Scrollable ImageView Android Problem (overscrolling)

Question

I got my image to at least SCROLL, but I don't want it to scroll past the image itself. I have variables called maxLeft, maxRight, etc that I have that I currently just set to

    ImageView img = (ImageView)findViewById(R.id.mapimg);
    DisplayMetrics dm = new DisplayMetrics();
    getWindowManager().getDefaultDisplay().getMetrics(dm);

    int maxX = (int)????;
    int maxY = (int)????;

    // set scroll limits
    final int maxLeft = (maxX * -1);
    final int maxRight = maxX;
    final int maxTop = (maxY * -1);
    final int maxBottom = maxY;

I've been messing around with what I could in place of the question marks I put there, but I seem to be stuck, especially when I try on different emulators. Any help would really be appreciated! Thanks

score 1 · Accepted Answer · edited May 23 '17 at 11:56

If I understand your question correctly, you want to extend ImageView to add scrolling. If that's the case, you don't want to use getWindowmanager() as that returns the dimensions of the entire screen (including the title bar). Rather, you want to extend ImageView and get the view's dimensions from onMeasure. You can check out my answer here where I added zoom functionality and panning to ImageView.

I used setImageMatrix and postTranslate to set a matrix equal to the image and move it. To track the image's location, I used the following:

float f[] = new float[9];
matrix.getValues(m); //see matrix documentation. inserts matrix values into f.
float x = m[Matrix.MTRANS_X];
float y = m[Matrix.MTRANS_Y];

Float x and y will track the top left corner of the image. Make sure if the next event will cause the image to scroll out of bounds, you adjust postTranslate to equal the border of the image. The answer i linked above should give you a good place to start, and if you also want zoom functionality, then you're in luck, because you don't have to do any additional work.

Scrollable ImageView Android Problem (overscrolling)

1 Answers1