Develop Reference

Android ImageView how to set initial zoom

I have already managed to create a view (ZoomableImageView) which will support zoom-in and zoom-out commands (pinch to zoom).
What I cannot manage, is how to set an initial zoom state for the view. For example, I'm listening to a double tap event (through a gesture listener of another class), and when I get the double tap event, I want to set the scale to 2 and zoom the image.
The code I am using is the one that Nicolas Tyler wrote for a ZoomableImageView: (link: https://stackoverflow.com/a/17649895/3249693)
Is there a way to set the initial zoom to the constructor or something without messing up the rest of the code?
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Matrix;
import android.graphics.PointF;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.ScaleGestureDetector;
import android.view.View;
import android.widget.ImageView;
public class ZoomableImageView extends ImageView
{
Matrix matrix = new Matrix();
static final int NONE = 0;
static final int DRAG = 1;
static final int ZOOM = 2;
static final int CLICK = 3;
int mode = NONE;
PointF last = new PointF();
PointF start = new PointF();
float minScale = 1f;
float maxScale = 4f;
float[] m;
float redundantXSpace, redundantYSpace;
float width, height;
float saveScale = 1f;
float right, bottom, origWidth, origHeight, bmWidth, bmHeight;
ScaleGestureDetector mScaleDetector;
Context context;
public ZoomableImageView(Context context, AttributeSet attr)
{
super(context, attr);
super.setClickable(true);
this.context = context;
mScaleDetector = new ScaleGestureDetector(context, new ScaleListener());
matrix.setTranslate(1f, 1f);
m = new float[9];
setImageMatrix(matrix);
setScaleType(ScaleType.MATRIX);
setOnTouchListener(new OnTouchListener()
{
#Override
public boolean onTouch(View v, MotionEvent event)
{
mScaleDetector.onTouchEvent(event);
matrix.getValues(m);
float x = m[Matrix.MTRANS_X];
float y = m[Matrix.MTRANS_Y];
PointF curr = new PointF(event.getX(), event.getY());
switch (event.getAction())
{
case MotionEvent.ACTION_DOWN:
last.set(event.getX(), event.getY());
start.set(last);
mode = DRAG;
break;
case MotionEvent.ACTION_POINTER_DOWN:
last.set(event.getX(), event.getY());
start.set(last);
mode = ZOOM;
break;
case MotionEvent.ACTION_MOVE:
if (mode == ZOOM || (mode == DRAG && saveScale > minScale))
{
float deltaX = curr.x - last.x;
float deltaY = curr.y - last.y;
float scaleWidth = Math.round(origWidth * saveScale);
float scaleHeight = Math.round(origHeight * saveScale);
if (scaleWidth < width)
{
deltaX = 0;
if (y + deltaY > 0)
deltaY = -y;
else if (y + deltaY < -bottom)
deltaY = -(y + bottom);
}
else if (scaleHeight < height)
{
deltaY = 0;
if (x + deltaX > 0)
deltaX = -x;
else if (x + deltaX < -right)
deltaX = -(x + right);
}
else
{
if (x + deltaX > 0)
deltaX = -x;
else if (x + deltaX < -right)
deltaX = -(x + right);
if (y + deltaY > 0)
deltaY = -y;
else if (y + deltaY < -bottom)
deltaY = -(y + bottom);
}
matrix.postTranslate(deltaX, deltaY);
last.set(curr.x, curr.y);
}
break;
case MotionEvent.ACTION_UP:
mode = NONE;
int xDiff = (int) Math.abs(curr.x - start.x);
int yDiff = (int) Math.abs(curr.y - start.y);
if (xDiff < CLICK && yDiff < CLICK)
performClick();
break;
case MotionEvent.ACTION_POINTER_UP:
mode = NONE;
break;
}
setImageMatrix(matrix);
invalidate();
return true;
}
});
}
#Override
public void setImageBitmap(Bitmap bm)
{
super.setImageBitmap(bm);
bmWidth = bm.getWidth();
bmHeight = bm.getHeight();
}
public void setMaxZoom(float x)
{
maxScale = x;
}
private class ScaleListener extends ScaleGestureDetector.SimpleOnScaleGestureListener
{
#Override
public boolean onScaleBegin(ScaleGestureDetector detector)
{
mode = ZOOM;
return true;
}
#Override
public boolean onScale(ScaleGestureDetector detector)
{
float mScaleFactor = detector.getScaleFactor();
float origScale = saveScale;
saveScale *= mScaleFactor;
if (saveScale > maxScale)
{
saveScale = maxScale;
mScaleFactor = maxScale / origScale;
}
else if (saveScale < minScale)
{
saveScale = minScale;
mScaleFactor = minScale / origScale;
}
right = width * saveScale - width - (2 * redundantXSpace * saveScale);
bottom = height * saveScale - height - (2 * redundantYSpace * saveScale);
if (origWidth * saveScale <= width || origHeight * saveScale <= height)
{
matrix.postScale(mScaleFactor, mScaleFactor, width / 2, height / 2);
if (mScaleFactor < 1)
{
matrix.getValues(m);
float x = m[Matrix.MTRANS_X];
float y = m[Matrix.MTRANS_Y];
if (mScaleFactor < 1)
{
if (Math.round(origWidth * saveScale) < width)
{
if (y < -bottom)
matrix.postTranslate(0, -(y + bottom));
else if (y > 0)
matrix.postTranslate(0, -y);
}
else
{
if (x < -right)
matrix.postTranslate(-(x + right), 0);
else if (x > 0)
matrix.postTranslate(-x, 0);
}
}
}
}
else
{
matrix.postScale(mScaleFactor, mScaleFactor, detector.getFocusX(), detector.getFocusY());
matrix.getValues(m);
float x = m[Matrix.MTRANS_X];
float y = m[Matrix.MTRANS_Y];
if (mScaleFactor < 1) {
if (x < -right)
matrix.postTranslate(-(x + right), 0);
else if (x > 0)
matrix.postTranslate(-x, 0);
if (y < -bottom)
matrix.postTranslate(0, -(y + bottom));
else if (y > 0)
matrix.postTranslate(0, -y);
}
}
return true;
}
}
#Override
protected void onMeasure (int widthMeasureSpec, int heightMeasureSpec)
{
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
width = MeasureSpec.getSize(widthMeasureSpec);
height = MeasureSpec.getSize(heightMeasureSpec);
//Fit to screen.
float scale;
float scaleX = width / bmWidth;
float scaleY = height / bmHeight;
scale = Math.min(scaleX, scaleY);
matrix.setScale(scale, scale);
setImageMatrix(matrix);
saveScale = 1f;
// Center the image
redundantYSpace = height - (scale * bmHeight) ;
redundantXSpace = width - (scale * bmWidth);
redundantYSpace /= 2;
redundantXSpace /= 2;
matrix.postTranslate(redundantXSpace, redundantYSpace);
origWidth = width - 2 * redundantXSpace;
origHeight = height - 2 * redundantYSpace;
right = width * saveScale - width - (2 * redundantXSpace * saveScale);
bottom = height * saveScale - height - (2 * redundantYSpace * saveScale);
setImageMatrix(matrix);
}
}

