I'm trying to implement a ScrollView in Android that doesn't scroll when adding an item above the current scroll position.
The default implementation of ScrollView behaves as following:
Adding an item above the current scroll position:
Adding an item below the current scroll position:
How can I "lock" the ScrollView prior to adding an item above the current scroll position?
This is my layout file, I've currently overridden both the ScrollView and LinearLayout, but haven't made any alterations yet.
<LinearLayout
android:layout_height="fill_parent"
android:orientation="vertical"
android:layout_width="fill_parent">
<LinearLayout
android:id="#+id/LinearLayout02"
android:layout_height="wrap_content"
android:layout_width="fill_parent"
android:layout_alignParentBottom="true">
<Button
android:id="#+id/Button02"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1" android:text="Add To Top"
android:onClick="addToStart">
</Button>
<Button
android:id="#+id/Button03"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="Add to End"
android:onClick="addToEnd">
</Button>
</LinearLayout>
<com.poc.scroller.locable.lockablescrollerpoc.LockedScrollView xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:fillViewport="true"
android:scrollbarAlwaysDrawVerticalTrack="true"
android:verticalScrollbarPosition="right"
android:fadeScrollbars="false"
android:background="#color/scrollColor">
<com.poc.scroller.locable.lockablescrollerpoc.LockedLinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:id="#+id/Container">
</com.poc.scroller.locable.lockablescrollerpoc.LockedLinearLayout>
</com.poc.scroller.locable.lockablescrollerpoc.LockedScrollView>
</LinearLayout>
</android.support.constraint.ConstraintLayout>
Example Source Code:
https://github.com/Amaros90/android-lockable-scroller-poc
Thank you!
You can easily get the opposite behavior by using addOnLayoutChangeListener of your LinearLayout and reset the ScrollView's ScrollY. Here is the implementation in your ScrollViewActivity.onCreate
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.scrollview);
_linearLayout = (LockedLinearLayout)findViewById(R.id.Container);
_scrollView = (LockedScrollView)findViewById(R.id.ScrollView);
_layoutInflater = (LayoutInflater)getSystemService(Context.LAYOUT_INFLATER_SERVICE);
_linearLayout.addOnLayoutChangeListener(new View.OnLayoutChangeListener() {
#Override
public void onLayoutChange(View v, int left, int top, int right, int bottom, int oldLeft, int oldTop, int oldRight, int oldBottom) {
_scrollView.scrollTo(0, _scrollView.getScrollY() + (bottom - oldBottom ));
}
});
addExampleImage(10, _linearLayout);
}
Then you can easily flag the addToEnd function or check where the child was added to avoid changing scroll when some child is added to the bottom.
You can try to use RecyclerView and implement onDataSetChanged(). Then detect whether add to TOP or add to END button was pressed. Then use scrollToPositionWithOffset(int, int) to manage the scroll.
For example:
//Scroll item 3 to 20 pixels from the top
linearLayoutManager.scrollToPositionWithOffset(3, 20);
For restoring the scroll position of a RecyclerView, this is how to save the scroll positions (the two arguments for the method scrollToPositionWithOffset(int, int)):
int index = linearLayoutManager.findFirstVisibleItemPosition();
View v = linearLayoutManager.getChildAt(0);
int top = (v == null) ? 0 : (v.getTop() - linearLayoutManager.getPaddingTop())
Implementing this worked for me. You can check out the example app I added in the original question.
