How to access android MMS resources such as video/

问题:

I started developing an android app that have to interact with MMS attachements, in particular, get attachements such as text, bitmaps, audio, video etc. and store them on the phone in a specific folder.

So i started reading some books and some post on the web but it isn't a very common argument, and i didn't find an official way to do what i want to do.

I found a fairly good article here on stack-overflow here: How to Read MMS Data in Android?... it works very well for me, but there are 2 problems:

1. The article shows you how to get MMS data by querying over the "hidden" SMS-MMS content provider, and as far as i know, Google doesn't guarantee that they'll keep the current structure in every android's future relase.
2. The article only explains how to get Text data and Bitmap data from MMS...what about video/audio? I tried to get a video/audio stream from an InputStream such as the example did with Bitmaps, unfortunately with no luck...

I'm very disappointed about the absence of official tutorial or "How-To" over this argument because SMS and MMS management is a very common need in mobile developement. I hope someone can help me....

Thanks in advance!!

回答1:

I found a fairly simple way to read Video/Audio data from MMS, so i decided to publish this part of my class that provides MMS attachements, for all users that need this.

private static final int RAW_DATA_BLOCK_SIZE = 16384; //Set the block size used to write a ByteArrayOutputStream to byte[]
public static final int ERROR_IO_EXCEPTION = 1;
public static final int ERROR_FILE_NOT_FOUND = 2;



public static byte[] LoadRaw(Context context, Uri uri, int Error){
    InputStream inputStream = null;
    byte[] ret = new byte[0];

    //Open inputStream from the specified URI
    try {
        inputStream = context.getContentResolver().openInputStream(uri);

        //Try read from the InputStream
        if(inputStream!=null)
            ret = InputStreamToByteArray(inputStream);

    } 
    catch (FileNotFoundException e1) {
        Error = ERROR_FILE_NOT_FOUND;
    } 
    catch (IOException e) {
        Error = ERROR_IO_EXCEPTION;
    }
    finally{
        if (inputStream != null) {
            try {
                inputStream.close();
            } 
            catch (IOException e) {
                //Problem on closing stream. 
                //The return state does not change. 
                Error = ERROR_IO_EXCEPTION;
            }
        }
    }


    //Return
    return ret;
}


//Create a byte array from an open inputStream. Read blocks of RAW_DATA_BLOCK_SIZE byte
private static byte[] InputStreamToByteArray(InputStream inputStream) throws IOException{
    ByteArrayOutputStream buffer = new ByteArrayOutputStream();
    int nRead;
    byte[] data = new byte[RAW_DATA_BLOCK_SIZE];

    while ((nRead = inputStream.read(data, 0, data.length)) != -1) {
      buffer.write(data, 0, nRead);
    }
    buffer.flush();
    return buffer.toByteArray();
}

In this way you can extract "Raw" data such as Audio/Video/Images from MMS by passing:

1. the context where you need to use this function
2. the URI of the MMS part that contains data you want to extract (for ex. "content://mms/part/2")
3. the byref param that returns an eventual error code thrown by the procedure.

Once you have your byte[], you can create an empty File and then use a FileOutputStream to write the byte[] into it. If the file path\extension is correct and if your app has all the right permissions, you'll be able to store your data.

PS. This procedure has been tested a few times and it worked, but i don't exclude can be some unmanaged exception cases that may produce error states. IMHO it can be improoved too...