捏在Android中缩放NetworkImageview

Question

我正在使用NetworkImageview在API调用中显示来自url的图像。

我还必须放大和缩小该图像。使用某些类，我们可以直接实现诸如TouchImageView缩放功能，但不能设置图像url。

那么我们如何在NetworkImageview上实现缩放功能。

有人可以帮忙吗？

我已经在这里问过，但没有得到任何回应吗？

Answer 1

只需使用毕加索。 http://square.github.io/picasso/该库应该可以解决您的问题。

Answer 2

我已经在TeamUsa项目中实现了此功能

公共类TeamUsaNetworkImageViewZoomIn扩展了NetworkImageView {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 TeamUsaNetworkImageViewZoomIn(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())
            {
                //when one finger is touching
                //set the mode to DRAG
                case MotionEvent.ACTION_DOWN:
                    last.set(event.getX(), event.getY());
                    start.set(last);
                    mode = DRAG;
                    break;
                //when two fingers are touching
                //set the mode to ZOOM
                case MotionEvent.ACTION_POINTER_DOWN:
                    last.set(event.getX(), event.getY());
                    start.set(last);
                    mode = ZOOM;
                    break;
                //when a finger moves
                //If mode is applicable move image
                case MotionEvent.ACTION_MOVE:
                    //if the mode is ZOOM or
                    //if the mode is DRAG and already zoomed
                    if (mode == ZOOM || (mode == DRAG && saveScale > minScale))
                    {
                        float deltaX = curr.x - last.x;// x difference
                        float deltaY = curr.y - last.y;// y difference
                        float scaleWidth = Math.round(origWidth * saveScale);// width after applying current scale
                        float scaleHeight = Math.round(origHeight * saveScale);// height after applying current scale
                        //if scaleWidth is smaller than the views width
                        //in other words if the image width fits in the view
                        //limit left and right movement
                        if (scaleWidth < width)
                        {
                            deltaX = 0;
                            if (y + deltaY > 0)
                                deltaY = -y;
                            else if (y + deltaY < -bottom)
                                deltaY = -(y + bottom);
                        }
                        //if scaleHeight is smaller than the views height
                        //in other words if the image height fits in the view
                        //limit up and down movement
                        else if (scaleHeight < height)
                        {
                            deltaY = 0;
                            if (x + deltaX > 0)
                                deltaX = -x;
                            else if (x + deltaX < -right)
                                deltaX = -(x + right);
                        }
                        //if the image doesnt fit in the width or height
                        //limit both up and down and left and 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);
                        }
                        //move the image with the matrix
                        matrix.postTranslate(deltaX, deltaY);
                        //set the last touch location to the current
                        last.set(curr.x, curr.y);
                    }
                    break;
                //first finger is lifted
                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;
                // second finger is lifted
                case MotionEvent.ACTION_POINTER_UP:
                    mode = NONE;
                    break;
            }
            setImageMatrix(matrix);
            invalidate();
            return true;
        }

    });
}

@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 =  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);
}

}