【移动应用开发技术】Android中怎么自定义一个底部上拉控件

【移动应用开发技术】Android中怎么自定义一个底部上拉控件

Android中怎么自定义一个底部上拉控件，相信很多没有经验的人对此束手无策，为此本文总结了问题出现的原因和解决方法，通过这篇文章希望你能解决这个问题。1.在Project的build.gradle文件中添加：allprojects

{

repositories

{

...

maven

{

url

'https://jitpack.io'

}

}

}2.在Module的build.gradle文件中添加：dependencies

{

compile

'com.github.qingmei2:SlideBottomLayout-Android:1.2.3'

}3.Addviewinyourlayout:需要注意的是：为了简单实现，笔者偷了个懒，设定为该布局下只能有一个直接的子View(类似ScrollView)因此如果您添加需要一个布局，请在外面嵌套一个ViewGroup：<com.qingmei2.library.SlideBottomLayout

android:id="@+id/slideLayout"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:layout_alignParentBottom="true"

android:layout_marginTop="200dp"

app:handler_height="50dp">

<!--app:handler_height:该属性就是您要暴露出来Handle的高度，详见下方的TextView(id=handle)-->

<!--Just

one

child-->

<LinearLayout

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:orientation="vertical">

<TextView

android:id="@+id/handle"

android:layout_width="match_parent"

android:layout_height="50dp"

android:background="#d95858"

android:gravity="center"

android:text="handle"

android:textColor="@android:color/white"

android:textSize="16sp"

/>

<android.support.v7.widget.RecyclerView

android:id="@+id/recycler_view"

android:layout_width="match_parent"

android:layout_height="wrap_content">

</android.support.v7.widget.RecyclerView>

</LinearLayout>

</com.qingmei2.library.SlideBottomLayout>实现步骤具体代码如下，其中上述需求的设置方式都已经在代码中声明：先看下属性声明：<?xml

version="1.0"

encoding="utf-8"?>

<resources>

<declare-styleable

name="SlideBottomLayout">

<attr

name="handler_height"

format="dimension"></attr>

</declare-styleable>

</resources>public

class

SlideBottomLayout

extends

LinearLayout

{

public

void

setShortSlideListener(ShortSlideListener

listener)

{

this.shortSlideListener

=

listener;

}

private

ShortSlideListener

shortSlideListener;

/**

*

The

{@link

MotionEvent#ACTION_DOWN}

gesture

location.

*/

private

int

downY;

/**

*

The

{@link

MotionEvent#ACTION_MOVE}

gesture

location.

*/

private

int

moveY;

/**

*

the

value

of

moved

distance

by

the

gesture.

When

the

value

was

modified

and

not

exceed

*

the

{@link

#movedMaxDis},

then

make

this

ViewGroup

move.

*/

private

int

movedDis;

/**

*

The

max

distance

that

the

{@link

SlideBottomLayout}

can

scroll

to,

it

used

to

compare

with

the

*

{@link

#downY},

determine

whether

it

can

slide

by

the

gesture.

*/

private

int

movedMaxDis;

/**

*

ChildView

of

the

{@link

SlideBottomLayout},

you

can

set

a

Layout

such

as

the

{@link

LinearLayout}、

*

{@link

android.widget.RelativeLayout}

ect.

*

We

set

the

rules

that

{@link

SlideBottomLayout}

just

can

have

one

child-view,

or

else

get

a

*

{@link

RuntimeException}

at

{@link

#onFinishInflate()}

*/

private

View

childView;

/**

*

The

control

{@link

SlideBottomLayout}

automatically

switches

the

threshold

of

the

state.

if

*

this

ViewGroup

moved

distance

more

than

{@link

#movedMaxDis}

*

it,

switch

the

state

of

*

{@link

#arriveTop}

right

now.

*

</p>

*

See

the

{@link

#touchActionUp(float)}.

*/

private

float

hideWeight

=

0.25f;

//3.注意，这个接口用来设置「需要自定义自动到达顶部/隐藏的阈值」

public

void

setHideWeight(float

hideWeight)

{

if

(hideWeight

<=

0

||

hideWeight

>

1)

throw

new

IllegalArgumentException("hideWeight

should

belong

(0f,1f]");

this.hideWeight

=

hideWeight;

}

private

Scroller

mScroller;

/**

*

It

means

the

{@link

#childView}

is

arriving

the

top

of

parent

or

else.

*/

private

boolean

arriveTop

=

false;

/**

*

the

{@link

#childView}

Initially

visible

height

*/

private

float

visibilityHeight;

//1.初始化Handle显示高度，建议您在xml中设置对应属性来实现该效果

public

void

setVisibilityHeight(float

visibilityHeight)

{

this.visibilityHeight

=

visibilityHeight;

}

public

SlideBottomLayout(@NonNull

Context

context)

{

super(context);

}

public

SlideBottomLayout(@NonNull

Context

context,

@Nullable

AttributeSet

attrs)

{

super(context,

attrs);

initAttrs(context,

attrs);

}

public

SlideBottomLayout(@NonNull

Context

context,

@Nullable

AttributeSet

attrs,

int

defStyleAttr)

{

super(context,

attrs,

defStyleAttr);

initAttrs(context,

attrs);

}

/**

*

Get

the

config

from

{@link

R.styleable},

then

init

other

configrations{@link

#initConfig(Context)}.

*

*

@param

context

the

{@link

Context}

*

@param

attrs

the

configs

in

layout

attrs.

