【移動(dòng)應(yīng)用開發(fā)技術(shù)】Android中如何自定義刮刮卡

【移動(dòng)應(yīng)用開發(fā)技術(shù)】Android中如何自定義刮刮卡

/upload/information/20200623/125/127721.gif/upload/information/20200623/125/127722.gif所涉及的知識(shí)點(diǎn)：實(shí)現(xiàn)思路：//背景圖

mBackGroundBitmap

=

BitmapFactory.decodeResource(getResources(),

R.mipmap.background);

@Override

protected

void

onDraw(Canvas

canvas)

{

//繪制背景層

canvas.drawBitmap(mBackGroundBitmap,

0,

0,

null);

}//背景圖

mBackGroundBitmap

=

BitmapFactory.decodeResource(getResources(),

R.mipmap.background);

//創(chuàng)建一個(gè)和背景圖大小一致的Bitmap對(duì)象作為裝載畫布

mForeGroundBitmap

=

Bitmap.createBitmap(mBackGroundBitmap.getWidth(),

mBackGroundBitmap.getHeight(),

Config.ARGB_8888);

//與Canvas進(jìn)行綁定

mCanvas

=

new

Canvas(mForeGroundBitmap);

//涂成灰色

mCanvas.drawColor(Color.GRAY);

@Override

protected

void

onDraw(Canvas

canvas)

{

//繪制背景層

canvas.drawBitmap(mBackGroundBitmap,

0,

0,

null);

//繪制前景層

canvas.drawBitmap(mForeGroundBitmap,

0,

0,

null);

}/upload/information/20200623/125/127723.jpgmPaint

=

new

Paint();

mPaint.setAlpha(0);

mPaint.setAntiAlias(true);

mPaint.setStyle(Paint.Style.STROKE);

mPaint.setStrokeCap(Paint.Cap.ROUND);

mPaint.setStrokeJoin(Paint.Join.ROUND);

mPaint.setStrokeWidth(80);

mPaint.setXfermode(new

PorterDuffXfermode(PorterDuff.Mode.DST_IN));

@Override

public

boolean

onTouchEvent(MotionEvent

event)

{

switch

(event.getAction())

{

case

MotionEvent.ACTION_DOWN:

mLastX

=

(int)

event.getX();

mLastY

=

(int)

event.getY();

mPath.moveTo(mLastX,

mLastY);

break;

case

MotionEvent.ACTION_MOVE:

mLastX

=

(int)

event.getX();

mLastY

=

(int)

event.getY();

mPath.lineTo(mLastX,

mLastY);

break;

case

MotionEvent.ACTION_UP:

break;

default:

break;

}

mCanvas.drawPath(mPath,

mPaint);

invalidate();

return

true;

}/upload/information/20200623/125/127724.png//文字畫筆

mTextPaint

=

new

Paint();

mTextPaint.setAntiAlias(true);

mTextPaint.setColor(Color.GREEN);

mTextPaint.setStyle(Paint.Style.FILL);

mTextPaint.setTextSize(30);

mTextPaint.getTextBounds(mText,

0,

mText.length(),

mRect);@Override

protected

void

onDraw(Canvas

canvas)

{

canvas.drawText(mText,

mBitmap.getWidth()

/

2

-

mRect.width()

/

2,

mBitmap.getHeight()

/

2

+

mRect.height()

/

2,

mTextPaint);

}//通過(guò)資源文件創(chuàng)建Bitmap對(duì)象

mBitmap

=

BitmapFactory.decodeResource(getResources(),

R.mipmap.background);

//新建同等大小的Bitmap對(duì)象

mForeBitmap

=

Bitmap.createBitmap(mBitmap.getWidth(),

mBitmap.getHeight(),

Bitmap.Config.ARGB_8888);

//雙緩沖,裝載畫布

mForeCanvas

=

new

Canvas(mForeBitmap);

mForeCanvas.drawBitmap(mBitmap,

0,

0,

null);private

Runnable

mRunnable

=

new

Runnable()

{

int[]

pixels;

@Override

public

void

run()

{

int

w

=

mForeBitmap.getWidth();

int

h

=

mForeBitmap.getHeight();

float

wipeArea

=

0;

float

totalArea

=

w

*

h;

pixels

=

new

int[w

*

h];

/**

*

pixels

接收位圖顏色值的數(shù)組

*

offset

寫入到pixels[]中的第一個(gè)像素索引值

*

stride

pixels[]中的行間距個(gè)數(shù)值(必須大于等于位圖寬度)。可以為負(fù)數(shù)

*

x

從位圖中讀取的第一個(gè)像素的x坐標(biāo)值。

*

y

從位圖中讀取的第一個(gè)像素的y坐標(biāo)值

*

width

從每一行中讀取的像素寬度

*

height

讀取的行數(shù)

*/

mForeBitmap.getPixels(pixels,

0,

w,

0,

0,

w,

h);

for

(int

i

=

0;

i

<

w;

i++)

{

for

(int

j

=

0;

j

<

h;

j++)

{

int

index

=

i

+

j

*

w;

if

(pixels[index]

==

0)

{

wipeArea++;

