[[434771]]

想了解更多內(nèi)容，請(qǐng)?jiān)L問：

51CTO和華為官方合作共建的鴻蒙技術(shù)社區(qū)

https://harmonyos.51cto.com

介紹

之前給大家介紹過【#星光計(jì)劃1.0# HarmonyOS 分布式之仿抖音應(yīng)用】，此次給大家介紹一下基于鴻蒙分布式數(shù)據(jù)服務(wù)開發(fā)的聊天室應(yīng)用，模擬現(xiàn)實(shí)中的聊天室對(duì)話，可以與小伙伴們互動(dòng)、分享自己的故事給小伙伴。

效果演示

項(xiàng)目類說明

主要知識(shí)點(diǎn)

分布式數(shù)據(jù)服務(wù)

官方介紹：分布式數(shù)據(jù)服務(wù)主要實(shí)現(xiàn)用戶設(shè)備中應(yīng)用程序的數(shù)據(jù)內(nèi)容的分布式同步。當(dāng)設(shè)備1上的應(yīng)用A在分布式數(shù)據(jù)庫中增、刪、改數(shù)據(jù)后，設(shè)備2上的應(yīng)用A也可以獲取到該數(shù)據(jù)庫變化，總結(jié)一句話：多個(gè)設(shè)備共用一個(gè)數(shù)據(jù)庫。

主頁代碼

沒有特別復(fù)雜的邏輯，主要是分布式數(shù)據(jù)服務(wù)的使用，關(guān)鍵地方都有注釋。

import com.ldd.myapp.bean.ChatDataBean; 
import com.ldd.myapp.provider.ChatProvider; 
import com.ldd.myapp.util.Tools; 
import ohos.aafwk.ability.AbilitySlice; 
import ohos.aafwk.content.Intent; 
import ohos.agp.components.Button; 
import ohos.agp.components.ListContainer; 
import ohos.agp.components.TextField; 
import ohos.app.Context; 
import ohos.bundle.IBundleManager; 
import ohos.data.distributed.common.*; 
import ohos.data.distributed.user.SingleKvStore; 
import ohos.utils.zson.ZSONArray; 
import ohos.utils.zson.ZSONObject; 
 
import java.util.ArrayList; 
import java.util.List; 
 
import static ohos.security.SystemPermission.DISTRIBUTED_DATASYNC; 
 
/** 
 * 主頁 
 */ 
public class MainAbilitySlice extends AbilitySlice { 
    private Context mContext; 
    // 聊天列表 
    private ListContainer lcList; 
    // 聊天數(shù)據(jù) 
    private final List<ChatDataBean> listData = new ArrayList<>(); 
    // 聊天數(shù)據(jù)適配器 
    private ChatProvider chatProvider; 
    // 輸入框 
    private TextField tfContent; 
    // 發(fā)送按鈕 
    private Button btnSend; 
 
    // 分布式數(shù)據(jù)庫管理器 
    private KvManager kvManager; 
    // 分布式數(shù)據(jù)庫 
    private SingleKvStore singleKvStore; 
    // 數(shù)據(jù)庫名稱 
    private static final String STORE_NAME = "ChatStore"; 
    // 存入的列表數(shù)據(jù)key 
    private static final String KEY_DATA = "key_data"; 
    // 存入的頭像索引 
    private static final String KEY_PIC_INDEX = "key_pic_index"; 
    private int picIndex = 0; 
 
    @Override 
    public void onStart(Intent intent) { 
        super.onStart(intent); 
        super.setUIContent(ResourceTable.Layout_ability_main); 
        mContext = this; 
        requestPermission(); 
        initComponent(); 
        initDatabase(); 
    } 
 
    /** 
     * 請(qǐng)求分布式權(quán)限 
     */ 
    private void requestPermission() { 
        if (verifySelfPermission(DISTRIBUTED_DATASYNC) != IBundleManager.PERMISSION_GRANTED) { 
            if (canRequestPermission(DISTRIBUTED_DATASYNC)) { 
                requestPermissionsFromUser(new String[]{DISTRIBUTED_DATASYNC}, 0); 
            } 
        } 
    } 
 
