Andriod Studio ListView doesn't update itself

Question

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>

Please share some snippets for Adapter, and how do you update the list. — Mike, Nov 29 '19 at 22:28

score 0 · Accepted Answer · answered Nov 30 '19 at 00:17

0

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

answered Nov 30 '19 at 00:17

Mike

2,547
3
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I did that and now when i click on any element it is deleted but still when i try to add an item and all the initial ones are on the screen, the program crashes. Why is that so? – Max Levytskyi Nov 30 '19 at 17:16
E/AndroidRuntime: FATAL EXCEPTION: main Process: com.example.lostrack, PID: 13176 java.lang.ArrayIndexOutOfBoundsException: length=5; index=5 at android.widget{...} . Do you need a full text of error? – Max Levytskyi Dec 01 '19 at 20:19

Andriod Studio ListView doesn't update itself

1 Answers1