[android-developers] Re: Write to another application's internal memory

You could try using android:process with the same process name on the manifest declaration of the activities in each app between which you wish communication to occur.  Note that they will also probably have to share a single heap, which may create problems, depending upon how much memory is consumed by the apps' activities collectively.  

The purpose of android:process on an activity is to specify that your activity should be launched in a process having a specific name. The choice of that name may be used either to isolate the activity in its own process (other than the one the launched it), or to force it to cohabit in a single process with other activities (potentially from different apps) that use the same name.

Per the Dev Guide (http://developer.android.com/guide/topics/manifest/activity-element.html):

"If the name assigned to this attribute begins with a colon (':'), a new process, private to the application, is created when it's needed and the activity runs in that process. If the process name begins with a lowercase character, the activity will run in a global process of that name, provided that it has permission to do so. This allows components in different applications to share a process, reducing resource usage."

Both apps also have to be signed by the same certificate.

Per http://developer.android.com/tools/publishing/app-signing.html:

"Application modularity – The Android system allows applications that are signed by the same certificate to run in the same process, if the applications so requests, so that the system treats them as a single application. In this way you can deploy your application in modules, and users can update each of the modules independently if needed.

"Code/data sharing through permissions – The Android system provides signature-based permissions enforcement, so that an application can expose functionality to another application that is signed with a specified certificate. By signing multiple applications with the same certificate and using signature-based permissions checks, your applications can share code and data in a secure manner."

Caveat: While I have successfully used android:process to provide a separate heap to a help activity within an app, I have not yet tried to use it to communicate between two separate apps.

On Monday, November 26, 2012 11:56:27 PM UTC-8, Android Test wrote:

Hi All,

I have 2 applications with different package names. E.g. App1 and App2.

App1 needs to write some files to App2's internal memory so that it could be uploaded to the backend.

I have used the following in App1 to do so:

filePath = getPackageManager().getPackageInfo("app2.package.name", 0).applicationInfo.dataDir;  

I can get the correct path but could not write to it. I checked the logcat, it is showing "Permission denied".

Am I missing something? What's else needs to be done?

Thanks in Advance

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