Java tutorial
/* * Copyright (C) 2015 The Android Open Source Project * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package android.support.design.internal; import android.content.Context; import android.content.res.ColorStateList; import android.content.res.Resources; import android.graphics.drawable.Drawable; import android.os.Build; import android.os.Bundle; import android.os.Parcelable; import android.support.annotation.LayoutRes; import android.support.annotation.NonNull; import android.support.annotation.Nullable; import android.support.annotation.RestrictTo; import android.support.annotation.StyleRes; import android.support.design.R; import android.support.v4.view.ViewCompat; import android.support.v4.view.WindowInsetsCompat; import android.support.v7.view.menu.MenuBuilder; import android.support.v7.view.menu.MenuItemImpl; import android.support.v7.view.menu.MenuPresenter; import android.support.v7.view.menu.MenuView; import android.support.v7.view.menu.SubMenuBuilder; import android.support.v7.widget.RecyclerView; import android.util.SparseArray; import android.view.LayoutInflater; import android.view.SubMenu; import android.view.View; import android.view.ViewGroup; import android.widget.LinearLayout; import android.widget.TextView; import java.util.ArrayList; import static android.support.annotation.RestrictTo.Scope.LIBRARY_GROUP; /** * @hide */ @RestrictTo(LIBRARY_GROUP) public class NavigationMenuPresenter implements MenuPresenter { private static final String STATE_HIERARCHY = "android:menu:list"; private static final String STATE_ADAPTER = "android:menu:adapter"; private static final String STATE_HEADER = "android:menu:header"; private NavigationMenuView mMenuView; LinearLayout mHeaderLayout; private Callback mCallback; MenuBuilder mMenu; private int mId; NavigationMenuAdapter mAdapter; LayoutInflater mLayoutInflater; int mTextAppearance; boolean mTextAppearanceSet; ColorStateList mTextColor; ColorStateList mIconTintList; Drawable mItemBackground; /** * Padding to be inserted at the top of the list to avoid the first menu item * from being placed underneath the status bar. */ private int mPaddingTopDefault; /** * Padding for separators between items */ int mPaddingSeparator; @Override public void initForMenu(Context context, MenuBuilder menu) { mLayoutInflater = LayoutInflater.from(context); mMenu = menu; Resources res = context.getResources(); mPaddingSeparator = res.getDimensionPixelOffset(R.dimen.design_navigation_separator_vertical_padding); } @Override public MenuView getMenuView(ViewGroup root) { if (mMenuView == null) { mMenuView = (NavigationMenuView) mLayoutInflater.inflate(R.layout.design_navigation_menu, root, false); if (mAdapter == null) { mAdapter = new NavigationMenuAdapter(); } mHeaderLayout = (LinearLayout) mLayoutInflater.inflate(R.layout.design_navigation_item_header, mMenuView, false); mMenuView.setAdapter(mAdapter); } return mMenuView; } @Override public void updateMenuView(boolean cleared) { if (mAdapter != null) { mAdapter.update(); } } @Override public void setCallback(Callback cb) { mCallback = cb; } @Override public boolean onSubMenuSelected(SubMenuBuilder subMenu) { return false; } @Override public void onCloseMenu(MenuBuilder menu, boolean allMenusAreClosing) { if (mCallback != null) { mCallback.onCloseMenu(menu, allMenusAreClosing); } } @Override public boolean flagActionItems() { return false; } @Override public boolean expandItemActionView(MenuBuilder menu, MenuItemImpl item) { return false; } @Override public boolean collapseItemActionView(MenuBuilder menu, MenuItemImpl item) { return false; } @Override public int getId() { return mId; } public void setId(int id) { mId = id; } @Override public Parcelable onSaveInstanceState() { if (Build.VERSION.SDK_INT >= 11) { // API 9-10 does not support ClassLoaderCreator, therefore things can crash if they're // loaded via different loaders. Rather than crash we just won't save state on those // platforms final Bundle state = new Bundle(); if (mMenuView != null) { SparseArray<Parcelable> hierarchy = new SparseArray<>(); mMenuView.saveHierarchyState(hierarchy); state.putSparseParcelableArray(STATE_HIERARCHY, hierarchy); } if (mAdapter != null) { state.putBundle(STATE_ADAPTER, mAdapter.createInstanceState()); } if (mHeaderLayout != null) { SparseArray<Parcelable> header = new