在Android里面每个app都有一个唯一的linux user ID，则这样权限就被设置成该应用程序的文件只对该用户可见，只对该应用程序自身可见；而我们可以使他们对其他的应用程序可见，可以通过SharedUserId，也就是让两个apk使用相同的userID，这样它们就可以看到对方的文件。为了节省资源，具有相同ID的apk也可以在相同的linux进程中进行(注意，并不是一定要在一个进程里面运行)，共享一个虚拟机。

try{final String sharedPackageNameString = "com.sihaixuan.datashare.a";Context context = createPackageContext(sharedPackageNameString, CONTEXT_IGNORE_SECURITY);Resources resources = context.getResources();String resName = getString(R.string.app_share_resource_string_name,"name a");int resiD = resources.getIdentifier(resName, "string",sharedPackageNameString);Log.d("App toney","shared from "+sharedPackageNameString +" : "+resources.getString(resiD));}catch (Exception e){Log.d("App toney", e.getLocalizedMessage());}

<shared-user name="com.sihaixuan.shareUserId" userId="10087">
    <sigs count="1">
        <cert index="12" />
    </sigs>
    <perms />
</shared-user><package name="com.toney.datashare.a" codePath="/data/app/com.toney.datashare.a-1.apk" nativeLibraryPath="/data/data/com.toney.datashare.a/lib"  flags="1073741824" ft="14cd4bf0230" it="14cd4bf032f" ut="14cd4bf032f" version="1" sharedUserId="10087">
    <sigs count="1">
    <cert index="12" />
    </sigs>
    <perms />
</package><package name="com.sihaixuan.datashare.b" codePath="/data/app/com.sihaixuan.datashare.b-1.apk" nativeLibraryPath="/data/data/com.sihaixuan.datashar e.b/lib" flags="1073741824" ft="14cd4bf40b0" it="14cd4bf4408" ut="14cd4bf4408" version="1" sharedUserId="10087">
    <sigs count="1">
    <cert index="12" />
    </sigs>
    <perms />
</package>

public class ProcessMap<E> {    //不同进程的进程名可以相同final ArrayMap<String, SparseArray<E>> mMap   = new ArrayMap<String, SparseArray<E>>();//通过 processName、 linux uid确定processRecordpublic E get(String name, int uid) {SparseArray<E> uids = mMap.get(name);if (uids == null) return null;return uids.get(uid);}public E put(String name, int uid, E value) {SparseArray<E> uids = mMap.get(name);if (uids == null) {uids = new SparseArray<E>(2);mMap.put(name, uids);}uids.put(uid, value);return value;}。。。。。。
}