You can take a peek here how they solved it. You can use this image view also, it's open source. Root project link here

Image zoom activity for android

I'm trying to implement the double tap and the pinch to zoom activity. I wrote some code for the first one but it seem not to work (i can use only the android emulator for eclipse for now. So I'm not sure if my result is the right one)
Anyway I'm not able to understand what am I doing wrong. I'm surely forgetting something.
This is my code:
public class ImageZoomView extends View implements OnGestureListener {
private static final int SCALING_FACTOR = 50;
private final int LANDSCAPE = 1;
private GestureDetector gestureDetector;
private Drawable image = null;
private int scalefactor = 0;
private int orientation;
private int zoomCtr = 0;
private long lastTouchTime = 0;
private int winX, winY, imageX, imageY, scrollX = 0, scrollY = 0, left,
top, bottom, right;
public ImageZoomView(Context context, int orientation) {
super(context);
setLayoutParams(new LayoutParams(LayoutParams.FILL_PARENT,
LayoutParams.FILL_PARENT));
this.orientation = orientation;
gestureDetector = new GestureDetector(this);
}
public void setImage(Drawable bitmap, Activity activity) {
image = bitmap;
imageSetting(activity);
}
public void setImage(Bitmap bitmap, Activity activity) {
image = new BitmapDrawable(bitmap).getCurrent();
imageSetting(activity);
}
/**
* Works in both landscape and portrait mode.
*/
private void imageSetting(Activity activity) {
scrollX = scrollY = 0;
scalefactor = 0;
imageX = winX = activity.getWindow().getWindowManager()
.getDefaultDisplay().getWidth();
imageY = winY = activity.getWindow().getWindowManager()
.getDefaultDisplay().getHeight();
if (orientation == LANDSCAPE) {
imageX = 3 * imageY / 4;
}
calculatePos();
}
public void calculatePos() {
int tempx, tempy;
tempx = imageX + imageX * scalefactor / 100;
tempy = imageY + imageY * scalefactor / 100;
left = (winX - tempx) / 2;
top = (winY - tempy) / 2;
right = (winX + tempx) / 2;
bottom = (winY + tempy) / 2;
invalidate();
}
/**
* Redraws the bitmap when zoomed or scrolled.
*/
#Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
if (image == null)
return;
image.setBounds(left + scrollX, top + scrollY, right + scrollX, bottom
+ scrollY);
image.draw(canvas);
}
public void zoomIn() {
scalefactor += SCALING_FACTOR;
calculatePos();
}
public void zoomOut() {
if (scalefactor == 0)
return;
scrollX = scrollY = 0;
scalefactor -= SCALING_FACTOR;
calculatePos();
}
public void scroll(int x, int y) {
scrollX += x / 5;
scrollY += y / 5;
if (scrollX + left > 0) {
scrollX = 0 - left;
} else if (scrollX + right < winX) {
scrollX = winX - right;
}
if (scrollY + top > 0) {
scrollY = 0 - top;
} else if (scrollY + bottom < winY) {
scrollY = winY - bottom;
}
invalidate();
}
#Override
public boolean onTouchEvent(MotionEvent me) {
boolean onTouchEvent = gestureDetector.onTouchEvent(me);
return onTouchEvent;
}
#Override
public boolean onDown(MotionEvent arg0) {
long thisTime = arg0.getEventTime();
if (thisTime - lastTouchTime < 250) {
lastTouchTime = -1;
onDoubleTap();
return true;
}
lastTouchTime = thisTime;
return true;
}
#Override
public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX,
float distanceY) {
if (zoomCtr == 0)
return false;
scroll((int) (e2.getX() - e1.getX()), (int) (e2.getY() - e1.getY()));
return true;
}
private void onDoubleTap() {
if (zoomCtr == 0) {
zoomCtr++;
zoomIn();
return;
}
zoomCtr--;
zoomOut();
}
}
And this is where I call the activity:
public class FullScreenPhoto extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_full_screen_photo);
Intent intent = getIntent();
String path = intent.getStringExtra("Path");
ImageView img = (ImageView)findViewById(R.id.photo);
img.setImageURI(Uri.parse(path));
ImageZoomView imageView = new ImageZoomView(
this,getWindow().getWindowManager().getDefaultDisplay().getOrientation());
this.setContentView(imageView);
}
}
It display the full image on the screen but when tapping on it, nothing happens.