SparseArray<>(); mHeaderLayout.saveHierarchyState(header); state.putSparseParcelableArray(STATE_HEADER, header); } return state; } return null; } @Override public void onRestoreInstanceState(final Parcelable parcelable) { if (parcelable instanceof Bundle) { Bundle state = (Bundle) parcelable; SparseArray<Parcelable> hierarchy = state.getSparseParcelableArray(STATE_HIERARCHY); if (hierarchy != null) { mMenuView.restoreHierarchyState(hierarchy); } Bundle adapterState = state.getBundle(STATE_ADAPTER); if (adapterState != null) { mAdapter.restoreInstanceState(adapterState); } SparseArray<Parcelable> header = state.getSparseParcelableArray(STATE_HEADER); if (header != null) { mHeaderLayout.restoreHierarchyState(header); } } } public void setCheckedItem(MenuItemImpl item) { mAdapter.setCheckedItem(item); } public View inflateHeaderView(@LayoutRes int res) { View view = mLayoutInflater.inflate(res, mHeaderLayout, false); addHeaderView(view); return view; } public void addHeaderView(@NonNull View view) { mHeaderLayout.addView(view); // The padding on top should be cleared. mMenuView.setPadding(0, 0, 0, mMenuView.getPaddingBottom()); } public void removeHeaderView(@NonNull View view) { mHeaderLayout.removeView(view); if (mHeaderLayout.getChildCount() == 0) { mMenuView.setPadding(0, mPaddingTopDefault, 0, mMenuView.getPaddingBottom()); } } public int getHeaderCount() { return mHeaderLayout.getChildCount(); } public View getHeaderView(int index) { return mHeaderLayout.getChildAt(index); } @Nullable public ColorStateList getItemTintList() { return mIconTintList; } public void setItemIconTintList(@Nullable ColorStateList tint) { mIconTintList = tint; updateMenuView(false); } @Nullable public ColorStateList getItemTextColor() { return mTextColor; } public void setItemTextColor(@Nullable ColorStateList textColor) { mTextColor = textColor; updateMenuView(false); } public void setItemTextAppearance(@StyleRes int resId) { mTextAppearance = resId; mTextAppearanceSet = true; updateMenuView(false); } @Nullable public Drawable getItemBackground() { return mItemBackground; } public void setItemBackground(@Nullable Drawable itemBackground) { mItemBackground = itemBackground; updateMenuView(false); } public void setUpdateSuspended(boolean updateSuspended) { if (mAdapter != null) { mAdapter.setUpdateSuspended(updateSuspended); } } public void dispatchApplyWindowInsets(WindowInsetsCompat insets) { int top = insets.getSystemWindowInsetTop(); if (mPaddingTopDefault != top) { mPaddingTopDefault = top; if (mHeaderLayout.getChildCount() == 0) { mMenuView.setPadding(0, mPaddingTopDefault, 0, mMenuView.getPaddingBottom()); } } ViewCompat.dispatchApplyWindowInsets(mHeaderLayout, insets); } private abstract static class ViewHolder extends RecyclerView.ViewHolder { public ViewHolder(View itemView) { super(itemView); } } private static class NormalViewHolder extends ViewHolder { public NormalViewHolder(LayoutInflater inflater, ViewGroup parent, View.OnClickListener listener) { super(inflater.inflate(R.layout.design_navigation_item, parent, false)); itemView.setOnClickListener(listener); } } private static class SubheaderViewHolder extends ViewHolder { public SubheaderViewHolder(LayoutInflater inflater, ViewGroup parent) { super(inflater.inflate(R.layout.design_navigation_item_subheader, parent, false)); } } private static class SeparatorViewHolder extends ViewHolder { public SeparatorViewHolder(LayoutInflater inflater, ViewGroup parent) { super(inflater.inflate(R.layout.design_navigation_item_separator, parent, false)); } } private static class HeaderViewHolder extends ViewHolder { public HeaderViewHolder(View itemView) { super(itemView); } } /** * Handles click events for the menu items. The items has to be {@link NavigationMenuItemView}. */ final View.OnClickListener mOnClickListener = new View.OnClickListener() { @Override public void onClick(View v) { NavigationMenuItemView itemView = (NavigationMenuItemView) v; setUpdateSuspended(true); MenuItemImpl item = itemView.getItemData(); boolean result = mMenu.performItemAction(item, NavigationMenuPresenter.this, 0); if (item != null && item.isCheckable() && result) { mAdapter.setCheckedItem(item); } setUpdateSuspended(false); updateMenuView(false); } }; private class NavigationMenuAdapter extends RecyclerView.Adapter<ViewHolder> { private static final String STATE_CHECKED_ITEM = "android:menu:checked"; private