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问题:
My specific question is: How I can achieve an effect like this: http://youtu.be/EJm7subFbQI
The bounce effect is not important, but i need the "sticky" effect for the headers. Where do I start?, In what can I base me? I need something that I can implement on API 8 to up.
Thanks.
回答1:
There are a few solutions that already exist for this problem. What you're describing are section headers and have come to be referred to as sticky section headers in Android.
- Sticky List Headers
- Sticky Scroll Views
- HeaderListView
回答2:
EDIT: Had some free time to add the code of fully working example. Edited the answer accordingly.
For those who don't want to use 3rd party code (or cannot use it directly, e.g. in Xamarin), this could be done fairly easily by hand.
The idea is to use another ListView for the header. This list view contains only the header items. It will not be scrollable by the user (setEnabled(false)), but will be scrolled from code based on main lists' scrolling. So you will have two lists - headerListview and mainListview, and two corresponding adapters headerAdapter and mainAdapter. headerAdapter only returns section views, while mainAdapter supports two view types (section and item). You will need a method that takes a position in the main list and returns a corresponding position in the sections list.
Main activity
public class MainActivity extends AppCompatActivity {
public static final int TYPE_SECTION = 0;
public static final int TYPE_ITEM = 1;
ListView mainListView;
ListView headerListView;
MainAdapter mainAdapter;
HeaderAdapter headerAdapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mainListView = (ListView)findViewById(R.id.list);
headerListView = (ListView)findViewById(R.id.header);
mainAdapter = new MainAdapter();
headerAdapter = new HeaderAdapter();
headerListView.setEnabled(false);
headerListView.setAdapter(headerAdapter);
mainListView.setAdapter(mainAdapter);
mainListView.setOnScrollListener(new AbsListView.OnScrollListener(){
@Override
public void onScrollStateChanged(AbsListView view, int scrollState){
}
@Override
public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
// this should return an index in the headers list, based one the index in the main list. The logic for this is highly dependent on your data.
int pos = mainAdapter.getSectionIndexForPosition(firstVisibleItem);
// this makes sure our headerListview shows the proper section (the one on the top of the mainListview)
headerListView.setSelection(pos);
// this makes sure that headerListview is scrolled exactly the same amount as the mainListview
if(mainAdapter.getItemViewType(firstVisibleItem + 1) == TYPE_SECTION){
headerListView.setSelectionFromTop(pos, mainListView.getChildAt(0).getTop());
}
}
});
}
public class MainAdapter extends BaseAdapter{
int count = 30;
@Override
public int getItemViewType(int position){
if((float)position / 10 == (int)((float)position/10)){
return TYPE_SECTION;
}else{
return TYPE_ITEM;
}
}
@Override
public int getViewTypeCount(){ return 2; }
@Override
public int getCount() { return count - 1; }
@Override
public Object getItem(int position) { return null; }
@Override
public long getItemId(int position) { return position; }
public int getSectionIndexForPosition(int position){ return position / 10; }
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View v = getLayoutInflater().inflate(R.layout.item, parent, false);
position++;
if(getItemViewType(position) == TYPE_SECTION){
((TextView)v.findViewById(R.id.text)).setText("SECTION "+position);
}else{
((TextView)v.findViewById(R.id.text)).setText("Item "+position);
}
return v;
}
}
public class HeaderAdapter extends BaseAdapter{
int count = 5;
@Override
public int getCount() { return count; }
@Override
public Object getItem(int position) { return null; }
@Override
public long getItemId(int position) { return position; }
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View v = getLayoutInflater().inflate(R.layout.item, parent, false);
((TextView)v.findViewById(R.id.text)).setText("SECTION "+position*10);
return v;
}
}
}
A couple of things to note here. We do not want to show the very first section in the main view list, because it would produce a duplicate (it's already shown in the header). To avoid that, in your mainAdapter.getCount():
return actualCount - 1;
and make sure the first line in your getView() method is
position++;
This way your main list will be rendering all cells but the first one.