public class LockableScrollView extends ScrollView {
private boolean _enabled = true;
public LockableScrollView(Context context, AttributeSet attrs) {
super(context, attrs);
super.setFillViewport(true);
}
#Override
public void addView(View layout, ViewGroup.LayoutParams params) {
super.addView(layout, params);
((ViewGroup)layout).setOnHierarchyChangeListener(new OnHierarchyChangeListener() {
#Override
public void onChildViewAdded(View layout, View item) {
if (_enabled) {
item.addOnLayoutChangeListener(new View.OnLayoutChangeListener() {
#Override
public void onLayoutChange(View item, int left, int top, int right, int bottom, int oldLeft, int oldTop, int oldRight, int oldBottom) {
item.removeOnLayoutChangeListener(this);
int scrollViewY = ((LockableScrollView)item.getParent().getParent()).getScrollY();
int layoutPosition = ((View)item.getParent()).getTop();
boolean shouldScroll = item.getTop() + layoutPosition <= scrollViewY || item.getBottom() + getTop() <= scrollViewY;
if (shouldScroll) {
final int childViewHeight = item.getHeight();
((View)item.getParent()).addOnLayoutChangeListener(new View.OnLayoutChangeListener() {
#Override
public void onLayoutChange(View layout, int left, int top, int right, int bottom, int oldLeft, int oldTop, int oldRight, int oldBottom) {
layout.removeOnLayoutChangeListener(this);
LockableScrollView scrollView = ((LockableScrollView)layout.getParent());
scrollView.scrollTo(scrollView.getScrollX(), scrollView.getScrollY() + childViewHeight);
}
});
}
}
});
}
}
#Override
public void onChildViewRemoved(View layout, View item) {
if (_enabled) {
int scrollViewY = ((LockableScrollView)layout.getParent()).getScrollY();
int layoutPosition = layout.getTop();
boolean shouldScroll = item.getTop() + layoutPosition <= scrollViewY || item.getBottom() + getTop() <= scrollViewY;
if (shouldScroll) {
final int childViewHeight = item.getHeight();
layout.addOnLayoutChangeListener(new View.OnLayoutChangeListener() {
#Override
public void onLayoutChange(View layout, int left, int top, int right, int bottom, int oldLeft, int oldTop, int oldRight, int oldBottom) {
layout.removeOnLayoutChangeListener(this);
LockableScrollView scrollView = ((LockableScrollView)layout.getParent());
scrollView.scrollTo(scrollView.getScrollX(), scrollView.getScrollY() - childViewHeight);
}
});
}
}
}
});
}
}
you can do it easily just get it..
first of all in onclick event store the int value by
using getFirstVisiblePosition()
example.
in onclick of add element button do this---
int currentpos = recycleview.getFirstVisiblePosition();
now after you insert elment to list/recyclerview---
recyclerview.scrolltoposition(currentpos);
thats it try if you want to do it without error..
Good Luck :)
Related
I have a BindingAdapter like
#BindingAdapter({ "onGlobalLayout" })
public static void setOnGlobalLayout(View view, ViewTreeObserver.OnGlobalLayoutListener onGlobalLayoutListener) {
ViewTreeObserver vto = view.getViewTreeObserver();
vto.addOnGlobalLayoutListener(onGlobalLayoutListener);
}
In XML I have a View like
<View
android:id="#+id/viewId"
bind:onGlobalLayout="#{viewModel.onLayoutListener}"
/>
In ViewModel I have
public ViewTreeObserver.OnGlobalLayoutListener onLayoutListener(View view){
return new ViewTreeObserver.OnGlobalLayoutListener() {
#Override
public void onGlobalLayout() {
// get x,y,width, height of view
}
};
}
Now I want to send the current View to ViewModel so I add a parametter View view to onLayoutListener but in XML I don't know how to send it.
Any help or suggestion would be great appreciated
UPDATE
Thank #pskink for suggest a better way for checking layout change.
With android:onLayoutChange I don't need BindingAdapter
<View
android:id="#+id/viewId"
android:onLayoutChange="#{viewModel.onLayoutListener(viewId)}"
/>
Java
public View.OnLayoutChangeListener onLayoutUpdateWeightSuccessfulListener(final View v) {
return new View.OnLayoutChangeListener() {
#Override
public void onLayoutChange(View v, int left, int top, int right, int bottom,
int oldLeft, int oldTop, int oldRight, int oldBottom) {
// left, top
}
};
}
simply pass your View id, it should work
bind:onGlobalLayout="#{viewModel.onLayoutListener(viewId)}"
I am using listview inside Viewpager where I need to set ListView height based on child and I need to add new Items when user scroll to last position of Listview. But the problem is when I am setting listview height dynamically its making current listview item visible(or selected). That's why getting (calling method to get data) automatically.
