我有一个自定义图像视图，并使用矩阵缩放实现了缩放/拖动功能。我的问题是，当我打开具有 imagview 的活动时，打开的图像小于 imageview。我希望图像完全适合图像视图。请建议我怎样才能做到这一点。
PS：我不能使用“fitXY”或除矩阵以外的任何比例类型（因为我使用矩阵来缩放全部）。我已经尝试过使用 centerInside、fitXy 等。
礼貌的Android 图像视图捏缩放：ImageView 扩展：
public class CustomImageVIew extends ImageView implements OnTouchListener {
private Matrix matrix = new Matrix();
private Matrix savedMatrix = new Matrix();
static final int NONE = 0;
static final int DRAG = 1;
static final int ZOOM = 2;
private int mode = NONE;
private PointF mStartPoint = new PointF();
private PointF mMiddlePoint = new PointF();
private Point mBitmapMiddlePoint = new Point();
private float oldDist = 1f;
private float matrixValues[] = {0f, 0f, 0f, 0f, 0f, 0f, 0f, 0f, 0f};
private float scale;
private float oldEventX = 0;
private float oldEventY = 0;
private float oldStartPointX = 0;
private float oldStartPointY = 0;
private int mViewWidth = -1;
private int mViewHeight = -1;
private int mBitmapWidth = -1;
private int mBitmapHeight = -1;
private boolean mDraggable = false;
public CustomImageVIew(Context context) {
this(context, null, 0);
}
public CustomImageVIew(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
public CustomImageVIew(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
this.setOnTouchListener(this);
}
@Override
public void onSizeChanged (int w, int h, int oldw, int oldh){
super.onSizeChanged(w, h, oldw, oldh);
mViewWidth = w;
mViewHeight = h;
}
public void setBitmap(Bitmap bitmap){
if(bitmap != null){
setImageBitmap(bitmap);
mBitmapWidth = bitmap.getWidth();
mBitmapHeight = bitmap.getHeight();
mBitmapMiddlePoint.x = (mViewWidth / 2) - (mBitmapWidth / 2);
mBitmapMiddlePoint.y = (mViewHeight / 2) - (mBitmapHeight / 2);
matrix.postTranslate(mBitmapMiddlePoint.x, mBitmapMiddlePoint.y);
this.setImageMatrix(matrix);
}
}
@Override
public boolean onTouch(View v, MotionEvent event){
switch (event.getAction() & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_DOWN:
savedMatrix.set(matrix);
mStartPoint.set(event.getX(), event.getY());
mode = DRAG;
break;
case MotionEvent.ACTION_POINTER_DOWN:
oldDist = spacing(event);
if(oldDist > 10f){
savedMatrix.set(matrix);
midPoint(mMiddlePoint, event);
mode = ZOOM;
}
break;
case MotionEvent.ACTION_UP:
case MotionEvent.ACTION_POINTER_UP:
mode = NONE;
break;
case MotionEvent.ACTION_MOVE:
if(mode == DRAG){
drag(event);
} else if(mode == ZOOM){
zoom(event);
}
break;
}
return true;
}
public void drag(MotionEvent event){
matrix.getValues(matrixValues);
float left = matrixValues[2];
float top = matrixValues[5];
float bottom = (top + (matrixValues[0] * mBitmapHeight)) - mViewHeight;
float right = (left + (matrixValues[0] * mBitmapWidth)) -mViewWidth;
float eventX = event.getX();
float eventY = event.getY();
float spacingX = eventX - mStartPoint.x;
float spacingY = eventY - mStartPoint.y;
float newPositionLeft = (left < 0 ? spacingX : spacingX * -1) + left;
float newPositionRight = (spacingX) + right;
float newPositionTop = (top < 0 ? spacingY : spacingY * -1) + top;
float newPositionBottom = (spacingY) + bottom;
boolean x = true;
boolean y = true;
if(newPositionRight < 0.0f || newPositionLeft > 0.0f){
if(newPositionRight < 0.0f && newPositionLeft > 0.0f){
x = false;
} else{
eventX = oldEventX;
mStartPoint.x = oldStartPointX;
}
}
if(newPositionBottom < 0.0f || newPositionTop > 0.0f){
if(newPositionBottom < 0.0f && newPositionTop > 0.0f){
y = false;
} else{
eventY = oldEventY;
mStartPoint.y = oldStartPointY;
}
}
if(mDraggable){
matrix.set(savedMatrix);
matrix.postTranslate(x? eventX - mStartPoint.x : 0, y? eventY - mStartPoint.y : 0);
this.setImageMatrix(matrix);
if(x)oldEventX = eventX;
if(y)oldEventY = eventY;
if(x)oldStartPointX = mStartPoint.x;
if(y)oldStartPointY = mStartPoint.y;
}
}
public void zoom(MotionEvent event){
matrix.getValues(matrixValues);
float newDist = spacing(event);
float bitmapWidth = matrixValues[0] * mBitmapWidth;
float bimtapHeight = matrixValues[0] * mBitmapHeight;
boolean in = newDist > oldDist;
if(!in && matrixValues[0] < 1){
return;
}
if(bitmapWidth > mViewWidth || bimtapHeight > mViewHeight){
mDraggable = true;
} else{
mDraggable = false;
}
float midX = (mViewWidth / 2);
float midY = (mViewHeight / 2);
matrix.set(savedMatrix);
scale = newDist / oldDist;
matrix.postScale(scale, scale, bitmapWidth > mViewWidth ? mMiddlePoint.x : midX, bimtapHeight > mViewHeight ? mMiddlePoint.y : midY);
this.setImageMatrix(matrix);
}
/** Determine the space between the first two fingers */
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);
}
/** Calculate the mid point of the first two fingers */
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);
}
}