【移動應用開發(fā)技術】在android應用中怎么添加一個上拉刷新下拉加載功能

【移動應用開發(fā)技術】在android應用中怎么添加一個上拉刷新下拉加載功能

在android應用中怎么添加一個上拉刷新下拉加載功能？針對這個問題，這篇文章詳細介紹了相對應的分析和解答，希望可以幫助更多想解決這個問題的小伙伴找到更簡單易行的方法。下拉刷新首先我們給出如下幾個參數(shù)，后面要用：

private

NestedScrollingParentHelper

helper

=

null;

private

boolean

IsRefresh

=

true;

private

boolean

IsLoad

=

true;

//滑動的總距離

private

int

totalY

=

0;

private

LinearLayout

headerLayout

=

null;

private

MyRecyclerView

myRecyclerView

=

null;

private

LinearLayout

footerLayout

=

null;既然是刷新，我們的滾動肯定是在父view之前的。所以我們需要在onNestedPreScroll這個方法里面寫上我們所需要改動的x，y值。我們需要用父view去攔截它。我們需要判斷dy的值是否大于0，因為大于0是刷新操作，小于0是加載操作。然后我們需要判斷recyclerview是否是縱向的而不是橫向的。public

void

onNestedPreScroll(View

target,

int

dx,

int

dy,

int[]

consumed)

{

if

(IsRefresh)

{

if

(dy

>

0)

{

if

(myRecyclerView.isOrientation(0))

{

totalY

+=

dy;

if

((totalY

/

2)

<=

0)

{

scrollTo(0,

totalY

/

2);

consumed[1]

=

dy;

}

else

{

scrollTo(0,

0);

consumed[1]

=

0;

}

}

return;

}

}上拉加載上面我也說了onNestedPreScroll這個方法中判斷dy<0才是加載操作。所以綜上所述，代碼變成了這樣：

public

void

onNestedPreScroll(View

target,

int

dx,

int

dy,

int[]

consumed)

{

if

(totalY

<

0

&&

myRecyclerView.isOrientation(0)

||

totalY

>

0

&&

myRecyclerView.isOrientation(1))

{

isfling

=

true;

}

if

(IsRefresh)

{

if

(dy

>

0)

{

if

(myRecyclerView.isOrientation(0))

{

totalY

+=

dy;

if

((totalY

/

2)

<=

0)

{

scrollTo(0,

totalY

/

2);

consumed[1]

=

dy;

}

else

{

scrollTo(0,

0);

consumed[1]

=

0;

}

}

return;

}

}

if

(IsLoad)

{

if

(dy

<

0)

{

if

(myRecyclerView.isOrientation(1))

{

totalY

+=

dy;

if

((totalY

/

2)

>=

0)

{

scrollTo(0,

totalY

/

2);

consumed[1]

=

dy;

}

else

{

scrollTo(0,

0);

consumed[1]

=

0;

}

}

return;

}

}

}最后我們需要在子view滑動結束后，實行如下操作：

//子view滑動結束調(diào)用

//dyUnconsumed

<

0

向下滾

//dyUnconsumed

>

0

向上滾

public

void

onNestedScroll(View

target,

int

dxConsumed,

int

dyConsumed,

int

dxUnconsumed,

int

dyUnconsumed)

{

if

(dyUnconsumed

!=

0)

{

totalY

+=

dyUnconsumed;

scrollTo(0,

totalY

/

2);

}

}其實最主要的兩個方法已經(jīng)解決了，其他到?jīng)]什么了，這邊，我把nestedscrolling的8個接口的功能和自定義recyclerview放出來。已變大家參考。希望大家都能實現(xiàn)自己的刷新加載。告別swiperefreshlayout。添加header和footer這里我們參考listview自帶的addheaderview和addfooterview。代碼如下：

public

void

addHeaderView(View

headerView,

int

headerHeight)

{

this.headerLayout.removeAllViews();

this.headerLayout.addView(headerView);

LayoutParams

layoutParams

=

new

LayoutParams(LayoutParams.MATCH_PARENT,

headerHeight);

layoutParams.topMargin

=

-headerHeight;

this.headerLayout.setLayoutParams(layoutParams);

}

public

void

addFooterView(View

footerView,

int

footerHeight)

{

this.footerLayout.removeAllViews();

this.footerLayout.addView(footerView);

this.footerLayout.setLayoutParams(new

LayoutParams(LayoutParams.MATCH_PARENT,

footerHeight));

}幾個接口的實現(xiàn)

public

boolean

onStartNestedScroll(View

child,

View

target,

int

nestedScrollAxes)

{

return

true;

}

public

void

onNestedScrollAccepted(View

child,

View

target,

int

axes)

{

helper.onNestedScrollAccepted(child,

target,

axes);

}

//父view攔截子view的滾動

public

void

onNestedPreScroll(View

target,

int

dx,

int

dy,

int[]

consumed)

