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.view.quiz; import android.content.Context; import android.graphics.drawable.Drawable; import android.support.annotation.ColorRes; import android.support.annotation.DrawableRes; import android.support.v4.content.ContextCompat; import android.support.v4.graphics.drawable.DrawableCompat; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.AbsListView; import android.widget.BaseAdapter; import android.widget.ImageView; import android.widget.TextView; import com.google.samples.apps.topeka.R; import com.google.samples.apps.topeka.model.Category; import com.google.samples.apps.topeka.model.quiz.Quiz; import java.util.List; /** * Adapter for displaying score cards. */ public class ScoreAdapter extends BaseAdapter { private final Category mCategory; private final int count; private final List<Quiz> mQuizList; private Drawable mSuccessIcon; private Drawable mFailedIcon; public ScoreAdapter(Category category) { mCategory = category; mQuizList = mCategory.getQuizzes(); count = mQuizList.size(); } @Override public int getCount() { return count; } @Override public Quiz getItem(int position) { return mQuizList.get(position); } @Override public long getItemId(int position) { if (position > count || position < 0) { return AbsListView.INVALID_POSITION; } return position; } @Override public View getView(int position, View convertView, ViewGroup parent) { if (null == convertView) { convertView = createView(parent); } final Quiz quiz = getItem(position); ViewHolder viewHolder = (ViewHolder) convertView.getTag(); viewHolder.mQuizView.setText(quiz.getQuestion()); viewHolder.mAnswerView.setText(quiz.getStringAnswer()); setSolvedStateForQuiz(viewHolder.mSolvedState, position); return convertView; } private void setSolvedStateForQuiz(ImageView solvedState, int position) { final Context context = solvedState.getContext(); final Drawable tintedImage; if (mCategory.isSolvedCorrectly(getItem(position))) { tintedImage = getSuccessIcon(context); } else { tintedImage = getFailedIcon(context); } solvedState.setImageDrawable(tintedImage); } private Drawable getSuccessIcon(Context context) { if (null == mSuccessIcon) { mSuccessIcon = loadAndTint(context, R.drawable.ic_tick, R.color.theme_green_primary); } return mSuccessIcon; } private Drawable getFailedIcon(Context context) { if (null == mFailedIcon) { mFailedIcon = loadAndTint(context, R.drawable.ic_cross, R.color.theme_red_primary); } return mFailedIcon; } /** * Convenience method to aid tintint of vector drawables at runtime. * * @param context The {@link Context} for this app. * @param drawableId The id of the drawable to load. * @param tintColor The tint to apply. * @return The tinted drawable. */ private Drawable loadAndTint(Context context, @DrawableRes int drawableId, @ColorRes int tintColor) { Drawable imageDrawable = ContextCompat.getDrawable(context, drawableId); if (imageDrawable == null) { throw new IllegalArgumentException("The drawable with id " + drawableId + " does not exist"); } DrawableCompat.setTint(DrawableCompat.wrap(imageDrawable), tintColor); return imageDrawable; } private View createView(ViewGroup parent) { View convertView; final LayoutInflater inflater = LayoutInflater.from(parent.getContext()); ViewGroup scorecardItem = (ViewGroup) inflater.inflate(R.layout.item_scorecard, parent, false); convertView = scorecardItem; ViewHolder holder = new ViewHolder(scorecardItem); convertView.setTag(holder); return convertView; } private class ViewHolder { final TextView mAnswerView; final TextView mQuizView; final ImageView mSolvedState; public ViewHolder(ViewGroup scorecardItem) { mQuizView = (TextView) scorecardItem.findViewById(R.id.quiz); mAnswerView = (TextView) scorecardItem.findViewById(R.id.answer); mSolvedState = (ImageView) scorecardItem.findViewById(R.id.solved_state); } } }