[英]RecyclerView scrolls one item at a time automatically when switching between the tabs using ViewPager
我有一個基本的布局設置:DrawerLayout,它由活動的主布局和導航視圖的布局組成。 主布局有一個 CoordinatorLayout 和所有必要的來實現折疊工具欄功能,以及一個 ViewPager,我稍后會在代碼中填充片段。 Fragment 的布局主要由 RecyclerView 和其他次要視圖組成。
問題如下:每當我向下滾動兩個選項卡中的任何一個並滑動到新選項卡並返回到原始選項卡時,RecyclerView 都會收到 onScrolled 回調(它不應該因為我沒有滾動RV 本身,但 ViewPager)具有負 deltaY 參數(這意味着方向是向上的),這會導致頂部的下一個項目因此變得可見。
一些注意事項:
儀表板_活動_布局.xml:
<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/coordinatorLayout"
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.design.widget.AppBarLayout
android:id="@+id/appBarLayout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:elevation="@dimen/toolbar_shadow_height">
<android.support.v7.widget.Toolbar
android:id="@+id/toolbar"
android:layout_width="match_parent"
android:layout_height="@dimen/toolbar_height"
android:paddingTop="@dimen/toolbar_padding_top"
app:layout_scrollFlags="scroll|enterAlwaysCollapsed"
app:titleTextAppearance="@style/TitleTextView"
tools:background="@color/colorPrimary"/>
<android.support.design.widget.TabLayout
android:id="@+id/tabLayout"
android:layout_width="match_parent"
android:layout_height="@dimen/dashboard_activity_content_tab_layout_height"
app:tabMode="fixed"
app:tabGravity="fill"
tools:background="@color/colorPrimary"/>
</android.support.design.widget.AppBarLayout>
<android.support.v4.view.ViewPager
android:id="@+id/viewPager"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:overScrollMode="never"
app:layout_behavior="@string/appbar_scrolling_view_behavior"
tools:background="@color/colorPrimaryDark"/>
<android.support.design.widget.FloatingActionButton
android:id="@+id/actionButtonFab"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_margin="@dimen/dashboard_activity_content_fab_margin"
android:layout_gravity="bottom|end"
android:src="@mipmap/ic_search_white_24dp"
app:fabSize="normal"
app:useCompatPadding="true"
tools:backgroundTint="@color/colorAccent"/>
DashboardActivity.java(相關部分):
private void initViewPager() {
mViewPager = findViewById(R.id.viewPager);
mAdapter = new DashboardViewPagerAdapter(getSupportFragmentManager());
mAdapter.setViewPagerId(mViewPager.getId());
mAdapter.setRecyclerViewStateListener(mRecyclerViewStateListener);
populateAdapter();
mViewPager.setAdapter(mAdapter);
mViewPager.setOffscreenPageLimit(mAdapter.getCount());
}
private void populateAdapter() {
BaseFragment baseFragment = mAdapter.getFragmentForPosition(TAB_TAB_1);
if(baseFragment == null) {
baseFragment = SomeFragment.newInstance(Common.SOME_TYPE_1);
}
mAdapter.addFragment(baseFragment);
baseFragment = mAdapter.getFragmentForPosition(TAB_TAB_2);
if(baseFragment == null) {
baseFragment = SomeFragment.newInstance(Common.SOME_TYPE_2);
}
mAdapter.addFragment(baseFragment);
baseFragment = mAdapter.getFragmentForPosition(TAB_TAB_3);
if(baseFragment == null) {
baseFragment = SomeOtherFragment.init();
}
mAdapter.addFragment(baseFragment);
}
private RecyclerViewStateListener mRecyclerViewStateListener = new RecyclerViewStateListener() {
@Override
public void onScrolledDownwards(RecyclerView recyclerView, int deltaY) {
// Hiding the FAB by animating it
DashboardCommon.hideActionButton(mActionButtonFab, mViewAnimator, true);
}
@Override
public void onScrolledUpwards(RecyclerView recyclerView, int deltaY) {
// Showing the FAB by animating it
DashboardCommon.showActionButton(mActionButtonFab, mViewAnimator, true);
}
};
SomeFragment.java(相關部分):
private void initRecyclerView() {
mRecyclerView = findViewById(R.id.recyclerView);
mRecyclerView.addOnScrollListener(new RecyclerViewScrollListener(this));
mLayoutManager = new LinearLayoutManager(
getContext(),
LinearLayoutManager.VERTICAL,
false
);
mRecyclerView.setLayoutManager(mLayoutManager);
mAdapter = new SomeRecyclerViewAdapter(getContext(), mItems);
mRecyclerView.setAdapter(mAdapter);
}
// mRecyclerViewStateListener is the listener passed from the
