I am trying to code a rotating menu for a children's app. The idea is to allow kids to change between different scenarios, each containing different animals.
The animals are represented on a round surface and, as the kids swipe right or left, the globe rotates with old animals fading out and new ones fading in, kinda like this:
The result I'm trying to reach is similar to the iOS iCarousel wheel effect.
Toxic Bakery's ViewPagerTransforms library (https://github.com/ToxicBakery/ViewPagerTransforms) has an effect called Rotate Down that is very similar, but I haven't been able to adjust it to my needs. The pages roll in on their own instead of rotating on a common axis.
I've also tried the CursorWheelLayout (https://github.com/BCsl/CursorWheelLayout), but there are many performance issues due to the images, making the app crash.
My most recent attempt has been the SpinMenu (https://github.com/Hitomis/SpinMenu), which is great. The fragments do rotate on a common axis, but only while zoomed out. I haven't figured out a way of making it change pages (as a ViewPager would) with the fragments rotating in and out of view.
Any suggestions on what to do to reach the desired result?
Here's the solution I found:
1) Implement the CarouselView library: https://gtomato.github.io/carouselview/
2) As CarouselView extends from RecyclerView, create the layout for the CarouselView to inflate (which I called carouselview_item):
<?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">
<ImageView
android:id="#+id/imageview"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="#drawable/ic_launcher_background"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</android.support.constraint.ConstraintLayout>
3) As CarouselView extends from RecyclerView, create a CarouselViewAdapter extending from RecyclerView.Adapter
public class CarouselViewAdapter extends RecyclerView.Adapter<CarouselViewAdapter.ViewHolder> {
private List<Fragment> list;
public CarouselViewAdapter(List<Fragment> list) {
this.list = list;
}
#NonNull
#Override
public CarouselViewAdapter.ViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.carouselview_item, parent, false);
return new ViewHolder(view);
}
#Override
public void onBindViewHolder(#NonNull CarouselViewAdapter.ViewHolder holder, int position) {
Fragment fragment = list.get(position);
holder.bind(object);
}
#Override
public int getItemCount() {
return list.size();
}
// In case you are using, let's say, RxJava for getting the list
public void setObjects(List<Fragment> list) {
if (list.size() == 0) {
this. = list;
} else {
this.list.addAll(list);
notifyDataSetChanged();
}
}
public class ViewHolder extends RecyclerView.ViewHolder {
private T example;
public ViewHolder(View itemView) {
super(itemView);
// Find your views:
// example = itemView.findViewById(R.id.example);
}
public void bind(T object){
// Bind the info you need to the view:
// example.setInfo(object.getInfo)
}
}
}
}
4) Set things up on the activity, including the desired Transformer and also the adapter:
public class MainActivity extends AppCompatActivity {
private CarouselView carouselView;
private List<Fragment> list;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initAssets();
Fragment object1 = new T(/* necessary parameters, if any*/);
Fragment object2 = new T(/* necessary parameters, if any*/);
Fragment object3 = new T(/* necessary parameters, if any*/);
list.add(object1);
list.add(object2);
list.add(object3);
carouselView.setTransformer(new WheelViewTransformer());
carouselView.setAdapter(new CarouselViewAdapter(list));
}
private void initAssets() {
carouselView = findViewById(R.id.carouselview);
list = new ArrayList<>();
}
}
It worked for me like that, although the performance isn't great due to the images I am using for now.
Enjoy!
Just in case somebody is familiar with InfiniteViewPager. I've also started an Issue there, but I was hoping perhaps somebody here might have some insight.
InfiniteViewPager: https://github.com/antonyt/InfiniteViewPager.
