How to save/recover image in memory on android?

Question

Hi, I have a Array of Bytes which is a image, from it, how can I save in the external memory and if there is no save in the internal memory android? and then how can I be recovering this image?

I need to save in a place that these images do not appear in the mobile gallery, only in the application.

Answer 1

Let’s first write a method that checks the existence of Sdcard and whether it is possible to write on it:

public boolean isExternalStorageWritable() {
    String state = Environment.getExternalStorageState();
    if (Environment.MEDIA_MOUNTED.equals(state)) {
        return true;
    }
    return false;
}

The method returns true whether it is possible to write on Sdcard or false if it does not exist or for any reason it is not possible to write on it.

We need two methods to save the byte[], one to save to internal memory and one to save to Sdcard.

Save to internal memory:

public void saveArrayToInternalStorage(String fileName, byte[] imagem){
    try{
        FileOutputStream fos = openFileOutput(fileName, Context.MODE_PRIVATE);
        fos.write(imagem);
        fos.close();
    }catch (IOException e) {
        Log.w("InternalStorage", "Error writing", e);
    }
}

Save to Sdcard:

So that the Mediastore do not see the images we will use getExternalFilesDir() to obtain the Path to Sdcard.

public void saveArrayToSDCard(String fileName, bytes[] imagem){
    File path = getExternalFilesDir(Environment.DIRECTORY_PICTURES);
    File file = new File(path, fileName);
    try{
        OutputStream os = new FileOutputStream(file);
        os.write(imagem);
        os.close()
    } catch (IOException e) {
        Log.w("ExternalStorage", "Error writing", e);
    }
}

How to use:

if(isExternalStorageWritable(){
   saveArrayToSDCard("nomeDaImagem", imagemEmBytes);
}else{
    saveArrayToInternalStorage("nomeDaImagem", imagemEmBytes);
}  

If the application is to run in versions prior to Android 4.4, it is necessary to get permission WRITE_EXTERNAL_STORAGE, add the following to Manifest

<manifest ...>
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"
                     android:maxSdkVersion="18" />
    ...
</manifest>  

Note: Images saved by these methods will be deleted when the application is uninstalled.

Source: Android Storage Options

Answer 2

From what I read in that topic of Soen the limit is 1 MB, more than that you would have to use the NDK.

In this same topic there is also another approach that uses the sqlite4java.

Take a look, it might be useful.