前 言

App數(shù)據(jù)持久化功能是每個(gè)App必不可少的功能，而Android最常用的數(shù)據(jù)持久化方式主要有以下的五種方式：

使用SharedPreferences存儲(chǔ)數(shù)據(jù)； 文件存儲(chǔ)數(shù)據(jù)； SQLite數(shù)據(jù)庫存儲(chǔ)數(shù)據(jù)； 使用ContentProvider存儲(chǔ)數(shù)據(jù)； 網(wǎng)絡(luò)存儲(chǔ)數(shù)據(jù)。

其中前四種都是緩存數(shù)據(jù)到本地，這篇主要講的是使用第三種方式來實(shí)現(xiàn)App中的收藏功能，不過不用Android原生自帶SQLite數(shù)據(jù)庫來存儲(chǔ)數(shù)據(jù)，而是使用第三方的Realm數(shù)據(jù)庫來來存儲(chǔ)數(shù)據(jù)。

Realm 本質(zhì)上是一個(gè)嵌入式數(shù)據(jù)庫，他并不是基于SQLite所構(gòu)建的。它擁有自己的數(shù)據(jù)庫存儲(chǔ)引擎，可以高效且快速地完成數(shù)據(jù)庫的構(gòu)建操作。和SQLite不同的是，它允許你在持久層直接和數(shù)據(jù)對象工作。在它之上是一個(gè)函數(shù)式風(fēng)格的查詢api，眾多的努力讓它比傳統(tǒng)的SQLite 操作更快 。

Realm不僅支持Android的接入，還支持IOS的接入。那么接下來就使用Realm數(shù)據(jù)庫實(shí)現(xiàn)Android App中的收藏功能吧。

需求分析

要使用Realm數(shù)據(jù)庫實(shí)現(xiàn)App中的收藏功能，需要實(shí)現(xiàn)以下幾個(gè)功能和步驟：

在Android項(xiàng)目接入Realm數(shù)據(jù)庫； 創(chuàng)建收藏?cái)?shù)據(jù)庫表； 實(shí)現(xiàn)對收藏?cái)?shù)據(jù)庫表進(jìn)行增刪查的操作； 數(shù)據(jù)庫表增刪查時(shí)界面實(shí)時(shí)渲染和更新。

接入Realm數(shù)據(jù)庫

然后在AS的外層build.gradle里的buildscript.dependencies添加Realm數(shù)據(jù)庫相關(guān)的依賴

buildscript { dependencies { ... classpath 'io.realm:realm-gradle-plugin:6.0.1' }}

然后在AS的內(nèi)層build.gradle里添加Realm數(shù)據(jù)庫相關(guān)的依賴

在頂部 apply plugin: ‘com.android.application’ 下添加 apply plugin: ‘realm-android’ 的聲明，如下圖

在定義的Application里初始化數(shù)據(jù)庫相關(guān)的配置（包括數(shù)據(jù)庫名稱和版本號，具體代碼看Demo源碼）

/** * 數(shù)據(jù)庫相關(guān)的配置 * * @param context */ private void initRealm(Context context) { try { Realm.init(context); RealmConfiguration config = new RealmConfiguration.Builder() .name(RealmConstant.REALM_DB_NAME) .schemaVersion(RealmConstant.REALM_DB_VERSION) .build(); Realm.setDefaultConfiguration(config); } catch (Exception e) { e.printStackTrace(); } }

創(chuàng)建收藏?cái)?shù)據(jù)庫表首先先創(chuàng)建一張收藏?cái)?shù)據(jù)庫表，代碼如下：

/** * 電影收藏?cái)?shù)據(jù)庫表名 */public class MovieCollectDBModel extends RealmObject { // 影視id，主鍵 @Required @PrimaryKey @Index private String movieId; // 影視名稱 @Required private String movieName; // 影視海報(bào)、封面 @Required private String poster; // 影視標(biāo)簽 @Required private String movieLabel; // 影視類型 @Required private String videoType; // 添加到數(shù)據(jù)的時(shí)間 @Required private String createdTime; // 以下省略字段的 set 和 get}