    /** 
     * 初始化組件 
     */ 
    private void initComponent() { 
        lcList = (ListContainer) findComponentById(ResourceTable.Id_lc_list); 
        tfContent = (TextField) findComponentById(ResourceTable.Id_tf_content); 
        tfContent.setAdjustInputPanel(true); 
        btnSend = (Button) findComponentById(ResourceTable.Id_btn_send); 
        btnSend.setEnabled(false); 
 
        // 初始化適配器 
        chatProvider = new ChatProvider(mContext, listData); 
        lcList.setItemProvider(chatProvider); 
 
        // 輸入框內(nèi)容變化監(jiān)聽 
        tfContent.addTextObserver((text, start, before, count) -> { 
            btnSend.setEnabled(text.length() != 0); 
        }); 
        // 點(diǎn)擊發(fā)送按鈕 
        btnSend.setClickedListener(component -> { 
            String content = tfContent.getText().trim(); 
            listData.add(new ChatDataBean(Tools.getDeviceId(mContext),picIndex,content)); 
            // 存入數(shù)據(jù)庫中 
            singleKvStore.putString(KEY_DATA, ZSONObject.toZSONString(listData)); 
 
            // 清空輸入框 
            tfContent.setText(""); 
        }); 
    } 
 
    /** 
     * 初始化分布式數(shù)據(jù)庫 
     */ 
    private void initDatabase() { 
        // 創(chuàng)建分布式數(shù)據(jù)庫管理器 
        kvManager = KvManagerFactory.getInstance().createKvManager(new KvManagerConfig(this)); 
 
        // 數(shù)據(jù)庫配置 
        Options options = new Options(); 
        options.setCreateIfMissing(true) // 設(shè)置數(shù)據(jù)庫不存在時(shí)是否創(chuàng)建 
                .setEncrypt(false) // 設(shè)置數(shù)據(jù)庫是否加密 
                .setKvStoreType(KvStoreType.SINGLE_VERSION); //數(shù)據(jù)庫類型 
        // 創(chuàng)建分布式數(shù)據(jù)庫 
        singleKvStore = kvManager.getKvStore(options, STORE_NAME); 
        // 監(jiān)聽數(shù)據(jù)庫數(shù)據(jù)改變 
        singleKvStore.subscribe(SubscribeType.SUBSCRIBE_TYPE_ALL, new KvStoreObserver() { 
            @Override 
            public void onChange(ChangeNotification changeNotification) { 
                List<Entry> insertEntries = changeNotification.getInsertEntries(); 
                List<Entry> updateEntries = changeNotification.getUpdateEntries(); 
 
                // 第一次存入數(shù)據(jù)，獲取insertEntries 
                if(insertEntries.size()>0){ 
                    for (Entry entry : insertEntries) { 
                        if (KEY_DATA.equals(entry.getKey())) { 
                            // 回調(diào)為非UI線程，需要在UI線程更新UI 
                            getUITaskDispatcher().syncDispatch(() -> { 
                                listData.clear(); 
                                listData.addAll(ZSONArray.stringToClassList(entry.getValue().getString(),ChatDataBean.class)); 
                                chatProvider.notifyDataChanged(); 
                                lcList.scrollTo(listData.size() - 1); 
                            }); 
                        } 
                    } 
                }else if(updateEntries.size()>0){ 
                    for (Entry entry : updateEntries) { 
                        if (KEY_DATA.equals(entry.getKey())) { 
                            // 回調(diào)為非UI線程，需要在UI線程更新UI 
                            getUITaskDispatcher().syncDispatch(() -> { 
                                listData.clear(); 
                                listData.addAll(ZSONArray.stringToClassList(entry.getValue().getString(),ChatDataBean.class)); 
                                chatProvider.notifyDataChanged(); 
                                lcList.scrollTo(listData.size() - 1); 
                            }); 
                        } 
                    } 
                } 
            } 
        }); 
 
        try { 
            picIndex = singleKvStore.getInt(KEY_PIC_INDEX); 
            singleKvStore.putInt(KEY_PIC_INDEX, picIndex + 1); 
        } catch (KvStoreException e) { 
            e.printStackTrace(); 
            // 沒有找到，首次進(jìn)入 
            if (e.getKvStoreErrorCode() == KvStoreErrorCode.KEY_NOT_FOUND) { 
                picIndex = 0; 
                singleKvStore.putInt(KEY_PIC_INDEX, picIndex + 1); 
            } 
        } 
    } 
 
