Java tutorial
/* * Copyright (C) 2016 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 com.android.settings.localepicker; import android.content.Context; import android.graphics.Canvas; import android.os.Bundle; import android.os.LocaleList; import android.support.v4.view.MotionEventCompat; import android.support.v7.widget.RecyclerView; import android.support.v7.widget.helper.ItemTouchHelper; import android.util.Log; import android.util.TypedValue; import android.view.LayoutInflater; import android.view.MotionEvent; import android.view.View; import android.view.ViewGroup; import android.widget.CompoundButton; import com.android.internal.app.LocalePicker; import com.android.internal.app.LocaleStore; import com.android.settings.R; import java.text.NumberFormat; import java.util.ArrayList; import java.util.List; import java.util.Locale; class LocaleDragAndDropAdapter extends RecyclerView.Adapter<LocaleDragAndDropAdapter.CustomViewHolder> { private static final String TAG = "LocaleDragAndDropAdapter"; private static final String CFGKEY_SELECTED_LOCALES = "selectedLocales"; private final Context mContext; private final List<LocaleStore.LocaleInfo> mFeedItemList; private final ItemTouchHelper mItemTouchHelper; private RecyclerView mParentView = null; private boolean mRemoveMode = false; private boolean mDragEnabled = true; private NumberFormat mNumberFormatter = NumberFormat.getNumberInstance(); class CustomViewHolder extends RecyclerView.ViewHolder implements View.OnTouchListener { private final LocaleDragCell mLocaleDragCell; public CustomViewHolder(LocaleDragCell view) { super(view); mLocaleDragCell = view; mLocaleDragCell.getDragHandle().setOnTouchListener(this); } public LocaleDragCell getLocaleDragCell() { return mLocaleDragCell; } @Override public boolean onTouch(View v, MotionEvent event) { if (mDragEnabled) { switch (MotionEventCompat.getActionMasked(event)) { case MotionEvent.ACTION_DOWN: mItemTouchHelper.startDrag(this); } } return false; } } public LocaleDragAndDropAdapter(Context context, List<LocaleStore.LocaleInfo> feedItemList) { this.mFeedItemList = feedItemList; this.mContext = context; final float dragElevation = TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 8, context.getResources().getDisplayMetrics()); this.mItemTouchHelper = new ItemTouchHelper( new ItemTouchHelper.SimpleCallback(ItemTouchHelper.UP | ItemTouchHelper.DOWN, 0 /* no swipe */) { @Override public boolean onMove(RecyclerView view, RecyclerView.ViewHolder source, RecyclerView.ViewHolder target) { onItemMove(source.getAdapterPosition(), target.getAdapterPosition()); return true; } @Override public void onSwiped(RecyclerView.ViewHolder viewHolder, int i) { // Swipe is disabled, this is intentionally empty. } private static final int SELECTION_GAINED = 1; private static final int SELECTION_LOST = 0; private static final int SELECTION_UNCHANGED = -1; private int mSelectionStatus = SELECTION_UNCHANGED; @Override public void onChildDraw(Canvas c, RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, float dX, float dY, int actionState, boolean isCurrentlyActive) { super.onChildDraw(c, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive); // We change the elevation if selection changed if (mSelectionStatus != SELECTION_UNCHANGED) { viewHolder.itemView .setElevation(mSelectionStatus == SELECTION_GAINED ? dragElevation : 0); mSelectionStatus = SELECTION_UNCHANGED; } } @Override public void onSelectedChanged(RecyclerView.ViewHolder viewHolder, int actionState) { super.onSelectedChanged(viewHolder, actionState); if (actionState == ItemTouchHelper.ACTION_STATE_DRAG) { mSelectionStatus = SELECTION_GAINED; } else if (actionState == ItemTouchHelper.ACTION_STATE_IDLE) { mSelectionStatus = SELECTION_LOST; } } }); } public void setRecyclerView(RecyclerView rv) { mParentView = rv; mItemTouchHelper.attachToRecyclerView(rv); } @Override public CustomViewHolder onCreateViewHolder(ViewGroup viewGroup, int i) { final LocaleDragCell item = (LocaleDragCell) LayoutInflater.from(mContext) .inflate(R.layout.locale_drag_cell, viewGroup, false); return new CustomViewHolder(item); } @Override public void onBindViewHolder(final CustomViewHolder holder, int i) { final LocaleStore.LocaleInfo feedItem = mFeedItemList.get(i); final LocaleDragCell dragCell = holder.getLocaleDragCell(); final String label = feedItem.getFullNameNative(); final String description = feedItem.getFullNameInUiLanguage(); dragCell.setLabelAndDescription(label, description); dragCell.setLocalized(feedItem.isTranslated()); dragCell.setMiniLabel(mNumberFormatter.format(i + 1)); dragCell.setShowCheckbox(mRemoveMode); dragCell.setShowMiniLabel(!mRemoveMode); dragCell.setShowHandle(!mRemoveMode && mDragEnabled); dragCell.setChecked(mRemoveMode ? feedItem.getChecked() : false); dragCell.setTag(feedItem); dragCell.getCheckbox().setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() { @Override