问题
I am newbie in Android.I have followed this Question and i successfully zoom an image this code is working fine can someone please help me how to write code for zoomin zoomout on button click.I am not getting how to achieve this task
Here is the Tutorial that i followed Tutorial Zoom Image and also follow "Salman's Ayub Answer"
Its working fine but i am failed to apply scale factor on zoom in and zoom out of image
回答1:
You need to add these 2 methods to your TouchImageView class:
public void zoomIn() {
oldScale = saveScale;
if(saveScale<=maxScale)
{
saveScale += .5;
matrix.setScale(saveScale, saveScale);
setImageMatrix(matrix);
invalidate();
// Center the image
// Center the image
if(bmHeight>bmWidth)
{
redundantXSpace = width - (saveScale * bmWidth);
redundantXSpace /= 2;
}
else
{
redundantYSpace = height - (saveScale * bmHeight) ;
redundantYSpace /= 2;
}
matrix.postTranslate(redundantXSpace , redundantYSpace );
setImageMatrix(matrix);
invalidate();
}
}
public void zoomOut() {
if(saveScale>=minScale)
{
saveScale -= .5;
matrix.setScale(saveScale, saveScale);
setImageMatrix(matrix);
invalidate();
// Center the image
if(bmHeight>bmWidth)
{
redundantXSpace = width - (saveScale * bmWidth);
redundantXSpace /= 2;
}
else
{
redundantYSpace = height - (saveScale * bmHeight) ;
redundantYSpace /= 2;
}
matrix.postTranslate(redundantXSpace , redundantYSpace );
setImageMatrix(matrix);
invalidate();
}
}
Here is the complete TouchImageView class code, along with these 2 methods:
public class TouchImageView extends ImageView {
public 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;
static final int CLICK = 3;
int mode = NONE;
float oldScale = 1.0f;
// Remember some things for zooming
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 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_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)) {
Log.d("******", "ZOOM OR 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);
}else if(mode == DRAG && saveScale == minScale) {
Log.d("******", "DRAG");
}
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 = detector.getScaleFactor();//(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 = 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);
}
public TouchImageView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
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)) {
Log.d("******", "ZOOM OR 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);
}else if(mode == DRAG && saveScale == minScale) {
Log.d("******", "DRAG");
}
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 TouchImageView(Context context, AttributeSet attrs) {
super(context, attrs);
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)) {
Log.d("******", "ZOOM OR 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);
}else if(mode == DRAG && saveScale == minScale) {
Log.d("******", "DRAG");
}
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 zoomIn() {
oldScale = saveScale;
if(saveScale<=maxScale)
{
saveScale += .5;
matrix.setScale(saveScale, saveScale);
setImageMatrix(matrix);
invalidate();
// Center the image
// Center the image
if(bmHeight>bmWidth)
{
redundantXSpace = width - (saveScale * bmWidth);
redundantXSpace /= 2;
}
else
{
redundantYSpace = height - (saveScale * bmHeight) ;
redundantYSpace /= 2;
}
matrix.postTranslate(redundantXSpace , redundantYSpace );
setImageMatrix(matrix);
invalidate();
}
}
public void zoomOut() {
if(saveScale>=minScale)
{
saveScale -= .5;
matrix.setScale(saveScale, saveScale);
setImageMatrix(matrix);
invalidate();
// Center the image
if(bmHeight>bmWidth)
{
redundantXSpace = width - (saveScale * bmWidth);
redundantXSpace /= 2;
}
else
{
redundantYSpace = height - (saveScale * bmHeight) ;
redundantYSpace /= 2;
}
matrix.postTranslate(redundantXSpace , redundantYSpace );
setImageMatrix(matrix);
invalidate();
}
}
}
Here how you can use them in your zoomIn/zoomOut buttons:
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.LAYOUT_NAME);
Button zoonIn = (Button)findViewById(R.id.ZOOM_IN_BUTTON_ID);
Button zoonOut = (Button)findViewById(R.id.ZOOM_OUT_BUTTON_ID);
final TouchImageView touch = (TouchImageView)findViewById(R.id.YOUR_TOUCH_IMAGE_VIEW_)ID);
Bitmap bImage = BitmapFactory.decodeResource(this.getResources(), R.drawable.DRAWABLE_ID);
touch.setImageBitmap(bImage);
touch.setMaxZoom(4f); //change the max level of zoom, default is 3f
zoonIn.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
touch.zoomIn();
}
});
zoonOut.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
touch.zoomOut();
}
});
}
I hope this helps.
回答2:
The easiest way to zoom in/out images on button, is to display it in a webView, then you can use all features offered by webView.
copy your image in assets folder, then load it in onCreate:
WebView mWebView = (WebView) findViewById(R.id.webView1);
mWebView.setScrollBarStyle(WebView.SCROLLBARS_OUTSIDE_OVERLAY);
mWebView.setBackgroundColor(Color.parseColor("#ffffff"));
mWebView.loadUrl("file:///android_asset/image.png");
mWebView.getSettings().setBuiltInZoomControls(true);
mWebView.setInitialScale(50);
回答3:
Try to use PhotoView. I think it does what you want out of the box.
来源：https://stackoverflow.com/questions/21414345/zoom-in-out-image-on-button-click-in-android