    @Override 
    protected void onStop() { 
        super.onStop(); 
        kvManager.closeKvStore(singleKvStore); 
    } 
} 

簡(jiǎn)單案例

1、config.json配置

"reqPermissions": [ 
      { 
        "reason": "多設(shè)備協(xié)同", 
        "name": "ohos.permission.DISTRIBUTED_DATASYNC", 
        "usedScene": { 
          "ability": [ 
            "MainAbility" 
          ], 
          "when": "always" 
        } 
      }, 
      { 
        "name": "ohos.permission.DISTRIBUTED_DEVICE_STATE_CHANGE" 
      }, 
      { 
        "name": "ohos.permission.GET_DISTRIBUTED_DEVICE_INFO" 
      }, 
      { 
        "name": "ohos.permission.GET_BUNDLE_INFO" 
      } 
    ] 

2、布局頁面

<?xml version="1.0" encoding="utf-8"?> 
<DirectionalLayout 
    xmlns:ohos="http://schemas.huawei.com/res/ohos" 
    ohos:height="match_parent" 
    ohos:width="match_parent" 
    ohos:alignment="center" 
    ohos:orientation="vertical"> 
 
    <Text 
        ohos:id="$+id:text" 
        ohos:height="match_content" 
        ohos:width="match_content" 
        ohos:text="數(shù)據(jù)：0" 
        ohos:text_size="15fp"/> 
 
    <Button 
        ohos:margin="20vp" 
        ohos:id="$+id:button" 
        ohos:height="match_content" 
        ohos:width="match_parent" 
        ohos:background_element="$graphic:button_bg" 
        ohos:padding="10vp" 
        ohos:text="點(diǎn)擊+1" 
        ohos:text_color="white" 
        ohos:text_size="15fp"/> 
 
</DirectionalLayout> 

3、MainAbilitySlice代碼

import ohos.aafwk.ability.AbilitySlice; 
import ohos.aafwk.content.Intent; 
import ohos.agp.components.Button; 
import ohos.agp.components.ListContainer; 
import ohos.agp.components.Text; 
import ohos.agp.components.TextField; 
import ohos.bundle.IBundleManager; 
import ohos.data.distributed.common.*; 
import ohos.data.distributed.user.SingleKvStore; 
import ohos.utils.zson.ZSONArray; 
 
import java.util.List; 
 
import static ohos.security.SystemPermission.DISTRIBUTED_DATASYNC; 
 
public class MainAbilitySlice extends AbilitySlice { 
    // 顯示數(shù)據(jù) 
    private Text text; 
    // 分布式數(shù)據(jù)庫管理器 
    private KvManager kvManager; 
    // 分布式數(shù)據(jù)庫 
    private SingleKvStore singleKvStore; 
    // 數(shù)據(jù)庫名稱 
    private static final String STORE_NAME = "MyStore"; 
    // 存入的數(shù)據(jù)key 
    private static final String KEY_COUNT = "key_count"; 
 
    @Override 
    public void onStart(Intent intent) { 
        super.onStart(intent); 
        super.setUIContent(ResourceTable.Layout_ability_main); 
        requestPermission(); 
        initDatabase(); 
        initComponent(); 
    } 
 
    /** 
     * 請(qǐng)求分布式權(quán)限 
     */ 
    private void requestPermission() { 
        if (verifySelfPermission(DISTRIBUTED_DATASYNC) != IBundleManager.PERMISSION_GRANTED) { 
            if (canRequestPermission(DISTRIBUTED_DATASYNC)) { 
                requestPermissionsFromUser(new String[]{DISTRIBUTED_DATASYNC}, 0); 
            } 
        } 
    } 
 