// DashboardActivity
@CallSuper
public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
if(mRecyclerViewStateListener != null) {
mRecyclerViewStateListener.onScrollStateChanged(recyclerView, newState);
}
}
@Override
public void onScrolled(RecyclerView recyclerView, int deltaX, int deltaY) {
if(mRecyclerViewStateListener != null) {
mRecyclerViewStateListener.onScrolled(recyclerView, deltaX, deltaY);
}
}
@Override
public void onScrolledDownwards(RecyclerView recyclerView, int deltaY) {
if(mRecyclerViewStateListener != null) {
mRecyclerViewStateListener.onScrolledDownwards(recyclerView, deltaY);
}
}
@Override
public void onScrolledUpwards(RecyclerView recyclerView, int deltaY) {
if(mRecyclerViewStateListener != null) {
mRecyclerViewStateListener.onScrolledUpwards(recyclerView, deltaY);
}
}
@Override
public void onBottomReached() {
if(mRecyclerViewStateListener != null) {
mRecyclerViewStateListener.onBottomReached();
}
}
@Override
public void onMidpointReached(int direction) {
if(mRecyclerViewStateListener != null) {
mRecyclerViewStateListener.onMidpointReached(direction);
}
}
@Override
public void onTopReached() {
if(mRecyclerViewStateListener != null) {
mRecyclerViewStateListener.onTopReached();
}
}
RecyclerViewScrollListener.java(相關部分):
public class RecyclerViewScrollListener extends RecyclerView.OnScrollListener {
public static final int DIRECTION_UNSPECIFIED = -1;
public static final int DIRECTION_UPWARDS = 0;
public static final int DIRECTION_DOWNWARDS = 1;
// Omitted...
private StateListener mStateListener;
public RecyclerViewScrollListener(StateListener stateListener) {
// Omitted..
mStateListener = stateListener;
}
@Override
public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
if(mStateListener != null) {
mStateListener.onScrollStateChanged(recyclerView, newState);
}
}
@Override
public void onScrolled(RecyclerView recyclerView, int deltaX, int deltaY) {
if(mStateListener != null) {
mStateListener.onScrolled(recyclerView, deltaX, deltaY);
}
f(deltaY > 0) {
// Recycler view's contents are moving downwards
// Notifying about the downwards scroll
if(mStateListener != null) {
mStateListener.onScrolledDownwards(recyclerView, deltaY);
}
// Omitted...
if(someConditionIsTrue) {
// Omitted...
// Notifying the listener
mStateListener.onBottomReached();
} else if((someOtherConditionIsTrue) {
mStateListener.onMidpointReached(DIRECTION_DOWNWARDS);
}
} else if(deltaY < 0) {
// Recycler view's contents are moving upwards
// Notifying about upwards scroll
if(mStateListener != null) {
mStateListener.onScrolledUpwards(recyclerView, deltaY);
}
// Omitted...
if(someConditionIsTrue) {
// Omitted..
// Notifying the listener
mStateListener.onTopReached();
} else if(someOtherConditionIsTrue) {
mStateListener.onMidpointReached(DIRECTION_UPWARDS);
}
}
}
public interface StateListener {
void onScrollStateChanged(RecyclerView recyclerView, int newState);
void onScrolled(RecyclerView recyclerView, int deltaX, int deltaY);
void onScrolledDownwards(RecyclerView recyclerView, int deltaY);
void onScrolledUpwards(RecyclerView recyclerView, int deltaY);
void onBottomReached();
void onMidpointReached(int direction);
void onTopReached();
}
}
使用 This 一次自動滾動一項
RecyclerView my_recycler_view= (RecyclerView) findViewById(R.id.my_recycler_view);
SnapHelper snapHelper = new PagerSnapHelper();
snapHelper.attachToRecyclerView(my_recycler_view);
快樂編碼干杯
希望會有所幫助
RecyclerView my_recycler_view= (RecyclerView) findViewById(R.id.my_recycler_view);
SnapHelper snapHelper = new PagerSnapHelper();
snapHelper.attachToRecyclerView(my_recycler_view);
盡管我在 2 年前發布了這個問題,但我還是決定提供一個答案。 遲到總比不到好,對吧?
據我所知,問題在於RecyclerView
項目的布局具有TextView
,其中包含android:textIsSelectable="true"
屬性。 原來,通過刪除該屬性,問題就消失了。 你可能會問,我是如何實現文本選擇的? 老實說,我不記得了,因為它是很久以前的事了。
無論如何,如果您遇到這樣的問題,請嘗試刪除android:textIsSelectable="true"
屬性,它可以很好地為您解決問題。
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