androidx.recyclerview.widget.RecyclerView#VERTICAL源码实例Demo

private boolean isLastColumn(int orientation, int position, int columnCount, int childCount) {
    if (orientation == RecyclerView.VERTICAL) {
        if (columnCount == 1) return true;
        return (position + 1) % columnCount == 0;
    } else {
        if (columnCount == 1) {
            return position + 1 == childCount;
        } else {
            int lastRawItemCount = childCount % columnCount;
            int rawCount = (childCount - lastRawItemCount) / columnCount + (lastRawItemCount > 0 ? 1 : 0);

            int rawPositionJudge = (position + 1) % columnCount;
            if (rawPositionJudge == 0) {
                int positionRaw = (position + 1) / columnCount;
                return rawCount == positionRaw;
            } else {
                int rawPosition = (position + 1 - rawPositionJudge) / columnCount + 1;
                return rawCount == rawPosition;
            }
        }
    }
}
 

@Override
public int computeVerticalScrollRange(RecyclerView.State state) {
    if (getOrientation() == RecyclerView.VERTICAL) {
        return super.computeVerticalScrollRange(state);
    }
    return computeVerticalScrollRange();
}
 

/**
 * 计算垂直滚动范围
 *
 * @return 滚动范围
 */
protected int computeVerticalScrollRange() {
    if (getOrientation() == RecyclerView.VERTICAL) {
        final RecyclerView view = getRecyclerView();
        return view == null ? 0 : view.computeVerticalScrollRange();
    }
    return getChildMaxHeight(mChildMaxHeight) + mTopDecorationMaxWidthOfChildMaxHeight +
            mBottomDecorationMaxWidthOfChildMaxHeight;
}
 

@Override
public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
    super.getItemOffsets(outRect, view, parent, state);

    if (mParent == null) {
        if (parent.getLayoutManager() instanceof LinearLayoutManager) {
            if (((LinearLayoutManager) parent.getLayoutManager()).getOrientation()
                    != RecyclerView.VERTICAL) {
                throw new IllegalArgumentException("Only support LinearLayoutManager.VERTICAL");
            }
        }
        mParent = parent;
        initListener();
    }
}
 

/**
 * 计算垂直滚动边界
 *
 * @return 滚动边界
 */
protected int computeVerticalScrollExtent() {
    if (getOrientation() == RecyclerView.VERTICAL) {
        final RecyclerView view = getRecyclerView();
        return view == null ? 0 : view.computeVerticalScrollExtent();
    }
    return getMeasuredHeight() - getPaddingTop() - getPaddingBottom();
}
 

public void init(Context context, DatePickerDialog.ScrollOrientation scrollOrientation) {
    @RecyclerView.Orientation
    int layoutOrientation = scrollOrientation == DatePickerDialog.ScrollOrientation.VERTICAL
            ? RecyclerView.VERTICAL
            : RecyclerView.HORIZONTAL;
    LinearLayoutManager linearLayoutManager = new LinearLayoutManager(context, layoutOrientation, false);
    setLayoutManager(linearLayoutManager);
    setLayoutParams(new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT));
    setVerticalScrollBarEnabled(false);
    setHorizontalScrollBarEnabled(false);
    setClipChildren(false);

    mContext = context;
    setUpRecyclerView(scrollOrientation);
}
 

@Override
public void fillView(IMELanguageWrapper entity, int size) {
    LinearLayoutManager layoutManager = new LinearLayoutManager(itemView.getContext(), RecyclerView.VERTICAL,false);
    binding.recyclerView.setLayoutManager(layoutManager);
    binding.layoutSetName.setText(entity.getMultiIMELanguage().getLayoutName());
    if(size <= 1){
        binding.removeBtn.setVisibility(View.GONE);
    }else{
        binding.removeBtn.setVisibility(View.VISIBLE);
    }
    adapter = new LanguageSettingAdapter();
    binding.recyclerView.setAdapter(adapter);
    adapter.setDataSet(entity.getMultiIMELanguage().getIMELanguageWrappers());

    binding.removeBtn.setOnClickListener(v -> {
        if(languageListener == null){
            return;
        }
        languageListener.onClickRemove(entity);
    });

    binding.recyclerView.setOnTouchListener((v, event) -> itemView.onTouchEvent(event));

    itemView.setOnClickListener(v -> {
        if(languageListener == null){
            return;
        }
        List<IMELanguage> imeList = entity.getMultiIMELanguage().getSubtypeIMEList();
        if (imeList.size() > 0) {
            languageListener.onClickChangeLayoutSet(imeList.get(0));
        }
    });
}
 