Code is given below:
int index = lvNetwork.getFirstVisiblePosition();
View v = lvNetwork.getChildAt(0);
int top = (v == null) ? 0 : v.getTop();
adapter = new NetworkAdapter(activity, R.layout.network_custom_row, networkDataArrayList);
adapter.notifyDataSetChanged();
lvNetwork.setAdapter(adapter);
Utils.setlistViewHeight(lvNetwork, activity);
lvNetwork.setSelectionFromTop(index, top);
lvNetwork.setOnScrollListener(new AbsListView.OnScrollListener() {
#Override
public void onScrollStateChanged(AbsListView view, int scrollState) {
}
#Override
public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
int finalItem = firstVisibleItem + visibleItemCount;
Log.d("dataCalling", "visible " + finalItem);
Log.d("dataCalling", "total " + totalItemCount);
if (finalItem == totalItemCount) {
if (preLast != finalItem) {
preLast = finalItem;
Log.d("dataCalling", String.valueOf(totalItemCount));
Log.d("dataCalling", "Page " + nextid);
progressBar.setVisibility(View.VISIBLE);
getNetworkFeed();
}
}
}
});
setlistviewHeight method inside Utils,
public static void setlistViewHeight(ListView listView, Context context) {
ListAdapter myListAdapter = listView.getAdapter();
if (myListAdapter == null) {
return;
}
int totalHeight = 0;
for (int size = 0; size < myListAdapter.getCount(); size++) {
View listItem = myListAdapter.getView(size, null, listView);
if (listItem instanceof ViewGroup)
listItem.setLayoutParams(new RelativeLayout.LayoutParams(
RelativeLayout.LayoutParams.WRAP_CONTENT,
RelativeLayout.LayoutParams.WRAP_CONTENT));
WindowManager wm = (WindowManager) context
.getSystemService(Context.WINDOW_SERVICE);
Display display = wm.getDefaultDisplay();
#SuppressWarnings("deprecation")
int screenWidth = display.getWidth();
int listViewWidth = screenWidth - 65;
int widthSpec = View.MeasureSpec.makeMeasureSpec(listViewWidth,
View.MeasureSpec.AT_MOST);
listItem.measure(widthSpec, 0);
totalHeight += listItem.getMeasuredHeight();
}
ViewGroup.LayoutParams params = listView.getLayoutParams();
params.height = totalHeight
+ (listView.getDividerHeight() * (myListAdapter.getCount()));
listView.setLayoutParams(params);
listView.requestLayout();
}
***This code works good if I do not need to set listview height dynamically.
What should I change here to make it work or any alternative solution to get desire result?
Any help will be appreciated.
But the problem is when I am setting listview height dynamically its making current listview item visible
Setting height dynamically is not the problem. Rather, the problem is you are setting the height of the listview as the maximum possible height of listview by calculating height of each item in the list. So what will happen is all the items of the listview will be populated at once and will remain inflated in the list.(NOTE : No view recycling will happen now)
That's why getting (calling method to get data) automatically
The call is happening because you are setting the height of the listview based on the total number of items in the list. What happens because of this is, all the elements in your listview will be in visible state at any given point of time. Which means your condition
if (finalItem == totalItemCount){}
will always be true because your visibleItemCount will always be totalItemCount which makes your final item always equal to totalItemCount. (you can verify this by debugging your app).
What should I change here to make it work or any alternative solution to get desire result?
The best solution I can think of is setting the height of listview if and only if the total height calcuated by you on the basis of heights of all the items is lesser than the height of the screen. Otherwise, set the height of the listview as MATCH_PARENT.
ViewGroup.LayoutParams params = listView.getLayoutParams();
Display display = getWindowManager().getDefaultDisplay();
Point size = new Point();
display.getSize(size);
int height = size.y;
if(totalHeight > height){
params.height = ViewGroup.LayoutParams.MATCH_PARENT;
}else {
Log.d("", "");
params.height = totalHeight
+ (listView.getDividerHeight() * (myListAdapter.getCount()));
}
So this code will prevent making all the views of the listview to become visible and hence onScroll visibleItemCount you will receive, will the no of items currently visible.
Ankit already explained you what's the problem with your code, let me share an alternate solution with you.
As its no good to use listview when you are already populating its items instead it's better to use scrollview and add items dynamically. Scrollview does not have a scroll listener so we customise it to make one.
