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.v17.preference; import android.os.Bundle; import android.support.annotation.NonNull; import android.support.annotation.Nullable; import android.support.v14.preference.MultiSelectListPreference; import android.support.v17.leanback.widget.VerticalGridView; import android.support.v4.util.ArraySet; import android.support.v7.preference.DialogPreference; import android.support.v7.preference.ListPreference; import android.support.v7.widget.RecyclerView; import android.text.TextUtils; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.Checkable; import android.widget.TextView; import java.util.Collections; import java.util.HashSet; import java.util.Set; public class LeanbackListPreferenceDialogFragment extends LeanbackPreferenceDialogFragment { private static final String SAVE_STATE_IS_MULTI = "LeanbackListPreferenceDialogFragment.isMulti"; private static final String SAVE_STATE_ENTRIES = "LeanbackListPreferenceDialogFragment.entries"; private static final String SAVE_STATE_ENTRY_VALUES = "LeanbackListPreferenceDialogFragment.entryValues"; private static final String SAVE_STATE_TITLE = "LeanbackListPreferenceDialogFragment.title"; private static final String SAVE_STATE_MESSAGE = "LeanbackListPreferenceDialogFragment.message"; private static final String SAVE_STATE_INITIAL_SELECTIONS = "LeanbackListPreferenceDialogFragment.initialSelections"; private static final String SAVE_STATE_INITIAL_SELECTION = "LeanbackListPreferenceDialogFragment.initialSelection"; private boolean mMulti; private CharSequence[] mEntries; private CharSequence[] mEntryValues; private CharSequence mDialogTitle; private CharSequence mDialogMessage; private Set<String> mInitialSelections; private String mInitialSelection; public static LeanbackListPreferenceDialogFragment newInstanceSingle(String key) { final Bundle args = new Bundle(1); args.putString(ARG_KEY, key); final LeanbackListPreferenceDialogFragment fragment = new LeanbackListPreferenceDialogFragment(); fragment.setArguments(args); return fragment; } public static LeanbackListPreferenceDialogFragment newInstanceMulti(String key) { final Bundle args = new Bundle(1); args.putString(ARG_KEY, key); final LeanbackListPreferenceDialogFragment fragment = new LeanbackListPreferenceDialogFragment(); fragment.setArguments(args); return fragment; } @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); if (savedInstanceState == null) { final DialogPreference preference = getPreference(); mDialogTitle = preference.getDialogTitle(); mDialogMessage = preference.getDialogMessage(); if (preference instanceof ListPreference) { mMulti = false; mEntries = ((ListPreference) preference).getEntries(); mEntryValues = ((ListPreference) preference).getEntryValues(); mInitialSelection = ((ListPreference) preference).getValue(); } else if (preference instanceof MultiSelectListPreference) { mMulti = true; mEntries = ((MultiSelectListPreference) preference).getEntries(); mEntryValues = ((MultiSelectListPreference) preference).getEntryValues(); mInitialSelections = ((MultiSelectListPreference) preference).getValues(); } else { throw new IllegalArgumentException( "Preference must be a ListPreference or " + "MultiSelectListPreference"); } } else { mDialogTitle = savedInstanceState.getCharSequence(SAVE_STATE_TITLE); mDialogMessage = savedInstanceState.getCharSequence(SAVE_STATE_MESSAGE); mMulti = savedInstanceState.getBoolean(SAVE_STATE_IS_MULTI); mEntries = savedInstanceState.getCharSequenceArray(SAVE_STATE_ENTRIES); mEntryValues = savedInstanceState.getCharSequenceArray(SAVE_STATE_ENTRY_VALUES); if (mMulti) { final String[] initialSelections = savedInstanceState.getStringArray(SAVE_STATE_INITIAL_SELECTIONS); mInitialSelections = new ArraySet<>(initialSelections != null ? initialSelections.length : 0); if (initialSelections != null) { Collections.addAll(mInitialSelections, initialSelections); } } else { mInitialSelection = savedInstanceState.getString(SAVE_STATE_INITIAL_SELECTION); } } } @Override public void onSaveInstanceState(Bundle outState) { super.onSaveInstanceState(outState); outState.putCharSequence(SAVE_STATE_TITLE, mDialogTitle); outState.putCharSequence(SAVE_STATE_MESSAGE, mDialogMessage); outState.putBoolean(SAVE_STATE_IS_MULTI, mMulti); outState.putCharSequenceArray(SAVE_STATE_ENTRIES, mEntries); outState.putCharSequenceArray(SAVE_STATE_ENTRY_VALUES, mEntryValues); if (mMulti) { outState.putStringArray(SAVE_STATE_INITIAL_SELECTIONS, mInitialSelections.toArray(new String[mInitialSelections.size()])); } else { outState.putString(SAVE_STATE_INITIAL_SELECTION, mInitialSelection); } } @Override public @Nullable View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { final View view = inflater.inflate(R.layout.leanback_list_preference_fragment, container, false); final VerticalGridView verticalGridView = (VerticalGridView) view.findViewById(android.R.id.list); verticalGridView.setWindowAlignment(VerticalGridView.WINDOW_ALIGN_BOTH_EDGE); verticalGridView.setFocusScrollStrategy(VerticalGridView.FOCUS_SCROLL_ALIGNED); verticalGridView.setAdapter(onCreateAdapter()); verticalGridView.requestFocus(); final