The following code sets up my InfiniteViewPager and hides a button depending on the position of the pager. It works, as in the button starts GONE, and appears when you swipe to a new position, but as you swipe back to "position 0" the button reappears. I believe this is because when I swipe back, the position is no longer really "position 0". I get the following in my logcat:
11-23 23:29:49.694 25109-25109/com.app.store D/InfinitePagerAdapter﹕ instantiateItem: real position: 3301
11-23 23:29:49.694 25109-25109/com.app.store D/InfinitePagerAdapter﹕ instantiateItem: virtual position: 1
This is the code for initiating my pager and the OnPageChangeListener.
private void init(Context context) {
View view = inflate(context, R.layout.listview_item, this);
view.setLayoutParams(new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT));
ViewPager viewPager;
CustomPagerAdapter adapter;
viewPager = (ViewPager) findViewById(R.id.view_pager);
adapter = new CustomPagerAdapter(context);
PagerAdapter wrappedAdapter = new InfinitePagerAdapter(adapter);
viewPager.setAdapter(wrappedAdapter);
//Hide the button unless showing image
final Button selectButton = (Button) findViewById(R.id.selectButton);
selectButton .setVisibility(GONE);
viewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
#Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
#Override
public void onPageSelected(int position) {
if(position==0)
selectButton.setVisibility(View.GONE);
else
selectButton.setVisibility(View.VISIBLE);
}
#Override
public void onPageScrollStateChanged(int state) {
}
});
Basically, I hide the button on "position 0" and show it for every other position using OnPageChangeListener. However, when I return to "position 0", it doesn't recognize "position 0" as "position 0", so it's not hiding the button.
Edit: I've included my XML
<com.antonyt.infiniteviewpager.InfiniteViewPager
android:id="#+id/view_pager"
android:layout_width="match_parent"
android:layout_height="500dp"
android:scaleType="centerCrop">
<android.support.v4.view.PagerTitleStrip
android:layout_width="wrap_content"
android:layout_height="wrap_content"
style="#style/custom_viewpagertitlestrip"
android:layout_gravity="top" />
</com.antonyt.infiniteviewpager.InfiniteViewPager>
Use this
if(position % size == 0)
selectButton.setVisibility(View.GONE);
else
selectButton.setVisibility(View.VISIBLE);
where size is total number of actual page.
I have a problem. I have a viewpager with 3 fragments inside. In first fragment i have some ImageViews.
First of all how make that imageviews visible with timer? I used thise code below but i have error which looks like: variable 'mImageView' is accessed from within inner class, needs to be declared class.
mImageView.setVisibility(View.INVISIBLE);
mImageView.postDelayed(new Runnable() {
public void run() {
mImageView.setVisibility(View.VISIBLE);
}
}, 5000);
How can i solve this problem?
Second I tried to move that elements (ImageViews) by X values when user start scrolling from first fragment to next fragment. It works but when i go to last 3-d fragment app crash. So why it happen?!
MainActivity.java
pager.setPageTransformer(false, new ViewPager.PageTransformer() {
#Override
public void transformPage(View page, float position) {
// transformation here
final float normalizedPosition = Math.abs(Math.abs(position) - 1);
page.setAlpha(normalizedPosition);
int pageWidth = page.getWidth();
if (position < -1) { // [-Infinity,-1)
// This page is way off-screen to the left.
page.setAlpha(0);
} else if (position <= 1) { // [-1,1]
ImageView mImageView = (ImageView)findViewById(R.id.imageView2);
mImageView.setTranslationX((float) (-(1 - position) * 1.7 * pageWidth));
mImageView.setVisibility(View.INVISIBLE);
mImageView.postDelayed(new Runnable() {
public void run() {
mImageView.setVisibility(View.VISIBLE);
}
}, 5000);
// The 0.5, 1.5 values you see here are what makes the view move in a different speed.
// The bigger the number, the faster the view will translate.
// The result float is preceded by a minus because the views travel in the opposite direction of the movement.
}
else{ // (1,+Infinity]
// This page is way off-screen to the right.
page.setAlpha(0);
}
}
});
Third: Is it possible to make move elements by circle when user scroll. Need any help!
For your first question, as I said in the comment, you need to make the mImageView variable final
final ImageView mImageView = (ImageView)findViewById(R.id.imageView2);
Then, the null pointer exception, is probably caused (as Blackbelt said), because you're using the activity's findViewById method, and probably the imageView you need is in the fragment view:
final ImageView mImageView = (ImageView) page.findViewById(R.id.imageView2);
And for your 3º question, please explain what you mean by "move by circle", then I'll update my post(if I can) with an answer.