}

}

}

if

(wipeArea

>

0

&&

totalArea

>

0)

{

int

percent

=

(int)

(wipeArea

*

100

/

totalArea);

if

(percent

>

50)

{

isClear

=

true;

postInvalidate();

}

}

}

};/upload/information/20200623/125/127725.png

@Override

protected

void

onDraw(Canvas

canvas)

{

canvas.drawText(mText,

mForeBitmap.getWidth()

/

2

-

mRect.width()

/

2,

mForeBitmap.getHeight()

/

2

+

mRect.height()

/

2,

mTextPaint);

if

(!isClear)

{

canvas.drawBitmap(mForeBitmap,

0,

0,

null);

}

}package

com.lcw.view;

import

android.content.Context;

import

android.graphics.Bitmap;

import

android.graphics.BitmapFactory;

import

android.graphics.Canvas;

import

android.graphics.Color;

import

android.graphics.Paint;

import

android.graphics.Path;

import

android.graphics.PorterDuff;

import

android.graphics.PorterDuffXfermode;

import

android.graphics.Rect;

import

android.util.AttributeSet;

import

android.view.MotionEvent;

import

android.view.View;

/**

*

刮刮卡(完善版)

*

Create

by:

chenwei.li

*

Date:

2017/7/22

*

Time:

下午7:25

*/

public

class

ScratchCardView2

extends

View

{

//處理文字

private

String

mText

=

"恭喜您中獎(jiǎng)啦!!";

private

Paint

mTextPaint;

private

Rect

mRect;

//處理圖層

private

Paint

mForePaint;

private

Path

mPath;

private

Bitmap

mBitmap;//加載資源文件

private

Canvas

mForeCanvas;//前景圖Canvas

private

Bitmap

mForeBitmap;//前景圖Bitmap

//記錄位置

private

int

mLastX;

private

int

mLastY;

private

volatile

boolean

isClear;//標(biāo)志是否被清除

public

ScratchCardView2(Context

context)

{

this(context,

null);

}

public

ScratchCardView2(Context

context,

AttributeSet

attrs)

{

this(context,

attrs,

0);

}

public

ScratchCardView2(Context

context,

AttributeSet

attrs,

int

defStyleAttr)

{

super(context,

attrs,

defStyleAttr);

init();

}

private

void

init()

{

mRect

=

new

Rect();

mPath

=

new

Path();

//文字畫筆

mTextPaint

=

new

Paint();

mTextPaint.setAntiAlias(true);

mTextPaint.setColor(Color.GREEN);

mTextPaint.setStyle(Paint.Style.FILL);

mTextPaint.setTextSize(30);

mTextPaint.getTextBounds(mText,

0,

mText.length(),

mRect);

//擦除畫筆

mForePaint

=

new

Paint();

mForePaint.setAntiAlias(true);

mForePaint.setAlpha(0);

mForePaint.setStrokeCap(Paint.Cap.ROUND);

mForePaint.setStrokeJoin(Paint.Join.ROUND);

mForePaint.setStyle(Paint.Style.STROKE);

mForePaint.setStrokeWidth(30);

mForePaint.setXfermode(new

PorterDuffXfermode(PorterDuff.Mode.DST_IN));

//通過(guò)資源文件創(chuàng)建Bitmap對(duì)象

mBitmap

=

BitmapFactory.decodeResource(getResources(),

R.mipmap.background);

mForeBitmap

=

Bitmap.createBitmap(mBitmap.getWidth(),

mBitmap.getHeight(),

Bitmap.Config.ARGB_8888);

//雙緩沖,裝載畫布

mForeCanvas

=

new

Canvas(mForeBitmap);

mForeCanvas.drawBitmap(mBitmap,

0,

0,

null);

}

@Override

protected

void

onDraw(Canvas

canvas)

{

canvas.drawText(mText,

mForeBitmap.getWidth()

/

2

-

mRect.width()

/

2,

mForeBitmap.getHeight()

/

2

+

mRect.height()

/

2,

mTextPaint);

if

(!isClear)

{

canvas.drawBitmap(mForeBitmap,

0,

0,

null);

}

}

@Override

public

boolean

onTouchEvent(MotionEvent

event)

{

switch

(event.getAction())

{

case

MotionEvent.ACTION_DOWN:

mLastX

=

(int)

event.getX();

mLastY

=

(int)

event.getY();

mPath.moveTo(mLastX,

mLastY);

break;

case

MotionEvent.ACTION_MOVE:

mLastX

=

(int)

event.getX();

mLastY

=

(int)

event.getY();

mPath.lineTo(mLastX,

mLastY);

break;

case

MotionEvent.ACTION_UP:

new

Thread(mRunnable).start();

break;

default:

break;

}

mForeCanvas.drawPath(mPath,

mForePaint);

invalidate();

return

true;

}

/**

*

開啟子線程計(jì)算被擦除的像素點(diǎn)

*/

private

Runnable

mRunnable

=

new

Runnable()

{

int[]

pixels;

@Override

public

void

run()

{

int

w

=

mForeBitmap.getWidth();

int

h

=

mForeBitmap.getHeight();

flo