@SuppressWarnings("unchecked")
private void applySectionGap(Rect outRect, RecyclerView.Adapter adapter, int position, int orientation) {
    // Section Gap Offset
    if (mSectionOffset > 0 && adapter instanceof FlexibleAdapter) {
        FlexibleAdapter flexibleAdapter = (FlexibleAdapter) adapter;
        IFlexible nextItem = flexibleAdapter.getItem(position + 1);

        // IMPORTANT: the check must be done on the BOTTOM of the section,
        // otherwise the sticky header will jump!
        if (flexibleAdapter.isHeader(nextItem)) {
            //Log.v("applySectionGap position=%s", position);
            if (orientation == RecyclerView.VERTICAL) {
                outRect.bottom += mSectionOffset;
            } else {
                outRect.right += mSectionOffset;
            }
        }
        if (position >= adapter.getItemCount() - mSectionGapOnLastItem) {
            //Log.v("applySectionGapOnLastPosition position=%s", position);
            if (orientation == RecyclerView.VERTICAL) {
                outRect.bottom += mSectionOffset;
            } else {
                outRect.right += mSectionOffset;
            }
        }
    }
}
 

private boolean directionVertical() {
    switch (LAYOUT_MODE){
        case LINEAR_LAYOUT:
            return ((LinearLayoutManager)mLayoutManager).getOrientation() == RecyclerView.VERTICAL;
        case GRID_LAYOUT:
            return ((GridLayoutManager)mLayoutManager).getOrientation() == RecyclerView.VERTICAL;
        case STAGGERED_LAYOUT:
            return ((StaggeredGridLayoutManager)mLayoutManager).getOrientation() == RecyclerView.VERTICAL;
    }
    return true;
}
 

@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    if (!checkPermissions(this, requiredPermissions()))
        return;
    setContentView(R.layout.activity_media_scrolling);

    final Intent callingIntent = getIntent();
    mediaChoose =
            callingIntent != null &&
                    (Intent.ACTION_GET_CONTENT.equals(callingIntent.getAction()) || Intent.ACTION_PICK.equals(callingIntent.getAction()));

    baldTitleBar = findViewById(R.id.bald_title_bar);
    recyclerView = findViewById(R.id.child);

    baldTitleBar.setTitle(title());

    final Point point = new Point();
    getWindowManager().getDefaultDisplay().getSize(point);
    final int num = (point.x / point.y) > 0 ? 6 : 3;
    final GridLayoutManager gridLayoutManager = new GridLayoutManager(this, num, RecyclerView.VERTICAL, REVERSED);

    recyclerView.setLayoutManager(gridLayoutManager);
    width = (int) ((recyclerView.getWidth() / 3) - TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 2, getResources().getDisplayMetrics()));
    cursor = cursor(getContentResolver());

    setupBeforeAdapter();
    adapter = new MediaRecyclerViewAdapter();
    recyclerView.setAdapter(adapter);

}
 

@Override
public int computeVerticalScrollOffset(RecyclerView.State state) {
    if (getOrientation() == RecyclerView.VERTICAL) {
        return super.computeVerticalScrollOffset(state);
    }
    return computeVerticalScrollOffset();
}
 

@Override
public int computeVerticalScrollExtent(RecyclerView.State state) {
    if (getOrientation() == RecyclerView.VERTICAL) {
        return super.computeVerticalScrollExtent(state);
    }
    return computeVerticalScrollExtent();
}
 

@Override
public void getItemOffsets(@NonNull Rect outRect, @NonNull View view, @NonNull RecyclerView parent, @NonNull RecyclerView.State state) {
    if (mDivider == null) {
        outRect.set(0, 0, 0, 0);
        return;
    }

    int pos = parent.indexOfChild(view);
    if (pos != -1 && isDecorated(pos)) {
        if (mOrientation == RecyclerView.VERTICAL)
            outRect.set(0, 0, 0, mDivider.getIntrinsicHeight());
        else outRect.set(0, 0, mDivider.getIntrinsicWidth(), 0);
    }
}
 

protected void draw(Canvas c, RecyclerView parent) {
    if (parent.getLayoutManager() == null) {
        return;
    }
    if (LayoutUtils.getOrientation(parent) == RecyclerView.VERTICAL) {
        drawVertical(c, parent);
    } else {
        drawHorizontal(c, parent);
    }
}
 

