display image from byteArray

Question

I have a Main class with has onCreate() method. in that method i have made the MapFile class' object.and called its readFile() and readIndex() methods. in readIndex() method i call another class named MapTile where i read the images tiles from my binary file and there i have to display my image.

Question is, how can I display an image without putting my code into onCreate(Bundle savedInstanceStare) method? I am trying this way but on first line it gives me NullPointerException.

ImageView image = (ImageView) findViewById(android.R.id.icon);           
Bitmap bMap = BitmapFactory.decodeByteArray(imageTile, 0, imageTile.length);
image.setImageBitmap(bMap);

Answer 1

adding a byte array to an android imageview:

        //byte[] chartData 
        ImageView imgViewer = (ImageView) findViewById(R.id.chart_image);
        Bitmap bm = BitmapFactory.decodeByteArray(chartData, 0, chartData.length);
        DisplayMetrics dm = new DisplayMetrics();
        getWindowManager().getDefaultDisplay().getMetrics(dm);

        imgViewer.setMinimumHeight(dm.heightPixels);
        imgViewer.setMinimumWidth(dm.widthPixels);
        imgViewer.setImageBitmap(bm);

Answer 2

I think your issue is not the byteArray but the findViewById. As you say that the NPE is on the first line. There are rules around this method you have two options to call it :

Either you use it to query a View you already have in the layout you called in setContentView
Or you use it on a View contained in a layout you inflated manually with a layout inflater

If you try to use it in your activity to call a View from any other layout than the one in setContentView that you have not inflated yourself, it will return null.