Android 从图像视图中挤压图像并获取其特定部分？

我正在开发一个android应用程序。图像视图中有一个图像。我想在其上添加收缩和拖动功能。我想在此视图上放置圆形图像视图。并选择此视图中出现的特定区域。我试过很多例子，但没有成功

public class ImageCropScreen extends Activity {
ImageView cropImage;
ImageView imageUser;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    requestWindowFeature(Window.FEATURE_NO_TITLE);
    setContentView(R.layout.image_crop_screen);

imageUser = (ImageView)findViewById(R.id.imageUser);
    Touch img = new Touch(this);
    img.setImageURI(Uri.parse(GetApplicationContext.getApplicationInstance().getImagePath()));
    img.setMaxZoom(4f);
    setContentView(img);

}

}

触摸类代码：-

公共类Touch扩展了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 Touch(Context context) {
    super(context);
    sharedConstructing(context);
}

public Touch(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();
}

矩阵；
//我们可能处于这三种状态之一
静态最终int NONE=0；
静态最终整数阻力=1；
静态最终整数缩放=2；
int模式=无；
//记住一些关于缩放的事情
PointF last=新的PointF（）；
PointF start=新的PointF（）；
浮动最小刻度=1f；
浮点最大刻度=3f；
浮动[]m；
int viewWidth，viewHeight；
静态最终int CLICK=3；
浮动存储比例=1f；
受保护的浮子起始宽度、起始高度；
int oldMeasuredWidth，oldMeasuredHeight；
scalegestruedetector mScaleDetector；
语境；
公众接触（上下文）{
超级（上下文）；
共享构造（上下文）；
}
公共接触（上下文、属性集属性）{
超级（上下文，attrs）；
共享构造（上下文）；
}
私有void共享构造（上下文）{
super.setClickable（true）；
this.context=上下文；
mScaleDetector=新的scalegestruedetector（上下文，新的ScaleListener（））；
矩阵=新矩阵（）；
m=新浮点数[9]；
setImageMatrix（矩阵）；
setScaleType（ScaleType.MATRIX）；
setOnTouchListener（新的OnTouchListener（）{
@凌驾
公共布尔onTouch（视图v，运动事件）{
mScaleDetector.onTouchEvent（事件）；
PointF curr=新的PointF（event.getX（），event.getY（））；
开关（event.getAction（））{
case MotionEvent.ACTION\u DOWN：
最后一组（当前）；
开始。设置（最后）；
模式=拖动；
打破
case MotionEvent.ACTION\u移动：
如果（模式==拖动）{
浮动deltaX=当前x-最后x；
浮动三角洲=当前y-最后y；
float Fixtranx=GetFixtragtrans（deltaX、viewWidth、，
原始宽度*保存比例）；
float fixTransY=GetFixtragtrans（deltaY、viewHeight、，
origHeight*保存比例）；
矩阵后翻译（fixtranx，fixtrany）；
fixTrans（）；
最后一组（当前x、当前y）；
}
打破
case MotionEvent.ACTION\u UP：
模式=无；
intxdiff=（int）Math.abs（curr.x-start.x）；
int yDiff=（int）Math.abs（curr.y-start.y）；
if（xDiff最大比例）{
saveScale=maxScale；
mScaleFactor=最大刻度/原始刻度；
}else if（保存比例<最小比例）{
saveScale=minScale；
mScaleFactor=最小刻度/原始刻度；
}
如果（origWidth*saveScale您可以使用以下自定义imageView..，它将实现您所需的所有功能

仔细阅读矩阵文档以及如何将其与画布对象一起使用向我们展示您已经尝试了什么？@Kanak sony我已经添加了代码我们是否应该运行您的代码来检查哪些工作正常，哪些不正常？您可以检查我的答案。我已经添加了belove..它具有您需要的功能。。