Another thing is that you want to make sure your headerListview's height matches the height of the list item. In this example the height is fixed, but it could be tricky if your items height is not set to an exact value in dp. Please refer to this answer for how to address this: https://stackoverflow.com/a/41577017/291688
Main layout
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/activity_main"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin">
<ListView
android:id="@+id/header"
android:layout_width="match_parent"
android:layout_height="48dp"/>
<ListView
android:id="@+id/list"
android:layout_below="@+id/header"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
</RelativeLayout>
Item / header layout
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="48dp">
<TextView
android:id="@+id/text"
android:gravity="center_vertical"
android:layout_width="match_parent"
android:layout_height="match_parent"
/>
</LinearLayout>
回答3:
Add this in your app.gradle file
compile 'se.emilsjolander:StickyScrollViewItems:1.1.0'
then my layout, where I have added android:tag ="sticky"
to specific views like textview or edittext not LinearLayout, looks like this. It also uses databinding, ignore that.
<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android">
<data>
<variable
name="temp"
type="com.lendingkart.prakhar.lendingkartdemo.databindingmodel.BusinessDetailFragmentModel" />
<variable
name="presenter"
type="com.lendingkart.prakhar.lendingkartdemo.presenters.BusinessDetailsPresenter" />
</data>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<com.lendingkart.prakhar.lendingkartdemo.customview.StickyScrollView
android:id="@+id/sticky_scroll"
android:layout_width="match_parent"
android:layout_height="match_parent">
<!-- scroll view child goes here -->
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<android.support.v7.widget.CardView xmlns:card_view="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="center"
card_view:cardCornerRadius="5dp"
card_view:cardUseCompatPadding="true">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<TextView
style="@style/group_view_text"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="@drawable/businessdetailtitletextviewbackground"
android:padding="@dimen/activity_horizontal_margin"
android:tag="sticky"
android:text="@string/business_contact_detail" />
<android.support.design.widget.TextInputLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="7dp">
<android.support.design.widget.TextInputEditText
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="@string/comapnyLabel"
android:textSize="16sp" />
</android.support.design.widget.TextInputLayout>
<android.support.design.widget.TextInputLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="5dp">
<android.support.design.widget.TextInputEditText
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="@string/contactLabel"
android:textSize="16sp" />
</android.support.design.widget.TextInputLayout>
<android.support.design.widget.TextInputLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="5dp">
<android.support.design.widget.TextInputEditText
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="@string/emailLabel"
android:textSize="16sp" />
</android.support.design.widget.TextInputLayout>
<android.support.design.widget.TextInputLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="5dp">
<android.support.design.widget.TextInputEditText
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="@string/NumberOfEmployee"
android:textSize="16sp" />
</android.support.design.widget.TextInputLayout>
</LinearLayout>
</android.support.v7.widget.CardView>
<android.support.v7.widget.CardView xmlns:card_view="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="center"
card_view:cardCornerRadius="5dp"
card_view:cardUseCompatPadding="true">
<TextView
style="@style/group_view_text"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="@drawable/businessdetailtitletextviewbackground"
android:padding="@dimen/activity_horizontal_margin"
android:tag="sticky"
android:text="@string/nature_of_business" />
</android.support.v7.widget.CardView>
<android.support.v7.widget.CardView xmlns:card_view="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="center"
card_view:cardCornerRadius="5dp"
card_view:cardUseCompatPadding="true">
<TextView
style="@style/group_view_text"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="@drawable/businessdetailtitletextviewbackground"
android:padding="@dimen/activity_horizontal_margin"
android:tag="sticky"
android:text="@string/taxation" />
</android.support.v7.widget.CardView>
</LinearLayout>
</com.lendingkart.prakhar.lendingkartdemo.customview.StickyScrollView>
</LinearLayout>
</layout>
style group for the textview looks this
<style name="group_view_text" parent="@android:style/TextAppearance.Medium">
<item name="android:layout_width">wrap_content</item>
<item name="android:layout_height">wrap_content</item>
<item name="android:textColor">@color/edit_text_color</item>
<item name="android:textSize">16dp</item>
<item name="android:layout_centerVertical">true</item>
<item name="android:textStyle">bold</item>
</style>
and the background for the textview goes like this:(@drawable/businessdetailtitletextviewbackground)
<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
<item>
<shape android:shape="rectangle">
<solid android:color="@color/edit_text_color" />
</shape>
</item>
<item android:bottom="2dp">
<shape android:shape="rectangle">
<solid android:color="@color/White" />
</shape>
</item>
</layer-list>
回答4:
You can reach this effect using SuperSLiM library. It provides you a LayoutManager for RecyclerView with interchangeable linear, grid, and staggered displays of views.
