Android对这种方法进行了封装，我们没有权限去调用这个方法，所以我们只能通过AIDL，然后利用Java的反射机制去调用系统级的方法。

下面上代码：（注释比较详细）

/**  * 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();  } }

下面是两个AIDL文件的代码。。。

步骤（Android Studio）：

1、在main文件夹下，建立一个aidl文件夹的文件夹

2、建立一个包，包名为android.content.pm

3、结构图

   *******PackageStats.aidl文件***************

/* //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;

****************IPackageStatusObserver.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;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);}