【移動應(yīng)用開發(fā)技術(shù)】Android使用Realm數(shù)據(jù)庫如何實現(xiàn)App中的收藏功能

這篇文章主要介紹了Android使用Realm數(shù)據(jù)庫如何實現(xiàn)App中的收藏功能，具有一定借鑒價值，感興趣的朋友可以參考下，希望大家閱讀完這篇文章之后大有收獲，下面讓在下帶著大家一起了解一下。App數(shù)據(jù)持久化功能是每個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存儲數(shù)據(jù)；文件存儲數(shù)據(jù)；SQLite數(shù)據(jù)庫存儲數(shù)據(jù)；使用ContentProvider存儲數(shù)據(jù)；網(wǎng)絡(luò)存儲數(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)庫來存儲數(shù)據(jù)，而是使用第三方的Realm數(shù)據(jù)庫來來存儲數(shù)據(jù)。Realm本質(zhì)上是一個嵌入式數(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)庫實現(xiàn)AndroidApp中的收藏功能吧。需求分析要使用Realm數(shù)據(jù)庫實現(xiàn)App中的收藏功能，需要實現(xiàn)以下幾個功能和步驟：在Android項目接入Realm數(shù)據(jù)庫；創(chuàng)建收藏數(shù)據(jù)庫表；實現(xiàn)對收藏數(shù)據(jù)庫表進行增刪查的操作；數(shù)據(jù)庫表增刪查時界面實時渲染和更新。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applyplugin:‘com.android.application'下添加applyplugin:‘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)建收藏數(shù)據(jù)庫表首先先創(chuàng)建一張收藏數(shù)據(jù)庫表，代碼如下：/**

*

電影收藏數(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、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。收藏數(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）

/**

*

添加收藏數(shù)據(jù)到本地數(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("收藏數(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("收藏數(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)時如果數(shù)據(jù)庫中已經(jīng)存在了該數(shù)據(jù)則進行更新操作，否則進行了新增操作。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數(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("暫無收藏數(shù)據(jù)可刪除");

return;

}

movieCollectDBModels.deleteAllFromRealm();

ToastUtil.showToast("收藏數(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）/**

*

查詢所有的收藏數(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)前用戶進入收藏界面的時候，需要從數(shù)據(jù)庫中拉取全部的收藏數(shù)據(jù)，可以剛才添加收藏時間進行倒序排序。數(shù)據(jù)庫表增刪查時界面的渲染和更新當(dāng)用戶進入主頁的時候，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)操作收藏數(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));

}

});

//

初始化本地數(shù)據(jù)庫幫助類

mRealmDBHelp

=

new

RealmDBHelp();

}

private

void

initRefresh()

{

//

開啟自動加載功能（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");

//

將不會再次觸發(fā)加載更多事件

refreshLayout.finishLoadMoreWithNoMoreData();

refreshLayout.setEnableLoadMore(false);

refreshLayout.finishLoadMore();

}

},

2000);

}

});

//觸發(fā)自動刷新

refreshLayout.autoRefresh();

}

private

void

initData()

{

//

模擬從網(wǎng)絡(luò)獲取到j(luò)son數(shù)據(jù)

app\src\main\assets\movieData.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);

}

//

查詢本地收藏數(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

{

//

添加收藏數(shù)據(jù)到本地數(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)

{

}

});

}

/**

*

查詢本地收藏數(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");

//

將不會再次觸發(fā)加載更多事件

refreshLayout.finishLoadMoreWithNoMoreData();

refreshLayout.setEnableLoadMore(false);

refreshLayout.finishLoadMore();

}

},

2000);

}

});

//觸發(fā)自動刷新

refreshLayout.autoRefresh();

}

private

void

initData()

{

queryAllCollectData();

}

/**

*

查詢本地收藏數(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.LDialogS