A good demo is located in github repository
It is simply to get such result
app:slm_headerDisplay="inline|sticky"
or
app:slm_headerDisplay="sticky"
回答5:
I have used one special class to achieve listview like iPhone.
You can find example with source code here. https://demonuts.com/android-recyclerview-sticky-header-like-iphone/
This class which has updated listview is as
import android.content.Context;
import android.graphics.drawable.Drawable;
import android.util.AttributeSet;
import android.util.TypedValue;
import android.view.Gravity;
import android.view.View;
import android.view.animation.AlphaAnimation;
import android.widget.AbsListView;
import android.widget.AdapterView;
import android.widget.FrameLayout;
import android.widget.ImageView;
import android.widget.ImageView.ScaleType;
import android.widget.ListView;
import android.widget.RelativeLayout;
public class HeaderListView extends RelativeLayout {
// TODO: Handle listViews with fast scroll
// TODO: See if there are methods to dispatch to mListView
private static final int FADE_DELAY = 1000;
private static final int FADE_DURATION = 2000;
private InternalListView mListView;
private SectionAdapter mAdapter;
private RelativeLayout mHeader;
private View mHeaderConvertView;
private FrameLayout mScrollView;
private AbsListView.OnScrollListener mExternalOnScrollListener;
public HeaderListView(Context context) {
super(context);
init(context, null);
}
public HeaderListView(Context context, AttributeSet attrs) {
super(context, attrs);
init(context, attrs);
}
private void init(Context context, AttributeSet attrs) {
mListView = new InternalListView(getContext(), attrs);
LayoutParams listParams = new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT);
listParams.addRule(ALIGN_PARENT_TOP);
mListView.setLayoutParams(listParams);
mListView.setOnScrollListener(new HeaderListViewOnScrollListener());
mListView.setVerticalScrollBarEnabled(false);
mListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
if (mAdapter != null) {
mAdapter.onItemClick(parent, view, position, id);
}
}
});
addView(mListView);
mHeader = new RelativeLayout(getContext());
LayoutParams headerParams = new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT);
headerParams.addRule(ALIGN_PARENT_TOP);
mHeader.setLayoutParams(headerParams);
mHeader.setGravity(Gravity.BOTTOM);
addView(mHeader);
// The list view's scroll bar can be hidden by the header, so we display our own scroll bar instead
Drawable scrollBarDrawable = getResources().getDrawable(R.drawable.scrollbar_handle_holo_light);
mScrollView = new FrameLayout(getContext());
LayoutParams scrollParams = new LayoutParams(scrollBarDrawable.getIntrinsicWidth(), LayoutParams.MATCH_PARENT);
scrollParams.addRule(ALIGN_PARENT_RIGHT);
scrollParams.rightMargin = (int) dpToPx(2);
mScrollView.setLayoutParams(scrollParams);
ImageView scrollIndicator = new ImageView(context);
scrollIndicator.setLayoutParams(new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT));
scrollIndicator.setImageDrawable(scrollBarDrawable);
scrollIndicator.setScaleType(ScaleType.FIT_XY);
mScrollView.addView(scrollIndicator);
mScrollView.setVisibility(INVISIBLE);
addView(mScrollView);
}
public void setAdapter(SectionAdapter adapter) {
mAdapter = adapter;
mListView.setAdapter(adapter);
}
public void setOnScrollListener(AbsListView.OnScrollListener l) {
mExternalOnScrollListener = l;
}
private class HeaderListViewOnScrollListener implements AbsListView.OnScrollListener {
private int previousFirstVisibleItem = -1;
private int direction = 0;
private int actualSection = 0;
private boolean scrollingStart = false;
private boolean doneMeasuring = false;
private int lastResetSection = -1;
private int nextH;
private int prevH;
private View previous;
private View next;
private AlphaAnimation fadeOut = new AlphaAnimation(1f, 0f);