CharSequence title = mDialogTitle; if (!TextUtils.isEmpty(title)) { final TextView titleView = (TextView) view.findViewById(R.id.decor_title); titleView.setText(title); } final CharSequence message = mDialogMessage; if (!TextUtils.isEmpty(message)) { final TextView messageView = (TextView) view.findViewById(android.R.id.message); messageView.setVisibility(View.VISIBLE); messageView.setText(message); } return view; } public RecyclerView.Adapter onCreateAdapter() { //final DialogPreference preference = getPreference(); if (mMulti) { return new AdapterMulti(mEntries, mEntryValues, mInitialSelections); } else { return new AdapterSingle(mEntries, mEntryValues, mInitialSelection); } } public class AdapterSingle extends RecyclerView.Adapter<ViewHolder> implements ViewHolder.OnItemClickListener { private final CharSequence[] mEntries; private final CharSequence[] mEntryValues; private CharSequence mSelectedValue; public AdapterSingle(CharSequence[] entries, CharSequence[] entryValues, CharSequence selectedValue) { mEntries = entries; mEntryValues = entryValues; mSelectedValue = selectedValue; } @Override public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) { final LayoutInflater inflater = LayoutInflater.from(parent.getContext()); final View view = inflater.inflate(R.layout.leanback_list_preference_item_single, parent, false); return new ViewHolder(view, this); } @Override public void onBindViewHolder(ViewHolder holder, int position) { holder.getWidgetView().setChecked(mEntryValues[position].equals(mSelectedValue)); holder.getTitleView().setText(mEntries[position]); } @Override public int getItemCount() { return mEntries.length; } @Override public void onItemClick(ViewHolder viewHolder) { final int index = viewHolder.getAdapterPosition(); if (index == RecyclerView.NO_POSITION) { return; } final CharSequence entry = mEntryValues[index]; final ListPreference preference = (ListPreference) getPreference(); if (index >= 0) { String value = mEntryValues[index].toString(); if (preference.callChangeListener(value)) { preference.setValue(value); mSelectedValue = entry; } } getFragmentManager().popBackStack(); notifyDataSetChanged(); } } public class AdapterMulti extends RecyclerView.Adapter<ViewHolder> implements ViewHolder.OnItemClickListener { private final CharSequence[] mEntries; private final CharSequence[] mEntryValues; private final Set<String> mSelections; public AdapterMulti(CharSequence[] entries, CharSequence[] entryValues, Set<String> initialSelections) { mEntries = entries; mEntryValues = entryValues; mSelections = new HashSet<>(initialSelections); } @Override public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) { final LayoutInflater inflater = LayoutInflater.from(parent.getContext()); final View view = inflater.inflate(R.layout.leanback_list_preference_item_multi, parent, false); return new ViewHolder(view, this); } @Override public void onBindViewHolder(ViewHolder holder, int position) { holder.getWidgetView().setChecked(mSelections.contains(mEntryValues[position].toString())); holder.getTitleView().setText(mEntries[position]); } @Override public int getItemCount() { return mEntries.length; } @Override public void onItemClick(ViewHolder viewHolder) { final int index = viewHolder.getAdapterPosition(); if (index == RecyclerView.NO_POSITION) { return; } final String entry = mEntryValues[index].toString(); if (mSelections.contains(entry)) { mSelections.remove(entry); } else { mSelections.add(entry); } final MultiSelectListPreference multiSelectListPreference = (MultiSelectListPreference) getPreference(); // Pass copies of the set to callChangeListener and setValues to avoid mutations if (multiSelectListPreference.callChangeListener(new HashSet<>(mSelections))) { multiSelectListPreference.setValues(new HashSet<>(mSelections)); mInitialSelections = mSelections; } else { // Change refused, back it out if (mSelections.contains(entry)) { mSelections.remove(entry); } else { mSelections.add(entry); } } notifyDataSetChanged(); } } public static class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener { public interface OnItemClickListener { void onItemClick(ViewHolder viewHolder); } private final Checkable mWidgetView; private final TextView mTitleView; private final ViewGroup mContainer; private final OnItemClickListener mListener; public ViewHolder(@NonNull View view, @NonNull OnItemClickListener listener) { super(view); mWidgetView = (Checkable) view.findViewById(R.id.button); mContainer = (ViewGroup) view.findViewById(R.id.container); mTitleView = (TextView) view.findViewById(android.R.id.title); mContainer.setOnClickListener(this); mListener = listener; } public Checkable getWidgetView() { return mWidgetView; } public TextView getTitleView() { return mTitleView; } public ViewGroup getContainer() { return mContainer; } @Override public void onClick(View v) { mListener.onItemClick(this); } } }