I have ListView and my own adapter. ListView item consists of TextView, icon image and image "trash can"(simply "trash"). The problem is when i click on any item it should be deleted but in fact the last item of ListView disappears. I checked ArrayList and the item I clicked on is deleted from there.
Also when i try to add new item the program just restore previous items and if all initial items are displayed and i try to add new the program crashes. Although in ArrayList items are added correctly.
Activity code
public class MyItemsActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.my_items);
myItemsList = findViewById(R.id.ListOfMyItems);
myItemsAdapter.arrayList.add(new MyItems("Keys", R.drawable.plus));
myItemsAdapter.arrayList.add(new MyItems("Wallet", R.drawable.plus));
myItemsAdapter.arrayList.add(new MyItems("Physics", R.drawable.plus));
myItemsAdapter.arrayList.add(new MyItems("umovnyy vasyl", R.drawable.plus));
myItemsAdapter.arrayList.add(new MyItems("Smartphone)", R.drawable.plus));
for (int i = 0; i<100; i++){
arrayList.add(new MyItems("Max)", R.drawable.plus));
}
myItemsList.addFooterView(new ImageView(this));
myItemsList.addHeaderView(new ImageView(this));
myItemsList.setAdapter(myItemsAdapter);
for (int i = 0; i<100; i++){
myItemsAdapter.arrayList.remove((5));
}
arrayList.add(new MyItems("Maxx)", R.drawable.plus));
myItemsAdapter.notifyDataSetChanged();
myItemsAdapter.notifyDataSetInvalidated();
myItemsList.setOnItemClickListener((parent, view, position, id) -> {
Toast.makeText(getApplicationContext(),
"Click ListItem Number " + position, Toast.LENGTH_SHORT)
.show();
myItemsAdapter.arrayList.remove((position-1));
myItemsAdapter.notifyDataSetChanged();
myItemsList.invalidateViews();
myItemsAdapter.notifyDataSetInvalidated();
});
}
ListView myItemsList;
ArrayList<MyItems> arrayList = new ArrayList<>();
MyItemsAdapter myItemsAdapter = new MyItemsAdapter(MyItemsActivity.this, arrayList);
public void addNewItem(View view) {
AlertDialog.Builder dialog = new AlertDialog.Builder(MyItemsActivity.this);
dialog.setView(R.layout.add_new_item);
AlertDialog alertDialog = dialog.create();
ListView a = alertDialog.getListView();
alertDialog.show();
myItemsList.invalidateViews();
}
public void addNewItemButtonClicked(View view){
LayoutInflater inflater = getLayoutInflater();
View v = inflater.inflate(R.layout.add_new_item, null);
EditText nameOfItem = v.findViewById(R.id.nameOfItem);
arrayList.add(new MyItems(nameOfItem.getText().toString(), R.drawable.forwardbutton));
myItemsAdapter.notifyDataSetChanged();
myItemsAdapter.notifyDataSetInvalidated();
}
public void notificationClicked(View view){
Toast.makeText(getApplicationContext(),
"Notification clicked", Toast.LENGTH_SHORT)
.show();
}
public void openMenu(View view) {
Intent intent = new Intent(getBaseContext(), MenuActivity.class);
startActivity(intent);
}
}
Adapter
class MyItemsAdapter extends BaseAdapter {
ArrayList<MyItems> arrayList;
Context context;
public MyItemsAdapter(Context context, ArrayList<MyItems> arrayList) {
this.arrayList=arrayList;
this.context=context;
}
@Override
public boolean areAllItemsEnabled() {
return false;
}
@Override
public boolean isEnabled(int position) {
return true;
}
@Override
public void registerDataSetObserver(DataSetObserver observer) {
observer.onChanged();
super.registerDataSetObserver(observer);
}
@Override
public void unregisterDataSetObserver(DataSetObserver observer) {
super.unregisterDataSetObserver(observer);
observer.onInvalidated();
}
@Override
public int getCount() {
return arrayList.size();
}
@Override
public MyItems getItem(int position) {
return arrayList.get(position);
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public boolean hasStableIds() {
return false;
}
@Override
public View getView(final int position, View convertView, ViewGroup parent) {
final MyItems myItems = arrayList.get(position);
if(convertView == null) {
LayoutInflater layoutInflater = LayoutInflater.from(context);
convertView = layoutInflater.inflate(R.layout.example_of_list_of_items, parent, false);
TextView nameOfItem = convertView.findViewById(R.id.exampleTextView);
ImageView itemCircle = convertView.findViewById(R.id.exampleImageViewIcon);
ImageView trash = convertView.findViewById(R.id.exampleImageViewTrash);
nameOfItem.setText(myItems.itemName);
itemCircle.setImageResource(myItems.itemImage);
trash.setImageResource(R.drawable.trash);
trash.setOnClickListener(v -> {
Toast.makeText(context, "lol "+position, Toast.LENGTH_SHORT).show();
arrayList.remove(position);
notifyDataSetChanged();
notifyDataSetInvalidated();
});
}
return convertView;
}
@Override
public int getItemViewType(int position) {
return position;
}
@Override
public int getViewTypeCount() {
return arrayList.size();
}
@Override
public boolean isEmpty() {
return false;
}
}
MyItems code
class MyItems {
String itemName;
int itemImage;
public MyItems(String itemName, int image) {
this.itemName = itemName;
this.itemImage = image;
}
}
Example of item
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent">
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:id="@+id/exampleTextView"
android:layout_width="170dp"
android:layout_height="wrap_content"
android:layout_marginStart="30dp"
android:layout_marginTop="20dp"
android:layout_marginEnd="85dp"
android:fadingEdge="horizontal|vertical"
android:layoutDirection="inherit"
android:lineSpacingExtra="14sp"
android:text="TextView"
android:textAlignment="textStart"
android:textColor="#000000"
android:textSize="20sp"
app:autoSizeMaxTextSize="20sp"
app:autoSizeMinTextSize="8sp"
app:layout_constraintEnd_toStartOf="@+id/exampleImageViewTrash"
app:layout_constraintStart_toEndOf="@+id/exampleImageViewLeft"
app:layout_constraintTop_toTopOf="parent" />
<ImageView
android:id="@+id/exampleImageViewLeft"
