Cannot save bitmap on phone memory

Question

I get an java null exception for the bitmap b in the following code: what could i do? Why doesn't the getDrawingCache function work in creating the bitmap; The onClickListener for the button that starts the action:

KaufenGListener = new OnClickListener() {

            @Override
            public void onClick(View v) {

                Coupon coupon = null;

                System.out.println("-- iv: " + couponView);

                if (clickedcoup == -1) {
                    Toast.makeText(getActivity(), "Please select a coupon", Toast.LENGTH_SHORT).show();
                } else {
                    for (int i = 0; i < coupons.size(); i++) {
                        if (clickedcoup == i) {
                            coupon = coupons.get(i);
                        }
                    }
                    String username;
                    Bitmap coupo = BitmapFactory.decodeResource(getResources(), R.drawable.coupon1);
                    Bitmap barcode = Util.generateEAN("9310779300005", getActivity(), coupo.getWidth() / 3);
                    // Drawable couponDraw = new
                    // BitmapDrawable(getResources(),b);
                    System.out.println("------------b : " + barcode);
                    if (user.address.Nachname != null) {
                        username = user.address.Nachname + " " + user.address.Vorname; // bla
                    } else {
                        username = "";
                    }
                    viewFlipperVino.setDisplayedChild(8);
                    // LayoutParams params = new LayoutParams();
                    // params.width=LayoutParams.MATCH_PARENT;
                    // params.height=(int) (params.width/1.5);

                    //couponView.buildDrawingCache();
                    couponView.setUp(coupo, barcode, coupon.Code, gutscheinName, username, coupon.Wert);
                    clickedcoup = -1;
                    String[] recipients = new String[] { "rosu_alin@ymail.com" };
                    String emailSubject = "Gutschein Schenken fur "+ gutscheinName;
                    String emailText = "Glückwunsch, Sie haben einen Gutschein für Wein & Co!!";
                    Intent intent = new Intent(Intent.ACTION_SEND);
                    intent.setType("plain/text");
                    intent.putExtra(Intent.EXTRA_EMAIL, recipients);
                    intent.putExtra(Intent.EXTRA_SUBJECT, emailSubject);
                    intent.putExtra(Intent.EXTRA_TEXT, emailText);
                    File root = Environment.getExternalStorageDirectory();
                    File file = new File(root, "gutschein.png");
                    try {
                        file.createNewFile();
                    } catch (IOException e1) {
                        e1.printStackTrace();
                    }                       
                    couponView.setDrawingCacheEnabled(true);
                    couponView.buildDrawingCache();
                    Bitmap b = couponView.getDrawingCache();
                    System.out.println("bitmapget drawin cache:   "+couponView.getDrawingCache());
                    Saver.saveImg(file, b, getActivity());
                    try {
                        System.out.println("bitmap"+b);
                           FileOutputStream out = new FileOutputStream(file);
                           b.compress(Bitmap.CompressFormat.PNG, 100, out);
                           System.out.println("bitmap.compress"+b.compress(Bitmap.CompressFormat.PNG, 100, out));
                    } catch (Exception e) {
                           e.printStackTrace();
                    }

                    if (!file.exists() || !file.canRead()) {
                        Toast.makeText(getActivity(), "Befestigung Fehler", Toast.LENGTH_SHORT).show();
                        return;
                    }
                    Uri uri = Uri.parse("file://" + file);
                    intent.putExtra(Intent.EXTRA_STREAM, uri);
                    startActivity(Intent.createChooser(intent, "Send email..."));
                }
            }

        };

This is the CouponView class that extends View: public class CouponView extends View {

private Bitmap coupon, barcode;
Paint paint = new Paint();
Paint paint2 = new Paint();
Paint paint3 = new Paint();
private String name;
private String code;
private String username;
private String wert;
int w;
int h;

public CouponView(Context context, AttributeSet attrs, int defStyle) {
    super(context, attrs, defStyle);
    init();
}

public CouponView(Context context, AttributeSet attrs) {
    super(context, attrs);
    init();
}

public CouponView(Context context) {
    super(context);
    init();
}

private void init() {

    paint.setColor(0xFF000000);
    paint.setTextSize(7);
    paint2.setColor(0xFF000000);
    paint2.setTextSize(10);
    paint3.setColor(0xFF000000);
    paint3.setTextSize(25);

