Java tutorial
/* * Copyright 2015 Google Inc. * * 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.google.samples.apps.topeka.fragment; import android.annotation.TargetApi; import android.os.Build; import android.os.Bundle; import android.support.annotation.Nullable; import android.support.v4.view.ViewCompat; import android.support.v4.view.animation.FastOutLinearInInterpolator; import android.view.ContextThemeWrapper; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.AdapterViewAnimator; import android.widget.ListView; import android.widget.ProgressBar; import android.widget.TextView; import com.google.samples.apps.topeka.R; import com.google.samples.apps.topeka.adapter.QuizAdapter; import com.google.samples.apps.topeka.adapter.ScoreAdapter; import com.google.samples.apps.topeka.helper.ApiLevelHelper; import com.google.samples.apps.topeka.helper.PreferencesHelper; import com.google.samples.apps.topeka.model.Category; import com.google.samples.apps.topeka.model.Player; import com.google.samples.apps.topeka.model.Theme; import com.google.samples.apps.topeka.model.quiz.Quiz; import com.google.samples.apps.topeka.persistence.TopekaDatabaseHelper; import com.google.samples.apps.topeka.widget.AvatarView; import com.google.samples.apps.topeka.widget.quiz.AbsQuizView; import java.util.List; /** * Encapsulates Quiz solving and displays it to the user. */ public class QuizFragment extends android.support.v4.app.Fragment { private static final String KEY_USER_INPUT = "USER_INPUT"; private TextView mProgressText; private int mQuizSize; private ProgressBar mProgressBar; private Category mCategory; private AdapterViewAnimator mQuizView; private ScoreAdapter mScoreAdapter; private QuizAdapter mQuizAdapter; private SolvedStateListener mSolvedStateListener; public static QuizFragment newInstance(String categoryId, SolvedStateListener solvedStateListener) { if (categoryId == null) { throw new IllegalArgumentException("The category can not be null"); } Bundle args = new Bundle(); args.putString(Category.TAG, categoryId); QuizFragment fragment = new QuizFragment(); if (solvedStateListener != null) { fragment.mSolvedStateListener = solvedStateListener; } fragment.setArguments(args); return fragment; } @Override public void onCreate(Bundle savedInstanceState) { String categoryId = getArguments().getString(Category.TAG); mCategory = TopekaDatabaseHelper.getCategoryWith(getActivity(), categoryId); super.onCreate(savedInstanceState); } @Override public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) { // Create a themed Context and custom LayoutInflater // to get nicely themed views in this Fragment. final Theme theme = mCategory.getTheme(); final ContextThemeWrapper context = new ContextThemeWrapper(getActivity(), theme.getStyleId()); final LayoutInflater themedInflater = LayoutInflater.from(context); return themedInflater.inflate(R.layout.fragment_quiz, container, false); } @Override public void onViewCreated(View view, @Nullable Bundle savedInstanceState) { mQuizView = (AdapterViewAnimator) view.findViewById(R.id.quiz_view); decideOnViewToDisplay(); setQuizViewAnimations(); final AvatarView avatar = (AvatarView) view.findViewById(R.id.avatar); setAvatarDrawable(avatar); initProgressToolbar(view); super.onViewCreated(view, savedInstanceState); } @TargetApi(Build.VERSION_CODES.LOLLIPOP) private void setQuizViewAnimations() { if (ApiLevelHelper.isLowerThan(Build.VERSION_CODES.LOLLIPOP)) { return; } mQuizView.setInAnimation(getActivity(), R.animator.slide_in_bottom); mQuizView.setOutAnimation(getActivity(), R.animator.slide_out_top); } private void initProgressToolbar(View view) { final int firstUnsolvedQuizPosition = mCategory.getFirstUnsolvedQuizPosition(); final List<Quiz> quizzes = mCategory.getQuizzes(); mQuizSize = quizzes.size(); mProgressText = (TextView) view.findViewById(R.id.progress_text); mProgressBar = ((ProgressBar) view.findViewById(R.id.progress)); mProgressBar.setMax(mQuizSize); setProgress(firstUnsolvedQuizPosition); } private void setProgress(int currentQuizPosition) { if (!isAdded()) { return; } mProgressText.setText(getString(R.string.quiz_of_quizzes, currentQuizPosition, mQuizSize)); mProgressBar.setProgress(currentQuizPosition); } @SuppressWarnings("ConstantConditions") private void setAvatarDrawable(AvatarView avatarView) { Player player = PreferencesHelper.getPlayer(getActivity()); avatarView.setAvatar(player.getAvatar().getDrawableId()); ViewCompat.animate(avatarView).setInterpolator(new FastOutLinearInInterpolator()).setStartDelay(500) .scaleX(1).scaleY(1).start(); } private void decideOnViewToDisplay() { final boolean isSolved = mCategory.isSolved(); if (isSolved) { showSummary(); if (null != mSolvedStateListener) { mSolvedStateListener.onCategorySolved(); } } else { mQuizView.setAdapter(getQuizAdapter()); mQuizView.setSelection(mCategory.getFirstUnsolvedQuizPosition()); } } @Override public void onSaveInstanceState(Bundle outState) { View focusedChild = mQuizView.getFocusedChild(); if (focusedChild instanceof ViewGroup) { View currentView = ((ViewGroup) focusedChild).getChildAt(0); if (currentView instanceof AbsQuizView) { outState.putBundle(KEY_USER_INPUT, ((AbsQuizView) currentView).getUserInput()); } } super.onSaveInstanceState(outState); } @Override public void onViewStateRestored(Bundle savedInstanceState) { restoreQuizState(savedInstanceState); super.onViewStateRestored(savedInstanceState); } private void restoreQuizState(final Bundle savedInstanceState) { if (null == savedInstanceState) { return; } mQuizView.addOnLayoutChangeListener(new View.OnLayoutChangeListener() { @Override public void onLayoutChange(View v, int left, int top, int right, int bottom, int oldLeft, int oldTop, int oldRight, int oldBottom) { mQuizView.removeOnLayoutChangeListener(this); View currentChild = mQuizView.getChildAt(0); if (currentChild instanceof ViewGroup) { final View potentialQuizView = ((ViewGroup) currentChild).getChildAt(0); if (potentialQuizView instanceof AbsQuizView) { ((AbsQuizView) potentialQuizView) .setUserInput(savedInstanceState.getBundle(KEY_USER_INPUT)); } } } }); } private QuizAdapter getQuizAdapter() { if (null == mQuizAdapter) { mQuizAdapter = new QuizAdapter(getActivity(), mCategory); } return mQuizAdapter; } /** * Displays the next page. * * @return <code>true</code> if there's another quiz to solve, else <code>false</code>. */ public boolean showNextPage() { if (null == mQuizView) { return false; } int nextItem = mQuizView.getDisplayedChild() + 1; setProgress(nextItem); final int count = mQuizView.getAdapter().getCount(); if (nextItem < count) { mQuizView.showNext(); TopekaDatabaseHelper.updateCategory(getActivity(), mCategory); return true; } markCategorySolved(); return false; } private void markCategorySolved() { mCategory.setSolved(true); TopekaDatabaseHelper.updateCategory(getActivity(), mCategory); } public void showSummary() { @SuppressWarnings("ConstantConditions") final ListView scorecardView = (ListView) getView().findViewById(R.id.scorecard); mScoreAdapter = getScoreAdapter(); scorecardView.setAdapter(mScoreAdapter); scorecardView.setVisibility(View.VISIBLE); mQuizView.setVisibility(View.GONE); } public boolean hasSolvedStateListener() { return mSolvedStateListener != null; } public void setSolvedStateListener(SolvedStateListener solvedStateListener) { mSolvedStateListener = solvedStateListener; if (mCategory.isSolved() && null != mSolvedStateListener) { mSolvedStateListener.onCategorySolved(); } } private ScoreAdapter getScoreAdapter() { if (null == mScoreAdapter) { mScoreAdapter = new ScoreAdapter(mCategory); } return mScoreAdapter; } /** * Interface definition for a callback to be invoked when the quiz is started. */ public interface SolvedStateListener { /** * This method will be invoked when the category has been solved. */ void onCategorySolved(); } }