MainActivity.java
// Initialize the ViewPager and set an adapter
ViewPager pager = (ViewPager) findViewById(R.id.pager);
pager.setAdapter(new ViewPagerAdapter(getSupportFragmentManager()));
ViewPagerAdapter.java
public class ViewPagerAdapter extends FragmentStatePagerAdapter {
private final int PAGES = 3;
private String[] titles={"News", "Organizations", "Map"};
public ViewPagerAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int position) {
switch (position) {
case 0:
return new TabFragment1();
case 1:
return new TabFragment2();
case 2:
return new TabFragment3();
default:
throw new IllegalArgumentException("The item position should be less or equal to:" + PAGES);
}
}
#Override
public CharSequence getPageTitle(int position) {
return titles[position];
}
#Override
public int getCount() {
return PAGES;
}
}
As you see for each page I have individual fragment documents. Here below one of them:
public class TabFragment1 extends Fragment{
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
return inflater.inflate(R.layout.fragment_tab_1, container, false);
}
}
fragment_tab_1.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<ImageView
android:layout_width="100dp"
android:layout_height="100dp"
android:src="#drawable/city"
android:id="#+id/imageView2"
android:layout_centerVertical="true"
android:layout_centerHorizontal="true" />
</RelativeLayout>
I have a RecyclerView with an TextView text box and a cross button ImageView. I have a button outside of the recyclerview that makes the cross button ImageView visible / gone.
I'm looking to remove an item from the recylerview, when that items cross button ImageView is pressed.
My adapter:
public class MyAdapter extends RecyclerView.Adapter<MyAdapter.ViewHolder> implements View.OnClickListener, View.OnLongClickListener {
private ArrayList<String> mDataset;
private static Context sContext;
public MyAdapter(Context context, ArrayList<String> myDataset) {
mDataset = myDataset;
sContext = context;
}
#Override
public MyAdapter.ViewHolder onCreateViewHolder(ViewGroup parent,int viewType) {
View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.my_text_view, parent, false);
ViewHolder holder = new ViewHolder(v);
holder.mNameTextView.setOnClickListener(MyAdapter.this);
holder.mNameTextView.setOnLongClickListener(MyAdapter.this);
holder.mNameTextView.setTag(holder);
return holder;
}
#Override
public void onBindViewHolder(ViewHolder holder, int position) {
holder.mNameTextView.setText(mDataset.get(position));
}
#Override
public int getItemCount() {
return mDataset.size();
}
#Override
public void onClick(View view) {
ViewHolder holder = (ViewHolder) view.getTag();
if (view.getId() == holder.mNameTextView.getId()) {
Toast.makeText(sContext, holder.mNameTextView.getText(), Toast.LENGTH_SHORT).show();
}
}
#Override
public boolean onLongClick(View view) {
ViewHolder holder = (ViewHolder) view.getTag();
if (view.getId() == holder.mNameTextView.getId()) {
mDataset.remove(holder.getPosition());
notifyDataSetChanged();
Toast.makeText(sContext, "Item " + holder.mNameTextView.getText() + " has been removed from list",
Toast.LENGTH_SHORT).show();
}
return false;
}
public static class ViewHolder extends RecyclerView.ViewHolder {
public TextView mNumberRowTextView;
public TextView mNameTextView;
public ViewHolder(View v) {
super(v);
mNameTextView = (TextView) v.findViewById(R.id.nameTextView);
}
}
}
My layout is:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:gravity="center_vertical"
android:id="#+id/layout">
<TextView
android:id="#+id/nameTextView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="18sp"
android:padding="5dp"
android:background="#drawable/greyline"/>
<ImageView
android:id="#+id/crossButton"
android:layout_width="16dp"
android:layout_height="16dp"
android:visibility="gone"
android:layout_marginLeft="50dp"
android:src="#drawable/cross" />
</LinearLayout>
How can I get something like an onClick working for my crossButton ImageView? Is there a better way? Maybe changing the whole item onclick into a remove the item? The recyclerview shows a list of locations that need to be edited. Any technical advice or comments / suggestions on best implementation would be hugely appreciated.
I have done something similar.