{

if

(totalY

<

0

&&

myRecyclerView.isOrientation(0)

||

totalY

>

0

&&

myRecyclerView.isOrientation(1))

{

isfling

=

true;

}

if

(IsRefresh)

{

if

(dy

>

0)

{

if

(myRecyclerView.isOrientation(0))

{

totalY

+=

dy;

if

((totalY

/

2)

<=

0)

{

scrollTo(0,

totalY

/

2);

consumed[1]

=

dy;

}

else

{

scrollTo(0,

0);

consumed[1]

=

0;

}

}

return;

}

}

if

(IsLoad)

{

if

(dy

<

0)

{

if

(myRecyclerView.isOrientation(1))

{

totalY

+=

dy;

if

((totalY

/

2)

>=

0)

{

scrollTo(0,

totalY

/

2);

consumed[1]

=

dy;

}

else

{

scrollTo(0,

0);

consumed[1]

=

0;

}

}

return;

}

}

}

//子view滑動結束調(diào)用

//dyUnconsumed

<

0

向下滾

//dyUnconsumed

>

0

向上滾

public

void

onNestedScroll(View

target,

int

dxConsumed,

int

dyConsumed,

int

dxUnconsumed,

int

dyUnconsumed)

{

if

(dyUnconsumed

!=

0)

{

totalY

+=

dyUnconsumed;

scrollTo(0,

totalY

/

2);

}

}

public

void

onStopNestedScroll(View

child)

{

helper.onStopNestedScroll(child);

if

(onTouchUpListener

!=

null)

{

isfling

=

false;

onTouchUpListener.touchUp();

}

}

public

boolean

onNestedFling(View

target,

float

velocityX,

float

velocityY,

boolean

consumed)

{

return

isfling;

}

public

boolean

onNestedPreFling(View

target,

float

velocityX,

float

velocityY)

{

return

isfling;

}

public

int

getNestedScrollAxes()

{

return

helper.getNestedScrollAxes();

}自定義recyclerview既然是自己寫的刷新加載框架，總不能還有自定義layout中在放個recyclerview。多麻煩，自定義一個，直接放在里面，然后分別放個header和footer就沒必要每次有頁面用到刷新都要寫一個布局。3個布局解決整個項目的刷新和加載。話不多說，代碼如下：

private

class

MyRecyclerView

extends

RecyclerView

{

private

StaggeredGridLayoutManager

staggeredGridLayoutManager

=

null;

private

LinearLayoutManager

linearLayoutManager

=

null;

private

GridLayoutManager

gridLayoutManager

=

null;

private

boolean

isScrollLoad

=

false;

private

boolean

isScrollRefresh

=

false;

public

MyRecyclerView(Context

context)

{

super(context);

setVerticalFadingEdgeEnabled(false);

setHorizontalFadingEdgeEnabled(false);

setVerticalScrollBarEnabled(false);

setHorizontalScrollBarEnabled(false);

setOverScrollMode(OVER_SCROLL_NEVER);

setItemAnimator(new

DefaultItemAnimator());

}

private

void

setMyLayoutManager(LayoutManager

layoutManager)

{

if

(layoutManager

instanceof

StaggeredGridLayoutManager)

{

staggeredGridLayoutManager

=

(StaggeredGridLayoutManager)

layoutManager;

}

else

if

(layoutManager

instanceof

GridLayoutManager)

{

gridLayoutManager

=

(GridLayoutManager)

layoutManager;

}

else

if

(layoutManager

instanceof

LinearLayoutManager)

{

linearLayoutManager

=

(LinearLayoutManager)

layoutManager;

}

setLayoutManager(layoutManager);

if

(!isVertical())

{

throw

new

NullPointerException("vertical!");

}

}

private

boolean

isOrientation(int

orientation)

{//orientation,0代表向下，1代表向上

if

(orientation

==

0)

return

isCanPullDown();

else

if

(orientation

==

1)

return

isCanPullUp();

return

false;

}

private

boolean

isCanPullDown()

{

return

!canScrollVertically(-1);

}

private

boolean

isCanPullUp()

{

return

!canScrollVertically(1);

}

//

private

int

scrollLoad()

{

//

int

lastItem

=

0;

//

int

itemCount

=

0;

//

int

spanCount

=

1;

//

if

(staggeredGridLayoutManager

!=

null)

{

//

lastItem

=

staggeredGridLayoutManager.findLastVisibleItemPositions(null)[0];

//

itemCount

=

staggeredGridLayoutManager.getItemCount();

//

spanCount

=

staggeredGridLayoutManager.getSpanCount();

//

}

else

if

(linearLayoutManager

!=

null)

{

//

lastItem

=

linearLayoutManager.findLastVisibleItemPosition();

//

itemCount

=

linearLayoutManager.getItemCount();

//

spanCount

=

1;

//

}

else

if

(gridLayoutManager

!=

null)

{

//

lastItem

=

gridLayoutManager.findLastVisibleItemPosition();

//

itemCount

=

gridLayoutManager.getItemCount();

/