Great create a class called ZoomFunctionality
ZoomFunctionality
package com.androidhive.work;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Matrix;
import android.graphics.PointF;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.ScaleGestureDetector;
import android.view.View;
import android.widget.ImageView;
public class ZoomFunctionality extends ImageView {
Matrix matrix = new Matrix();
// We can be in one of these 3 states
static final int NONE = 0;
static final int DRAG = 1;
static final int ZOOM = 2;
int mode = NONE;
// Remember some things for zooming
PointF last = new PointF();
PointF start = new PointF();
float minScale = 1f;
float maxScale = 3f;
float[] m;
float redundantXSpace, redundantYSpace;
float width, height;
static final int CLICK = 3;
float saveScale = 1f;
float right, bottom, origWidth, origHeight, bmWidth, bmHeight;
ScaleGestureDetector mScaleDetector;
Context context;
public ZoomFunctionality(Context context) {
super(context);
sharedConstructing(context);
}
public ZoomFunctionality(Context context, AttributeSet attrs) {
super(context, attrs);
sharedConstructing(context);
}
private void sharedConstructing(Context context) {
super.setClickable(true);
this.context = context;
mScaleDetector = new ScaleGestureDetector(context, new ScaleListener());
matrix.setTranslate(1f, 1f);
m = new float[9];
setImageMatrix(matrix);
setScaleType(ScaleType.MATRIX);
setOnTouchListener(new OnTouchListener() {
public boolean onTouch(View v, MotionEvent event) {
mScaleDetector.onTouchEvent(event);
matrix.getValues(m);
float x = m[Matrix.MTRANS_X];
float y = m[Matrix.MTRANS_Y];
PointF curr = new PointF(event.getX(), event.getY());
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
last.set(event.getX(), event.getY());
start.set(last);
mode = DRAG;
break;
case MotionEvent.ACTION_MOVE:
if (mode == DRAG) {
float deltaX = curr.x - last.x;
float deltaY = curr.y - last.y;
float scaleWidth = Math.round(origWidth * saveScale);
float scaleHeight = Math.round(origHeight * saveScale);
if (scaleWidth < width) {
deltaX = 0;
if (y + deltaY > 0)
deltaY = -y;
else if (y + deltaY < -bottom)
deltaY = -(y + bottom);
} else if (scaleHeight < height) {
deltaY = 0;
if (x + deltaX > 0)
deltaX = -x;
else if (x + deltaX < -right)
deltaX = -(x + right);
} else {
if (x + deltaX > 0)
deltaX = -x;
else if (x + deltaX < -right)
deltaX = -(x + right);
if (y + deltaY > 0)
deltaY = -y;
else if (y + deltaY < -bottom)
deltaY = -(y + bottom);
}
matrix.postTranslate(deltaX, deltaY);
last.set(curr.x, curr.y);
}
break;
case MotionEvent.ACTION_UP:
mode = NONE;
int xDiff = (int) Math.abs(curr.x - start.x);
int yDiff = (int) Math.abs(curr.y - start.y);
if (xDiff < CLICK && yDiff < CLICK)
performClick();
break;
case MotionEvent.ACTION_POINTER_UP:
mode = NONE;
break;
}
setImageMatrix(matrix);
invalidate();
return true; // indicate event was handled
}
});
}
#Override
public void setImageBitmap(Bitmap bm) {
super.setImageBitmap(bm);
if (bm != null) {
bmWidth = bm.getWidth();
bmHeight = bm.getHeight();
}
}
public void setMaxZoom(float x) {
maxScale = x;
}
private class ScaleListener extends
ScaleGestureDetector.SimpleOnScaleGestureListener {
#Override
public boolean onScaleBegin(ScaleGestureDetector detector) {
mode = ZOOM;
return true;
}
#Override
public boolean onScale(ScaleGestureDetector detector) {
float mScaleFactor = detector.getScaleFactor();
float origScale = saveScale;
saveScale *= mScaleFactor;
if (saveScale > maxScale) {
saveScale = maxScale;
mScaleFactor = maxScale / origScale;
} else if (saveScale < minScale) {
saveScale = minScale;
mScaleFactor = minScale / origScale;
}
right = width * saveScale - width
- (2 * redundantXSpace * saveScale);
bottom = height * saveScale - height
- (2 * redundantYSpace * saveScale);
if (origWidth * saveScale <= width
|| origHeight * saveScale <= height) {
matrix.postScale(mScaleFactor, mScaleFactor, width / 2,
height / 2);
if (mScaleFactor < 1) {
matrix.getValues(m);
float x = m[Matrix.MTRANS_X];
float y = m[Matrix.MTRANS_Y];
if (mScaleFactor < 1) {
if (Math.round(origWidth * saveScale) < width) {
if (y < -bottom)
matrix.postTranslate(0, -(y + bottom));
else if (y > 0)
matrix.postTranslate(0, -y);
} else {
if (x < -right)
matrix.postTranslate(-(x + right), 0);
else if (x > 0)
matrix.postTranslate(-x, 0);
}
}
}
} else {
matrix.postScale(mScaleFactor, mScaleFactor,
detector.getFocusX(), detector.getFocusY());
matrix.getValues(m);
float x = m[Matrix.MTRANS_X];
float y = m[Matrix.MTRANS_Y];
if (mScaleFactor < 1) {
if (x < -right)
matrix.postTranslate(-(x + right), 0);
else if (x > 0)
matrix.postTranslate(-x, 0);
if (y < -bottom)
matrix.postTranslate(0, -(y + bottom));
else if (y > 0)
matrix.postTranslate(0, -y);
}
}
return true;
}
}
#Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
width = MeasureSpec.getSize(widthMeasureSpec);
height = MeasureSpec.getSize(heightMeasureSpec);
// Fit to screen.
float scale;
float scaleX = (float) width / (float) bmWidth;
float scaleY = (float) height / (float) bmHeight;
scale = Math.min(scaleX, scaleY);
matrix.setScale(scale, scale);
setImageMatrix(matrix);
saveScale = 1f;
// Center the image
redundantYSpace = (float) height - (scale * (float) bmHeight);
redundantXSpace = (float) width - (scale * (float) bmWidth);
redundantYSpace /= (float) 2;
redundantXSpace /= (float) 2;
matrix.postTranslate(redundantXSpace, redundantYSpace);
origWidth = width - 2 * redundantXSpace;
origHeight = height - 2 * redundantYSpace;
right = width * saveScale - width - (2 * redundantXSpace * saveScale);
bottom = height * saveScale - height
- (2 * redundantYSpace * saveScale);
setImageMatrix(matrix);
}
}
Now when ever you want to call the ZoomFunctionality from your Activity just write the following statement
BitmapFactory.Options options = new BitmapFactory.Options();
options.inSampleSize = 2;
Bitmap bmp = BitmapFactory.decodeFile(filename, options);
ZoomFunctionality img = new ZoomFunctionality(this);
img.setImageBitmap(bmp);
img.setMaxZoom(4f);
setContentView(img);
Note
bmp: Is the bitmap image of which you want the zoom functionality
this: Its recommended that you use Activity.this
Its not necessary to use BitmapFactoryOptions but decoding from filename is required