該類繼承于Realm的RealmObject類，其中字段movieId作為該表的主鍵，也是數(shù)據(jù)在表里的唯一性。

收藏?cái)?shù)據(jù)庫表的增刪查添加影視數(shù)據(jù)到到數(shù)據(jù)庫的操作（增）

/** * 添加收藏?cái)?shù)據(jù)到本地?cái)?shù)據(jù)庫 * * @param mvId * @param mvName * @param movieImg * @param movieLabel * @param videoType */ public void addCollectToDB(String mvId, String mvName, String movieImg, String movieLabel, String videoType) { MovieCollectDBModel movieCollectDBModel = new MovieCollectDBModel(); movieCollectDBModel.setMovieId(mvId); movieCollectDBModel.setMovieName(mvName); movieCollectDBModel.setPoster(movieImg); movieCollectDBModel.setMovieLabel(movieLabel); movieCollectDBModel.setVideoType(videoType); movieCollectDBModel.setCreatedTime(BaseUtil.getNowDateTimeFormat()); mTransaction = mRealm.executeTransactionAsync(new Realm.Transaction() { @Override public void execute(Realm realm) { realm.copyToRealmOrUpdate(movieCollectDBModel); } }, new Realm.Transaction.OnSuccess() { @Override public void onSuccess() { L.i('收藏?cái)?shù)據(jù)添加成功！'); ToastUtil.showToast(String.format('%s 已收藏', mvName)); } }, new Realm.Transaction.OnError() { @Override public void onError(Throwable error) { L.i('收藏?cái)?shù)據(jù)添加失敗：' + error.toString()); ToastUtil.showToast(String.format('%s 收藏失敗', mvName)); } }); }

上面的代碼是Realm數(shù)據(jù)插入數(shù)據(jù)到數(shù)據(jù)庫的操作，這是一樣異步插入數(shù)據(jù)的方式。在業(yè)務(wù)場景的需要，可以改新增和更新數(shù)據(jù)的插入方式，比如插入數(shù)據(jù)時(shí)如果數(shù)據(jù)庫中已經(jīng)存在了該數(shù)據(jù)則進(jìn)行更新操作，否則進(jìn)行了新增操作。

從數(shù)據(jù)庫中刪除一條影視數(shù)據(jù)的操作（刪）

/** * 通過鍵值對來刪除指定收藏?cái)?shù)據(jù) * * @param key * @param value */ public void deleteByKeyCollectData(String key, String value) { RealmResults<MovieCollectDBModel> movieCollectDBModels = mRealm.where(MovieCollectDBModel.class) .equalTo(key, value) .findAllAsync(); movieCollectDBModels.addChangeListener(new RealmChangeListener<RealmResults<MovieCollectDBModel>>() { @Override public void onChange(RealmResults<MovieCollectDBModel> movieCollectDBModels1) { if (movieCollectDBModels1.isEmpty()) return; mRealm.executeTransaction(new Realm.Transaction() { @Override public void execute(Realm realm) { movieCollectDBModels1.deleteFromRealm(0); } }); } }); }

從數(shù)據(jù)庫中刪除全部影視數(shù)據(jù)的操作（刪）

/** * 清除全部收藏的數(shù)據(jù)庫內(nèi)容 */ public void deleteAllCollectData() { RealmResults<MovieCollectDBModel> movieCollectDBModels = mRealm.where(MovieCollectDBModel.class) .findAll(); mRealm.executeTransaction(new Realm.Transaction() { @Override public void execute(Realm realm) { if (movieCollectDBModels.isEmpty()) { ToastUtil.showToast('暫無收藏?cái)?shù)據(jù)可刪除'); return; } movieCollectDBModels.deleteAllFromRealm(); ToastUtil.showToast('收藏?cái)?shù)據(jù)已全部清空'); } }); }

從數(shù)據(jù)庫中查詢?nèi)坑耙晹?shù)據(jù)的操作（查）

/** * 查詢所有的收藏?cái)?shù)據(jù) * * @param listener */ public void queryAllCollectData(RealmChangeListener<RealmResults<MovieCollectDBModel>> listener) { RealmResults<MovieCollectDBModel> movieCollectDBModels = mRealm.where(MovieCollectDBModel.class) .sort('createdTime', Sort.DESCENDING) .findAllAsync(); movieCollectDBModels.addChangeListener(listener); }

當(dāng)前用戶進(jìn)入收藏界面的時(shí)候，需要從數(shù)據(jù)庫中拉取全部的收藏?cái)?shù)據(jù)，可以剛才添加收藏時(shí)間進(jìn)行倒序排序。