In your MyAdapter:
public class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener{
public CardView mCardView;
public TextView mTextViewTitle;
public TextView mTextViewContent;
public ImageView mImageViewContentPic;
public ImageView imgViewRemoveIcon;
public ViewHolder(View v) {
super(v);
mCardView = (CardView) v.findViewById(R.id.card_view);
mTextViewTitle = (TextView) v.findViewById(R.id.item_title);
mTextViewContent = (TextView) v.findViewById(R.id.item_content);
mImageViewContentPic = (ImageView) v.findViewById(R.id.item_content_pic);
//......
imgViewRemoveIcon = (ImageView) v.findViewById(R.id.remove_icon);
mTextViewContent.setOnClickListener(this);
imgViewRemoveIcon.setOnClickListener(this);
v.setOnClickListener(this);
mTextViewContent.setOnLongClickListener(new View.OnLongClickListener() {
#Override
public boolean onLongClick(View view) {
if (mItemClickListener != null) {
mItemClickListener.onItemClick(view, getPosition());
}
return false;
}
});
}
#Override
public void onClick(View v) {
//Log.d("View: ", v.toString());
//Toast.makeText(v.getContext(), mTextViewTitle.getText() + " position = " + getPosition(), Toast.LENGTH_SHORT).show();
if(v.equals(imgViewRemoveIcon)){
removeAt(getPosition());
}else if (mItemClickListener != null) {
mItemClickListener.onItemClick(v, getPosition());
}
}
}
public void setOnItemClickListener(final OnItemClickListener mItemClickListener) {
this.mItemClickListener = mItemClickListener;
}
public void removeAt(int position) {
mDataset.remove(position);
notifyItemRemoved(position);
notifyItemRangeChanged(position, mDataSet.size());
}
Edit:
getPosition() is deprecated now, use getAdapterPosition() instead.
first of all, item should be removed from the list!
mDataSet.remove(getAdapterPosition());
then:
notifyItemRemoved(getAdapterPosition());
notifyItemRangeChanged(getAdapterPosition(), mDataSet.size()-getAdapterPosition());
if still item not removed use this magic method :)
private void deleteItem(int position) {
mDataSet.remove(position);
notifyItemRemoved(position);
notifyItemRangeChanged(position, mDataSet.size());
holder.itemView.setVisibility(View.GONE);
}
Kotlin version
private fun deleteItem(position: Int) {
mDataSet.removeAt(position)
notifyItemRemoved(position)
notifyItemRangeChanged(position, mDataSet.size)
holder.itemView.visibility = View.GONE
}
The Problem
RecyclerView was built to display data in an efficient and responsive manner.
Usually you have a dataset which is passed to your adapter and is looped through to display your data.
Here your dataset is:
private ArrayList<String> mDataset;
The point is that RecyclerView is not connected to your dataset, and therefore is unaware of your dataset changes.
It just reads data once and displays it through your ViewHolder, but a change to your dataset will not propagate to your UI.
This means that whenever you make a deletion/addition on your data list, those changes won't be reflected to your RecyclerView directly. (i.e. you remove the item at index 5, but the 6th element remains in your recycler view).
A (old school) solution
RecyclerView exposes some methods for you to communicate your dataset changes, reflecting those changes directly on your list items.
The standard Android APIs allow you to bind the process of data removal (for the purpose of the question) with the process of View removal.
The methods we are talking about are:
notifyItemChanged(index: Int)
notifyItemInserted(index: Int)
notifyItemRemoved(index: Int)
notifyItemRangeChanged(startPosition: Int, itemCount: Int)
notifyItemRangeInserted(startPosition: Int, itemCount: Int)
notifyItemRangeRemoved(startPosition: Int, itemCount: Int)
A Complete (old school) Solution
If you don't properly specify what happens on each addition, change or removal of items, RecyclerView list items are animated unresponsively because of a lack of information about how to move the different views around the list.
The following code will allow RecyclerView to precisely play the animation with regards to the view that is being removed (And as a side note, it fixes any IndexOutOfBoundExceptions, marked by the stacktrace as "data inconsistency").
void remove(position: Int) {
dataset.removeAt(position)
notifyItemChanged(position)
notifyItemRangeRemoved(position, 1)
}
Under the hood, if we look into RecyclerView we can find documentation explaining that the second parameter we pass to notifyItemRangeRemoved is the number of items that are removed from the dataset, not the total number of items (As wrongly reported in some others information sources).
