如何以编程方式更改位图？

Question

I have this condition and all is working but i think it's a mess code. Can you please help me for a better codes which i want to update of the bitmap of background i only change the mBg.

I have this condition and all is working but i think it's a mess code. Can you please help me for a better codes which i want to update of the bitmap of background i only change the mBg.

Bitmap mBg;

  mBackground = Bitmap.createBitmap(1800, 1200, Bitmap.Config.RGB_565);
    // Put back and top images in your res folder
    BitmapFactory.Options options = new BitmapFactory.Options();
    options.inPreferredConfig = Bitmap.Config.ARGB_8888;

    File f = new File(AppConstant.filepathone);
    Bitmap mImageone = decodeFile(f);
    File g = new File(AppConstant.filepathtwo);
    Bitmap mImagetwo = decodeFile(g);
    File h = new File(AppConstant.filepaththree);
    Bitmap mImagethree = decodeFile(h);
    File i = new File(AppConstant.filepathfour);
    Bitmap mImagefour = decodeFile(i);

    if (sharedpreferences.getString("getFrame", "getFrame") == "Frame1") {
        mBg = BitmapFactory.decodeResource(getResources(),
                R.drawable.frameone);
        Bitmap mBack = Bitmap.createScaledBitmap(mBg, 1800, 1200, true);
        Bitmap mImaget = Bitmap.createScaledBitmap(mImagetwo, 515, 360,
                true);
        Bitmap mImageth = Bitmap.createScaledBitmap(mImagethree, 515, 360,
                true);
        Bitmap mImagef = Bitmap.createScaledBitmap(mImagefour, 515, 360,
                true);
        Bitmap mImageo = Bitmap.createScaledBitmap(mImageone, 1080, 635,
                true);

        mCanvas = new Canvas(mBackground);
        mCanvas.drawARGB(255, 150, 150, 10);
        mCanvas.drawBitmap(mBack, 0, 0, null);
        mCanvas.drawBitmap(mImaget, 75, 75, null);
        mCanvas.drawBitmap(mImageo, 75, 490, null);
        mCanvas.drawBitmap(mImageth, 645, 75, null);
        mCanvas.drawBitmap(mImagef, 1215, 75, null);

    } else if (sharedpreferences.getString("getFrame", "getFrame") == "Frame2") {
        mBg = BitmapFactory.decodeResource(getResources(),
                R.drawable.frametwo);
        Bitmap mBack = Bitmap.createScaledBitmap(mBg, 1800, 1200, true);
        Bitmap mImaget = Bitmap.createScaledBitmap(mImagetwo, 515, 360,
                true);
        Bitmap mImageth = Bitmap.createScaledBitmap(mImagethree, 515, 360,
                true);
        Bitmap mImagef = Bitmap.createScaledBitmap(mImagefour, 515, 360,
                true);
        Bitmap mImageo = Bitmap.createScaledBitmap(mImageone, 1080, 635,
                true);

        mCanvas = new Canvas(mBackground);
        mCanvas.drawARGB(255, 150, 150, 10);
        mCanvas.drawBitmap(mBack, 0, 0, null);
        mCanvas.drawBitmap(mImaget, 75, 75, null);
        mCanvas.drawBitmap(mImageo, 75, 490, null);
        mCanvas.drawBitmap(mImageth, 645, 75, null);
        mCanvas.drawBitmap(mImagef, 1215, 75, null);

    } else if (sharedpreferences.getString("getFrame", "getFrame") == "Frame3") {
        mBg = BitmapFactory.decodeResource(getResources(),
                R.drawable.framethree);
        Bitmap mBack = Bitmap.createScaledBitmap(mBg, 1800, 1200, true);
        Bitmap mImaget = Bitmap.createScaledBitmap(mImagetwo, 515, 360,
                true);
        Bitmap mImageth = Bitmap.createScaledBitmap(mImagethree, 515, 360,
                true);
        Bitmap mImagef = Bitmap.createScaledBitmap(mImagefour, 515, 360,
                true);
        Bitmap mImageo = Bitmap.createScaledBitmap(mImageone, 1080, 635,
                true);