TouchImageView.java
package com.animation.sound;
import android.content.Context;
import android.graphics.Matrix;
import android.graphics.PointF;
import android.graphics.drawable.Drawable;
import android.util.AttributeSet;
import android.util.Log;
import android.view.MotionEvent;
import android.view.ScaleGestureDetector;
import android.view.View;
import android.widget.ImageView;
public class TouchImageView extends ImageView {
Matrix matrix;
// We can be in one of these 3 states
static final int NONE = 0;
static final int DRAG = 1;
static final int ZOOM = 2;
int mode = NONE;
// Remember some things for zooming
PointF last = new PointF();
PointF start = new PointF();
float minScale = 1f;
float maxScale = 3f;
float[] m;
int viewWidth, viewHeight;
static final int CLICK = 3;
float saveScale = 1f;
protected float origWidth, origHeight;
int oldMeasuredWidth, oldMeasuredHeight;
ScaleGestureDetector mScaleDetector;
Context context;
public TouchImageView(Context context) {
super(context);
sharedConstructing(context);
}
public TouchImageView(Context context, AttributeSet attrs) {
super(context, attrs);
sharedConstructing(context);
}
private void sharedConstructing(Context context) {
super.setClickable(true);
this.context = context;
mScaleDetector = new ScaleGestureDetector(context, new ScaleListener());
matrix = new Matrix();
m = new float[9];
setImageMatrix(matrix);
setScaleType(ScaleType.MATRIX);
setOnTouchListener(new OnTouchListener() {
#Override
public boolean onTouch(View v, MotionEvent event) {
mScaleDetector.onTouchEvent(event);
PointF curr = new PointF(event.getX(), event.getY());
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
last.set(curr);
start.set(last);
mode = DRAG;
break;
case MotionEvent.ACTION_MOVE:
if (mode == DRAG) {
float deltaX = curr.x - last.x;
float deltaY = curr.y - last.y;
float fixTransX = getFixDragTrans(deltaX, viewWidth,
origWidth * saveScale);
float fixTransY = getFixDragTrans(deltaY, viewHeight,
origHeight * saveScale);
matrix.postTranslate(fixTransX, fixTransY);
fixTrans();
last.set(curr.x, curr.y);
}
break;
case MotionEvent.ACTION_UP:
mode = NONE;
int xDiff = (int) Math.abs(curr.x - start.x);
int yDiff = (int) Math.abs(curr.y - start.y);
if (xDiff < CLICK && yDiff < CLICK)
performClick();
break;
case MotionEvent.ACTION_POINTER_UP:
mode = NONE;
break;
}
setImageMatrix(matrix);
invalidate();
return true; // indicate event was handled
}
});
}
public void setMaxZoom(float x) {
maxScale = x;
}
private class ScaleListener extends
ScaleGestureDetector.SimpleOnScaleGestureListener {
#Override
public boolean onScaleBegin(ScaleGestureDetector detector) {
mode = ZOOM;
return true;
}
#Override
public boolean onScale(ScaleGestureDetector detector) {
float mScaleFactor = detector.getScaleFactor();
float origScale = saveScale;
saveScale *= mScaleFactor;
if (saveScale > maxScale) {
saveScale = maxScale;
mScaleFactor = maxScale / origScale;
} else if (saveScale < minScale) {
saveScale = minScale;
mScaleFactor = minScale / origScale;
}
if (origWidth * saveScale <= viewWidth
|| origHeight * saveScale <= viewHeight)
matrix.postScale(mScaleFactor, mScaleFactor, viewWidth / 2,
viewHeight / 2);
else
matrix.postScale(mScaleFactor, mScaleFactor,
detector.getFocusX(), detector.getFocusY());
fixTrans();
return true;
}
}
void fixTrans() {
matrix.getValues(m);
float transX = m[Matrix.MTRANS_X];
float transY = m[Matrix.MTRANS_Y];
float fixTransX = getFixTrans(transX, viewWidth, origWidth * saveScale);
float fixTransY = getFixTrans(transY, viewHeight, origHeight
* saveScale);
if (fixTransX != 0 || fixTransY != 0)
matrix.postTranslate(fixTransX, fixTransY);
}
float getFixTrans(float trans, float viewSize, float contentSize) {
float minTrans, maxTrans;
if (contentSize <= viewSize) {
minTrans = 0;
maxTrans = viewSize - contentSize;
} else {
minTrans = viewSize - contentSize;
maxTrans = 0;
}
if (trans < minTrans)
return -trans + minTrans;
if (trans > maxTrans)
return -trans + maxTrans;
return 0;
}
float getFixDragTrans(float delta, float viewSize, float contentSize) {
if (contentSize <= viewSize) {
return 0;
}
return delta;
}
#Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
viewWidth = MeasureSpec.getSize(widthMeasureSpec);
viewHeight = MeasureSpec.getSize(heightMeasureSpec);
//
// Rescales image on rotation
//
if (oldMeasuredHeight == viewWidth && oldMeasuredHeight == viewHeight
|| viewWidth == 0 || viewHeight == 0)
return;
oldMeasuredHeight = viewHeight;
oldMeasuredWidth = viewWidth;
if (saveScale == 1) {
// Fit to screen.
float scale;
Drawable drawable = getDrawable();
if (drawable == null || drawable.getIntrinsicWidth() == 0
|| drawable.getIntrinsicHeight() == 0)
return;
int bmWidth = drawable.getIntrinsicWidth();
int bmHeight = drawable.getIntrinsicHeight();
Log.d("bmSize", "bmWidth: " + bmWidth + " bmHeight : " + bmHeight);
float scaleX = (float) viewWidth / (float) bmWidth;
float scaleY = (float) viewHeight / (float) bmHeight;
scale = Math.min(scaleX, scaleY);
matrix.setScale(scale, scale);
// Center the image
float redundantYSpace = (float) viewHeight
- (scale * (float) bmHeight);
float redundantXSpace = (float) viewWidth
- (scale * (float) bmWidth);
redundantYSpace /= (float) 2;
redundantXSpace /= (float) 2;
matrix.postTranslate(redundantXSpace, redundantYSpace);
origWidth = viewWidth - 2 * redundantXSpace;
origHeight = viewHeight - 2 * redundantYSpace;
setImageMatrix(matrix);
}
fixTrans();
}
}
put this lines In MainActivity.java class...
TouchImageView imgView;
imgView = (TouchImageView) findViewById(R.id.imgmstlv);
And More Info. Follow this link Zoom In & Zoom out

how to handel viewpager swipe disable on pinchzoom?

