Save inner RecyclerView's state
The scroll position was being lost when navigating away from the list
and back again.
Bug: 135700452
Test: Manually
Change-Id: Ie73a911c249574a8109cc6beaaa041c13e4f1e8b
diff --git a/car-apps-common/src/com/android/car/apps/common/widget/PagedRecyclerView.java b/car-apps-common/src/com/android/car/apps/common/widget/PagedRecyclerView.java
index 08ba31b..71adcf2 100644
--- a/car-apps-common/src/com/android/car/apps/common/widget/PagedRecyclerView.java
+++ b/car-apps-common/src/com/android/car/apps/common/widget/PagedRecyclerView.java
@@ -21,8 +21,11 @@
import android.car.drivingstate.CarUxRestrictions;
import android.content.Context;
import android.content.res.TypedArray;
+import android.os.Parcel;
+import android.os.Parcelable;
import android.util.AttributeSet;
import android.util.Log;
+import android.util.SparseArray;
import android.view.View;
import android.view.ViewTreeObserver.OnGlobalLayoutListener;
@@ -49,8 +52,6 @@
private static final boolean DEBUG = false;
private static final String TAG = "PagedRecyclerView";
- private Context mContext;
-
private final CarUxRestrictionsUtil mCarUxRestrictionsUtil;
private final CarUxRestrictionsUtil.OnUxRestrictionsChangedListener mListener;
@@ -227,26 +228,19 @@
return;
}
- mContext = context;
- mNestedRecyclerView = new RecyclerView(mContext, attrs,
+ mNestedRecyclerView = new RecyclerView(context, attrs,
R.style.PagedRecyclerView_NestedRecyclerView);
- PagedRecyclerViewLayoutManager layoutManager = new PagedRecyclerViewLayoutManager(context);
- super.setLayoutManager(layoutManager);
-
- PagedRecyclerViewAdapter adapter = new PagedRecyclerViewAdapter();
- super.setAdapter(adapter);
-
+ super.setLayoutManager(new PagedRecyclerViewLayoutManager(context));
+ super.setAdapter(new PagedRecyclerViewAdapter());
super.setNestedScrollingEnabled(false);
super.setClipToPadding(false);
// Gutter
- int defaultGutterSize = getResources().getDimensionPixelSize(R.dimen.car_scroll_bar_margin);
mGutter = a.getInt(R.styleable.PagedRecyclerView_gutter, Gutter.BOTH);
- mGutterSize = defaultGutterSize;
+ mGutterSize = getResources().getDimensionPixelSize(R.dimen.car_scroll_bar_margin);
- int carMargin = mContext.getResources().getDimensionPixelSize(
- R.dimen.car_scroll_bar_margin);
+ int carMargin = getResources().getDimensionPixelSize(R.dimen.car_scroll_bar_margin);
mScrollBarContainerWidth = a.getDimensionPixelSize(
R.styleable.PagedRecyclerView_scrollBarContainerWidth, carMargin);
@@ -516,7 +510,9 @@
@VisibleForTesting(otherwise = VisibleForTesting.PRIVATE)
public void layoutBothForTesting(int l, int t, int r, int b) {
super.layout(l, t, r, b);
- mNestedRecyclerView.layout(l, t, r, b);
+ if (mScrollBarEnabled) {
+ mNestedRecyclerView.layout(l, t, r, b);
+ }
}
@Override
@@ -562,14 +558,14 @@
private void createScrollBarFromConfig() {
if (DEBUG) Log.d(TAG, "createScrollBarFromConfig");
final String clsName = mScrollBarClass == null
- ? mContext.getString(R.string.config_scrollBarComponent) : mScrollBarClass;
+ ? getContext().getString(R.string.config_scrollBarComponent) : mScrollBarClass;
if (clsName == null || clsName.length() == 0) {
throw andLog("No scroll bar component configured", null);
}
Class<?> cls;
try {
- cls = mContext.getClassLoader().loadClass(clsName);
