Android系统缓存相关

PackageManager pm = context.getPackageManager();
try {
    Method mmethod = PackageManager.class.getMethod("getPackageSizeInfo", String.class,IPackageStatsObserver.class);

    List<PackageInfo> packageInfos = pm.getInstalledPackages(0);
    
    // 数据变化的观察者,来自IPackageStatsObserver.Stub
    DataChangedObserver dataChangedObserver = new DataChangedObserver();
    
    for (PackageInfo packageInfo : packageInfos) {
        // 系统的方法背hide，因此使用反射机制来获取该方法
        mmethod.invoke(pm, packageInfo.packageName, dataChangedObserver);
    }
} catch (Exception e) {
    e.printStackTrace();
}

/**
 * 扫描结果的观察者 需要权限 <uses-permission
 * android:name="android.permission.GET_PACKAGE_SIZE"/>
 * 
 * @author chenhao24
 * 
 */
private class DataChangedObserver extends IPackageStatsObserver.Stub {
    @Override
    public void onGetStatsCompleted(PackageStats pStats, boolean succeeded) throws RemoteException {

        if (!succeeded) {
            return;
        }
        
        // 获取缓存大小
        long cacheSize = pStats.cacheSize;
        
        // 获取应用的名称
        String packageName = pStats.packageName;
    }
}

PackageManager pm = context.getPackageManager();
try {
    // 使用反射
    Method mmethod = PackageManager.class.getMethod("freeStorageAndNotify", Long.class,IPackageDataObserver.class);
    mmethod.invoke(pm, Integer.MAX_VALUE,new ApplyDataObserver());
} catch (Exception e) {
    e.printStackTrace();
}

/**
 * 申请空间，消除缓存的数据观察者
 * @author chenhao24
 *
 */
private class ApplyDataObserver extends IPackageDataObserver.Stub{
    @Override
    public void onRemoveCompleted(String packageName, boolean succeeded)throws RemoteException {
        if(! succeeded){
            Log.i(TAG,"release sys cache error");
            return;
        }
        Log.i(TAG,"release sys cache success");
    }
}