I am new in viewpager component I am used custom viewpager with multiple images.and i want to do when my image in zooming mode during that period swiping disable and when swipe enable that time zooming enable. is it possible my code is here. advance in thanks.
Viewpager
public class SwipeableViewPager extends ViewPager {
private boolean enabled;
public SwipeableViewPager (Context context, AttributeSet attrs) {
super(context, attrs);
}
#Override
public boolean onTouchEvent(MotionEvent event) {
if (this.enabled) {
return super.onTouchEvent(event);
}
return false;
}
#Override
public boolean onInterceptTouchEvent(MotionEvent event) {
if (this.enabled) {
return super.onInterceptTouchEvent(event);
}
return false;
}
public void setPagingEnabled(boolean enabled) {
this.enabled = enabled;
}
}
imageview zoomig
public class TouchImageView extends ImageView {
Matrix matrix = new Matrix();
// We can be in one of these 3 states
static final int NONE = 0;
static final int DRAG = 1;
static final int ZOOM = 2;
int mode = NONE;
static NonSwipeableViewPager PagerLeft;
// Remember some things for zooming
PointF last = new PointF();
PointF start = new PointF();
float minScale = 1f;
float maxScale = 3f;
float[] m;
static boolean b =false;
float redundantXSpace, redundantYSpace;
float width, height;
static final int CLICK = 3;
float saveScale = 1f;
float right, bottom, origWidth, origHeight, bmWidth, bmHeight;
ScaleGestureDetector mScaleDetector;
Context context;
public TouchImageView(Context context) {
super(context);
sharedConstructing(context);
}
public TouchImageView(Context context, AttributeSet attrs) {
super(context, attrs);
sharedConstructing(context);
}
private void sharedConstructing(Context context) {
super.setClickable(true);
this.context = context;
mScaleDetector = new ScaleGestureDetector(context, new ScaleListener());
matrix.setTranslate(1f, 1f);
m = new float[9];
setImageMatrix(matrix);
setScaleType(ScaleType.MATRIX);
setOnTouchListener(new OnTouchListener() {
#Override
public boolean onTouch(View v, MotionEvent event) {
mScaleDetector.onTouchEvent(event);
matrix.getValues(m);
float x = m[Matrix.MTRANS_X];
float y = m[Matrix.MTRANS_Y];
PointF curr = new PointF(event.getX(), event.getY());
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
Log.v("event","ACTION_DOWN");
TouchImageView.b = false;
last.set(event.getX(), event.getY());
start.set(last);
mode = DRAG;
break;
case MotionEvent.ACTION_MOVE:
if (mode == DRAG) {
float deltaX = curr.x - last.x;
float deltaY = curr.y - last.y;
float scaleWidth = Math.round(origWidth * saveScale);
float scaleHeight = Math.round(origHeight * saveScale);
if (scaleWidth < width) {
deltaX = 0;
if (y + deltaY > 0){
deltaY = -y;
}
else if (y + deltaY < -bottom){
deltaY = -(y + bottom);
}
} else if (scaleHeight < height) {
deltaY = 0;
if (x + deltaX > 0)
deltaX = -x;
else if (x + deltaX < -right)
deltaX = -(x + right);
}else {
if (x + deltaX > 0){
deltaX = -x;
}
else if (x + deltaX < -right){
deltaX = -(x + right);
}
if (y + deltaY > 0){
deltaY = -y;
}
else if (y + deltaY < -bottom){
deltaY = -(y + bottom);
}
}
matrix.postTranslate(deltaX, deltaY);
last.set(curr.x, curr.y);
}
break;
case MotionEvent.ACTION_UP:
Log.v("event","ACTION_UP");
mode = NONE;
int xDiff = (int) Math.abs(curr.x - start.x);
int yDiff = (int) Math.abs(curr.y - start.y);
if (xDiff < CLICK && yDiff < CLICK){
Log.v("event","ACTION_UP xDiff < CLICK && yDiff < CLICK");
performClick();
}
break;
case MotionEvent.ACTION_POINTER_UP:
TouchImageView.b = true;
Log.v("event","ACTION_POINTER_UP");
mode = NONE;
break;
case MotionEvent.ACTION_POINTER_3_DOWN:
Log.v("event","ACTION_HOVER_MOVE");
break;
}
/*getLayoutParams().height = (int) getWidthFromMatrix(matrix,
TouchImageView.this);
getLayoutParams().width = (int) getHeightFromMatrix(matrix,
TouchImageView.this);*/
setImageMatrix(matrix);
invalidate();
return true; // indicate event was handled
}
});
}
#Override
public void setImageBitmap(Bitmap bm) {
super.setImageBitmap(bm);
if (bm != null) {
bmWidth = bm.getWidth();
bmHeight = bm.getHeight();
}
}
public void setMaxZoom(float x) {
maxScale = x;
}
private class ScaleListener extends
ScaleGestureDetector.SimpleOnScaleGestureListener {
#Override
public boolean onScaleBegin(ScaleGestureDetector detector) {
mode = ZOOM;
return true;
}
#SuppressLint("NewApi")
#TargetApi(8)
#Override
public boolean onScale(ScaleGestureDetector detector) {
float mScaleFactor = (float) Math.min(
Math.max(.95f, detector.getScaleFactor()), 1.05);
float origScale = saveScale;
saveScale *= mScaleFactor;
if (saveScale > maxScale) {
saveScale = maxScale;
mScaleFactor = maxScale / origScale;
} else if (saveScale < minScale) {
saveScale = minScale;
mScaleFactor = minScale / origScale;
}
right = width * saveScale - width
- (2 * redundantXSpace * saveScale);
bottom = height * saveScale - height
- (2 * redundantYSpace * saveScale);
if (origWidth * saveScale <= width
|| origHeight * saveScale <= height) {
matrix.postScale(mScaleFactor, mScaleFactor, width / 2,
height / 2);
if (mScaleFactor < 1) {
matrix.getValues(m);
float x = m[Matrix.MTRANS_X];
float y = m[Matrix.MTRANS_Y];
if (mScaleFactor < 1) {
if (Math.round(origWidth * saveScale) < width) {
if (y < -bottom)
matrix.postTranslate(0, -(y + bottom));
else if (y > 0)
matrix.postTranslate(0, -y);
} else {
if (x < -right)
matrix.postTranslate(-(x + right), 0);
else if (x > 0)
matrix.postTranslate(-x, 0);
}
}
}
} else {
matrix.postScale(mScaleFactor, mScaleFactor,
detector.getFocusX(), detector.getFocusY());
matrix.getValues(m);
float x = m[Matrix.MTRANS_X];
float y = m[Matrix.MTRANS_Y];
if (mScaleFactor < 1) {
if (x < -right)
matrix.postTranslate(-(x + right), 0);
else if (x > 0)
matrix.postTranslate(-x, 0);
if (y < -bottom)
matrix.postTranslate(0, -(y + bottom));
else if (y > 0)
matrix.postTranslate(0, -y);
}
}
return true;
}
}
#Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
width = MeasureSpec.getSize(widthMeasureSpec);
height = MeasureSpec.getSize(heightMeasureSpec);
// Fit to screen.
float scale;
float scaleX = (float) width / (float) bmWidth;
float scaleY = (float) height / (float) bmHeight;
scale = Math.min(scaleX, scaleY);
matrix.setScale(scale, scale);
setImageMatrix(matrix);
saveScale = 1f;
// Center the image
redundantYSpace = (float) height - (scale * (float) bmHeight);
redundantXSpace = (float) width - (scale * (float) bmWidth);
redundantYSpace /= (float) 2;
redundantXSpace /= (float) 2;
matrix.postTranslate(redundantXSpace, redundantYSpace);
origWidth = width - 2 * redundantXSpace;
origHeight = height - 2 * redundantYSpace;
right = width * saveScale - width - (2 * redundantXSpace * saveScale);
bottom = height * saveScale - height
- (2 * redundantYSpace * saveScale);
setImageMatrix(matrix);
}
}