MyScrollView.Java
public class MyScrollView extends ScrollView {
public interface OnScrollListener {
void onScrollChanged(int l, int t, int oldl, int oldt);
}
private OnScrollListener onScrollListener;
public OnScrollListener getOnScrollListener() {
return onScrollListener;
}
public void setOnScrollListener(OnScrollListener onScrollListener) {
this.onScrollListener = onScrollListener;
}
public MyScrollView(Context context) {
super(context);
}
public MyScrollView(Context context, AttributeSet attrs) {
super(context, attrs);
}
public MyScrollView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
}
#Override
protected void onScrollChanged(int l, int t, int oldl, int oldt) {
super.onScrollChanged(l, t, oldl, oldt);
if (onScrollListener != null) {
onScrollListener.onScrollChanged(l, t, oldl, oldt);
}
}
}
We use the scrolllistener in activity like this -
import android.graphics.Rect;
import android.os.AsyncTask;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.LinearLayout;
import android.widget.ProgressBar;
import android.widget.TextView;
public class NewScrollActivity extends AppCompatActivity {
private MyScrollView scrollView;
private LinearLayout container;
private ProgressBar progressBar;
int maxItem = 20;
private View lastItemView;
boolean alreadyExecutingRequest = false;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_new_scroll);
progressBar = (ProgressBar) findViewById(R.id.progressBar);
scrollView = (MyScrollView) findViewById(R.id.scrollView);
scrollView.setOnScrollListener(scrollListener);
container = (LinearLayout) findViewById(R.id.container);
addItemsAsynchronously();
}
private MyScrollView.OnScrollListener scrollListener = new MyScrollView.OnScrollListener() {
#Override
public void onScrollChanged(int l, int t, int oldl, int oldt) {
if (lastItemView != null && !alreadyExecutingRequest) {
Rect scrollBounds = new Rect();
scrollView.getHitRect(scrollBounds);
if (lastItemView.getLocalVisibleRect(scrollBounds)) {
// Any portion of the lastitem view, even a single pixel, is within the visible window
addItemsAsynchronously();
}
}
}
};
private void addItemsAsynchronously() {
new AsyncTask<Void,Void,Void>() {
#Override
protected void onPreExecute() {
super.onPreExecute();
progressBar.setVisibility(View.VISIBLE);
alreadyExecutingRequest = true;
}
#Override
protected Void doInBackground(Void... voids) {
try {
Thread.sleep(3000);
} catch (InterruptedException e) {
e.printStackTrace();
}
return null;
}
#Override
protected void onPostExecute(Void aVoid) {
super.onPostExecute(aVoid);
progressBar.setVisibility(View.GONE);
addItemsToContainer();
alreadyExecutingRequest = false;
}
}.execute();
}
private void addItemsToContainer() {
int lastAddedItem = container.getChildCount();
for (int i=lastAddedItem;i<maxItem;i++) {
View view = LayoutInflater.from(this).inflate(R.layout.new_item, null);
TextView textView = (TextView) view.findViewById(R.id.textView);
textView.setText("Item - " + i);
container.addView(view);
}
lastItemView = container.getChildAt(container.getChildCount() -1);
maxItem+=10;
}
}
Here what we did is we checked the last item bound with the scrollview bounds, so it the view is visible then we are at the bottom, so add further items.
activity_new_scroll.xml
<?xml version="1.0" encoding="utf-8"?>
<com.sj.textinputlayout.MyScrollView xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/scrollView"
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"
tools:context="com.sj.textinputlayout.NewScrollActivity">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<LinearLayout
android:id="#+id/container"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical" />
<ProgressBar android:id="#+id/progressBar"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:visibility="gone"
android:layout_gravity="center_horizontal"/>
</LinearLayout>
</com.sj.textinputlayout.MyScrollView>
new_item.xml
<?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:padding="10dp"
android:layout_height="wrap_content">
<TextView android:id="#+id/textView"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</LinearLayout>
I am using recylerview in my application and whenever new element is added to recyclerview, it scrolls to last element by using
recyclerView.scrollToPosition(adapter.getCount());
But, whenever keyboard opens(because of editTextView), it resizes the view and recyclerview gets smaller, but couldn't scroll to last element.
android:windowSoftInputMode="adjustResize"
I even tried to used the following code to scroll to last element, but it didn't work
editTextView.setOnFocusChangeListener(new View.OnFocusChangeListener() {
#Override
public void onFocusChange(View v, boolean hasFocus) {
if(hasFocus){
recyclerView.scrollToPosition(chatAdapter.getItemCount());
}
}
});
I can try adjustPan to shift the pan up, but it is hiding my toolbar.
Please suggest any way to rectify the issue.
You can catch keyboard up changes using recyclerview.addOnLayoutChangeListener().