數(shù)據(jù)庫表增刪查時(shí)界面的渲染和更新當(dāng)用戶進(jìn)入主頁的時(shí)候，首次從網(wǎng)絡(luò)獲取數(shù)據(jù)，然后遍歷一下網(wǎng)絡(luò)獲取數(shù)據(jù)是否已經(jīng)有數(shù)據(jù)操作收藏?cái)?shù)據(jù)庫中，如果有的話則需要提示用戶該數(shù)據(jù)已經(jīng)被收藏并更改收藏圖標(biāo)。

public class MainActivity extends AppCompatActivity { private MovieAdapter adapter; private List<MovieDataModel.DataBean> mList = new ArrayList<>(); private RealmDBHelp mRealmDBHelp; private boolean refreshType; @BindView(R.id.mTitleBar) TitleBar mTitleBar; @BindView(R.id.homeMovieList) RecyclerView homeMovieList; @BindView(R.id.refreshLayout) RefreshLayout refreshLayout; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); initView(); initRefresh(); } private void initView() { ButterKnife.bind(this); mTitleBar.setOnTitleBarListener(new OnTitleBarListener() { @Override public void onLeftClick(View v) { } @Override public void onTitleClick(View v) { } @Override public void onRightClick(View v) { // 跳轉(zhuǎn)至我的收藏界面 startActivity(new Intent(MainActivity.this, MovieCollectActivity.class)); } }); // 初始化本地?cái)?shù)據(jù)庫幫助類 mRealmDBHelp = new RealmDBHelp(); } private void initRefresh() { // 開啟自動(dòng)加載功能（非必須） refreshLayout.setEnableAutoLoadMore(true); refreshLayout.setOnRefreshListener(new OnRefreshListener() { @Override public void onRefresh(@NonNull final RefreshLayout refreshLayout) { refreshLayout.getLayout().postDelayed(new Runnable() { @Override public void run() { refreshType = true; // 加載數(shù)據(jù) initData(); refreshLayout.finishRefresh(); refreshLayout.resetNoMoreData();//setNoMoreData(false); } }, 2000); } }); refreshLayout.setOnLoadMoreListener(new OnLoadMoreListener() { @Override public void onLoadMore(@NonNull final RefreshLayout refreshLayout) { refreshLayout.getLayout().postDelayed(new Runnable() { @Override public void run() { refreshType = false; ToastUtil.showToast('暫無更多的數(shù)據(jù)啦'); // 將不會(huì)再次觸發(fā)加載更多事件 refreshLayout.finishLoadMoreWithNoMoreData(); refreshLayout.setEnableLoadMore(false); refreshLayout.finishLoadMore(); } }, 2000); } }); //觸發(fā)自動(dòng)刷新 refreshLayout.autoRefresh(); } private void initData() { // 模擬從網(wǎng)絡(luò)獲取到j(luò)son數(shù)據(jù) appsrcmainassetsmovieData.json String jsonData = BaseUtil.getAssetsJson(this, 'movieData.json');// L.i('jsonData：' + jsonData); if (TextUtils.isEmpty(jsonData)) { ToastUtil.showToast('Json數(shù)據(jù)為空'); return; } if (mList != null) mList.clear(); // 將json數(shù)據(jù)解析為Java實(shí)體對象 MovieDataModel movieDataModel = new Gson().fromJson(jsonData, MovieDataModel.class); List<MovieDataModel.DataBean> dataBeanList = movieDataModel.getData(); for (MovieDataModel.DataBean dataBean : dataBeanList) { MovieDataModel.DataBean data = new MovieDataModel.DataBean(); data.setMvid(dataBean.getMvid()); data.setName(dataBean.getName()); data.setPoster(dataBean.getPoster()); data.setUpdateStatus(dataBean.getUpdateStatus()); data.setTag(dataBean.getTag()); data.setVideo_type(dataBean.getVideo_type()); mList.add(data); } // 查詢本地收藏?cái)?shù)據(jù)庫中是否存在收藏的數(shù)據(jù)（更改收藏圖標(biāo)用的） queryAllCollectData(); try { // 設(shè)置適配器 homeMovieList.setLayoutManager(new GridLayoutManager(this, 3)); adapter = new MovieAdapter(this, mList); homeMovieList.setAdapter(adapter); } catch (Exception e) { e.printStackTrace(); } // 設(shè)置條目的點(diǎn)擊事件 adapter.setItemClikListener(new MovieAdapter.OnItemClikListener() { @Override public void onItemClik(View view, int position) { String mvId = mList.get(position).getMvid(); String mvName = mList.get(position).getName(); String movieImg = mList.get(position).getPoster(); String movieTag = mList.get(position).getTag(); String videoType = mList.get(position).getVideo_type(); boolean isCollect = mList.get(position).isCollect(); if (isCollect) { // 如果已經(jīng)收藏了則清除該條收藏 // 根據(jù)Id來刪除一條數(shù)據(jù) mRealmDBHelp.deleteByKeyCollectData('movieId', mvId); mList.get(position).setCollect(false); ToastUtil.showToast(String.format('%s 已取消收藏', mvName)); } else { // 添加收藏?cái)?shù)據(jù)到本地?cái)?shù)據(jù)庫 mRealmDBHelp.addCollectToDB(mvId, mvName, movieImg, movieTag, videoType); mList.get(position).setCollect(true); } // 通知適配器數(shù)據(jù)改變重新更新界面 adapter.notifyDataSetChanged(); } @Override public void onItemLongClik(View view, int position) { } }); } /** * 查詢本地收藏?cái)?shù)據(jù)庫中是否存在收藏的數(shù)據(jù)（更改收藏圖標(biāo)用的） */ private void queryAllCollectData() { mRealmDBHelp.queryAllCollectData(new RealmChangeListener<RealmResults<MovieCollectDBModel>>() { @Override public void onChange(RealmResults<MovieCollectDBModel> movieCollectDBModels) { if (movieCollectDBModels.isEmpty()) { return; } for (MovieCollectDBModel movieCollectDBModel : movieCollectDBModels) { for (int i = 0; i < mList.size(); i++) { if (mList.get(i).getMvid().equals(movieCollectDBModel.getMovieId())) { mList.get(i).setCollect(true); break; } } } } }); } @Override protected void onStop() { super.onStop(); mRealmDBHelp.closeTransaction(); } @Override protected void onDestroy() { super.onDestroy(); mRealmDBHelp.close(); }}