private boolean noHeaderUpToHeader = false;
private boolean didScroll = false;
@Override
public void onScrollStateChanged(AbsListView view, int scrollState) {
if (mExternalOnScrollListener != null) {
mExternalOnScrollListener.onScrollStateChanged(view, scrollState);
}
didScroll = true;
}
@Override
public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
if (mExternalOnScrollListener != null) {
mExternalOnScrollListener.onScroll(view, firstVisibleItem, visibleItemCount, totalItemCount);
}
if (!didScroll) {
return;
}
firstVisibleItem -= mListView.getHeaderViewsCount();
if (firstVisibleItem < 0) {
mHeader.removeAllViews();
return;
}
updateScrollBar();
if (visibleItemCount > 0 && firstVisibleItem == 0 && mHeader.getChildAt(0) == null) {
addSectionHeader(0);
lastResetSection = 0;
}
int realFirstVisibleItem = getRealFirstVisibleItem(firstVisibleItem, visibleItemCount);
if (totalItemCount > 0 && previousFirstVisibleItem != realFirstVisibleItem) {
direction = realFirstVisibleItem - previousFirstVisibleItem;
actualSection = mAdapter.getSection(realFirstVisibleItem);
boolean currIsHeader = mAdapter.isSectionHeader(realFirstVisibleItem);
boolean prevHasHeader = mAdapter.hasSectionHeaderView(actualSection - 1);
boolean nextHasHeader = mAdapter.hasSectionHeaderView(actualSection + 1);
boolean currHasHeader = mAdapter.hasSectionHeaderView(actualSection);
boolean currIsLast = mAdapter.getRowInSection(realFirstVisibleItem) == mAdapter.numberOfRows(actualSection) - 1;
boolean prevHasRows = mAdapter.numberOfRows(actualSection - 1) > 0;
boolean currIsFirst = mAdapter.getRowInSection(realFirstVisibleItem) == 0;
boolean needScrolling = currIsFirst && !currHasHeader && prevHasHeader && realFirstVisibleItem != firstVisibleItem;
boolean needNoHeaderUpToHeader = currIsLast && currHasHeader && !nextHasHeader && realFirstVisibleItem == firstVisibleItem && Math.abs(mListView.getChildAt(0).getTop()) >= mListView.getChildAt(0).getHeight() / 2;
noHeaderUpToHeader = false;
if (currIsHeader && !prevHasHeader && firstVisibleItem >= 0) {
resetHeader(direction < 0 ? actualSection - 1 : actualSection);
} else if ((currIsHeader && firstVisibleItem > 0) || needScrolling) {
if (!prevHasRows) {
resetHeader(actualSection-1);
}
startScrolling();
} else if (needNoHeaderUpToHeader) {
noHeaderUpToHeader = true;
} else if (lastResetSection != actualSection) {
resetHeader(actualSection);
}
previousFirstVisibleItem = realFirstVisibleItem;
}
if (scrollingStart) {
int scrolled = realFirstVisibleItem >= firstVisibleItem ? mListView.getChildAt(realFirstVisibleItem - firstVisibleItem).getTop() : 0;
if (!doneMeasuring) {
setMeasurements(realFirstVisibleItem, firstVisibleItem);
}
int headerH = doneMeasuring ? (prevH - nextH) * direction * Math.abs(scrolled) / (direction < 0 ? nextH : prevH) + (direction > 0 ? nextH : prevH) : 0;
mHeader.scrollTo(0, -Math.min(0, scrolled - headerH));
if (doneMeasuring && headerH != mHeader.getLayoutParams().height) {
LayoutParams p = (LayoutParams) (direction < 0 ? next.getLayoutParams() : previous.getLayoutParams());
p.topMargin = headerH - p.height;
mHeader.getLayoutParams().height = headerH;
mHeader.requestLayout();
}
}
if (noHeaderUpToHeader) {
if (lastResetSection != actualSection) {
addSectionHeader(actualSection);
lastResetSection = actualSection + 1;
}
mHeader.scrollTo(0, mHeader.getLayoutParams().height - (mListView.getChildAt(0).getHeight() + mListView.getChildAt(0).getTop()));
}
}
private void startScrolling() {
scrollingStart = true;
doneMeasuring = false;
lastResetSection = -1;
}
private void resetHeader(int section) {
scrollingStart = false;
addSectionHeader(section);
mHeader.requestLayout();
lastResetSection = section;
}
private void setMeasurements(int realFirstVisibleItem, int firstVisibleItem) {
if (direction > 0) {
