

*/

private

void

addPoint2List(int

x,

int

y)

{

Wave

w

=

new

Wave();

w.cx

=

x;

w.cy=y;

Paint

pa=new

Paint();

pa.setColor(colors[(int)(Math.random()*4)]);

pa.setAntiAlias(true);

pa.setStyle(Paint.Style.STROKE);

w.p

=

pa;

wList.add(w);

}

private

int

[]

colors

=

new

int[]{Color.BLUE,Color.RED,Color.YELLOW,Color.GREEN};

private

class

Wave

{

//圆心

int

cx;

int

cy;

//画笔

Paint

p;

//半径

int

r;

}

}MyRing.javapackage

com.example.mhy.shuibowen;

import

android.content.Context;

import

android.graphics.Canvas;

import

android.graphics.Color;

import

android.graphics.Paint;

import

android.os.Handler;

import

android.os.Message;

import

android.util.AttributeSet;

import

android.view.MotionEvent;

import

android.view.View;

/**

*

Created

by

mhy

on

2016/6/16.

*/

public

class

MyRing

extends

View

{

/**

*

圆心的X坐标

*/

private

float

cx;

/**

*

圆心的Y坐标

*/

private

float

cy;

/**

*

圆环半径

*/

private

float

radius

=

0;

/**

*

默认画笔

*/

private

Paint

paint;

private

boolean

isRuning

=

false;

public

MyRing(Context

context,

AttributeSet

attrs)

{

super(context,

attrs);

initView();

}

private

void

initView()

{

radius

=

0;

paint

=

new

Paint();

paint.setAntiAlias(true);

paint.setStyle(Paint.Style.STROKE);

//

空心圆

paint.setStrokeWidth(radius

/

4);

//

画笔宽度

半径4分之一

paint.setColor(Color.GREEN);

//

画笔颜色

paint.setAlpha(255);

//不透明

}

@Override

protected

void

onMeasure(int

widthMeasureSpec,

int

heightMeasureSpec)

{

super.onMeasure(widthMeasureSpec,

heightMeasureSpec);

}

@Override

protected

void

onLayout(boolean

changed,

int

l,

int

t,

int

r,

int

b)

{

if(changed)

{

cx

=

getWidth()

/

2;

cy

=

getHeight()

/

2;

}

}

@Override

protected

void

onDraw(Canvas

canvas)

{

canvas.drawCircle(cx,

cy,

radius,

paint);

}

@Override

protected

void

onAttachedToWindow()

{

super.onAttachedToWindow();

}

@Override

protected

void

onDetachedFromWindow()

{

super.onDetachedFromWindow();

isRuning

=

false;

}

@Override

public

boolean

onTouchEvent(MotionEvent

event)

{

super.onTouchEvent(event);

if(event.getAction()

==

MotionEvent.ACTION_DOWN)

{

cx

=

event.getX();

cy

=

event.getY();

initView();

startAnim();

}

return

true;

}

private

Handler

handler

=

new

Handler(){

@