当galleryview首次显示图像时，它显示它已缩放到最大可能的尺寸以适合屏幕（如我所愿）。在我点击后，creen 图像将恢复其原始大小。如何保持图像缩放？
class ImageAdapterr extends BaseAdapter {
/** The parent context */
private Context myContext;
/** Simple Constructor saving the 'parent' context. */
public ImageAdapterr(Context c) {
this.myContext = c;
}
Matrix savedMatrix = new Matrix();
/** Returns the amount of images we have defined. */
public int getCount() {
return UILApplication.photo_buffer_big.size();
}
/* Use the array-Positions as unique IDs */
public Object getItem(int position) {
return position;
}
public long getItemId(int position) {
return position;
}
/**
* Returns a new ImageView to be displayed, depending on the position
* passed.
*/
public View getView(final int position, View convertView,
ViewGroup parent) {
imView = new ImageView(this.myContext);
current = imView;
imgPos = position;
ImageLoader imageLoader = new ImageLoader(app.getApplicationContext());
imageLoader.DisplayImage(UILApplication.photo_buffer_big.get(imgPos),
imView);
/* Image should be scaled as width/height are set. */
imView.setScaleType(ImageView.ScaleType.FIT_CENTER);
/* Set the Width/Height of the ImageView. */
imView.setLayoutParams(new Gallery.LayoutParams(
LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT));
imView.setOnTouchListener(new OnTouchListener() {
private static final String TAG = "Touch";
// These matrices will be used to move and zoom image
PointF start = new PointF();
public PointF mid = new PointF();
// We can be in one of these 3 states
public static final int NONE = 0;
public static final int DRAG = 1;
public static final int ZOOM = 2;
public int mode = NONE;
float oldDist;
public boolean onTouch(View v, MotionEvent event) {
ImageView view = (ImageView) v;
view.setScaleType(ImageView.ScaleType.MATRIX);
switch (event.getAction() & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_DOWN:
savedMatrix.set(matrix);
start.set(event.getX(), event.getY());
Log.d(TAG, "mode=DRAG");
mode = DRAG;
break;
case MotionEvent.ACTION_POINTER_DOWN:
oldDist = spacing(event);
Log.d(TAG, "oldDist=" + oldDist);
if (oldDist > 10f) {
savedMatrix.set(matrix);
midPoint(mid, event);
mode = ZOOM;
Log.d(TAG, "mode=ZOOM");
}
break;
case MotionEvent.ACTION_MOVE:
if (mode == DRAG) {
matrix.set(savedMatrix);
matrix.postTranslate(event.getX() - start.x,
event.getY() - start.y);
} else if (mode == ZOOM) {
float newDist = spacing(event);
Log.d(TAG, "newDist=" + newDist);
if (newDist > 10f) {
matrix.set(savedMatrix);
float scale = newDist / oldDist;
matrix.postScale(scale, scale, mid.x, mid.y);
}
}
break;
case MotionEvent.ACTION_UP:
case MotionEvent.ACTION_POINTER_UP:
mode = NONE;
Log.d(TAG, "mode=NONE");
break;
}
// Perform the transformation
Log.d("point",
(event.getX() - start.x) + " "
+ (event.getY() - start.y));
// Log.d("point",start.x +" "+start.y);
float[] values = new float[9];
matrix.getValues(values);
float a = values[Matrix.MTRANS_X];
float b = values[Matrix.MTRANS_Y];
Log.d("touch matrix", values[Matrix.MPERSP_0] + " "
+ values[Matrix.MPERSP_1] + " "
+ values[Matrix.MPERSP_2]);
Log.d("touch matrix scale", values[Matrix.MSCALE_X] + " "
+ values[Matrix.MSCALE_Y]);
Log.d("touch matrix scew", values[Matrix.MSKEW_X] + " "
+ values[Matrix.MSKEW_Y]);
Log.d("touch matrix trans", values[Matrix.MTRANS_X] + " "
+ values[Matrix.MTRANS_Y]);
if (reset == 1) {
matrix.reset();
savedMatrix.reset();
}
view.setImageMatrix(matrix);
onFront = view;
reset = 0;
// images.set(position, view);
return true; // indicate event was handled
}
private float spacing(MotionEvent event) {
float x = event.getX(0) - event.getX(1);
float y = event.getY(0) - event.getY(1);
return (float) Math.sqrt(x * x + y * y);
}
private void midPoint(PointF point, MotionEvent event) {
float x = event.getX(0) + event.getX(1);
float y = event.getY(0) + event.getY(1);
point.set(x / 2, y / 2);
}
});
return imView;
}
/**
* Returns the size (0.0f to 1.0f) of the views depending on the
* 'offset' to the center.
*/
public float getScale(boolean focused, int offset) {
/* Formula: 1 / (2 ^ offset) */
return Math.max(0, 1.0f / (float) Math.pow(2, Math.abs(offset)));
}
}
编辑：如果添加
view.setScaleType(ImageView.ScaleType.FIT_CENTER);
/* Set the Width/Height of the ImageView. */
view.setLayoutParams(new Gallery.LayoutParams(
LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT));
到 onTouch 图像保持缩放，但不再可拖动。