Android：在缩放后找到ImageView上的绝对点击位置（使用矩阵布局使用捏合缩放）

我正在使用 Hello Android，第 3 版中的代码来实现捏合缩放功能。使用此功能后，捏合缩放工作正常，但缩放后我想获得图像视图上的绝对单击位置。

这是我的代码

package org.example.touch;
import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.Matrix;
import android.graphics.PointF;
import android.os.Bundle;
import android.util.FloatMath;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;
import android.widget.GridView;
import android.widget.ImageView;

public class Touch extends Activity implements OnTouchListener {
private static final String TAG = "Touch";

private static final float MIN_ZOOM = 1.0f;
private static final float MAX_ZOOM = 5.0f;

// These matrices will be used to move and zoom image
Matrix matrix = new Matrix();
Matrix savedMatrix = 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;
int mode = NONE;

// Remember some things for zooming
PointF start = new PointF();
PointF mid = new PointF();
float oldDist = 1f;

ImageView image2;
image2 = (ImageView)this.findViewById(R.id.imageView2);
image2.setOnTouchListener(new OnTouchListener() {

                public boolean onTouch(View v, MotionEvent event) {

                     ImageView view = (ImageView) image2;
                      // Handle touch events here...
                        switch (event.getAction() & MotionEvent.ACTION_MASK) {
                        case MotionEvent.ACTION_DOWN:
                            savedMatrix.set(matrix);
                            start.set(event.getX(), event.getY());
                            mode = DRAG;
                            break;
                        case MotionEvent.ACTION_POINTER_DOWN:
                            oldDist = spacing(event);
                            if (oldDist > 10f) {
                                savedMatrix.set(matrix);
                                midPoint(mid, event);
                                mode = ZOOM;
                            }
                            break;
                        case MotionEvent.ACTION_UP:
                        case MotionEvent.ACTION_POINTER_UP:
                            mode = NONE;
                            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);
                                if (newDist > 10f) {
                                    matrix.set(savedMatrix);
                                    float scale = newDist / oldDist;
                                    matrix.postScale(scale, scale, mid.x, mid.y);
                                }
                            }
                            break;
                        }
                        view.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 FloatMath.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);
        }

您可以使用当前应用于图像视图的矩阵将点映射到原始默认点或从原始默认点映射点。

//points from a touch/click event on the zoomed/translated imageview
float X;
float Y;

float initialPoints = new float[]{X, Y};

//invert the matrix and map points back
    if(transformMatrix.invert(inverseTransformMatrix))
            inverseTransformMatrix.mapPoints(initialFocalPoints);

initialPoints现在包含原始点，即如果没有将矩阵应用于图像视图，则单击点所在的位置

EDIT：应该在某个地方添加这个，这样你就知道它们是什么。

Matrix inverseTransformMatrix = new Matrix();
Matrix transformMatrix = new Matrix();