Android: Custom ImageView

I'm trying to add touch functionality to an image by creating a custom ImageView, however when I run it I am getting a Null point exception in the logcat. My code is as follow:
TouchImageView.java
package com.android.wayfinder;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Matrix;
import android.graphics.PointF;
import android.view.MotionEvent;
import android.view.ScaleGestureDetector;
import android.view.View;
import android.widget.ImageView;
public class TouchImageView extends ImageView {
Matrix matrix = new Matrix();
// We can be in one of these 3 states
static final int NONE = 0;
static final int DRAG = 1;
static final int ZOOM = 2;
int mode = NONE;
// Remember some things for zooming
PointF last = new PointF();
PointF start = new PointF();
float minScale = 1f;
float maxScale = 3f;
float[] m;
float redundantXSpace, redundantYSpace;
float width, height;
static final int CLICK = 3;
float saveScale = 1f;
float right, bottom, origWidth, origHeight, bmWidth, bmHeight;
ScaleGestureDetector mScaleDetector;
Context context;
public TouchImageView(Context context) {
super(context);
super.setClickable(true);
this.context = context;
mScaleDetector = new ScaleGestureDetector(context, new ScaleListener());
matrix.setTranslate(1f, 1f);
m = new float[9];
setImageMatrix(matrix);
setScaleType(ScaleType.MATRIX);
setOnTouchListener(new OnTouchListener() {
public boolean onTouch(View v, MotionEvent event) {
mScaleDetector.onTouchEvent(event);
matrix.getValues(m);
float x = m[Matrix.MTRANS_X];
float y = m[Matrix.MTRANS_Y];
PointF curr = new PointF(event.getX(), event.getY());
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
last.set(event.getX(), event.getY());
start.set(last);
mode = DRAG;
break;
case MotionEvent.ACTION_MOVE:
if (mode == DRAG) {
float deltaX = curr.x - last.x;
float deltaY = curr.y - last.y;
float scaleWidth = Math.round(origWidth * saveScale);
float scaleHeight = Math.round(origHeight * saveScale);
if (scaleWidth < width) {
deltaX = 0;
if (y + deltaY > 0)
deltaY = -y;
else if (y + deltaY < -bottom)
deltaY = -(y + bottom);
} else if (scaleHeight < height) {
deltaY = 0;
if (x + deltaX > 0)
deltaX = -x;
else if (x + deltaX < -right)
deltaX = -(x + right);
} else {
if (x + deltaX > 0)
deltaX = -x;
else if (x + deltaX < -right)
deltaX = -(x + right);
if (y + deltaY > 0)
deltaY = -y;
else if (y + deltaY < -bottom)
deltaY = -(y + bottom);
}
matrix.postTranslate(deltaX, deltaY);
last.set(curr.x, curr.y);
}
break;
case MotionEvent.ACTION_UP:
mode = NONE;
int xDiff = (int) Math.abs(curr.x - start.x);
int yDiff = (int) Math.abs(curr.y - start.y);
if (xDiff < CLICK && yDiff < CLICK)
performClick();
break;
case MotionEvent.ACTION_POINTER_UP:
mode = NONE;
break;
}
setImageMatrix(matrix);
invalidate();
return true; // indicate event was handled
}
});
}
#Override
public void setImageBitmap(Bitmap bm) {
super.setImageBitmap(bm);
bmWidth = bm.getWidth();
bmHeight = bm.getHeight();
}
public void setMaxZoom(float x)
{
maxScale = x;
}
private class ScaleListener extends ScaleGestureDetector.SimpleOnScaleGestureListener {
#Override
public boolean onScaleBegin(ScaleGestureDetector detector) {
mode = ZOOM;
return true;
}
#Override
public boolean onScale(ScaleGestureDetector detector) {
float mScaleFactor = (float)Math.min(Math.max(.95f, detector.getScaleFactor()), 1.05);
float origScale = saveScale;
saveScale *= mScaleFactor;
if (saveScale > maxScale) {
saveScale = maxScale;
mScaleFactor = maxScale / origScale;
} else if (saveScale < minScale) {
saveScale = minScale;
mScaleFactor = minScale / origScale;
}
right = width * saveScale - width - (2 * redundantXSpace * saveScale);
bottom = height * saveScale - height - (2 * redundantYSpace * saveScale);
if (origWidth * saveScale <= width || origHeight * saveScale <= height) {
matrix.postScale(mScaleFactor, mScaleFactor, width / 2, height / 2);
if (mScaleFactor < 1) {
matrix.getValues(m);
float x = m[Matrix.MTRANS_X];
float y = m[Matrix.MTRANS_Y];
if (mScaleFactor < 1) {
if (Math.round(origWidth * saveScale) < width) {
if (y < -bottom)
matrix.postTranslate(0, -(y + bottom));
else if (y > 0)
matrix.postTranslate(0, -y);
} else {
if (x < -right)
matrix.postTranslate(-(x + right), 0);
else if (x > 0)
matrix.postTranslate(-x, 0);
}
}
}
} else {
matrix.postScale(mScaleFactor, mScaleFactor, detector.getFocusX(), detector.getFocusY());
matrix.getValues(m);
float x = m[Matrix.MTRANS_X];
float y = m[Matrix.MTRANS_Y];
if (mScaleFactor < 1) {
if (x < -right)
matrix.postTranslate(-(x + right), 0);
else if (x > 0)
matrix.postTranslate(-x, 0);
if (y < -bottom)
matrix.postTranslate(0, -(y + bottom));
else if (y > 0)
matrix.postTranslate(0, -y);
}
}
return true;
}
}
#Override
protected void onMeasure (int widthMeasureSpec, int heightMeasureSpec)
{
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
width = MeasureSpec.getSize(widthMeasureSpec);
height = MeasureSpec.getSize(heightMeasureSpec);
//Fit to screen.
float scale;
float scaleX = (float)width / (float)bmWidth;
float scaleY = (float)height / (float)bmHeight;
scale = Math.min(scaleX, scaleY);
matrix.setScale(scale, scale);
setImageMatrix(matrix);
saveScale = 1f;
// Center the image
redundantYSpace = (float)height - (scale * (float)bmHeight) ;
redundantXSpace = (float)width - (scale * (float)bmWidth);
redundantYSpace /= (float)2;
redundantXSpace /= (float)2;
matrix.postTranslate(redundantXSpace, redundantYSpace);
origWidth = width - 2 * redundantXSpace;
origHeight = height - 2 * redundantYSpace;
right = width * saveScale - width - (2 * redundantXSpace * saveScale);
bottom = height * saveScale - height - (2 * redundantYSpace * saveScale);
setImageMatrix(matrix);
}
}
ImageView.xml
<?xml version="1.0" encoding="utf-8"?>
<com.android.wayfinder.TouchImageView xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/arasnalaoi"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:src="#drawable/aras_na_laoi" />
Activity:
public class ImageActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
TouchImageView touch = (TouchImageView) this.findViewById(R.id.arasnalaoi);
touch.setImageBitmap(BitmapFactory.decodeResource(this.getResources(), R.drawable.aras_na_laoi));
touch.setMaxZoom(4f);
setContentView(touch);
setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);
}
}
The null pointer exception is pointing at the line: touch.setImageBitmap...
I'm absolutely stumpt so any help would be greatly appreciated.
Shaw