/**
* Notify any registered observers that the <code>itemCount</code> items previously
* located at <code>positionStart</code> have been removed from the data set. The items
* previously located at and after <code>positionStart + itemCount</code> may now be found
* at <code>oldPosition - itemCount</code>.
*
* <p>This is a structural change event. Representations of other existing items in the data
* set are still considered up to date and will not be rebound, though their positions
* may be altered.</p>
*
* #param positionStart Previous position of the first item that was removed
* #param itemCount Number of items removed from the data set
*/
public final void notifyItemRangeRemoved(int positionStart, int itemCount) {
mObservable.notifyItemRangeRemoved(positionStart, itemCount);
}
Open source solutions
You can let a library like FastAdapter, Epoxy or Groupie take care of the business, and even use an observable recycler view with data binding.
New ListAdapter
Google recently introduced a new way of writing the recycler view adapter, which works really well and supports reactive data.
It is a new approach and requires a bit of refactoring, but it is 100% worth switching to it, as it makes everything smoother.
here is the documentation, and here a medium article explaining it
Here are some visual supplemental examples. See my fuller answer for examples of adding and removing a range.
Add single item
Add "Pig" at index 2.
String item = "Pig";
int insertIndex = 2;
data.add(insertIndex, item);
adapter.notifyItemInserted(insertIndex);
Remove single item
Remove "Pig" from the list.
int removeIndex = 2;
data.remove(removeIndex);
adapter.notifyItemRemoved(removeIndex);
Possibly a duplicate answer but quite useful for me. You can implement the method given below in RecyclerView.Adapter<RecyclerView.ViewHolder>
and can use this method as per your requirements, I hope it will work for you
public void removeItem(#NonNull Object object) {
mDataSetList.remove(object);
notifyDataSetChanged();
}
I tried all the above answers, but inserting or removing items to recyclerview causes problem with the position in the dataSet. Ended up using delete(getAdapterPosition()); inside the viewHolder which worked great at finding the position of items.
The problem I had was I was removing an item from the list that was no longer associated with the adapter to make sure you are modifying the correct adapter you can implement a method like this in your adapter:
public void removeItemAtPosition(int position) {
items.remove(position);
}
And call it in your fragment or activity like this:
adapter.removeItemAtPosition(position);
public class MyAdapter extends RecyclerView.Adapter<MyAdapter.MyViewHolder> {
private Context context;
private List<cardview_widgets> list;
public MyAdapter(Context context, List<cardview_widgets> list) {
this.context = context;
this.list = list;
}
#NonNull
#Override
public MyViewHolder onCreateViewHolder(#NonNull ViewGroup viewGroup, int i) {
View view = LayoutInflater.from(this.context).inflate(R.layout.fragment1_one_item,
viewGroup, false);
return new MyViewHolder(view);
}
public static class MyViewHolder extends RecyclerView.ViewHolder {
TextView txtValue;
TextView txtCategory;
ImageView imgInorEx;
ImageView imgCategory;
TextView txtDate;
public MyViewHolder(#NonNull View itemView) {
super(itemView);
txtValue= itemView.findViewById(R.id.id_values);
txtCategory= itemView.findViewById(R.id.id_category);
imgInorEx= itemView.findViewById(R.id.id_inorex);
imgCategory= itemView.findViewById(R.id.id_imgcategory);
txtDate= itemView.findViewById(R.id.id_date);
}
}
#NonNull
#Override
public void onBindViewHolder(#NonNull final MyViewHolder myViewHolder, int i) {
myViewHolder.txtValue.setText(String.valueOf(list.get(i).getValuee()));
myViewHolder.txtCategory.setText(list.get(i).getCategory());
myViewHolder.imgInorEx.setBackgroundColor(list.get(i).getImg_inorex());
myViewHolder.imgCategory.setImageResource(list.get(i).getImg_category());
myViewHolder.txtDate.setText(list.get(i).getDate());
myViewHolder.itemView.setOnLongClickListener(new View.OnLongClickListener() {
#Override
public boolean onLongClick(View v) {
list.remove(myViewHolder.getAdapterPosition());
notifyDataSetChanged();
return false;
}
});
}
#Override
public int getItemCount() {
return list.size();
}}
i hope this help you.
if you want to remove item you should do this:
first remove item:
phones.remove(position);
in next step you should notify your recycler adapter that you remove an item by this code:
notifyItemRemoved(position);
notifyItemRangeChanged(position, phones.size());
but if you change an item do this:
first change a parameter of your object like this:
Service s = services.get(position);
s.done = "Cancel service";
services.set(position,s);
or new it like this :
Service s = new Service();
services.set(position,s);
then notify your recycler adapter that you modify an item by this code:
notifyItemChanged(position);
notifyItemRangeChanged(position, services.size());
hope helps you.
