【移动应用开发技术】怎么在Android应用中实现㝉滑动选择控件

【移动应用开发技术】怎么在Android应用中实现㝉滑动选择控件

这篇文章给大家介绍怎么在Android应用中实现㝉滑动选择控件，内容非常详细，感兴趣的小伙伴们可以参考借鉴，希望对大家能有所帮助。实现步骤这里分解为3个动作:Down、Move、Up来进行分析，博主文采不好，大家直接看流程图吧！！代码分析前置知识1、这个地方使用的是RecyclerView的代码，使用RecyclerView只能使用LinearLayoutManager,ListView的运行效果稍微要比RecyclerView差一些//这里使用dispatchTouchEvent，因为onTouchEvent容易被OnTouchListener截取

@Override

public

boolean

dispatchTouchEvent(MotionEvent

ev)

{

LayoutManager

manager

=

getLayoutManager();

//获取第一个和最后一个显示的Item对应的相对Position

if

(manager

instanceof

LinearLayoutManager)

{

mFirstVisiblePosition

=

((LinearLayoutManager)

manager).findFirstVisibleItemPosition();

mLastVisiblePosition

=

((LinearLayoutManager)

manager).findLastVisibleItemPosition();

}

switch

(ev.getAction())

{

case

MotionEvent.ACTION_DOWN:

//获取按下时的位置,x,y

int

startX

=

(int)

ev.getX();

int

startY

=

(int)

ev.getY();

int

preX

=

startX;

mPreY

=

startY;

mPreFirstVisiblePosition

=

mFirstVisiblePosition;

mPrePosition

=

mStartPosition

=

pointToPosition(startX,

startY);

if

(mStartPosition

>

-1)

{

//获取当前Item的View

View

child

=

getChildAt(mStartPosition);

if

(null

!=

child)

{

//获取响应域，一般响应域里面就是一个CheckBox

View

tmpCheckBoxContainer

=

child.findViewWithTag("checkbox_layout");

if

(null

!=

tmpCheckBoxContainer

&&

tmpCheckBoxContainer.getVisibility()

==

VISIBLE)

{

mCheckBoxWidth

=

tmpCheckBoxContainer.getWidth();

//获取响应域的范围，一定要用这种获取绝对位置的方式，不然会受到padding或者是margin的影响

int[]

location

=

new

int[2];

tmpCheckBoxContainer.getLocationOnScreen(location);

mCheckBoxX

=

location[0];

//判断按下的位置是否是在响应域内

if

(startX

>=

mCheckBoxX

&&

startX

<=

(mCheckBoxX

+

mCheckBoxWidth))

{

Log.d(LOG_TAG,

"dispatchTouchEvent()

DOWN

mStartPosition:

"

+

mStartPosition);

//设置截取事件的标志位

mIsNeedScrollCheck

=

true;

//设置为第一次滑动，这是用作判断折返的

mIsFirstMove

=

true;

setStartCheckBoxState();

//截获Checkbox的点击事件，防止两次选中

return

true;

}

else

{

mIsNeedScrollCheck

=

false;

}

}

else

{

mIsNeedScrollCheck

=

false;

Log.e(LOG_TAG,

"dispatchTouchEvent()

",

new

Throwable("Cannot

get

CheckBoxContainer!"));

}

}

else

{

Log.e(LOG_TAG,

"dispatchTouchEvent()

",

new

Throwable("Cannot

get

item

view!"));

}

}

break;

case

MotionEvent.ACTION_MOVE:

//获取当前位置

int

currentX

=

(int)

ev.getX();

int

currentY

=

(int)

ev.getY();

//获取当前的item

int

currentPosition

=

pointToPosition(currentX,

currentY);

//判断是否允许滑动选中

if

(mIsNeedScrollCheck

&&

-1

!=

mFirstVisiblePosition

&&

-1

!=

mLastVisiblePosition

&&

-1

!=

currentPosition)

{

//判断是否在下一个Item的像英语

if

((currentPosition

+

mFirstVisiblePosition)

!=

(mPrePosition

+

mPreFirstVisiblePosition)

&&

currentX

>=

mCheckBoxX

&&

currentX

<=

(mCheckBoxX

+

mCheckBoxWidth))

{

Log.i(LOG_TAG,

"**********************************

dispatchTouchEvent()

********************************");

Log.d(LOG_TAG,

"dispatchTouchEvent()

