android - Taking Screenshot

Question

I'm developing an application for taking screenshots in the device. In this application, we can draw anything on the screen. For this I am using Canvas, Paint and Path to do this.

I'm using this code to take screenshots:

        public void saveScreenshot() 
    {
        if (ensureSDCardAccess()) 
        {
            Bitmap bitmap = Bitmap.createBitmap(getWidth(), getHeight(), Bitmap.Config.ARGB_8888);
            Canvas canvas = new Canvas(bitmap);
            onDraw(canvas);
            File file = new File(mScreenshotPath + "/" + System.currentTimeMillis() + ".jpg");
            FileOutputStream fos;
            try {
                fos = new FileOutputStream(file);
                bitmap.compress(Bitmap.CompressFormat.JPEG, 100, fos);
                fos.close();
            } catch (FileNotFoundException e) {
                Log.e("Panel", "FileNotFoundException", e);
            } catch (IOException e) {
                Log.e("Panel", "IOEception", e);
            }
        }
    }

    /**
     * Helper method to ensure that the given path exists.
     * TODO: check external storage state
     */
    private boolean ensureSDCardAccess() {
        File file = new File(mScreenshotPath);
        if (file.exists()) {
            return true;
        } else if (file.mkdirs()) {
            return true;
        }
        return false;
    }

However, when the following line is run:

Bitmap bitmap = Bitmap.createBitmap(getWidth(), getHeight(), Bitmap.Config.ARGB_8888);

my application closes with the following exception:

11-28 15:05:46.291: E/AndroidRuntime(8209): java.lang.IllegalArgumentException: width and height must be > 0

If I change the height and width, the screenshot is taken, but it's empty:

Why is that happening? What am I doing wrong?

Answer 1

You can do it like this,

Give the id for your main Layout & after you display the content on the screen write the below code on some Listener say button click or menu item or any such Listener(make sure you call these line after your layout is display else it will give a blank screen).

        View content = findViewById(R.id.myLayout);
        content.setDrawingCacheEnabled(true);
        getScreen(content);

method getScreen(content)

private void getScreen(View content)
    {
        Bitmap bitmap = content.getDrawingCache();
        File file = new File("/sdcard/test.png");
        try 
        {
            file.createNewFile();
            FileOutputStream ostream = new FileOutputStream(file);
            bitmap.compress(CompressFormat.PNG, 100, ostream);
            ostream.close();
        } 
        catch (Exception e) 
        {
            e.printStackTrace();
        }
    }

Also don't for to add permission for writing file to SDCard.

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