*/

private

void

initAttrs(Context

context,

AttributeSet

attrs)

{

final

TypedArray

ta

=

context.obtainStyledAttributes(attrs,

R.styleable.SlideBottomLayout);

visibilityHeight

=

ta.getDimension(R.styleable.SlideBottomLayout_handler_height,

0);

ta.recycle();

initConfig(context);

}

private

void

initConfig(Context

context)

{

if

(mScroller

==

null)

mScroller

=

new

Scroller(context);

this.setBackgroundColor(Color.TRANSPARENT);

}

/**

*

It

start

a

judgement

for

ensure

the

child-view

be

unique

in

this

method，then

assgin

it

*

to

{{@link

#childView}.

*

this

method

will

be

called

before

the

{@link

#onMeasure(int,

int)}

*/

@Override

protected

void

onFinishInflate()

{

super.onFinishInflate();

if

(getChildCount()

==

0

||

getChildAt(0)

==

null)

{

throw

new

RuntimeException("there

have

no

child-View

in

the

SlideBottomLayout！");

}

if

(getChildCount()

>

1)

{

throw

new

RuntimeException("there

just

alow

one

child-View

in

the

SlideBottomLayout!");

}

childView

=

getChildAt(0);

}

@Override

protected

void

onMeasure(int

widthMeasureSpec,

int

heightMeasureSpec)

{

super.onMeasure(widthMeasureSpec,

heightMeasureSpec);

movedMaxDis

=

(int)

(childView.getMeasuredHeight()

-

visibilityHeight);

}

@Override

protected

void

onLayout(boolean

changed,

int

l,

int

t,

int

r,

int

b)

{

super.onLayout(changed,

l,

t,

r,

b);

childView.layout(0,

movedMaxDis,

childView.getMeasuredWidth(),

childView.getMeasuredHeight()

+

movedMaxDis);

}

@Override

public

boolean

onTouchEvent(MotionEvent

event)

{

final

float

dy

=

event.getY();

switch

(event.getAction())

{

case

MotionEvent.ACTION_DOWN:

if

(touchActionDown(dy))

return

true;

break;

case

MotionEvent.ACTION_MOVE:

if

(touchActionMove(dy))

return

true;

break;

case

MotionEvent.ACTION_UP:

if

(touchActionUp(dy))

return

true;

break;

}

return

super.onTouchEvent(event);

}

@Override

public

void

computeScroll()

{

puteScroll();

if

(mScroller

==

null)

mScroller

=

new

Scroller(getContext());

if

(mSputeScrollOffset())

{

scrollTo(0,

mScroller.getCurrY());

postInvalidate();

}

}

/**

*

When

the

touch

event

is

{@link

MotionEvent#ACTION_UP},

*

then

judge

the

state

of

view

group

and

control

the

{@link

Scroller}

to

scroll.

*

<p>

*

In

this

ViewGroup,

we

set

the

rules

that

is

if

this

scroll

gesture's

move

distance

*

more

than

{@link

#movedMaxDis}

*

{@link

#hideWeight}(default

hideWeight

value

is

1/4

heights

*

of

this

ViewGroup),

then

call

{@link

#hide()}

or

{@link

#show()}

right

now.

which

method

will

*

be

call

depends

on

{@link

#arriveTop}.

*

<p

*

if

the

scroll

gesture's

move

distance

don't

reach

the

goal

value,

then

call

the

*

{@link

ShortSlideListener#onShortSlide(float)}

if

you

call

{@link

#setShortSlideListener(ShortSlideListener)}

*

init

this

ViewGroup.

else

will

call

{@link

#hide()}.

*

*

@param

eventY

The

location

of

trigger

*

@return

Be

used

to

determine

consume

this

event

or

else.

*/

public

boolean

touchActionUp(float

eventY)

{

if

(movedDis

>

movedMaxDis

*

hideWeight)

{

switchVisible();

}

else

{

if

(shortSlideListener

!=

null)

{

shortSlideListener.onShortSlide(eventY);

}

else

{

hide();

}

}

return

true;

}

/**

*

When

the

touch

event

is

{@link

MotionEvent#ACTION_MOVE},

*

then

judge

the

state

of

view

group

and

control

the

{@link

Scroller}

to

scroll.

*

<p>

*

In

this

ViewGroup,

we

set

the

rules

that

is

if

this

scroll

gesture's

move

distance

*

more

than

{@link

#movedMaxDis}

*

{@link

#hideWeight}(default

hideWeight

value

is

1/4

heights

of

this

ViewGroup),

*

then

call

{@link

#hide()}

or

{@link

#show()}

right

now.

*

<p>

*

*

@param

eventY

The

location

of

trigger

*

@return

Be

used

to

determine

consume

this

event

or

else.

*/

public

boolean

touchActionMove(float

eventY)

{

moveY

=

(int)

eventY;

//the

dy

is

sum

of

the

move

distance,

the

value

>

0

means

scroll

up,

the

value

<

0

means

scroll

down.

final

int

dy

=

downY

-

moveY;

if

(dy

>

0)

{

//scroll

up

movedDis

+=

dy;

if

(movedDis

>

movedMaxDis)

movedDis

=

movedMaxDis;

if

(movedDis

<

movedMaxDis)

{

scrollBy(0,

dy);

downY

=

moveY;

return

true;

}

}

else

{

//scroll

down

movedDis

+=

dy;

if

(movedDis

<

0)

movedDis

=

0;

if

(movedDis

>

0)

{

scrollBy(0,

dy);

}

downY

=

moveY;

return

true;

}

return

false;

}

/**

*

When

the

touch

event

is

{@link

MotionEvent#ACTION_DOWN},

*

Record

the

location

of

this

action.

*

*

@param

eventY

The

location

of

trigger

*

@return

Be

used

to

determine

consume

this

event

or

else.

*/

public

boolean

touchA