If bottom is smaller than oldBottom then keyboard is in up state.
if ( bottom < oldBottom) {
recyclerview.postDelayed(new Runnable() {
#Override
public void run() {
recyclerview.smoothScrollToPosition(bottomPosition);
}
}, 100);
}
Add this your activity or fragment:
if (Build.VERSION.SDK_INT >= 11) {
recyclerView.addOnLayoutChangeListener(new View.OnLayoutChangeListener() {
#Override
public void onLayoutChange(View v,
int left, int top, int right, int bottom,
int oldLeft, int oldTop, int oldRight, int oldBottom) {
if (bottom < oldBottom) {
recyclerView.postDelayed(new Runnable() {
#Override
public void run() {
recyclerView.smoothScrollToPosition(
recyclerView.getAdapter().getItemCount() - 1);
}
}, 100);
}
}
});
}
It works for me
LinearLayoutManager layoutManager = new LinearLayoutManager(context);
layoutManager.setStackFromEnd(true);
recyclerView.setLayoutManager(layoutManager);
I found the postDelayed to be unnecessary and using adapter positions doesn't account for when the recycler is scrolled to somewhere in the middle of an item. I achieved the look I wanted with this:
recycler.addOnLayoutChangeListener((view, left, top, right, bottom, oldLeft, oldTop, oldRight, oldBottom) -> {
if (bottom < oldBottom) {
messageRecycler.scrollBy(0, oldBottom - bottom);
}
})
Although this an old question, I experienced this problem today and I found out that none of of the above method works. This is my solution
recyclerView.addOnLayoutChangeListener(new View.OnLayoutChangeListener() {
#Override
public void onLayoutChange(View v,
int left, int top, int right, int bottom,
int oldLeft, int oldTop, int oldRight, int oldBottom) {
if (bottom < oldBottom) {
final int lastAdapterItem = mAdapter.getItemCount() - 1;
recyclerView.post(new Runnable() {
#Override
public void run() {
int recyclerViewPositionOffset = -1000000;
View bottomView = linearLayoutManager.findViewByPosition(lastAdapterItem);
if (bottomView != null) {
recyclerViewPositionOffset = 0 - bottomView.getHeight();
}
linearLayoutManager.scrollToPositionWithOffset(lastAdapterItem, recyclerViewPositionOffset);
}
});
}
});
}
This works.
private RecyclerView mRecyclerView;
private RecyclerView.Adapter mAdapter;
private LinearLayoutManager mManager;
...
mManager = new LinearLayoutManager(this);
mRecyclerView.setLayoutManager(mManager);
(initialize and set adapter.)
mRecyclerView.addOnLayoutChangeListener(new View.OnLayoutChangeListener() {
#Override
public void onLayoutChange(View v, int left, int top, int right, int bottom, int oldLeft, int oldTop, int oldRight, int oldBottom) {
if (bottom < oldBottom) scrollToBottom();
}
});
private void scrollToBottom() {
mManager.smoothScrollToPosition(mRecyclerView, null, mAdapter.getItemCount());
}
recyclerView.smoothScrollToPosition(recyclerView.getAdapter().getItemCount());
It works properly in support library version 27.0.1
There is nothing to set in the manifest.
val currentScrollPosition = 0
recyclerView.addOnScrollListener(object : RecyclerView.OnScrollListener() {
override fun onScrolled(recyclerView: RecyclerView?, dx: Int, dy: Int) {
super.onScrolled(recyclerView, dx, dy)
currentScrollPosition = recyclerView.computeVerticalScrollOffset() + recyclerView.computeVerticalScrollExtent()
}
override fun onScrollStateChanged(recyclerView: RecyclerView?, newState: Int) { }
})
storyList.addOnLayoutChangeListener { view, left, top, right, bottom, oldLeft, oldTop, oldRight, oldBottom ->
if (bottom < oldBottom) {
if (currentScrollPosition >= recyclerView.computeVerticalScrollRange()) {
recyclerVIew.post {
recyclerView.overScrollMode = RecyclerView.OVER_SCROLL_NEVER
recyclerView.smoothScrollBy(0, recyclerView.computeVerticalScrollRange() - recyclerView.computeVerticalScrollOffset() + recyclerView.computeVerticalScrollExtent())
}
}
} else {
recyclerView.overScrollMode = RecyclerView.OVER_SCROLL_ALWAYS
}
}
layoutManager.scrollToPositionWithOffset(chatMessageAdapter.getItemCount() - 1, 0);
You can use addOnItemTouchListener to see the scrolling change:
private Boolean scrollListerActivate = true;
mRecyclerViewTop.addOnScrollListener(new RecyclerView.OnScrollListener() {
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
if(scrollListerActivate == true) {
scrollListTopManager();
}
}
});
To scroll for last (or other) position you should use scrollListTopManager method:
public void scrollListTopManager() {
int position = 0;
int itemCount = mRecyclerViewTop.getAdapter().getItemCount();
position = itemCount - 1;
mRecyclerViewTop.scrollToPosition(position);
}
You should also use addOnItemTouchListener to stop using scrollListTopManager method, if you want to scroll manually:
mRecyclerViewTop.addOnItemTouchListener(new RecyclerView.OnItemTouchListener() {
#Override
public boolean onInterceptTouchEvent(RecyclerView recyclerView, MotionEvent
motionEvent) {
scrollListerActivate = false;
return false;
}
#Override
public void onTouchEvent(RecyclerView recyclerView, MotionEvent motionEvent)
{}
#Override
public void onRequestDisallowInterceptTouchEvent(boolean b) {}
});
When you open chat you will get last message at the end of recycle view:
layoutManager.setStackFromEnd(true);
recyclerView.setLayoutManager(layoutManager);
Below code will make adjustments according to keyboard!
