Question

I have some Java code that takes a screen shot and outputs a png, that is meant to be saved to the phones ‘pictures’ gallery. It looks like this:

    package org.apache.cordova;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;

import org.apache.cordova.api.Plugin;
import org.apache.cordova.api.PluginResult;
import org.json.JSONArray;

import android.graphics.Bitmap;
import android.os.Environment;
import android.view.View;



public class Screenshot extends Plugin {

    @Override

    public PluginResult execute(String action, JSONArray args, String callbackId) {
        // starting on ICS, some WebView methods
        // can only be called on UI threads
        final Plugin that = this;
        final String id = callbackId;
        super.cordova.getActivity().runOnUiThread(new Runnable() {
            //@Override
            public void run() {
                View view = webView.getRootView();

                view.setDrawingCacheEnabled(true);
                Bitmap bitmap = Bitmap.createBitmap(view.getDrawingCache());
                view.setDrawingCacheEnabled(false);

                try {
                    File folder = new File(Environment.getExternalStorageDirectory(), "Pictures");
                    if (!folder.exists()) {
                        folder.mkdirs();

                    }

                    File f = new File(folder, "screenshot_" + System.currentTimeMillis() + ".png");
                    System.out.println(folder);
                    System.out.println("screenshot_" + System.currentTimeMillis() + ".png");
                    FileOutputStream fos = new FileOutputStream(f);
                    bitmap.compress(Bitmap.CompressFormat.PNG, 100, fos);
                    that.success(new PluginResult(PluginResult.Status.OK), id);
                    System.out.println("get here?");

                } catch (IOException e) {
                    that.success(new PluginResult(PluginResult.Status.IO_EXCEPTION, e.getMessage()), id);
                    System.out.println("and here?");
                }
            }
        });

        PluginResult result = new PluginResult(PluginResult.Status.NO_RESULT);
        result.setKeepCallback(true);
        return result;
    }

}

Now for the purposes of the project I am working on, I would like to not save t to the gallery, but instead output a base64 string that can be manipulated. I am new to Java but after looking through some stuff came across a base64 Java encoder. But there seems to be an android util method called Base64OutputStream.

The code I think I need to replace is:

FileOutputStream fos = new FileOutputStream(f);
bitmap.compress(Bitmap.CompressFormat.PNG, 100, fos);

At first I tried:

Base64OutputStream os = new Base64OutputStream();

But it threw errors, then I have been playing about with other bits of code I found. Such as:

ByteArrayOutputStream os = new ByteArrayOutputStream();
OutputStream b64 = new Base64.OutputStream(os);
ImageIO.write(bi, "png", b64);
String result = os.toString("UTF-8");

It again didn’t work, instead of implementing a base64 encoding library for a small section of my project, I was wondering if anyone could point me in the right direction, or tell me if im on the right path. I am new to Java, but feel that the android provided Base64OutputStream must be the key. Anyone have any pointers?

Answer 1

Try this code this should work for you…

        ByteArrayOutputStream baos = new ByteArrayOutputStream();  
        bitmap.compress(Bitmap.CompressFormat.JPEG, 100, baos);
        byte[] b = baos.toByteArray();
        base64String = Base64.encodeToString(b, Base64.DEFAULT);