nextH = realFirstVisibleItem >= firstVisibleItem ? mListView.getChildAt(realFirstVisibleItem - firstVisibleItem).getMeasuredHeight() : 0;
}
previous = mHeader.getChildAt(0);
prevH = previous != null ? previous.getMeasuredHeight() : mHeader.getHeight();
if (direction < 0) {
if (lastResetSection != actualSection - 1) {
addSectionHeader(Math.max(0, actualSection - 1));
next = mHeader.getChildAt(0);
}
nextH = mHeader.getChildCount() > 0 ? mHeader.getChildAt(0).getMeasuredHeight() : 0;
mHeader.scrollTo(0, prevH);
}
doneMeasuring = previous != null && prevH > 0 && nextH > 0;
}
private void updateScrollBar() {
if (mHeader != null && mListView != null && mScrollView != null) {
int offset = mListView.computeVerticalScrollOffset();
int range = mListView.computeVerticalScrollRange();
int extent = mListView.computeVerticalScrollExtent();
mScrollView.setVisibility(extent >= range ? View.INVISIBLE : View.VISIBLE);
if (extent >= range) {
return;
}
int top = range == 0 ? mListView.getHeight() : mListView.getHeight() * offset / range;
int bottom = range == 0 ? 0 : mListView.getHeight() - mListView.getHeight() * (offset + extent) / range;
mScrollView.setPadding(0, top, 0, bottom);
fadeOut.reset();
fadeOut.setFillBefore(true);
fadeOut.setFillAfter(true);
fadeOut.setStartOffset(FADE_DELAY);
fadeOut.setDuration(FADE_DURATION);
mScrollView.clearAnimation();
mScrollView.startAnimation(fadeOut);
}
}
private void addSectionHeader(int actualSection) {
View previousHeader = mHeader.getChildAt(0);
if (previousHeader != null) {
mHeader.removeViewAt(0);
}
if (mAdapter.hasSectionHeaderView(actualSection)) {
mHeaderConvertView = mAdapter.getSectionHeaderView(actualSection, mHeaderConvertView, mHeader);
mHeaderConvertView.setLayoutParams(new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT));
mHeaderConvertView.measure(MeasureSpec.makeMeasureSpec(mHeader.getWidth(), MeasureSpec.EXACTLY), MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED));
mHeader.getLayoutParams().height = mHeaderConvertView.getMeasuredHeight();
mHeaderConvertView.scrollTo(0, 0);
mHeader.scrollTo(0, 0);
mHeader.addView(mHeaderConvertView, 0);
} else {
mHeader.getLayoutParams().height = 0;
mHeader.scrollTo(0, 0);
}
mScrollView.bringToFront();
}
private int getRealFirstVisibleItem(int firstVisibleItem, int visibleItemCount) {
if (visibleItemCount == 0) {
return -1;
}
int relativeIndex = 0, totalHeight = mListView.getChildAt(0).getTop();
for (relativeIndex = 0; relativeIndex < visibleItemCount && totalHeight < mHeader.getHeight(); relativeIndex++) {
totalHeight += mListView.getChildAt(relativeIndex).getHeight();
}
int realFVI = Math.max(firstVisibleItem, firstVisibleItem + relativeIndex - 1);
return realFVI;
}
}
public ListView getListView() {
return mListView;
}
public void addHeaderView(View v) {
mListView.addHeaderView(v);
}
private float dpToPx(float dp) {
return TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, dp, getContext().getResources().getDisplayMetrics());
}
protected class InternalListView extends ListView {
public InternalListView(Context context, AttributeSet attrs) {
super(context, attrs);
}
@Override
protected int computeVerticalScrollExtent() {
return super.computeVerticalScrollExtent();
}
@Override
protected int computeVerticalScrollOffset() {
return super.computeVerticalScrollOffset();
}
@Override
protected int computeVerticalScrollRange() {
return super.computeVerticalScrollRange();
}
}
}
XML usage
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout 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:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<com.example.parsaniahardik.listview_stickyheader_ios.HeaderListView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="@+id/lv">
</com.example.parsaniahardik.listview_stickyheader_ios.HeaderListView>