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在应用中, 为了提高用户体验, 会提供更新版本的功能. 那么如何实现呢? 我写了一个简单的Demo, 说明一下, 需要注意几个细节. 使用了Retrofit和Rx处理网络请求.

Github下载地址

1. 逻辑

访问服务器, 根据是否包含新版本, 判断是否需要更新.
下载Apk, 下载完成后, 自动安装, 高版本会覆盖低版本.

逻辑:

public class MainActivity extends AppCompatActivity {        private static final String APP_NAME = "Ped_android";      private static final String VERSION = "1.0.0";      private static final String INFO_NAME = "计步器";      private static final String STORE_APK = "chunyu_apk";        @Bind(R.id.main_b_install_apk) Button mBInstallApk;        private UpdateAppUtils.UpdateCallback mUpdateCallback; // 更新回调        @Override      protected void onCreate(Bundle savedInstanceState) {          super.onCreate(savedInstanceState);          setContentView(R.layout.activity_main);          ButterKnife.bind(this);            mUpdateCallback = new UpdateAppUtils.UpdateCallback() {              @Override public void onSuccess(UpdateInfo updateInfo) {                  Toast.makeText(MainActivity.this, "有更新", Toast.LENGTH_SHORT).show();                  UpdateAppUtils.downloadApk(MainActivity.this, updateInfo, INFO_NAME, STORE_APK);              }                @Override public void onError() {                  Toast.makeText(MainActivity.this, "无更新", Toast.LENGTH_SHORT).show();              }          };            mBInstallApk.setOnClickListener(new View.OnClickListener() {              @Override public void onClick(View v) {                  UpdateAppUtils.checkUpdate(APP_NAME, VERSION, mUpdateCallback);              }          });      }  }

UpdateAppUtils是核心下载类. 输入App的代号, 版本号, 异步回调, 发送到服务器, 判断是否需要更新. 如果存在新版本, 则下载Apk, 并自动安装更新.

2. 网络请求

更新请求, 参数是App代号和当前版本号.

/** * 更新服务 * <p> * Created by wangchenlong on 16/1/4. */  public interface UpdateService {      String ENDPOINT = "http://www.chunyuyisheng.com";        // 获取个人信息      @GET("/cmsapi/app/update")      Observable<UpdateInfo> getUpdateInfo(              @Query("appName") String appName,              @Query("version") String version);  }

创建服务的工厂类.

/** * 创建Retrofit服务 * <p> * Created by wangchenlong on 16/1/4. */  public class ServiceFactory {      public static <T> T createServiceFrom(final Class<T> serviceClass, String endpoint) {          Retrofit adapter = new Retrofit.Builder()                  .baseUrl(endpoint)                  .addCallAdapterFactory(RxJavaCallAdapterFactory.create()) // 添加Rx适配器                  .addConverterFactory(GsonConverterFactory.create()) // 添加Gson转换器                  .build();          return adapter.create(serviceClass);      }  }

更新信息的Json类.

/** * 更新信息(JSON) * <p> * Created by wangchenlong on 16/1/4. */  public class UpdateInfo {      public Data data; // 信息      public Integer error_code; // 错误代码      public String error_msg; // 错误信息        public static class Data {          public String curVersion; // 当前版本          public String appURL; // 下载地址          public String description; // 描述          public String minVersion; // 最低版本          public String appName; // 应用名称      }        @Override public String toString() {          return "当前版本: " + data.curVersion + ", 下载地址: " + data.appURL + ", 描述信息: " + data.description                  + ", 最低版本: " + data.minVersion + ", 应用代称: " + data.appName                  + ", 错误代码: " + error_code + ", 错误信息: " + error_msg;      }  }

3. 请求和下载

更新库的主类, 包含检查更新(checkUpdate)和下载Apk(downloadApk)两个重要方法.