recyclerView.addOnLayoutChangeListener(new View.OnLayoutChangeListener() {
#Override
public void onLayoutChange(View v, int left, int top, int right, int bottom, int oldLeft, int oldTop, int oldRight, int oldBottom) {
if ( bottom <= oldBottom) {
recyclerview.postDelayed(new Runnable() {
#Override
public void run() {
recyclerview.smoothScrollToPosition(bottom);
}
}, 100);
}
}
});
Bind the RecyclerView inside NestedScrollView
<android.support.v4.widget.NestedScrollView
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.v7.widget.RecyclerView
android:id="#+id/recycler_view"
android:layout_width="match_parent"
android:layout_height="wrap_content"/>
</android.support.v4.widget.NestedScrollView>
I have a recyclerview with a gridlayout. What I want is when the user scrolls to the end of the list (see my bad mockup), there should be an empty space with a height of 50dp, which isn't the same dimensions as my grid.
Note that this space is only visible at the very end end, as I do not want to change the layout. I could make it so that the recycerview has a margin bottom of 50dp, but I do not want to do that.
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:fab="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.v7.widget.RecyclerView
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/recyclerView"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity"
android:scrollbars="vertical"
/>
</RelativeLayout>
<RecyclerView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="50dp"
android:clipToPadding="false"
/>
This is best achieved with an item decoration.
Here's an example that works with a LinearLayoutManager - you'll have to adjust to suit for your Grid layout. What it does is checks each item to see if it's the last one, and if it is it adds the offset to the bottom of it. For a Grid layout, the hard part is figuring out whether your item position is in the last row or not.
// After setting layout manager, adapter, etc...
float offsetPx = getResources().getDimension(R.dimen.bottom_offset_dp);
BottomOffsetDecoration bottomOffsetDecoration = new BottomOffsetDecoration((int) offsetPx);
mRecyclerView.addItemDecoration(bottomOffsetDecoration);
...
static class BottomOffsetDecoration extends RecyclerView.ItemDecoration {
private int mBottomOffset;
public BottomOffsetDecoration(int bottomOffset) {
mBottomOffset = bottomOffset;
}
#Override
public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
super.getItemOffsets(outRect, view, parent, state);
int dataSize = state.getItemCount();
int position = parent.getChildAdapterPosition(view);
if (dataSize > 0 && position == dataSize - 1) {
outRect.set(0, 0, 0, mBottomOffset);
} else {
outRect.set(0, 0, 0, 0);
}
}
}
For a GridLayoutManager, inside the getItemOffsets method you could do something similar to this to figure out if it's the last row:
GridLayoutManager grid = (GridLayoutManager)parent.getLayoutManager();
if ((dataSize - position) <= grid.getSpanCount()) {
outRect.set(0, 0, 0, mBottomOffset);
} else {
outRect.set(0, 0, 0, 0);
}
I had the similar issue. After reading all others replies and I found the changes in layout xml for recyclerview worked for my recycler view as expected:
android:paddingBottom="127dp"
android:clipToPadding="false"
android:scrollbarStyle="outsideOverlay"
The complete layout looks like:
<android.support.v7.widget.RecyclerView
android:id="#+id/library_list"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginStart="160dp"
android:layout_marginEnd="160dp"
tools:listitem="#layout/library_list_item" />
For the effect of before and after see the link at androidblog.us:
Adding Space to End of Android Recylerview
Let me know how it works for you.