}

public void setUp(Bitmap coupon, Bitmap barcode, String code, String name, String username,String wert) {
    this.coupon = coupon;
    this.barcode = barcode;
    this.name = name;
    this.username = username;
    this.code = code;
    this.wert = wert;
     w = coupon.getWidth();
     h = coupon.getHeight();
    System.out.println("height"+h);
    System.out.println("width"+w);

    invalidate();
}

@Override
protected void onDraw(Canvas canvas) {
    super.onDraw(canvas);
    System.out.println("-------------CouponView.onDraw()");
    canvas.drawBitmap(coupon, 0, 0, null);
    canvas.drawBitmap(barcode, w/1.61f, h/1.20f, null);
    canvas.drawText("9310779300005", w/1.429f, h/1.018f, paint);
    canvas.drawText("9310779300005", w/18.12f , h/1.073f, paint2);
    canvas.drawText(code, w/1.8875f, h/1.073f, paint2);
    canvas.drawText(username, w/11.32f, h/10.3f, paint2);
    canvas.drawText(name, w/11.32f, h/5.936f, paint2);
    canvas.drawText(wert, w/1.294f, h/1.641f, paint3);
}
}

After my logic, I set the drawingcache for the couponView to (true) and then i start building the drawingcache. And then i initiate to the bitmap the getDrawingCache(). That alone should work on saving my file.What am i missing? Also the Saves.saveIMG function does the same thing as the try catch after it (i only took it from a colleague because it was more organized. and i though it uses the imageView to save, not the bitmap.

public class Saver {
public static void saveImg(File pic, Bitmap picture,Context context) {
    folderExists(pic);
    try {
        FileOutputStream out = new FileOutputStream(pic);
        picture.compress(Bitmap.CompressFormat.JPEG, 100, out);
        Log.i(Saver.class.toString(), " picture writed at: " + pic.getAbsolutePath());
        Toast.makeText(context, "pic saved", Toast.LENGTH_SHORT).show();
    } catch (Exception e) {
        pic.delete();
        Log.i(Saver.class.toString(), " picture writing error: " + e.getMessage());
        Toast.makeText(context, "pic not saved", Toast.LENGTH_SHORT).show();
    }
}

private static void folderExists(File dir) {
    System.out.println("-=-=- : " + dir.getAbsolutePath());
    if (!dir.getParentFile().exists()) {
        dir.mkdirs();
    }

}

But the System.out.prinln("bitmap=",b); line returns bitmap=null, so i guess that the bitmap b is the problem, because getDrawingCache is not loading it — rosu alin, Aug 16 '12 at 14:56
Huh? `System.out.println` doesn't do anything in android, http://stackoverflow.com/questions/2220547/why-doesnt-system-out-println-work-in-android — slayton, Aug 16 '12 at 15:24
mine does, watch your LogCat and see that Syso writes in there — rosu alin, Aug 20 '12 at 07:07

score 1 · Answer 1 · answered Aug 16 '12 at 14:56

Not sure exactly what is wrong with your code, yet this works for me to save and read bitmaps from the phones memory:

Write Bitmap to memory:

public void writeBitmapToMemory(String filename, Bitmap bitmap) {
        FileOutputStream fos;
        // Use the compress method on the Bitmap object to write image to the OutputStream
        try {
            fos = this.openFileOutput(filename, Context.MODE_PRIVATE);
            // Writing the bitmap to the output stream
            bitmap.compress(Bitmap.CompressFormat.PNG, 100, fos);
            fos.close();

        } 
        catch (FileNotFoundException e) {
            e.printStackTrace();


        } 
        catch (IOException e) {
            e.printStackTrace();


        }

    }

To read:

public Bitmap readBitmapFromMemory(String filename) {
        Bitmap defautBitmap = null;
        File filePath = this.getFileStreamPath(filename);
        FileInputStream fi;
        try {
            fi = new FileInputStream(filePath);
            defautBitmap = BitmapFactory.decodeStream(fi);

        } 
        catch (FileNotFoundException e) {
            e.printStackTrace();

        }

        return defautBitmap;

    }

I hope this helps.

The problem is that from the beginning the bitmap is null. So that part of the code i think i made ok, or atleast it doesn't have errors. The problem with my code is getting the bitmap from the imageView (couponView). Something over there is wrong, and is not creating my bitmap correctly — rosu alin, Aug 16 '12 at 15:04

score 0 · Accepted Answer · answered Aug 20 '12 at 07:56

I first created an empty bitmap, and used it as a canvas to draw into it. Code:

couponView.setDrawingCacheEnabled(true);
  couponView.buildDrawingCache();
  couponView.setUp(coupo, barcode, coupon.Code, gutscheinName, username, coupon.Wert);
  Bitmap b = Bitmap.createBitmap(couponView.w, couponView.h, 
                            Config.ARGB_8888);
  Canvas canvas = new Canvas(b);
  couponView.draw(canvas);
  Saver.saveImg(file, b, getActivity());
  Uri uri = Uri.parse("file://" + file);
  intent.putExtra(Intent.EXTRA_STREAM, uri);
  startActivity(Intent.createChooser(intent, "Send email..."));

Cannot save bitmap on phone memory

2 Answers2