Я начинаю новую деятельность с RecyclerView из основной деятельности.Элементы отображаются правильно.Но на свитке произошло нечто странное.Элементы не отображаются правильно.Тот же RecyclerView работает правильно, если он находится на главном экране.
![enter image description here](https://i.stack.imgur.com/mWz2Y.png)
это копия кода отсюда
Mainактивность:
public class MainActivity extends AppCompatActivity {
ImageButton templatButton;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
templatButton = findViewById(R.id.template_button);
templatButton.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
Intent myIntent = new Intent(getBaseContext(), NewActivity.class);
startActivity(myIntent);
}
});
}
}
activity_main.xml
<?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">
<ImageButton
android:id="@+id/template_button"
android:layout_width="180dp"
android:layout_height="180dp"
android:layout_marginStart="8dp"
android:layout_marginBottom="28dp"
android:background="@drawable/template_icon"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintStart_toStartOf="parent" />
</android.support.constraint.ConstraintLayout>
метод onCreate в новом действии:
public class NewActivity extends AppCompatActivity {
RecyclerView recyclerView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_list);
// Initializing list view with the custom adapter
ArrayList <Item> itemList = new ArrayList<Item>();
ItemArrayAdapter itemArrayAdapter = new ItemArrayAdapter(R.layout.list_item, itemList);
recyclerView = (RecyclerView) findViewById(R.id.item_list);
recyclerView.setLayoutManager(new LinearLayoutManager(this));
recyclerView.setItemAnimator(new DefaultItemAnimator());
recyclerView.setAdapter(itemArrayAdapter);
// Populating list items
for(int i=0; i<100; i++) {
itemList.add(new Item("Item " + i));
}
}
}
адаптер массива элементов:
public class ItemArrayAdapter extends RecyclerView.Adapter<ItemArrayAdapter.ViewHolder> {
//All methods in this adapter are required for a bare minimum recyclerview adapter
private int listItemLayout;
private ArrayList<Item> itemList;
// Constructor of the class
public ItemArrayAdapter(int layoutId, ArrayList<Item> itemList) {
listItemLayout = layoutId;
this.itemList = itemList;
}
// get the size of the list
@Override
public int getItemCount() {
return itemList == null ? 0 : itemList.size();
}
// specify the row layout file and click for each row
@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(listItemLayout, parent, false);
ViewHolder myViewHolder = new ViewHolder(view);
return myViewHolder;
}
// load data in each row element
@Override
public void onBindViewHolder(final ViewHolder holder, final int listPosition) {
TextView item = holder.item;
item.setText(itemList.get(listPosition).getName());
}
// Static inner class to initialize the views of rows
static class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
public TextView item;
public ViewHolder(View itemView) {
super(itemView);
itemView.setOnClickListener(this);
item = (TextView) itemView.findViewById(R.id.row_item);
}
@Override
public void onClick(View view) {
Log.d("onclick", "onClick " + getLayoutPosition() + " " + item.getText());
}
}
}
activitiy_list.xml
<?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"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent"
>
<android.support.v7.widget.RecyclerView
android:id="@+id/item_list"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:scrollbars="vertical"
/>
</LinearLayout>
list_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:layout_height="match_parent">
<TextView
android:id="@+id/row_item"
android:layout_width="match_parent"
android:layout_height="50dp"
android:gravity="center"/>
</LinearLayout>