android:layout_width="25dp"
android:layout_height="23dp"
android:layout_marginStart="32dp"
android:layout_marginTop="24dp"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:srcCompat="@mipmap/ic_launcher_round" />
<ImageView
android:id="@+id/exampleImageViewTrash"
android:layout_width="49dp"
android:layout_height="47dp"
android:layout_marginTop="12dp"
android:layout_marginEnd="20dp"
android:cropToPadding="true"
android:fitsSystemWindows="true"
android:focusableInTouchMode="false"
android:focusable="false"
android:clickable="false"
android:scaleType="centerInside"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:srcCompat="@drawable/trash" />
<androidx.constraintlayout.widget.Guideline
android:id="@+id/guideline2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="horizontal"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintGuide_begin="70dp"
app:layout_constraintStart_toStartOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>
</LinearLayout>
Code of main screen
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent">
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="99dp">
<androidx.constraintlayout.widget.Guideline
android:id="@+id/guideline"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="horizontal"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintGuide_begin="127dp"
app:layout_constraintStart_toStartOf="parent" />
<TextView
android:id="@+id/myItemsTextView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/my_items"
android:textColor="#000000"
android:textSize="36sp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<ImageView
android:id="@+id/menuImageView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_margin="20dp"
android:clickable="true"
android:focusable="true"
android:onClick="openMenu"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:srcCompat="@drawable/menu" />
<ImageView
android:id="@+id/notificationImageView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginEnd="16dp"
android:clickable="true"
android:focusable="true"
android:onClick="notificationClicked"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:srcCompat="@drawable/notification" />
</androidx.constraintlayout.widget.ConstraintLayout>
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<ListView
android:id="@+id/ListOfMyItems"
android:layout_width="wrap_content"
android:layout_height="0dp"
android:layout_marginStart="1dp"
android:layout_marginTop="30dp"
android:layout_marginEnd="1dp"
android:layout_marginBottom="100dp"
android:alwaysDrawnWithCache="true"
android:animateLayoutChanges="true"
android:choiceMode="singleChoice"
android:clickable="false"
android:clipToPadding="false"
android:descendantFocusability="beforeDescendants"
android:dividerHeight="1dp"
android:footerDividersEnabled="true"
android:headerDividersEnabled="true"
android:isScrollContainer="true"
android:layoutDirection="ltr"
android:scrollbars="vertical"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="1.0"
tools:listfooter="@android:layout/simple_list_item_1">
</ListView>
<LinearLayout
android:layout_width="409dp"
android:layout_height="70dp"
android:layout_marginStart="1dp"
android:layout_marginTop="1dp"
android:layout_marginEnd="1dp"
android:focusable="auto"
android:orientation="horizontal"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/ListOfMyItems">
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:clickable="true"
android:focusable="true">
<TextView
android:id="@+id/addNewItemTextView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="-1dp"
android:layout_marginTop="16dp"
android:layout_marginEnd="70dp"
android:clickable="true"
android:focusable="true"
android:onClick="addNewItem"
android:text="@string/add_new_item"
android:textColor="#000000"
android:textSize="30sp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toEndOf="@+id/plusImageView"
app:layout_constraintTop_toTopOf="parent" />
<ImageView
android:id="@+id/plusImageView"
android:layout_width="67dp"
android:layout_height="74dp"
android:layout_marginStart="56dp"
android:clickable="false"
android:focusable="true"
android:onClick="addNewItem"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:srcCompat="@drawable/plus" />
</androidx.constraintlayout.widget.ConstraintLayout>
</LinearLayout>
</androidx.constraintlayout.widget.ConstraintLayout>
</LinearLayout>
Code for AlertDialog adding new item
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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="300dp"
android:orientation="vertical">
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="300dp"
android:background="#FFFFFF">
<EditText
android:id="@+id/nameOfItem"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="100dp"
android:ems="10"
android:hint="Enter name"
android:inputType="textPersonName"
android:singleLine="true"
android:textColor="#000000"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<Button
android:id="@+id/button2"
android:layout_width="wrap_content"
android:layout_height="48dp"
android:layout_marginTop="9dp"
android:background="@android:drawable/btn_default_small"
android:onClick="addNewItemButtonClicked"
android:text="Button"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/nameOfItem" />
</androidx.constraintlayout.widget.ConstraintLayout>
</LinearLayout>
Looks like your data is not properly updated inside the Adapter's getView method. You should try to update the item inside the Adapter when contentView is not null. For performance reason, there is a pattern called ViewHolder used inside the adapter. Refer to Android listview using ViewHolder for more info. Just create Holder when contentView is null and set the data when it isn't. Hope it helps.
P.S. ListView is considered deprecated. Use RecyclerView instead. It has already built-in ViewHolder pattern and is more flexible