Hi all, I'm having trouble displaying an oversized scrolling image. I
accomplished this originally by creating the custom class below to
replace the standard ImageView. My original large image was a png that
was a little over 1000x1000 in resolution and about 722kb in size. For
that image, the class below worked flawlessley. But now I need to do
the same thing with a MUCH larger image and I'm wondering if this is
not the best way to go about it. My new image is about 5000x5000 and
I've produced varying versions from png's that were up to 6MB to jpg's
that were 1.5MB. All of these images cause my app to crash instantly
without any changes to the code (besides referencing the larger
image). The important thing I need to do is be able to scroll and
zoom, and I'm starting to think the only way I'm going to get this
working is to slice my image up and create some sort of scrolling
GridView inside an AbsoluteLayout, that only loads the slices that are
displayed on screen. This is a bit more work than I was hoping to put
into this app, but can anyone give me any advice on which direction I
should be heading?
Below is my ScrollingImageView class for reference. It works
flawlessly if the image is not too big, so feel free to use it however
you'd like.
Thanks in advance,
G
import android.content.Context;
import android.view.GestureDetector;
import android.view.MotionEvent;
import android.view.GestureDetector.OnGestureListener;
import android.widget.AbsoluteLayout;
import android.widget.ImageView;
import android.widget.LinearLayout;
public class ScrollingImageView extends AbsoluteLayout implements
OnGestureListener {
private GestureDetector mGestureDetector;
private ImageView mImageView;
public ScrollingImageView(Context context, int imageResId, int
imageWidth, int imageHeight) {
super(context);
mImageView = new ImageView(context);
mImageView.setImageResource(imageResId);
this.addView(mImageView, new
LinearLayout.LayoutParams(imageWidth,
imageHeight));
mGestureDetector = new GestureDetector(this);
mGestureDetector.setIsLongpressEnabled(false);
}
@Override
public boolean onDown(MotionEvent e) {
return false;
}
@Override
public boolean onFling(MotionEvent e1, MotionEvent e2, float
velocityX,
float velocityY) {
// TODO Auto-generated method stub
return false;
}
@Override
public void onLongPress(MotionEvent e) {
}
@Override
public boolean onScroll(MotionEvent e1, MotionEvent e2, float
distanceX,
float distanceY) {
int scrollWidth = mImageView.getWidth() - this.getWidth();
if ((this.getScrollX() >= 0) && (this.getScrollX() <=
scrollWidth) && (scrollWidth > 0)) {
int moveX = (int)distanceX;
if (((moveX + this.getScrollX()) >= 0) && ((Math.abs(moveX)
+ Math.abs(this.getScrollX())) <= scrollWidth)) {
this.scrollBy(moveX, 0);
}
else {
if (distanceX >= 0) {
this.scrollBy(scrollWidth - Math.max(Math.abs
(moveX), Math.abs(this.getScrollX())), 0);
}
else {
this.scrollBy(-Math.min(Math.abs(moveX), Math.abs
(this.getScrollX())), 0);
}
}
}
int scrollHeight = mImageView.getHeight() - this.getHeight();
if ((this.getScrollY() >= 0) && (this.getScrollY() <=
scrollHeight) && (scrollHeight > 0)) {
int moveY = (int)distanceY;
if (((moveY + this.getScrollY()) >= 0) && ((Math.abs(moveY)
+ Math.abs(this.getScrollY())) <= scrollHeight)) {
this.scrollBy(0, moveY);
}
else {
if (distanceY >= 0) {
this.scrollBy(0, scrollHeight - Math.max(Math.abs
(moveY), Math.abs(this.getScrollY())));
}
else {
this.scrollBy(0, -Math.min(Math.abs(moveY), Math.abs
(this.getScrollY())));
}
}
}
return true;
}
@Override
public void onShowPress(MotionEvent e) {
// TODO Auto-generated method stub
}
@Override
public boolean onSingleTapUp(MotionEvent e) {
// TODO Auto-generated method stub
return false;
}
@Override
public boolean dispatchTouchEvent(MotionEvent ev) {
mGestureDetector.onTouchEvent(ev);
return true;
}
public void zoomIn() {
int h = mImageView.getHeight();
int w = mImageView.getWidth();
h *= 2;
w *= 2;
this.removeAllViews();
this.addView(mImageView, new LinearLayout.LayoutParams(w, h));
}
public void zoomOut() {
this.scrollTo(0, 0);
int h = mImageView.getHeight();
int w = mImageView.getWidth();
h /= 2;
w /= 2;
this.removeAllViews();
this.addView(mImageView, new LinearLayout.LayoutParams(w, h));
}
}
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