/** * 更新管理器 * <p> * Created by wangchenlong on 16/1/6. */  @SuppressWarnings("unused")  public class UpdateAppUtils {        @SuppressWarnings("unused")      private static final String TAG = "DEBUG-WCL: " + UpdateAppUtils.class.getSimpleName();        /** * 检查更新 */      @SuppressWarnings("unused")      public static void checkUpdate(String appCode, String curVersion, UpdateCallback updateCallback) {          UpdateService updateService =                  ServiceFactory.createServiceFrom(UpdateService.class, UpdateService.ENDPOINT);            updateService.getUpdateInfo(appCode, curVersion)                  .subscribeOn(Schedulers.newThread())                  .observeOn(AndroidSchedulers.mainThread())                  .subscribe(updateInfo -> onNext(updateInfo, updateCallback),                          throwable -> onError(throwable, updateCallback));      }        // 显示信息      private static void onNext(UpdateInfo updateInfo, UpdateCallback updateCallback) {          Log.e(TAG, "返回数据: " + updateInfo.toString());          if (updateInfo.error_code != 0 || updateInfo.data == null ||                  updateInfo.data.appURL == null) {              updateCallback.onError(); // 失败          } else {              updateCallback.onSuccess(updateInfo);          }      }        // 错误信息      private static void onError(Throwable throwable, UpdateCallback updateCallback) {          updateCallback.onError();      }        /** * 下载Apk, 并设置Apk地址, * 默认位置: /storage/sdcard0/Download * * @param context 上下文 * @param updateInfo 更新信息 * @param infoName 通知名称 * @param storeApk 存储的Apk */      @SuppressWarnings("unused")      public static void downloadApk(              Context context, UpdateInfo updateInfo,              String infoName, String storeApk      ) {          if (!isDownloadManagerAvailable()) {              return;          }            String description = updateInfo.data.description;          String appUrl = updateInfo.data.appURL;            if (appUrl == null || appUrl.isEmpty()) {              Log.e(TAG, "请填写\"App下载地址\"");              return;          }            appUrl = appUrl.trim(); // 去掉首尾空格            if (!appUrl.startsWith("http")) {              appUrl = "http://" + appUrl; // 添加Http信息          }            Log.e(TAG, "appUrl: " + appUrl);            DownloadManager.Request request;          try {              request = new DownloadManager.Request(Uri.parse(appUrl));          } catch (Exception e) {              e.printStackTrace();              return;          }          request.setTitle(infoName);          request.setDescription(description);          if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {              request.allowScanningByMediaScanner();              request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);          }          request.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS, storeApk);            Context appContext = context.getApplicationContext();          DownloadManager manager = (DownloadManager)                  appContext.getSystemService(Context.DOWNLOAD_SERVICE);            // 存储下载Key          SharedPreferences sp = PreferenceManager.getDefaultSharedPreferences(appContext);          sp.edit().putLong(PrefsConsts.DOWNLOAD_APK_ID_PREFS, manager.enqueue(request)).apply();      }        // 最小版本号大于9      private static boolean isDownloadManagerAvailable() {          return Build.VERSION.SDK_INT >= Build.VERSION_CODES.GINGERBREAD;      }        // 错误回调      public interface UpdateCallback {          void onSuccess(UpdateInfo updateInfo);            void onError();      }  }

检查更新: 创建服务, 在新线程中发送请求, 在主线程中接收数据, 判断成功和失败.

    /** * 检查更新 */      @SuppressWarnings("unused")      public static void checkUpdate(String appCode, String curVersion, UpdateCallback updateCallback) {          UpdateService updateService =                  ServiceFactory.createServiceFrom(UpdateService.class, UpdateService.ENDPOINT);            updateService.getUpdateInfo(appCode, curVersion)                  .subscribeOn(Schedulers.newThread())                  .observeOn(AndroidSchedulers.mainThread())                  .subscribe(updateInfo -> onNext(updateInfo, updateCallback),                          throwable -> onError(throwable, updateCallback));      }

下载Apk: 转换和解析Url, 设置通知信息和存储位置, 存储下载Id, 自动安装更新.

