如何获取Android应用程序大小

/**
  * 作用：-----获取包的大小-----
  * @param context 上下文
  * @param pkgName app的包名
  * @param appInfo 实体类，用于存放App的某些信息
  */
 public static void getPkgSize(final Context context, String pkgName, final PhoneAppInfo appInfo) {
  // getPackageSizeInfo是PackageManager中的一个private方法，所以需要通过反射的机制来调用
  Method method;
  try {
   method = PackageManager.class.getMethod("getPackageSizeInfo",
     new Class[]{String.class, IPackageStatsObserver.class});
   // 调用 getPackageSizeInfo 方法，需要两个参数：1、需要检测的应用包名；2、回调
   method.invoke(context.getPackageManager(), pkgName,
     new IPackageStatsObserver.Stub() {
      @Override
      public void onGetStatsCompleted(PackageStats pStats, boolean succeeded) throws RemoteException {
       if (succeeded && pStats != null) {
        synchronized (PhoneAppInfo.class) {
         appInfo.setCatchSize(pStats.cacheSize);//缓存大小
         appInfo.setDataSize(pStats.dataSize); //数据大小
         appInfo.setCodeSize(pStats.codeSize); //应用大小
         appInfo.setAppSize(pStats.cacheSize + pStats.codeSize + pStats.dataSize);//应用的总大小
         Log.d("asdasdxx",appInfo.getAppSize()+"");
        }
       }
      }
     });
  } catch (NoSuchMethodException | InvocationTargetException | IllegalAccessException e) {
   e.printStackTrace();
  }
 }

/* //device/java/android/android/view/WindowManager.aidl
**
** Copyright 2007, The Android Open Source Project
**
** Licensed under the Apache License, Version 2.0 (the "License"); 
** you may not use this file except in compliance with the License. 
** You may obtain a copy of the License at 
**
**  http://www.apache.org/licenses/LICENSE-2.0 
**
** Unless required by applicable law or agreed to in writing, software 
** distributed under the License is distributed on an "AS IS" BASIS, 
** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 
** See the License for the specific language governing permissions and 
** limitations under the License.
*/
package android.content.pm;
parcelable PackageStats;

/*
**
** Copyright 2007, The Android Open Source Project
**
** Licensed under the Apache License, Version 2.0 (the "License");
** you may not use this file except in compliance with the License.
** You may obtain a copy of the License at
**
**  http://www.apache.org/licenses/LICENSE-2.0
**
** Unless required by applicable law or agreed to in writing, software
** distributed under the License is distributed on an "AS IS" BASIS,
** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
** See the License for the specific language governing permissions and
** limitations under the License.
*/
package android.content.pm;
import android.content.pm.PackageStats;
/**
 * API for package data change related callbacks from the Package Manager.
 * Some usage scenarios include deletion of cache directory, generate
 * statistics related to code, data, cache usage(TODO)
 * {@hide}
 */
oneway interface IPackageStatsObserver {
 void onGetStatsCompleted(in PackageStats pStats, boolean succeeded);
}