David
You can try the below code, remember "I do not test this code"
public class MyRecyclerView extends RecyclerView {
private Context context;
public MyRecyclerView(Context context) {
super(context);
this.context = context;
}
public MyRecyclerView(Context context, AttributeSet attrs) {
super(context, attrs);
this.context = context;
}
public MyRecyclerView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
this.context = context;
}
#Override
protected void onScrollChanged(int l, int t, int oldl, int oldt) {
View view = (View) getChildAt(getChildCount()-1);
int diff = (view.getBottom()-(getHeight()+getScrollY()+view.getTop()));
if( diff == 0 ){ // if diff is zero, then the bottom has been reached
TextView tv = new TextView(context);
tv.setHeight(dpToPx(50));
addView(tv,getChildCount());//update --> add to last
requestLayout();
}
super.onScrollChanged(l, t, oldl, oldt);
}
public int dpToPx(int dp) {
DisplayMetrics displayMetrics = context.getResources().getDisplayMetrics();
int px = Math.round(dp * (displayMetrics.xdpi / DisplayMetrics.DENSITY_DEFAULT));
return px;
}
}
and in layout:
<your_packagae.MyRecyclerView
android:id="#+id/recyclerView"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:scrollbars="vertical"
/>
Make a class name with BottomOffsetDecoration
public class BottomOffsetDecoration extends RecyclerView.ItemDecoration {
private int mBottomOffset;
public BottomOffsetDecoration(int bottomOffset) {
mBottomOffset = bottomOffset;
}
#Override
public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
super.getItemOffsets(outRect, view, parent, state);
int dataSize = state.getItemCount();
int position = parent.getChildAdapterPosition(view);
if (dataSize > 0 && position == dataSize - 1) {
outRect.set(0, 0, 0, mBottomOffset);
} else {
outRect.set(0, 0, 0, 0);
}
}
}
then Add these line after adding adapter and layoutmanager to recyclerview
float offsetPx = getResources().getDimension(R.dimen.bottom_offset_dp);
BottomOffsetDecoration bottomOffsetDecoration = new BottomOffsetDecoration((int) offsetPx);
rv.addItemDecoration(bottomOffsetDecoration);
and for GridLayout Add these lines after assigning recyclerview layout manager
GridLayoutManager grid = (GridLayoutManager)parent.getLayoutManager();
if ((dataSize - position) <= grid.getSpanCount()) {
outRect.set(0, 0, 0, mBottomOffset);
} else {
outRect.set(0, 0, 0, 0);
}
I have a FrameLayout, when I try to get its params like this:
ViewGroup.LayoutParams params = cameraPreviewFrameLayout.getLayoutParams();
int layoutHeight = params.height;
int layoutWidth = params.width;
Here, layoutHeight is -2 and layoutWidth is -1. This is my XML:
<FrameLayout
android:id="#+id/liveActivity_cameraPreviewFrameLayout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_centerInParent="true"/>
I am performing this action from onCreate, but also I tried to to it through onStart(), with the same result. Obviously the height and width of this layout is not these values.
How can I retrieve the size of the layout effectively?
The values returned are correct, because:
-2 stands for LayoutParams.WRAP_CONENT
-1 stands for LayoutParams.MATCH_PARENT
If you want to get exact values, you'll need to use the methods getHeight and getWidth. However those methods can only be used once the layout has been measured, so delay your call like this:
cameraPreviewFrameLayout.post(new Runnable() {
#Override
public void run() {
View v = cameraPreviewFrameLayout;
Log.e("TAG", v.getWidth() + ":" + v.getHeight());
}
});
Proper way to getting size of layout after or inside onLayoutChange method call
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
final FrameLayout layout = (FrameLayout) findViewById(R.id.liveActivity_cameraPreviewFrameLayout);
layout.addOnLayoutChangeListener(new View.OnLayoutChangeListener() {
#Override
public void onLayoutChange(View v, int left, int top, int right, int bottom, int oldLeft, int oldTop, int oldRight, int oldBottom) {
int width = right - left;
int height = bottom - top;
Log.v("TAG", String.format("%d - %d", width, height));
//Or
Log.v("TAG", String.format("%d - %d", layout.getWidth(), layout.getHeight()));
//And after this method call, calling layout.getWidth() and layout.getHeight() will give right values
}
});
}