    /** * 下载Apk, 并设置Apk地址, * 默认位置: /storage/sdcard0/Download * * @param context 上下文 * @param updateInfo 更新信息 * @param infoName 通知名称 * @param storeApk 存储的Apk */      @SuppressWarnings("unused")      public static void downloadApk(              Context context, UpdateInfo updateInfo,              String infoName, String storeApk      ) {          if (!isDownloadManagerAvailable()) {              return;          }            String description = updateInfo.data.description;          String appUrl = updateInfo.data.appURL;            if (appUrl == null || appUrl.isEmpty()) {              Log.e(TAG, "请填写\"App下载地址\"");              return;          }            appUrl = appUrl.trim(); // 去掉首尾空格            if (!appUrl.startsWith("http")) {              appUrl = "http://" + appUrl; // 添加Http信息          }            Log.e(TAG, "appUrl: " + appUrl);            DownloadManager.Request request;          try {              request = new DownloadManager.Request(Uri.parse(appUrl));          } catch (Exception e) {              e.printStackTrace();              return;          }          request.setTitle(infoName);          request.setDescription(description);          if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {              request.allowScanningByMediaScanner();              request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);          }          request.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS, storeApk);            Context appContext = context.getApplicationContext();          DownloadManager manager = (DownloadManager)                  appContext.getSystemService(Context.DOWNLOAD_SERVICE);            // 存储下载Key          SharedPreferences sp = PreferenceManager.getDefaultSharedPreferences(appContext);          sp.edit().putLong(PrefsConsts.DOWNLOAD_APK_ID_PREFS, manager.enqueue(request)).apply();      }

使用DownloadManager下载文件是Android的推荐方式.
存储下载Id(manager.enqueue(request))是为了在安装应用时, 找到Apk.
默认存储地址/storage/sdcard0/Download.

4.自动安装

注册广播接收器, 接收消息ACTION_DOWNLOAD_COMPLETE, 下载完成会发送广播. 获取下载文件的Uri, 进行匹配, 发送安装消息, 自动安装.

/** * 安装下载接收器 * <p> * Created by wangchenlong on 16/1/5. */  public class InstallReceiver extends BroadcastReceiver {        private static final String TAG =              "DEBUG-WCL: " + InstallReceiver.class.getSimpleName();        // 安装下载接收器      @Override public void onReceive(Context context, Intent intent) {          if (intent.getAction().equals(DownloadManager.ACTION_DOWNLOAD_COMPLETE)) {              long downloadApkId = intent.getLongExtra(DownloadManager.EXTRA_DOWNLOAD_ID, -1);              installApk(context, downloadApkId);          }      }        // 安装Apk      private void installApk(Context context, long downloadApkId) {          // 获取存储ID          SharedPreferences sp = PreferenceManager.getDefaultSharedPreferences(context);          long id = sp.getLong(PrefsConsts.DOWNLOAD_APK_ID_PREFS, -1L);            if (downloadApkId == id) {              DownloadManager dManager = (DownloadManager) context.getSystemService(Context.DOWNLOAD_SERVICE);              Intent install = new Intent(Intent.ACTION_VIEW);              Uri downloadFileUri = dManager.getUriForDownloadedFile(downloadApkId);              if (downloadFileUri != null) {                  install.setDataAndType(downloadFileUri, "application/vnd.android.package-archive");                  install.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);                  context.startActivity(install);              } else {                  Log.e(TAG, "下载失败");              }          }      }  }

安装本应用下载的Apk, 不安装其他Apk, 存储下载Id, 与广播Id进行匹配.
下载失败, 也会发送下载完成(ACTION_DOWNLOAD_COMPLETE)广播, Uri可能为空, 需要判断, 否则发生崩溃.

OK, that’s all! Enjoy It!