收藏界面的代碼，包括查詢和刪除操作。

public class MovieCollectActivity extends AppCompatActivity { private RealmDBHelp mRealmDBHelp; private List<MovieCollectModel> mList = new ArrayList<>(); private MovieCollectAdapter adapter; private boolean refreshType; @BindView(R.id.mTitleBar) TitleBar mTitleBar; @BindView(R.id.movieCollectList) RecyclerView movieCollectList; @BindView(R.id.empty_view) RelativeLayout empty_view; @BindView(R.id.refreshLayout) RefreshLayout refreshLayout; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_movie_collect); initView(); initRefresh(); } private void initView() { ButterKnife.bind(this); mTitleBar.setOnTitleBarListener(new OnTitleBarListener() { @Override public void onLeftClick(View v) { finish(); } @Override public void onTitleClick(View v) { } @Override public void onRightClick(View v) { deleteRealmDB(); } }); mRealmDBHelp = new RealmDBHelp(); } private void initRefresh() { // 開啟自動(dòng)加載功能（非必須） refreshLayout.setEnableAutoLoadMore(true); refreshLayout.setOnRefreshListener(new OnRefreshListener() { @Override public void onRefresh(@NonNull final RefreshLayout refreshLayout) { refreshLayout.getLayout().postDelayed(new Runnable() { @Override public void run() { refreshType = true; // 加載數(shù)據(jù) initData(); refreshLayout.finishRefresh(); refreshLayout.resetNoMoreData();//setNoMoreData(false); } }, 2000); } }); refreshLayout.setOnLoadMoreListener(new OnLoadMoreListener() { @Override public void onLoadMore(@NonNull final RefreshLayout refreshLayout) { refreshLayout.getLayout().postDelayed(new Runnable() { @Override public void run() { refreshType = false; ToastUtil.showToast('暫無更多的數(shù)據(jù)啦'); // 將不會(huì)再次觸發(fā)加載更多事件 refreshLayout.finishLoadMoreWithNoMoreData(); refreshLayout.setEnableLoadMore(false); refreshLayout.finishLoadMore(); } }, 2000); } }); //觸發(fā)自動(dòng)刷新 refreshLayout.autoRefresh(); } private void initData() { queryAllCollectData(); } /** * 查詢本地收藏?cái)?shù)據(jù)庫中所有的數(shù)據(jù) */ private void queryAllCollectData() { mRealmDBHelp.queryAllCollectData(new RealmChangeListener<RealmResults<MovieCollectDBModel>>() { @Override public void onChange(RealmResults<MovieCollectDBModel> movieCollectDBModels) { if (movieCollectDBModels.isEmpty()) { return; } if (mList != null) mList.clear(); for (MovieCollectDBModel movieCollectDBModel : movieCollectDBModels) { MovieCollectModel data = new MovieCollectModel(); data.setMovieId(movieCollectDBModel.getMovieId()); data.setMovieName(movieCollectDBModel.getMovieName()); data.setPoster(movieCollectDBModel.getPoster()); data.setMovieTag(movieCollectDBModel.getMovieLabel()); data.setVideoType(movieCollectDBModel.getVideoType()); data.setCreatedTime(movieCollectDBModel.getCreatedTime()); mList.add(data); } runOnUiThread(new Runnable() { @Override public void