如何使用SAP OData offline库实现Android应用的离线模式

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打开Android studio，在工程的build.gradle里加入下面的依赖，导入SAP OData offline库：

implementation group:'com.sap.cloud.android', name:'offline-odata', version: sdkVersion

点击Sync now：

新建一个java文件：SAPServiceManager.java

使用的import如下：

import android.content.Context;import android.util.Log;import android.widget.Toast;import com.sap.cloud.mobile.odata.core.AndroidSystem;import com.sap.cloud.mobile.odata.offline.OfflineODataDefiningQuery;import com.sap.cloud.mobile.odata.offline.OfflineODataException;import com.sap.cloud.mobile.odata.offline.OfflineODataParameters;import com.sap.cloud.mobile.odata.offline.OfflineODataProvider;import java.net.MalformedURLException;import java.net.URL;// 将OfflineODataProvider注释掉，改为OfflineODataProvider//private OnlineODataProvider provider;private OfflineODataProvider provider;private static final String TAG = SAPServiceManager.class.getName();

OData offiline datastore的setup方法：

public void openODataStore(Action0 callback, Context context) {    setupOfflineOData(callback, context);}private void setupOfflineOData(Action0 callback, Context context) {    try {        if (configurationData.loadData()) {            Toast.makeText(context, "Opening the offline store which may take a few moments the first time it is opened.", Toast.LENGTH_LONG).show();            //Initialize application context for use by OfflineODataProvider            AndroidSystem.setContext(context);            //commonly set parameters include setStoreEncryptionKey, setStoreName, setStorePath            OfflineODataParameters offParam = new OfflineODataParameters();            String serviceUrl = configurationData.getServiceUrl();            URL url = new URL(serviceUrl + CONNECTION_ID_ESPMCONTAINER);            provider = new OfflineODataProvider(url, offParam, ClientProvider.get());            //Specifies which entities we wish to include in the offline store            provider.addDefiningQuery(new OfflineODataDefiningQuery("Customers", "Customers", false));        }  } catch (MalformedURLException e) {      e.printStackTrace();  } catch (OfflineODataException e) {      e.printStackTrace();  }  //opens the offline store.  This can take a minute or so the first time it is called as it is created and populated.  Log.d(TAG, "About to call open on the offline store.");  provider.open(() -> {      Log.d(TAG, "Offline store opened.");      eSPMContainer = new ESPMContainer(provider);      callback.call();      syncOfflineData();  //TODO could be triggered via a menu action  }, (OfflineODataException offlineODataException) -> {      Log.d(TAG, "Offline store did not open.", offlineODataException);  });}public void syncOfflineData() {    //send the local changes to the back end OData service    Log.d(TAG, "About to call provider.upload.");    provider.upload(() -> {        Log.d(TAG, "Successfully uploaded the changed data.");        //get changes from the back end OData service.        provider.download(() -> {            Log.d(TAG, "Successfully downloaded the changed data.");        }, (error) -> {            Log.d(TAG, "Failed when downloading the changed data with error: " + error.getMessage());        });    }, (error) -> {        Log.d(TAG, "Failed when uploading the changed data with error: " + error.getMessage());    });}public String getServiceRoot() {    if (configurationData.loadData()) {        String serviceUrl = configurationData.getServiceUrl();        if (serviceRoot == null) {            serviceRoot = serviceUrl + "/" + CONNECTION_ID_ESPMCONTAINER;        }    }    else {        throw new IllegalStateException("SAPService manager configurationData.loadData() failed.");    }    return serviceRoot;}

新建LogonActivity.java，调用之前实现的sapServiceManager.openODataStore:

第一次运行应用，会发现offline OData store的初始化日志：

现在可以测试离线模式了，打开移动设备的飞行模式：

选择存储于OData offline store上的某个客户，点击编辑按钮：

修改city字段：

关闭该应用，关闭设备的飞行模式，再启动该应用，在logcat里能观察到之前处于离线模式修改的数据已经自动同步到了后台online store里：

以上就是如何使用SAP OData offline库实现Android应用的离线模式，小编相信有部分知识点可能是我们日常工作会见到或用到的。希望你能通过这篇文章学到更多知识。更多详情敬请关注行业资讯频道。