Android 手机 应用管理 中是如何获取到 应用信息的

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）

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/**    * 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***************

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/* //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******************

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/* ** ** 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); } 添加权限 <uses-permission android:name="android.permission.GET_PACKAGE_SIZE"></uses-permission>  使用方法  public void  queryPacakgeSize(String pkgName) throws Exception{           if ( pkgName != null){               //使用放射机制得到PackageManager类的隐藏函数getPackageSizeInfo               PackageManager pm = getPackageManager();  //得到pm对象               try {                   //通过反射机制获得该隐藏函数                   Method getPackageSizeInfo = pm.getClass().getDeclaredMethod("getPackageSizeInfo", String.class,IPackageStatsObserver.class);                   //调用该函数，并且给其分配参数 ，待调用流程完成后会回调PkgSizeObserver类的函数                   getPackageSizeInfo.invoke(pm, pkgName,new PkgSizeObserver());               }                catch(Exception ex){                   Log.e(TAG, "NoSuchMethodException") ;                   ex.printStackTrace() ;                   throw ex ;  // 抛出异常               }            }       }             //aidl文件形成的Bindler机制服务类       public class PkgSizeObserver extends IPackageStatsObserver.Stub{           /*** 回调函数，           * @param pStatus ,返回数据封装在PackageStats对象中           * @param succeeded  代表回调成功           */            @Override           public void onGetStatsCompleted(PackageStats pStats, boolean succeeded)                   throws RemoteException {               // TODO Auto-generated method stub              cachesize = pStats.cacheSize  ; //缓存大小               datasize = pStats.dataSize  ;  //数据大小                codesize = pStats.codeSize  ;  //应用程序大小               totalsize = cachesize + datasize + codesize ;               Log.i(TAG, "cachesize--->"+cachesize+" datasize---->"+datasize+ " codeSize---->"+codesize)  ;           }       }       //系统函数，字符串转换 long -String (kb)       private String formateFileSize(long size){           return Formatter.formatFileSize(MainActivity.this, size);        }