        mCanvas = new Canvas(mBackground);
        mCanvas.drawARGB(255, 150, 150, 10);
        mCanvas.drawBitmap(mBack, 0, 0, null);
        mCanvas.drawBitmap(mImaget, 75, 75, null);
        mCanvas.drawBitmap(mImageo, 75, 490, null);
        mCanvas.drawBitmap(mImageth, 645, 75, null);
        mCanvas.drawBitmap(mImagef, 1215, 75, null);
    }

    try {
        String friendlydate = DateFormat.getTimeInstance(DateFormat.MEDIUM)
                .format(new Date());
        friendlydate = friendlydate.replace(':', '_');
        String filename = friendlydate + ".jpg";
        mBitmapDrawable = new BitmapDrawable(mBackground);
        Bitmap mNewSaving = mBitmapDrawable.getBitmap();
        String FtoSave = mTempDir + filename;
        File mFile = new File(FtoSave);
        mFileOutputStream = new FileOutputStream(mFile);

        // mNewSaving.recycle();
        mNewSaving.compress(Bitmap.CompressFormat.PNG, 100,
                mFileOutputStream);
        mFileOutputStream.flush();
        mFileOutputStream.close();
        mFileOutputStream = null;

Answer 1

Here are some tips for you

1. In java you should never use the "==" operator to compare strings. Use String.equals() method like in if (sharedpreferences.getString("getFrame", "getFrame").equals("Frame1") otherwise you'd be comparing their pointers and not their actual contents.

2. The only thing that changes depending on the value of the shared preference "getFrame" is the variable mbg so it's actually the only thing you need to put inside those if blocks. Your entire if block would be reduced into this:
   

    if (sharedpreferences.getString("getFrame", "getFrame").equals("Frame1")) { mBg = BitmapFactory.decodeResource(getResources(), R.drawable.frameone); } else if (sharedpreferences.getString("getFrame", "getFrame").equals("Frame2")) { mBg = BitmapFactory.decodeResource(getResources(), R.drawable.frametwo); } else if (sharedpreferences.getString("getFrame", "getFrame").equals("Frame3")) { mBg = BitmapFactory.decodeResource(getResources(), R.drawable.framethree); } Bitmap mBack = Bitmap.createScaledBitmap(mBg, 1800, 1200, true); Bitmap mImaget = Bitmap.createScaledBitmap(mImagetwo, 515, 360, true); Bitmap mImageth = Bitmap.createScaledBitmap(mImagethree, 515, 360, true); Bitmap mImagef = Bitmap.createScaledBitmap(mImagefour, 515, 360, true); Bitmap mImageo = Bitmap.createScaledBitmap(mImageone, 1080, 635, true); mCanvas = new Canvas(mBackground); mCanvas.drawARGB(255, 150, 150, 10); mCanvas.drawBitmap(mBack, 0, 0, null); mCanvas.drawBitmap(mImaget, 75, 75, null); mCanvas.drawBitmap(mImageo, 75, 490, null); mCanvas.drawBitmap(mImageth, 645, 75, null); mCanvas.drawBitmap(mImagef, 1215, 75, null); 

3. You can make the selection of mBg variable even more efficient if you call this method many times by creating a map that maps the frame name to a resource that has already been decoded. To do so you would declare and populate a map like the following one preferably inside the onCreate() method of your Activity:
   

    Map<String, Bitmap> mBgMap = new HashMap<>(); mBgMap.put("Frame1", BitmapFactory.decodeResource(getResources(), R.drawable.frameone)); mBgMap.put("Frame2", BitmapFactory.decodeResource(getResources(), R.drawable.frametwo)); mBgMap.put("Frame3", BitmapFactory.decodeResource(getResources(), R.drawable.framethree)); 

And then just replace that clumsy if block by:

    mBg = mBgMap.get(sharedpreferences.getString("getFrame", "getFrame"));

Answer 2

try this

String uri = "@drawable/myresource.png";
int imageResource = getResources().getIdentifier(uri, null, getPackageName());
imageview= (ImageView)findViewById(R.id.imageView);
Drawable res = getResources().getDrawable(imageResource);
imageView.setImageDrawable(res);