MOVE

mCurrentPosition:

"

+

currentPosition);

Log.d(LOG_TAG,

"dispatchTouchEvent()

MOVE

mFirstVisiblePosition:

"

+

mFirstVisiblePosition);

Log.d(LOG_TAG,

"dispatchTouchEvent()

MOVE

mPrePosition:

"

+

mPrePosition);

Log.d(LOG_TAG,

"dispatchTouchEvent()

MOVE

mPreFirstVisiblePosition:

"

+

mPreFirstVisiblePosition);

Log.i(LOG_TAG,

"**********************************

dispatchTouchEvent()

********************************");

//折返回来时要改变前一个的Checkbox的状态

if

(mIsFirstMove)

{

mIsFirstMove

=

false;

if

(currentY

>=

mPreY)

{

mUpOrDown

=

false;

}

else

{

mUpOrDown

=

true;

}

}

else

{

if

((currentPosition

+

mFirstVisiblePosition)

>

(mPrePosition

+

mPreFirstVisiblePosition)

&&

mUpOrDown)

{

changeCheckBoxState(mPrePosition);

mUpOrDown

=

false;

}

else

if

((currentPosition

+

mFirstVisiblePosition)

<

(mPrePosition

+

mPreFirstVisiblePosition)

&&

!mUpOrDown)

{

changeCheckBoxState(mPrePosition);

mUpOrDown

=

true;

}

}

changeCheckBoxState(currentPosition);

}

//判断是否是在最后一个item上滑动，如果是则进行自动向下滑动，如果是在第一个上下滑动，则自动向上滑动

//Log.d(LOG_TAG,

"dispatchTouchEvent()

MOVE:

"

+

(mLastVisiblePosition

-

mCurrentPosition

-

mFirstVisiblePosition));

if

((mLastVisiblePosition

-

mFirstVisiblePosition

-

currentPosition)

<

1

&&

currentY

>

mPreY)

{

//自动向下滑

Log.d(LOG_TAG,

"dispatchTouchEvent()

MOVE

mCount:

"

+

mCount);

View

child

=

getChildAt(currentPosition);

if

(null

!=

child

&&

0

==

mCount

%

5)

{

scrollToPosition(mLastVisiblePosition

+

1);

}

mCount++;

}

else

if

(currentPosition

<

2

&&

currentY

<

mPreY)

{

//自动向上滑

View

child

=

getChildAt(currentPosition);

Log.d(LOG_TAG,

"dispatchTouchEvent()

MOVE

mCount:

"

+

mCount);

//mCount用于降低滑动的频率，频率太快容易滑动的看不清楚

if

(null

!=

child

&&

0

==

mCount

%

5)

{

scrollToPosition(mFirstVisiblePosition

-

1);

}

mCount++;

}

mPreY

=

currentY;

mPrePosition

=

currentPosition;

mPreFirstVisiblePosition

=

mFirstVisiblePosition;

return

true;

}

break;

case

MotionEvent.ACTION_UP:

if

(mIsNeedScrollCheck)

{

mCount

=

0;

return

false;

}

break;

}

return

super.dispatchTouchEvent(ev);

}其他的代码片段//改变开始的CheckBox状态

private

void

setStartCheckBoxState()

{

View

child

=

getChildAt(mStartPosition);

if

(null

!=

child)

{

ViewGroup

checkBoxContainer

=

(ViewGroup)

child.findViewWithTag("checkbox_layout");

if

(null

!=

checkBoxContainer)

{

CheckBox

checkBox

=

(CheckBox)

checkBoxContainer.getChildAt(0);

if

(null

!=

checkBox

&&

checkBox.getVisibility()

==

VISIBLE)

{

checkBox.toggle();

}

}

}

}//判断当前Item的Position，相对位置

private

int

pointToPosition(int

x,

int

y)

{

Rect

frame

=

mTouchFrame;

if

(frame

==

null)

{

mTouchFrame

=

new

Rect();

frame

=

mTouchFrame;

}

final

int

count

=

getChildCount();

for

(int

i

=

count

-

1;

i

>=

0;

i--)

{

final

View

child

=

getChildAt(i);

if

(child.getVisibility()

==

View.VISIBLE)

{

child.getHitRect(frame);

if

(frame.contains(x,

y))

{

return

i;

}

}

}

return

-1;

}//改变Position的选中状态

public

void

changeC