You are getting the NullPointerException because you call findViewById before you set a content view for the activity, so TouchImageView touch = (TouchImageView) this.findViewById(R.id.arasnalaoi) can not find any view with R.id.arasnalaoi as id, it will surely return null, yes, touch is null, that's why a NullPointerException is thrown.

Your call to this.findViewById returns null (i.e. touch is null). It cannot find the R.id.arasnalaoi TouchImageView because you haven't loaded a content view into your activity yet.
You'll want to do things in a different order, i.e.
Load your content using setContentView(R.layout.imageView);, assuming your xml is in the layout folder.
Find your view using TouchImageView touch = (TouchImageView) this.findViewById(R.id.arasnalaoi);
Set the properies of the touch object.

Code works on API 8 and can't on API 9 or 10

For some reason my code works perfectly for Froyo(API 8) but gives me a Stopped Unexpectedly/Force Close error when I try to run it on API 9 or 10, AVD and phones give me the same error message. Any idea as to why?
My code for review:
All pages look similar to ViewActivity.java. only difference id the drawable called.
ViewActivity.java:
import android.app.Activity;
import android.content.Intent;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
public class ViewActivity extends Activity {
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//creates view
TouchImageView img = new TouchImageView(this);
//sets image
Bitmap image = BitmapFactory.decodeResource(getResources(), R.drawable.largeimage1);
img.setImageBitmap(image);
img.setMaxZoom(3f);
setContentView(img);
}
//Creates the options menu
#Override
public boolean onCreateOptionsMenu(Menu menu) {
super.onCreateOptionsMenu(menu);
getMenuInflater().inflate(R.menu.echooptions, menu);
return true;
}
//Starts the chosen menu activity
#Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case R.id.back_item:
Intent intentb = new Intent(this, page16.class);
startActivity(intentb);
return true;
case R.id.next_item:
Intent intentn = new Intent(this, page2.class);
startActivity(intentn);
return true;
case R.id.about_menu_item:
Intent intenta = new Intent(this, AboutActivity.class);
startActivity(intenta);
return true;
case R.id.tablecontents:
return true;
case R.id.page1:
Intent intent1 = new Intent(this, ViewActivity.class);
startActivity(intent1);
return true;
case R.id.page2:
Intent intent2 = new Intent(this, page2.class);
startActivity(intent2);
return true;
default:
return super.onOptionsItemSelected(item);
}
}
}
TouchImageView.java:
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Matrix;
import android.graphics.PointF;
import android.view.MotionEvent;
import android.view.ScaleGestureDetector;
import android.view.View;
import android.widget.ImageView;
public class TouchImageView extends ImageView {
Matrix matrix = new Matrix();
// We can be in one of these 3 states
static final int NONE = 0;
static final int DRAG = 1;
static final int ZOOM = 2;
int mode = NONE;
// Remember some things for zooming
PointF last = new PointF();
PointF start = new PointF();
float minScale = 1f;
float maxScale = 3f;
float[] m;
float redundantXSpace, redundantYSpace;
float width, height;
static final int CLICK = 3;
float saveScale = 1f;
float right, bottom, origWidth, origHeight, bmWidth, bmHeight;
ScaleGestureDetector mScaleDetector;
Context context;
public TouchImageView(Context context) {
super(context);
super.setClickable(true);
this.context = context;
mScaleDetector = new ScaleGestureDetector(context, new ScaleListener());
matrix.setTranslate(1f, 1f);
m = new float[9];
setImageMatrix(matrix);
setScaleType(ScaleType.MATRIX);
setOnTouchListener(new OnTouchListener() {
#Override
public boolean onTouch(View v, MotionEvent event) {
mScaleDetector.onTouchEvent(event);
matrix.getValues(m);
float x = m[Matrix.MTRANS_X];
float y = m[Matrix.MTRANS_Y];
PointF curr = new PointF(event.getX(), event.getY());
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
last.set(event.getX(), event.getY());
start.set(last);
mode = DRAG;
break;
case MotionEvent.ACTION_MOVE:
if (mode == DRAG) {
float deltaX = curr.x - last.x;
float deltaY = curr.y - last.y;
float scaleWidth = Math.round(origWidth * saveScale);
float scaleHeight = Math.round(origHeight * saveScale);
if (scaleWidth < width) {