String str = arrayList.get(position);
arrayList.remove(str);
MyAdapter.this.notifyDataSetChanged();
To Method onBindViewHolder Write This Code
holder.remove.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Cursor del=dbAdapter.ExecuteQ("delete from TblItem where Id="+values.get(position).getId());
values.remove(position);
notifyDataSetChanged();
}
});
Incase Anyone wants to implement something like this in Main class instead of Adapter class, you can use:
public void removeAt(int position) {
peopleListUser.remove(position);
friendsListRecycler.getAdapter().notifyItemRemoved(position);
friendsListRecycler.getAdapter().notifyItemRangeChanged(position, peopleListUser.size());
}
where friendsListRecycler is the Adapter name
you must to remove this item from arrayList of data
myDataset.remove(holder.getAdapterPosition());
notifyItemRemoved(holder.getAdapterPosition());
notifyItemRangeChanged(holder.getAdapterPosition(), getItemCount());
//////// set the position
holder.cancel.setTag(position);
///// click to remove an item from recycler view and an array list
holder.cancel.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
int positionToRemove = (int)view.getTag(); //get the position of the view to delete stored in the tag
mDataset.remove(positionToRemove);
notifyDataSetChanged();
}
});
make interface into custom adapter class and handling click event on recycler view..
onItemClickListner onItemClickListner;
public void setOnItemClickListner(CommentsAdapter.onItemClickListner onItemClickListner) {
this.onItemClickListner = onItemClickListner;
}
public interface onItemClickListner {
void onClick(Contact contact);//pass your object types.
}
#Override
public void onBindViewHolder(ItemViewHolder holder, int position) {
// below code handle click event on recycler view item.
holder.itemView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
onItemClickListner.onClick(mContectList.get(position));
}
});
}
after define adapter and bind into recycler view called below code..
adapter.setOnItemClickListner(new CommentsAdapter.onItemClickListner() {
#Override
public void onClick(Contact contact) {
contectList.remove(contectList.get(contectList.indexOf(contact)));
adapter.notifyDataSetChanged();
}
});
}
In case you are wondering like I did where can we get the adapter position in the method getadapterposition(); its in viewholder object.so you have to put your code like this
mdataset.remove(holder.getadapterposition());
In the activity:
mAdapter.updateAt(pos, text, completed);
mAdapter.removeAt(pos);
In the your adapter:
void removeAt(int position) {
list.remove(position);
notifyItemRemoved(position);
notifyItemRangeChanged(position, list.size());
}
void updateAt(int position, String text, Boolean completed) {
TodoEntity todoEntity = list.get(position);
todoEntity.setText(text);
todoEntity.setCompleted(completed);
notifyItemChanged(position);
}
in 2022, after trying everything the whole internet given below is the answer
In MyViewHolder class
private myAdapter adapter;
inside MyViewHolder function initalise adapter
adapter = myAdapter.this
inside onclick
int position = getAdapterPosition()
list.remove(position);
adapter.notifyItemRemoved(position);
my question is how to access and change the checkBox mode for any item in a listactivity. I have an XML template file with a checkbox and a textview, and these define a row. Here's what I'm trying so far:
#Override
protected void onListItemClick(ListView l, View v, int position, long id) {
super.onListItemClick(l, v, position, id);
Toast.makeText(this, "You selected: " + Integer.toString(position), Toast.LENGTH_LONG).show();
CheckBox checkbox = (CheckBox) findViewById(R.id.checkbox);
if (checkbox.isChecked() == false) {
checkbox.setChecked(true);
} else {
checkbox.setChecked(false);
}
}
Obviously though using R.id.checkbox only toggles the first checkbox (actually, it does the first checkbox of whatever part of the list I'm looking at on my screen). I'm not sure what function to use to get the checkbox of any row though. The Toast works fine btw, so at least it registers position properly.
