Snippets

Oleg Chulakov Studio Android Picker

Updated by Владимир Самсонов
View revision

File Picker Init.kt Added

  • Ignore whitespace
  • Hide word diff 
+pickerRecycler.setLayoutManager(
+  new SlideLayoutManager(
+      getContext(), pickerRecycler, layoutPosition -> {}));
+SnapHelper snapHelper = new LinearSnapHelper();
+snapHelper.attachToRecyclerView(pickerRecycler);
+PickerAdapter pickerAdapter = new PickerAdapter(new ArrayList<String>() {{
+    add("РАЗ");
+    add("ДВА");
+  }}
+);
+pickerRecycler.setAdapter(pickerAdapter);
+pickerRecycler.scrollToPosition(Integer.MAX_VALUE / 2);
Updated by Владимир Самсонов
View revision

File SlideLayoutManager.kt Added

  • Ignore whitespace
  • Hide word diff 
+public class SlideLayoutManager extends LinearLayoutManager {
+
+  private Context context;
+  private RecyclerView recyclerView;
+  private OnItemSelectedListener listener;
+
+  public SlideLayoutManager(
+      Context context,
+      RecyclerView recyclerView,
+      OnItemSelectedListener listener) {
+    super(context);
+    this.context = context;
+    this.listener = listener;
+    this.recyclerView = recyclerView;
+  }
+
+  @Override
+  public void onLayoutChildren(RecyclerView.Recycler recycler, RecyclerView.State state) {
+    super.onLayoutChildren(recycler, state);
+    scaleDownView();
+  }
+
+  @Override
+  public void onScrollStateChanged(int state) {
+    super.onScrollStateChanged(state);
+    if (state == RecyclerView.SCROLL_STATE_IDLE) {
+      float minDistance = recyclerView.getHeight();
+      int position = -1;
+      for (int i = 0; i < recyclerView.getChildCount(); i++) {
+        View child = recyclerView.getChildAt(i);
+        float distanceFromCenter = distanceFromCenter(child);
+        if (distanceFromCenter < minDistance) {
+          minDistance = distanceFromCenter;
+          position = recyclerView.getChildLayoutPosition(child);
+        }
+        listener.onItemSelected(position);
+      }
+    }
+  }
+
+  @Override
+  public int scrollVerticallyBy(int dy, RecyclerView.Recycler recycler, RecyclerView.State state) {
+    if (getOrientation() == LinearLayoutManager.VERTICAL) {
+      int scrolled = super.scrollVerticallyBy(dy, recycler, state);
+      scaleDownView();
+      return scrolled;
+    } else {
+      return 0;
+    }
+  }
+
+  private float distanceFromCenter(View child) {
+      float mid = getHeight() / 2.0f;
+      float childMid = (getDecoratedBottom(child) + getDecoratedTop(child)) / 2.0f;
+      return Math.abs(mid - childMid);
+  }
+
+  private void scaleDownView() {
+    for (int i = 0; i < getChildCount(); i++) {
+      View child = getChildAt(i);
+      TextView textView = child.findViewById(R.id.text);
+      float distanceFromCenter = distanceFromCenter(child);
+      float scale = (float) (1 - Math.sqrt(distanceFromCenter / getHeight()) * 0.33f);
+      textView.setScaleX(scale);
+      textView.setScaleY(scale);
+    }
+  }
+
+  public interface OnItemSelectedListener {
+    void onItemSelected(int layoutPosition);
+  }
+}
Created by Владимир Самсонов
View revision

File PickerAdapter.kt Added

  • Ignore whitespace
  • Hide word diff 
+public class PickerAdapter extends RecyclerView.Adapter<PickerItemHolder> {
+
+  private List<String> items;
+
+  public PickerAdapter(List<String> items) {
+    this.items = items;
+  }
+
+  @NonNull
+  @Override
+  public PickerItemHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
+        return new PickerItemHolder(
+            DataBindingUtil.inflate(
+                LayoutInflater.from(parent.getContext()),
+                R.layout.picker_item,
+                parent,
+                false));
+  }
+
+  @Override
+  public void onBindViewHolder(@NonNull PickerItemHolder holder, int position) {
+    int arrayPosition = position % items.size();
+    holder.binding.text.setText(items.get(arrayPosition));
+  }
+
+  @Override
+  public int getItemCount() {
+    return Integer.MAX_VALUE;
+  }
+
+  public List<String> getItems() {
+    return items;
+  }
+
+  public class PickerItemHolder extends RecyclerView.ViewHolder {
+    PickerItemBinding binding;
+    public PickerItemHolder(@NonNull PickerItemBinding binding) {
+      super(binding.getRoot());
+      this.binding = binding;
+    }
+  }
+}
HTTPS SSH

You can clone a snippet to your computer for local editing. Learn more.