【移动应用开发技术】怎么在Android中实现一个图片随手指旋转功能

【移动应用开发技术】怎么在Android中实现一个图片随手指旋转功能

这篇文章主要为大家详细介绍了怎么在Android中实现一个图片随手指旋转功能，文中示例代码介绍的非常详细，具有一定的参考价值，发现的小伙伴们可以参考一下：在View中进行重绘，主要是通过计算角度及距离来实现。实现类代码如下：package

com.example.roatedemo;

import

java.util.Calendar;

import

android.content.Context;

import

android.graphics.Bitmap;

import

android.graphics.BitmapFactory;

import

android.graphics.Canvas;

import

android.graphics.Matrix;

import

android.graphics.Paint;

import

android.util.Log;

import

android.view.MotionEvent;

import

android.view.View;

public

class

RotateView

extends

View

{

private

Paint

mPaint

=

new

Paint();

private

Bitmap

bitmaplittele;//中间不动的图片

private

Bitmap

bitmapBig;//随手指转动的图片

private

Bitmap

bitmapOut;//外围不动的图片

//

圆心坐标

private

float

mPointX

=

0,

mPointY

=

0;

private

int

flag

=

0;

//

半径

private

int

mRadius

=

0;

//

旋转角度

private

int

mAngle

=

0;

private

int

beginAngle

=

0,

currentAngle

=

0;

private

String

TAG

=

"NewView";

int

bitMap[]

=

{

R.drawable.circle0,

R.drawable.circle1,

R.drawable.circle2

};

int

imageIndex

=

0;

boolean

isUp

=

false,isTouch=false;

Context

mContext;

RotateViewListener

listener;

long

beginTime,endTime;

Calendar

now;

public

RotateView(Context

context,

int

px,

int

py,

int

radius,RotateViewListener

listener)

{

super(context);

mContext

=

context;

this.listener

=

listener;

mPointX

=

px;

mPointY

=

py;

mRadius

=

radius;

bitmaplittele

=

BitmapFactory.decodeResource(getResources(),

R.drawable.a1_pointer).copy(Bitmap.Config.ARGB_8888,

true);

bitmapBig

=

BitmapFactory.decodeResource(getResources(),

bitMap[0])

.copy(Bitmap.Config.ARGB_8888,

true);

bitmapOut

=

BitmapFactory.decodeResource(getResources(),

R.drawable.bigcir).copy(Bitmap.Config.ARGB_8888,

true);

setBackgroundResource(R.drawable.back);

Log.e(TAG,

"RotateViewBegin");

}

@Override

public

boolean

dispatchTouchEvent(MotionEvent

e)

{

switch

(e.getAction()

&

MotionEvent.ACTION_MASK)

{

case

MotionEvent.ACTION_DOWN:

now

=

Calendar.getInstance();

beginTime

=

now.getTimeInMillis();

beginAngle

=

computeCurrentAngle(e.getX(),

e.getY());

isUp

=

false;

//如果点击触摸范围在圈外，则不处理

if

(getDistance(e.getX(),

e.getY())>bitmapOut.getWidth()/2)

{

isTouch=false;

}else

{

isTouch=true;

}

return

true;

case

MotionEvent.ACTION_MOVE:

if

(!isTouch)

{

return

true;

}

currentAngle

=

computeCurrentAngle(e.getX(),

e.getY());

invalidate();

return

true;

case

MotionEvent.ACTION_UP:

isUp

=

true;

if

(!isTouch)

{

return

true;

}

now

=

Calendar.getInstance();

endTime

=

now.getTimeInMillis();

if

(SetClick(e.getX(),

e.getY()))

{

return

true;

}

if

(mAngle

>

0)

{

int

count

=

mAngle

/

120

+

(mAngle

%

120

>

60

?

1

:

0);

imageIndex

=

(imageIndex

+

count)

%

3;

}

else

if

(mAngle

<

0)

{

mAngle

=

-mAngle;

int

count

=

mAngle

/

120

+

(mAngle

%

120

>

60

?

