Bitmap to Base 64 Encode String

Question

I'm trying to convert an image to a bitmap and then encode it in a base64 string.I'm getting a null pointer exception on the line

 bMap.compress(Bitmap.CompressFormat.PNG, COMPRESSION_QUALITY,
            byteArrayBitmapStream);

what is wrong? Note that I am inputing the file name with the picture "pic2.jpg" to the method below.

below is my code:

    private String convertToBitmap (String name){
    File imgFile = new File (name);
    Bitmap bMap = BitmapFactory.decodeFile(imgFile.getAbsolutePath());
    final int COMPRESSION_QUALITY = 100;
    String encodedImage;
    ByteArrayOutputStream byteArrayBitmapStream = new ByteArrayOutputStream();
    bMap.compress(Bitmap.CompressFormat.PNG, COMPRESSION_QUALITY,
            byteArrayBitmapStream);
    byte[] b = byteArrayBitmapStream.toByteArray();
    encodedImage = Base64.encodeToString(b, Base64.DEFAULT);
    return encodedImage;
}

below my log cat:

03-22 23:03:44.916 18331-18331/? I/art: Not late-enabling -Xcheck:jni (already on)
03-22 23:03:44.916 18331-18331/? W/art: Unexpected CPU variant for X86 using defaults: x86
03-22 23:03:45.029 18331-18331/com.example.reynaldo.getimageserver W/System: ClassLoader referenced unknown path: /data/app/com.example.reynaldo.getimageserver-2/lib/x86
03-22 23:03:45.038 18331-18331/com.example.reynaldo.getimageserver I/InstantRun: Instant Run Runtime started. Android package is com.example.reynaldo.getimageserver, real application class is null.
03-22 23:03:45.124 18331-18331/com.example.reynaldo.getimageserver W/System: ClassLoader referenced unknown path: /data/app/com.example.reynaldo.getimageserver-2/lib/x86
03-22 23:03:45.372 18331-18331/com.example.reynaldo.getimageserver W/art: Before Android 4.1, method android.graphics.PorterDuffColorFilter android.support.graphics.drawable.VectorDrawableCompat.updateTintFilter(android.graphics.PorterDuffColorFilter, android.content.res.ColorStateList, android.graphics.PorterDuff$Mode) would have incorrectly overridden the package-private method in android.graphics.drawable.Drawable
03-22 23:03:45.676 18331-18361/com.example.reynaldo.getimageserver D/NetworkSecurityConfig: No Network Security Config specified, using platform default
03-22 23:03:45.865 18331-18367/com.example.reynaldo.getimageserver I/OpenGLRenderer: Initialized EGL, version 1.4
03-22 23:03:45.865 18331-18367/com.example.reynaldo.getimageserver D/OpenGLRenderer: Swap behavior 1
03-22 23:03:45.908 18331-18367/com.example.reynaldo.getimageserver E/EGL_emulation: tid 18367: eglSurfaceAttrib(1174): error 0x3009 (EGL_BAD_MATCH)
03-22 23:03:45.909 18331-18367/com.example.reynaldo.getimageserver W/OpenGLRenderer: Failed to set EGL_SWAP_BEHAVIOR on surface 0xb493fe00, error=EGL_BAD_MATCH

`I'm getting a null pointer exception on the line` do you mean that `bMap` is null ? — Atef Hares, Mar 23 '17 at 03:13
I believe so, I'm thinking that the file path I'm using is not correct. But I've gotten the file path from the terminal and put it in the method and still doesn't work. — Geek96, Mar 23 '17 at 03:18
Maybe the file is too big. Check this answer: http://stackoverflow.com/a/8442683/5241603 — K.Sopheak, Mar 23 '17 at 03:21
@Geek96 yes, be sure of the path, as If the specified file name is null, or cannot be decoded into a bitmap, the function returns null , check [docs](https://developer.android.com/reference/android/graphics/BitmapFactory.html#decodeFile(java.lang.String)). use `try catch` and print logs — Atef Hares, Mar 23 '17 at 03:26
the name of the file is pic2.jpg which is in Drawable folder of Android — Geek96, Mar 23 '17 at 04:04
`name of the file is pic2.jpg which is in Drawable folder of Android`. Well then you cannot use the `File` class to begin with. Please study how to handle files from drawables. — greenapps, Mar 23 '17 at 07:24
You really want to convert your jpg file in drawables to a png first before uploading? Why? — greenapps, Mar 23 '17 at 07:28

score 0 · Answer 1 · answered Mar 23 '17 at 04:09

Try this

    Bitmap bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.image); // your pic2
    ByteArrayOutputStream stream = new ByteArrayOutputStream();
    bitmap.compress(Bitmap.CompressFormat.PNG, 100, stream);
    byte[] bitmapdata = stream.toByteArray();
    encodedImage = Base64.encodeToString(bitmapdata, Base64.DEFAULT);
    return encodedImage;

score 0 · Answer 2 · answered Mar 23 '17 at 04:57

Bitmap bitmap = optimizePhoto();
ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
bitmap.compress(Bitmap.CompressFormat.PNG, 100, byteArrayOutputStream);
byte[] byteArray = byteArrayOutputStream.toByteArray();
Strng encoded = Base64.encodeToString(byteArray, Base64.DEFAULT);

If you need to optimize image furthur

private Bitmap optimizePhoto() {
        // Get the dimensions of the View
        int targetW = 300;
        int targetH = 300;

        // Get the dimensions of the bitmap
        BitmapFactory.Options bmOptions = new BitmapFactory.Options();
        bmOptions.inJustDecodeBounds = true;
        BitmapFactory.decodeFile(getArguments().getString("imagePath"), bmOptions);
        int photoW = bmOptions.outWidth;
        int photoH = bmOptions.outHeight;

        // Determine how much to scale down the image
        int scaleFactor = Math.min(photoW / targetW, photoH / targetH);

        // Decode the image file into a Bitmap sized to fill the View
        bmOptions.inJustDecodeBounds = false;
        bmOptions.inSampleSize = scaleFactor;
        bmOptions.inPurgeable = true;

        Bitmap bitmap = BitmapFactory.decodeFile(getArguments().getString("imagePath"), bmOptions);

        return bitmap;
    }

score 0 · Answer 3 · answered Mar 23 '17 at 06:11

You should try this:

 private String convertToBitmap (String name){
            File imgFile = new File (name);
            Bitmap bMap = BitmapFactory.decodeFile(imgFile.getAbsolutePath());
             if (bMap != null) {
                     bMap = Bitmap.createScaledBitmap(bMap, 256, 256, true);
            String encodedImage;
            ByteArrayOutputStream byteArrayBitmapStream = new ByteArrayOutputStream();
           bm.compress(Bitmap.CompressFormat.JPEG, 100, byteArrayBitmapStream);
            byte[] b = byteArrayBitmapStream.toByteArray();
            encodedImage = Base64.encodeToString(b, Base64.DEFAULT);
            StringBuilder sb = new StringBuilder();

            sb.append(encodedImage);
            encodeString = sb.toString();
            return encodedImage;
        }
}

Bitmap to Base 64 Encode String

3 Answers3