    /** 
     * 初始化分布式數(shù)據(jù)庫 
     */ 
    private void initDatabase() { 
        // 創(chuàng)建分布式數(shù)據(jù)庫管理器 
        kvManager = KvManagerFactory.getInstance().createKvManager(new KvManagerConfig(this)); 
 
        // 數(shù)據(jù)庫配置 
        Options options = new Options(); 
        options.setCreateIfMissing(true) // 設(shè)置數(shù)據(jù)庫不存在時(shí)是否創(chuàng)建 
                .setEncrypt(false) // 設(shè)置數(shù)據(jù)庫是否加密 
                .setKvStoreType(KvStoreType.SINGLE_VERSION); //數(shù)據(jù)庫類型 
        // 創(chuàng)建分布式數(shù)據(jù)庫 
        singleKvStore = kvManager.getKvStore(options, STORE_NAME); 
        // 監(jiān)聽數(shù)據(jù)庫數(shù)據(jù)改變 
        singleKvStore.subscribe(SubscribeType.SUBSCRIBE_TYPE_ALL, new KvStoreObserver() { 
            @Override 
            public void onChange(ChangeNotification changeNotification) { 
                List<Entry> insertEntries = changeNotification.getInsertEntries(); 
                List<Entry> updateEntries = changeNotification.getUpdateEntries(); 
 
                // 第一次存入數(shù)據(jù)，獲取insertEntries 
                if (insertEntries.size() > 0) { 
                    for (Entry entry : insertEntries) { 
                        if (KEY_COUNT.equals(entry.getKey())) { 
                            // 回調(diào)為非UI線程，需要在UI線程更新UI 
                            getUITaskDispatcher().syncDispatch(() -> { 
                                int count = entry.getValue().getInt(); 
                                text.setText("數(shù)據(jù)："+count); 
                            }); 
                        } 
                    } 
                } else if (updateEntries.size() > 0) { 
                    for (Entry entry : updateEntries) { 
                        if (KEY_COUNT.equals(entry.getKey())) { 
                            // 回調(diào)為非UI線程，需要在UI線程更新UI 
                            getUITaskDispatcher().syncDispatch(() -> { 
                                int count = entry.getValue().getInt(); 
                                text.setText("數(shù)據(jù)："+count); 
                            }); 
                        } 
                    } 
                } 
            } 
        }); 
 
    } 
 
    /** 
     * 初始化組件 
     */ 
    private void initComponent() { 
        text = (Text) findComponentById(ResourceTable.Id_text); 
        Button button = (Button) findComponentById(ResourceTable.Id_button); 
 
        // 點(diǎn)擊事件 
        button.setClickedListener(component -> { 
            try { 
                int count = singleKvStore.getInt(KEY_COUNT); 
                singleKvStore.putInt(KEY_COUNT, count + 1); 
            } catch (KvStoreException e) { 
                e.printStackTrace(); 
                // 沒有找到，首次進(jìn)入 
                if (e.getKvStoreErrorCode() == KvStoreErrorCode.KEY_NOT_FOUND) { 
                    int count = 0; 
                    singleKvStore.putInt(KEY_COUNT, count + 1); 
                } 
            } 
        }); 
    } 
} 

注釋比較詳細(xì)，主要注意2個(gè)點(diǎn)：

1. 獲取數(shù)據(jù)時(shí)加入try catch塊，處理key未找到的情況
2. 數(shù)據(jù)庫數(shù)據(jù)改變監(jiān)聽回調(diào)是非UI線程，如果更新UI必須切換到UI線程

以上簡(jiǎn)單案例就是讓你快速掌握分布式數(shù)據(jù)服務(wù)：多個(gè)設(shè)備相同的應(yīng)用之間使用同一個(gè)數(shù)據(jù)庫。

想了解更多內(nèi)容，請(qǐng)?jiān)L問：

51CTO和華為官方合作共建的鴻蒙技術(shù)社區(qū)

https://harmonyos.51cto.com