run() { parsingMovieList(); } }); } }); } private void parsingMovieList() { movieCollectList.setLayoutManager(new GridLayoutManager(this, 3)); adapter = new MovieCollectAdapter(this, mList); movieCollectList.setAdapter(adapter); if (mList.isEmpty()) { empty_view.setVisibility(View.VISIBLE); movieCollectList.setVisibility(View.GONE); } else { movieCollectList.setVisibility(View.VISIBLE); empty_view.setVisibility(View.GONE); } adapter.setItemClikListener(new MovieCollectAdapter.OnItemClikListener() { @Override public void onItemClik(View view, int position) { // 根據(jù)Id來刪除一條數(shù)據(jù) deleteByKeyCollectData(position); } @Override public void onItemLongClik(View view, int position) { } }); } /** * 根據(jù)Id來刪除一條數(shù)據(jù) * * @param position */ private void deleteByKeyCollectData(int position) { IOSMsgDialog.Companion.init(getSupportFragmentManager()) .setTitle('清除影視提示') .setMessage('是否要清除該條影視收藏的數(shù)據(jù)？') .setAnimStyle(R.style.LDialogScaleAnimation) .setNegativeButton('否', new View.OnClickListener() { @Override public void onClick(View v) { } }) .setPositiveButton('是', new View.OnClickListener() { @Override public void onClick(View v) { // 根據(jù)Id來刪除一條數(shù)據(jù) mRealmDBHelp.deleteByKeyCollectData('movieId', mList.get(position).getMovieId()); mList.remove(position); adapter.notifyDataSetChanged(); } }, Color.RED) .setDismissListener(new OnDialogDismissListener() { @Override public void onDismiss(DialogInterface dialog) { } }).setCancelableOutside(true).show(); } /** * 刪除本地?cái)?shù)據(jù)庫中全部的收藏?cái)?shù)據(jù) */ private void deleteRealmDB() { IOSMsgDialog.Companion.init(getSupportFragmentManager()) .setTitle('清空全部收藏?cái)?shù)據(jù)提示') .setMessage('是否要立即清空全部我的收藏的數(shù)據(jù)？如果要清除單條數(shù)據(jù)的話請點(diǎn)擊單條數(shù)據(jù)列表。') .setAnimStyle(R.style.LDialogScaleAnimation) .setNegativeButton('否', new View.OnClickListener() { @Override public void onClick(View v) { } }) .setPositiveButton('是', new View.OnClickListener() { @Override public void onClick(View v) { // 清除全部收藏的數(shù)據(jù)庫內(nèi)容 mRealmDBHelp.deleteAllCollectData(); mList.clear(); empty_view.setVisibility(View.VISIBLE); movieCollectList.setVisibility(View.GONE); adapter.notifyDataSetChanged(); } }, Color.RED) .setDismissListener(new OnDialogDismissListener() { @Override public void onDismiss(DialogInterface dialog) { } }).setCancelableOutside(true).show(); } @Override protected void onDestroy() { super.onDestroy(); mRealmDBHelp.close(); }}

界面運(yùn)行效果圖如下：

apk安裝包下載體驗(yàn)地址：

可以掃描以下二維碼進(jìn)行下載安裝，或者點(diǎn)擊以下鏈接 http://app.fukaimei.top/MovieCollect 進(jìn)行下載安裝體驗(yàn)。

總結(jié)

到此這篇關(guān)于Android使用Realm數(shù)據(jù)庫實(shí)現(xiàn)App中的收藏功能(代碼詳解)的文章就介紹到這了,更多相關(guān)android realm數(shù)據(jù)庫實(shí)現(xiàn)app收藏內(nèi)容請搜索好吧啦網(wǎng)以前的文章或繼續(xù)瀏覽下面的相關(guān)文章希望大家以后多多支持好吧啦網(wǎng)！