+ cls = getContext().getClassLoader().loadClass(clsName);
} catch (Throwable t) {
throw andLog("Error loading scroll bar component: " + clsName, t);
}
@@ -579,7 +575,7 @@
throw andLog("Error creating scroll bar component: " + clsName, t);
}
- mScrollBarUI.initialize(mContext, mNestedRecyclerView, mScrollBarContainerWidth,
+ mScrollBarUI.initialize(getContext(), mNestedRecyclerView, mScrollBarContainerWidth,
mScrollBarPosition, mScrollBarAboveRecyclerView);
mScrollBarUI.setPadding(mScrollBarPaddingStart, mScrollBarPaddingEnd);
@@ -639,4 +635,61 @@
Log.e(TAG, msg, t);
throw new RuntimeException(msg, t);
}
+
+ @Override
+ public Parcelable onSaveInstanceState() {
+ Parcelable superState = super.onSaveInstanceState();
+ SavedState ss = new SavedState(superState, getContext());
+ if (mScrollBarEnabled) {
+ mNestedRecyclerView.saveHierarchyState(ss.mNestedRecyclerViewState);
+ }
+ return ss;
+ }
+
+ @Override
+ public void onRestoreInstanceState(Parcelable state) {
+ if (!(state instanceof SavedState)) {
+ Log.w(TAG, "onRestoreInstanceState called with an unsupported state");
+ super.onRestoreInstanceState(state);
+ } else {
+ SavedState ss = (SavedState) state;
+ super.onRestoreInstanceState(ss.getSuperState());
+ if (mScrollBarEnabled) {
+ mNestedRecyclerView.restoreHierarchyState(ss.mNestedRecyclerViewState);
+ }
+ }
+ }
+
+ static class SavedState extends BaseSavedState {
+ SparseArray mNestedRecyclerViewState;
+ Context mContext;
+
+ SavedState(Parcelable superState, Context c) {
+ super(superState);
+ mContext = c;
+ mNestedRecyclerViewState = new SparseArray();
+ }
+
+ private SavedState(Parcel in) {
+ super(in);
+ mNestedRecyclerViewState = in.readSparseArray(mContext.getClassLoader());
+ }
+
+ @Override
+ public void writeToParcel(Parcel out, int flags) {
+ super.writeToParcel(out, flags);
+ out.writeSparseArray(mNestedRecyclerViewState);
+ }
+
+ public static final Parcelable.Creator<SavedState> CREATOR =
+ new Parcelable.Creator<SavedState>() {
+ public SavedState createFromParcel(Parcel in) {
+ return new SavedState(in);
+ }
+
+ public SavedState[] newArray(int size) {
+ return new SavedState[size];
+ }
+ };
+ }
}
diff --git a/car-apps-common/src/com/android/car/apps/common/widget/PagedRecyclerViewAdapter.java b/car-apps-common/src/com/android/car/apps/common/widget/PagedRecyclerViewAdapter.java
index 623a3d4..bc35a37 100644
--- a/car-apps-common/src/com/android/car/apps/common/widget/PagedRecyclerViewAdapter.java
+++ b/car-apps-common/src/com/android/car/apps/common/widget/PagedRecyclerViewAdapter.java
@@ -25,18 +25,11 @@
import com.android.car.apps.common.R;
-import java.util.ArrayList;
-
/**
* The adapter for the parent recyclerview in {@link PagedRecyclerView} widget.
*/
final class PagedRecyclerViewAdapter
extends RecyclerView.Adapter<PagedRecyclerViewAdapter.NestedRowViewHolder> {
- private ArrayList<String> mItem = new ArrayList<>();
-
- PagedRecyclerViewAdapter() {
- this.mItem.add("nested_RecyclerView");
- }
@Override
public PagedRecyclerViewAdapter.NestedRowViewHolder onCreateViewHolder(ViewGroup parent,
@@ -55,7 +48,7 @@
// Return the size of your dataset (invoked by the layout manager)
@Override
public int getItemCount() {
- return mItem.size();
+ return 1;
}
/**