public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) { LocaleStore.LocaleInfo feedItem = (LocaleStore.LocaleInfo) dragCell.getTag(); feedItem.setChecked(isChecked); } }); } @Override public int getItemCount() { int itemCount = (null != mFeedItemList ? mFeedItemList.size() : 0); if (itemCount < 2 || mRemoveMode) { setDragEnabled(false); } else { setDragEnabled(true); } return itemCount; } void onItemMove(int fromPosition, int toPosition) { if (fromPosition >= 0 && toPosition >= 0) { final LocaleStore.LocaleInfo saved = mFeedItemList.get(fromPosition); mFeedItemList.remove(fromPosition); mFeedItemList.add(toPosition, saved); } else { // TODO: It looks like sometimes the RecycleView tries to swap item -1 // I did not see it in a while, but if it happens, investigate and file a bug. Log.e(TAG, String.format(Locale.US, "Negative position in onItemMove %d -> %d", fromPosition, toPosition)); } notifyItemChanged(fromPosition); // to update the numbers notifyItemChanged(toPosition); notifyItemMoved(fromPosition, toPosition); // We don't call doTheUpdate() here because this method is called for each item swap. // So if we drag something across several positions it will be called several times. } void setRemoveMode(boolean removeMode) { mRemoveMode = removeMode; int itemCount = mFeedItemList.size(); for (int i = 0; i < itemCount; i++) { mFeedItemList.get(i).setChecked(false); notifyItemChanged(i); } } boolean isRemoveMode() { return mRemoveMode; } void removeItem(int position) { int itemCount = mFeedItemList.size(); if (itemCount <= 1) { return; } if (position < 0 || position >= itemCount) { return; } mFeedItemList.remove(position); notifyDataSetChanged(); } void removeChecked() { int itemCount = mFeedItemList.size(); for (int i = itemCount - 1; i >= 0; i--) { if (mFeedItemList.get(i).getChecked()) { mFeedItemList.remove(i); } } notifyDataSetChanged(); doTheUpdate(); } int getCheckedCount() { int result = 0; for (LocaleStore.LocaleInfo li : mFeedItemList) { if (li.getChecked()) { result++; } } return result; } LocaleStore.LocaleInfo getFirstChecked() { for (LocaleStore.LocaleInfo li : mFeedItemList) { if (li.getChecked()) { return li; } } return null; } void addLocale(LocaleStore.LocaleInfo li) { mFeedItemList.add(li); notifyItemInserted(mFeedItemList.size() - 1); doTheUpdate(); } public void doTheUpdate() { int count = mFeedItemList.size(); final Locale[] newList = new Locale[count]; for (int i = 0; i < count; i++) { final LocaleStore.LocaleInfo li = mFeedItemList.get(i); newList[i] = li.getLocale(); } final LocaleList ll = new LocaleList(newList); updateLocalesWhenAnimationStops(ll); } private LocaleList mLocalesToSetNext = null; private LocaleList mLocalesSetLast = null; public void updateLocalesWhenAnimationStops(final LocaleList localeList) { if (localeList.equals(mLocalesToSetNext)) { return; } // This will only update the Settings application to make things feel more responsive, // the system will be updated later, when animation stopped. LocaleList.setDefault(localeList); mLocalesToSetNext = localeList; final RecyclerView.ItemAnimator itemAnimator = mParentView.getItemAnimator(); itemAnimator.isRunning(new RecyclerView.ItemAnimator.ItemAnimatorFinishedListener() { @Override public void onAnimationsFinished() { if (mLocalesToSetNext == null || mLocalesToSetNext.equals(mLocalesSetLast)) { // All animations finished, but the locale list did not change return; } LocalePicker.updateLocales(mLocalesToSetNext); mLocalesSetLast = mLocalesToSetNext; mLocalesToSetNext = null; mNumberFormatter = NumberFormat.getNumberInstance(Locale.getDefault()); } }); } private void setDragEnabled(boolean enabled) { mDragEnabled = enabled; } /** * Saves the list of checked locales to preserve status when the list is destroyed. * (for instance when the device is rotated) * @param outInstanceState Bundle in which to place the saved state */ public void saveState(Bundle outInstanceState) { if (outInstanceState != null) { final ArrayList<String> selectedLocales = new ArrayList<>(); for (LocaleStore.LocaleInfo li : mFeedItemList) { if (li.getChecked()) { selectedLocales.add(li.getId()); } } outInstanceState.putStringArrayList(CFGKEY_SELECTED_LOCALES, selectedLocales); } } /** * Restores the list of checked locales to preserve status when the list is recreated. * (for instance when the device is rotated) * @param savedInstanceState Bundle with the data saved by {@link #saveState(Bundle)} */ public void restoreState(Bundle savedInstanceState) { if (savedInstanceState != null && mRemoveMode) { final ArrayList<String> selectedLocales = savedInstanceState .getStringArrayList(CFGKEY_SELECTED_LOCALES); if (selectedLocales == null || selectedLocales.isEmpty()) { return; } for (LocaleStore.LocaleInfo li : mFeedItemList) { li.setChecked(selectedLocales.contains(li.getId())); } notifyItemRangeChanged(0, mFeedItemList.size()); } } }