@Override
public void onLayoutChildren(RecyclerView.Recycler recycler, RecyclerView.State state) {
    if (mColumnSizeChanged && mColumnSize > 0) {
        int totalSpace;
        if (getOrientation() == RecyclerView.VERTICAL) {
            totalSpace = getWidth() - getPaddingRight() - getPaddingLeft();
        } else {
            totalSpace = getHeight() - getPaddingTop() - getPaddingBottom();
        }

        int spanCount;
        switch (mStrategy) {
            default:
            case STRATEGY_MIN_SIZE:
                spanCount = getSpanCountForMinSize(totalSpace, mColumnSize);
                break;
            case STRATEGY_SUITABLE_SIZE:
                spanCount = getSpanCountForSuitableSize(totalSpace, mColumnSize);
                break;
        }
        setSpanCount(spanCount);
        mColumnSizeChanged = false;

        if (null != mListeners) {
            for (int i = 0, n = mListeners.size(); i < n; i++) {
                mListeners.get(i).onUpdateSpanCount(spanCount);
            }
        }
    }
    super.onLayoutChildren(recycler, state);
}
 

private boolean isFirstColumn(int orientation, int position, int columnCount, int childCount) {
    if (orientation == RecyclerView.VERTICAL) {
        if (columnCount == 1) return true;
        return position % columnCount == 0;
    } else {
        return position < columnCount;
    }
}
 

@NonNull
protected LinearLayoutManager createLayoutManager(@NonNull RecyclerView recyclerView) {
    return new LinearLayoutManager(recyclerView.getContext(), RecyclerView.VERTICAL, false);
}
 

@Override
public RecyclerView.LayoutManager getLayoutManager() {
    return new GridLayoutManager(mContext, 3, RecyclerView.VERTICAL, false);
}
 

private void setupLayout() {
    final LinearLayoutManager llm = new LinearLayoutManager(this, RecyclerView.VERTICAL, false);
    llm.setItemPrefetchEnabled(true);
    mHomeRv.setLayoutManager(llm);
    mHomeRv.setHasFixedSize(true);
    adapter = new HomeAdapter(this);
    mHomeRv.setAdapter(adapter);

    adapter.setOnHomeClickedListener(position -> {
        Bundle transitionbundle = ActivityOptions.makeSceneTransitionAnimation(this).toBundle();
        switch (position) {
            default:
            case 0:
                startActivity(new Intent(this, PieActivity.class), transitionbundle);
                break;

            case 1:
                startActivity(new Intent(this, RingActivity.class), transitionbundle);
                break;

            case 2:
                startActivity(new Intent(this, FillActivity.class), transitionbundle);
                break;

            case 3:
                startActivity(new Intent(this, AdaptiveColorsActivity.class), transitionbundle);
                break;

            case 4:
                startActivity(new Intent(this, GradientColorsActivity.class), transitionbundle);
                break;

            case 5:
                startActivity(new Intent(this, TextFormatterActivity.class), transitionbundle);
                break;

            case 6:
                Uri url = Uri.parse(getString(R.string.github_url));
                Intent intent = new Intent(Intent.ACTION_VIEW, url);
                if (intent.resolveActivity(getPackageManager()) != null) {
                    startActivity(intent);
                }
                break;
        }
    });
}
 

private void initViews(View view) {

        stopwatch = view.findViewById(R.id.stopwatch);
        stopwatch.setStopwatchListener(this);



        savedItemList = new ArrayList<>();
        LinearLayoutManager linearLayoutManager = new LinearLayoutManager(getContext(), RecyclerView.VERTICAL, true);
        StopWatchAdapter stopWatchAdapter = new StopWatchAdapter(savedItemList);

        recyclerView = view.findViewById(R.id.rv_values);
        recyclerView.setLayoutManager(linearLayoutManager);
        recyclerView.setAdapter(stopWatchAdapter);

        startBtn = view.findViewById(R.id.btn_start);
        startBtn.setOnClickListener(this);

        stopBtn = view.findViewById(R.id.btn_stop);
        stopBtn.setOnClickListener(this);

        saveBtn = view.findViewById(R.id.btn_save);
        saveBtn.setOnClickListener(this);
    }