deltaX = 0;
if (y + deltaY > 0)
deltaY = -y;
else if (y + deltaY < -bottom)
deltaY = -(y + bottom);
} else if (scaleHeight < height) {
deltaY = 0;
if (x + deltaX > 0)
deltaX = -x;
else if (x + deltaX < -right)
deltaX = -(x + right);
} else {
if (x + deltaX > 0)
deltaX = -x;
else if (x + deltaX < -right)
deltaX = -(x + right);
if (y + deltaY > 0)
deltaY = -y;
else if (y + deltaY < -bottom)
deltaY = -(y + bottom);
}
matrix.postTranslate(deltaX, deltaY);
last.set(curr.x, curr.y);
}
break;
case MotionEvent.ACTION_UP:
mode = NONE;
int xDiff = (int) Math.abs(curr.x - start.x);
int yDiff = (int) Math.abs(curr.y - start.y);
if (xDiff < CLICK && yDiff < CLICK)
performClick();
break;
case MotionEvent.ACTION_POINTER_UP:
mode = NONE;
break;
}
setImageMatrix(matrix);
invalidate();
return true; // indicate event was handled
}
});
}
#Override
public void setImageBitmap(Bitmap bm) {
super.setImageBitmap(bm);
bmWidth = bm.getWidth();
bmHeight = bm.getHeight();
}
public void setMaxZoom(float x)
{
maxScale = x;
}
private class ScaleListener extends ScaleGestureDetector.SimpleOnScaleGestureListener {
#Override
public boolean onScaleBegin(ScaleGestureDetector detector) {
mode = ZOOM;
return true;
}
#Override
public boolean onScale(ScaleGestureDetector detector) {
float mScaleFactor = (float)Math.min(Math.max(.95f, detector.getScaleFactor()), 1.05);
float origScale = saveScale;
saveScale *= mScaleFactor;
if (saveScale > maxScale) {
saveScale = maxScale;
mScaleFactor = maxScale / origScale;
} else if (saveScale < minScale) {
saveScale = minScale;
mScaleFactor = minScale / origScale;
}
right = width * saveScale - width - (2 * redundantXSpace * saveScale);
bottom = height * saveScale - height - (2 * redundantYSpace * saveScale);
if (origWidth * saveScale <= width || origHeight * saveScale <= height) {
matrix.postScale(mScaleFactor, mScaleFactor, width / 2, height / 2);
if (mScaleFactor < 1) {
matrix.getValues(m);
float x = m[Matrix.MTRANS_X];
float y = m[Matrix.MTRANS_Y];
if (mScaleFactor < 1) {
if (Math.round(origWidth * saveScale) < width) {
if (y < -bottom)
matrix.postTranslate(0, -(y + bottom));
else if (y > 0)
matrix.postTranslate(0, -y);
} else {
if (x < -right)
matrix.postTranslate(-(x + right), 0);
else if (x > 0)
matrix.postTranslate(-x, 0);
}
}
}
} else {
matrix.postScale(mScaleFactor, mScaleFactor, detector.getFocusX(), detector.getFocusY());
matrix.getValues(m);
float x = m[Matrix.MTRANS_X];
float y = m[Matrix.MTRANS_Y];
if (mScaleFactor < 1) {
if (x < -right)
matrix.postTranslate(-(x + right), 0);
else if (x > 0)
matrix.postTranslate(-x, 0);
if (y < -bottom)
matrix.postTranslate(0, -(y + bottom));
else if (y > 0)
matrix.postTranslate(0, -y);
}
}
return true;
}
}
#Override
protected void onMeasure (int widthMeasureSpec, int heightMeasureSpec)
{
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
width = MeasureSpec.getSize(widthMeasureSpec);
height = MeasureSpec.getSize(heightMeasureSpec);
//Fit to screen.
float scale;
float scaleX = (float)width / (float)bmWidth;
float scaleY = (float)height / (float)bmHeight;
scale = Math.min(scaleX, scaleY);
matrix.setScale(scale, scale);
setImageMatrix(matrix);
saveScale = 1f;
// Center the image
redundantYSpace = (float)height - (scale * (float)bmHeight) ;
redundantXSpace = (float)width - (scale * (float)bmWidth);
redundantYSpace /= (float)2;
redundantXSpace /= (float)2;
matrix.postTranslate(redundantXSpace, redundantYSpace);
origWidth = width - 2 * redundantXSpace;
origHeight = height - 2 * redundantYSpace;
right = width * saveScale - width - (2 * redundantXSpace * saveScale);
bottom = height * saveScale - height - (2 * redundantYSpace * saveScale);
setImageMatrix(matrix);
}
}

InstantiationException: mil.Army.page2 implies it can't create an instance of class page2. I think this is usually thrown when you try to instantiate an abstract class or interface. According to this it can be thrown because the class doesn't have a default (zero-argument) constructor. I don't know why it would work only on API 8 since this seems to be a Java issue, but it seems to be a possible cause.
EDIT: May also try to simply rebuild the project. In Eclipse, just clean it by going to Project->Clean.
EDIT: I also came across this as well that seems to b related:
Why do I get an InstantiationException if I try to start a service?