Thanks for any help.
EDIT - I'm now trying to subclass the SimpleCursorAdapter to better control the behaviour I want. Here is that subclass:
public class musicPlaylist extends SimpleCursorAdapter {
private Cursor c;
private Context context;
private ArrayList<String> checkList = new ArrayList<String>();
private final static int SELECTED = 1;
private final static int NOT_SELECTED = 0;
public musicPlaylist(Context context, int layout, Cursor c,
String[] from, int[] to) {
super(context, layout, c, from, to);
this.c = c;
this.context = context;
}
public View getView(int pos, View inView, ViewGroup parent) {
View v = inView;
if (v == null) {
LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
v = inflater.inflate(R.layout.song_item, null);
}
this.c.moveToPosition(pos);
int columnIndex = this.c.getColumnIndexOrThrow(MediaStore.Audio.Media.DISPLAY_NAME);
String song = this.c.getString(columnIndex);
TextView sTitle = (TextView) v.findViewById(R.id.text1);
sTitle.setText(song);
v.setId(NOT_SELECTED);
v.setTag(song);
v.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
// TODO Auto-generated method stub
if (v.getId() == NOT_SELECTED) {
v.setId(SELECTED);
Toast.makeText(context, "Test: " + v.getId(), Toast.LENGTH_SHORT).show();
v.setBackgroundColor(Color.parseColor("#FFFFFF"));
} else {
v.setId(NOT_SELECTED);
Toast.makeText(context, "Test: " + v.getId(), Toast.LENGTH_SHORT).show();
v.setBackgroundColor(Color.parseColor("#000000"));
}
}
});
return v;
}
}
And for reference, here is the XML of the ListActivity I'm making:
<?xml version="1.0" encoding="utf-8"?>
<ListView android:id="#android:id/list"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_weight="1"
android:drawSelectorOnTop="false"
android:fastScrollEnabled="true"
android:cacheColorHint="#00000000"
/>
<TextView android:id="#android:id/empty"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:text="No data"/>
Current behaviour: the list of songs from the SD card is made into a nice scrollable list. I do get somewhat proper responses from getView()'s onClick: The first time I click an item, it Toasts that its tag is "1" and its background goes white, while the second time I toast the same item, I get "0" and the background goes black, which is as expected.
The problem is if I select item1 (making its background white) and then scroll down, I'll notice that item11, item21, item31, ... , etc ALSO have white backgrounds. But when I click on them, their ID attribute goes to "1", meaning they've technically never been clicked before! So basically when the scroll "refreshes" to the next list of 10, it copies the color scheme of the first 10...?
Hope I explained it clearly.
I think this is bit deeper question and not direct answer is needed.
What do you want to achieve? Do you really want to make selected ONLY the checkboxes that you see on screen? Mind that this might be pretty random - list view only holds item views for the checkboxes that are visible on screen and they are reused for other items whenever the item is scrolled outside the screen.
I'd say that almost for sure you need to change state of all the checkboxes in your list (even those not visible) or some subset of them (like section). Which really translates into the proper way it should be done:
modify your data model appropriately
marking the appropriate flags selected in corresponding data model elements
(some boolean values you store per item)
call notifyDataSetChanged() on your adapter.
As a result, list view will recreate all the views which are visible on screen. Assuming that your "getView()" in adapter is written correctly, it will read the right model and update checked state on the item appropriately.
By notifyDataSetChanged - if you have 10 items visible on screen you will have 10 times getView() called for every item visible.
I recommend using android:choiceMode="multipleChoice" instead of manually manipulating your rows this way. The row widget will need to implement the Checkable interface, which can either be done by using CheckedTextView as the row itself, or creating a subclass of your desired container and implementing Checkable on it.
You use "global" view instead your row view. Try like that:
#Override
protected void onListItemClick(ListView l, View v, int position, long id) {
super.onListItemClick(l, v, position, id);
CheckBox checkbox = (CheckBox) v.findViewById(R.id.checkbox);
if (checkbox.isChecked() == false) {
checkbox.setChecked(true);
} else {
checkbox.setChecked(false);
}
}