1

:

0);

imageIndex

=

(imageIndex

+

3

-

count)

%

3;

}

bitmapBig

=

BitmapFactory.decodeResource(getResources(),

bitMap[imageIndex]).copy(Bitmap.Config.ARGB_8888,

true);

bitmapBig

=

adjustPhotoRotation(bitmapBig,

imageIndex

*

120);

invalidate();

if

(mAngle

>=

60)

{

listener.onModChange(imageIndex);

}

return

true;

}

return

false;

}

@Override

public

void

onDraw(Canvas

canvas)

{

//

Log.i(TAG,

"onDraw");

//

大圆

drawInCenter(canvas,

bitmapOut,

mPointX,

mPointY,

TAG);

//

外圈

if

(isUp)

{

mAngle

=

0;

}

else

{

mAngle

=

currentAngle

-

beginAngle;

}

Bitmap

tempBig

=

adjustPhotoRotation(bitmapBig,

mAngle);

//

Log.i(TAG,

"mAngle:"+mAngle);

drawInCenter(canvas,

tempBig,

mPointX,

mPointY

+

10,

TAG);

//

小圆(中间的圆心)

drawInCenter(canvas,

bitmaplittele,

mPointX,

mPointY

-

10,

TAG);

}

Bitmap

adjustPhotoRotation(Bitmap

bm,

final

int

orientationDegree)

{

if

(orientationDegree

==

0)

{

return

bm;

}

Matrix

m

=

new

Matrix();

m.setRotate(orientationDegree,

(float)

bm.getWidth()

/

2,

(float)

bm.getHeight()

/

2);

try

{

Bitmap

bm1

=

Bitmap.createBitmap(bm,

0,

0,

bm.getWidth(),

bm.getHeight(),

m,

true);

return

bm1;

}

catch

(OutOfMemoryError

ex)

{

}

return

null;

}

private

void

drawInCenter(Canvas

canvas,

Bitmap

bitmap,

float

left,

float

top,

String

text)

{

canvas.drawBitmap(bitmap,

left

-

bitmap.getWidth()

/

2,

top

-

bitmap.getHeight()

/

2,

null);

}

//

子控件位置改变重新计算角度

private

int

computeCurrentAngle(float

x,

float

y)

{

//

根据圆心坐标计算角度

float

distance

=

(float)

Math

.sqrt(((x

-

mPointX)

*

(x

-

mPointX)

+

(y

-

mPointY)

*

(y

-

mPointY)));

int

degree

=

(int)

(Math.acos((x

-

mPointX)

/

distance)

*

180

/

Math.PI);

if

(y

<

mPointY)

{

degree

=

-degree;

}

if

(degree

<

0)

{

degree

+=

360;

}

//

Log.i("RoundSpinView",

"x:"

+

x

+

",y:"

+

y

+

",degree:"

+

degree);

return

degree;

}

//

获取距离圆心的距离

private

float

getDistance(float

x,

float

y)

{

//

根据圆心坐标计算角度

float

distance

=

(float)

Math

.sqrt(((x

-

mPointX)

*

(x

-

mPointX)

+

(y

-

mPointY)

*

(y

-

mPointY)));

return

distance;

}

//点击

private

boolean

SetClick(float

x,

float

y)

{

float

distance

=

getDistance(x,

y);

if

(mAngle>10||mAngle<-10)

{

return

false;

}else

if(endTime-beginTime>1000){

return

false;

}

if

(distance

<

bitmapBig.getWidth()

/

2)

{

int

mod

=

0;

if

(beginAngle

<

90

||

330

<

beginAngle)

{

mod

=

(imageIndex+3-1)%3;

}

else

if

(90

<

beginAngle

&&

210

>

beginAngle)

{

mod

=

(imageIndex+3-2)%3;

}

else{

mod

=

imageIndex;

}

//回调到主界面进行处理。

listener.onModClick(mod);

}

return

true;

}

public

interface

RotateViewListener

{

void

onModClick(int

mode);

void

onModChange(int

mode);

}

}

Activity中调用代码：package

com.example.roatedemo;

import

com.example.roatedemo.RotateView.RotateViewListener;

import

android.app.Activity;

import

android.content.Context;

import

android.os.Bundle;

import

android.util.DisplayMetrics;

import

android.util.Log;

import

android.widget.Toast;

public

class

MainActivity

extends

Activity

implements

RotateViewListener{

RotateView

rotateView;

String

TAG="MainActivity";

Context

mContext;

@Override

protected

void

onCreate(Bundle

savedInstanceState)

{

super.onCreate(savedInstanceState);

mContext

=

this;

int

height,width;

DisplayMetrics

displayMet