static final String STATE_ACTION_VIEWS = "android:menu:action_views"; private static final int VIEW_TYPE_NORMAL = 0; private static final int VIEW_TYPE_SUBHEADER = 1; private static final int VIEW_TYPE_SEPARATOR = 2; private static final int VIEW_TYPE_HEADER = 3; private final ArrayList<NavigationMenuItem> mItems = new ArrayList<>(); private MenuItemImpl mCheckedItem; private boolean mUpdateSuspended; NavigationMenuAdapter() { prepareMenuItems(); } @Override public long getItemId(int position) { return position; } @Override public int getItemCount() { return mItems.size(); } @Override public int getItemViewType(int position) { NavigationMenuItem item = mItems.get(position); if (item instanceof NavigationMenuSeparatorItem) { return VIEW_TYPE_SEPARATOR; } else if (item instanceof NavigationMenuHeaderItem) { return VIEW_TYPE_HEADER; } else if (item instanceof NavigationMenuTextItem) { NavigationMenuTextItem textItem = (NavigationMenuTextItem) item; if (textItem.getMenuItem().hasSubMenu()) { return VIEW_TYPE_SUBHEADER; } else { return VIEW_TYPE_NORMAL; } } throw new RuntimeException("Unknown item type."); } @Override public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) { switch (viewType) { case VIEW_TYPE_NORMAL: return new NormalViewHolder(mLayoutInflater, parent, mOnClickListener); case VIEW_TYPE_SUBHEADER: return new SubheaderViewHolder(mLayoutInflater, parent); case VIEW_TYPE_SEPARATOR: return new SeparatorViewHolder(mLayoutInflater, parent); case VIEW_TYPE_HEADER: return new HeaderViewHolder(mHeaderLayout); } return null; } @Override public void onBindViewHolder(ViewHolder holder, int position) { switch (getItemViewType(position)) { case VIEW_TYPE_NORMAL: { NavigationMenuItemView itemView = (NavigationMenuItemView) holder.itemView; itemView.setIconTintList(mIconTintList); if (mTextAppearanceSet) { itemView.setTextAppearance(mTextAppearance); } if (mTextColor != null) { itemView.setTextColor(mTextColor); } ViewCompat.setBackground(itemView, mItemBackground != null ? mItemBackground.getConstantState().newDrawable() : null); NavigationMenuTextItem item = (NavigationMenuTextItem) mItems.get(position); itemView.setNeedsEmptyIcon(item.needsEmptyIcon); itemView.initialize(item.getMenuItem(), 0); break; } case VIEW_TYPE_SUBHEADER: { TextView subHeader = (TextView) holder.itemView; NavigationMenuTextItem item = (NavigationMenuTextItem) mItems.get(position); subHeader.setText(item.getMenuItem().getTitle()); break; } case VIEW_TYPE_SEPARATOR: { NavigationMenuSeparatorItem item = (NavigationMenuSeparatorItem) mItems.get(position); holder.itemView.setPadding(0, item.getPaddingTop(), 0, item.getPaddingBottom()); break; } case VIEW_TYPE_HEADER: { break; } } } @Override public void onViewRecycled(ViewHolder holder) { if (holder instanceof NormalViewHolder) { ((NavigationMenuItemView) holder.itemView).recycle(); } } public void update() { prepareMenuItems(); notifyDataSetChanged(); } /** * Flattens the visible menu items of {@link #mMenu} into {@link #mItems}, * while inserting separators between items when necessary. */ private void prepareMenuItems() { if (mUpdateSuspended) { return; } mUpdateSuspended = true; mItems.clear(); mItems.add(new NavigationMenuHeaderItem()); int currentGroupId = -1; int currentGroupStart = 0; boolean currentGroupHasIcon = false; for (int i = 0, totalSize = mMenu.getVisibleItems().size(); i < totalSize; i++) { MenuItemImpl item = mMenu.getVisibleItems().get(i); if (item.isChecked()) { setCheckedItem(item); } if (item.isCheckable()) { item.setExclusiveCheckable(false); } if (item.hasSubMenu()) { SubMenu subMenu = item.getSubMenu(); if (subMenu.hasVisibleItems()) { if (i != 0) { mItems.add(new NavigationMenuSeparatorItem(mPaddingSeparator, 0)); } mItems.add(new NavigationMenuTextItem(item)); boolean subMenuHasIcon = false; int subMenuStart = mItems.size(); for (int j = 0, size = subMenu.size(); j < size; j++) { MenuItemImpl subMenuItem = (MenuItemImpl) subMenu.getItem(j); if (subMenuItem.isVisible()) { if (!subMenuHasIcon && subMenuItem.getIcon() != null) { subMenuHasIcon = true; } if (subMenuItem.isCheckable()) { subMenuItem.setExclusiveCheckable(false); } if (item.isChecked()) { setCheckedItem(item); } mItems.add(new NavigationMenuTextItem(subMenuItem)); } } if (subMenuHasIcon) { appendTransparentIconIfMissing(subMenuStart, mItems.size()); } } } else { int groupId = item.getGroupId(); if (groupId != currentGroupId) { // first item in group currentGroupStart = mItems.size(); currentGroupHasIcon = item.getIcon() != null; if (i != 0) { currentGroupStart++; mItems.add(new NavigationMenuSeparatorItem(mPaddingSeparator, mPaddingSeparator)); } } else if (!currentGroupHasIcon && item.getIcon() != null) { currentGroupHasIcon = true; appendTransparentIconIfMissing(currentGroupStart, mItems.size()); } NavigationMenuTextItem textItem = new NavigationMenuTextItem(item); textItem.needsEmptyIcon = currentGroupHasIcon; mItems.add(textItem); currentGroupId = groupId; } } mUpdateSuspended = false; } private void appendTransparentIconIfMissing(int startIndex, int endIndex) { for (int i = startIndex; i < endIndex; i++) { NavigationMenuTextItem textItem = (NavigationMenuTextItem) mItems.get(i); textItem.needsEmptyIcon = true; } } public void setCheckedItem(MenuItemImpl checkedItem) { if (mCheckedItem == checkedItem || !checkedItem.isCheckable()) { return; } if (mCheckedItem != null) { mCheckedItem.setChecked(false); } mCheckedItem = checkedItem; checkedItem.setChecked(true); } public Bundle createInstanceState() { Bundle state = new Bundle(); if (mCheckedItem != null) { state.putInt(STATE_CHECKED_ITEM, mCheckedItem.getItemId()); } // Store the states of the action views. SparseArray<ParcelableSparseArray> actionViewStates = new SparseArray<>(); for (int i = 0, size = mItems.size(); i < size; i++) { NavigationMenuItem navigationMenuItem = mItems.get(i); if (navigationMenuItem instanceof NavigationMenuTextItem) { MenuItemImpl item = ((NavigationMenuTextItem) navigationMenuItem).getMenuItem(); View actionView = item != null ? item.getActionView() : null; if (actionView != null) { ParcelableSparseArray container = new ParcelableSparseArray(); actionView.saveHierarchyState(container); actionViewStates.put(item.getItemId(), container); } } } state.putSparseParcelableArray(STATE_ACTION_VIEWS, actionViewStates); return state; } public void restoreInstanceState(Bundle state) { int checkedItem = state.getInt(STATE_CHECKED_ITEM, 0); if (checkedItem != 0) { mUpdateSuspended = true; for (int i = 0, size = mItems.size(); i < size; i++) { NavigationMenuItem item = mItems.get(i); if (item instanceof NavigationMenuTextItem) { MenuItemImpl menuItem = ((NavigationMenuTextItem) item).getMenuItem(); if (menuItem != null && menuItem.getItemId() == checkedItem) { setCheckedItem(menuItem); break; } } } mUpdateSuspended = false; prepareMenuItems(); } // Restore the states of the action views. SparseArray<ParcelableSparseArray> actionViewStates = state .getSparseParcelableArray(STATE_ACTION_VIEWS); if (actionViewStates != null) { for (int i = 0, size = mItems.size(); i < size; i++) { NavigationMenuItem navigationMenuItem = mItems.get(i); if (!(navigationMenuItem instanceof NavigationMenuTextItem)) { continue; } MenuItemImpl item = ((NavigationMenuTextItem) navigationMenuItem).getMenuItem(); if (item == null) { continue; } View actionView = item.getActionView(); if (actionView == null) { continue; } ParcelableSparseArray container = actionViewStates.get(item.getItemId()); if (container == null) { continue; } actionView.restoreHierarchyState(container); } } } public void setUpdateSuspended(boolean updateSuspended) { mUpdateSuspended = updateSuspended; } } /** * Unified data model for all sorts of navigation menu items. */ private interface NavigationMenuItem { } /** * Normal or subheader items. */ private static class NavigationMenuTextItem implements NavigationMenuItem { private final MenuItemImpl mMenuItem; boolean needsEmptyIcon; NavigationMenuTextItem(MenuItemImpl item) { mMenuItem = item; } public MenuItemImpl getMenuItem() { return mMenuItem; } } /** * Separator items. */ private static class NavigationMenuSeparatorItem implements NavigationMenuItem { private final int mPaddingTop; private final int mPaddingBottom; public NavigationMenuSeparatorItem(int paddingTop, int paddingBottom) { mPaddingTop = paddingTop; mPaddingBottom = paddingBottom; } public int getPaddingTop() { return mPaddingTop; } public int getPaddingBottom() { return mPaddingBottom; } } /** * Header (not subheader) items. */ private static class NavigationMenuHeaderItem implements NavigationMenuItem { NavigationMenuHeaderItem() { } // The actual content is hold by NavigationMenuPresenter#mHeaderLayout. } }