Android ImageView 缩放、旋转、位置变化问题

Question

我正在使用以下代码来制作图像，该图像将旋转，捏合放大。用户可以通过拖动来确定其位置。

activity_img_match.xml

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_weight="1"
        android:background="@drawable/brokenbone"
        android:gravity="center_vertical|center_horizontal" >

        <ImageView
            android:id="@+id/bonestruct"
            android:layout_width="fill_parent"
            android:layout_height="fill_parent"
            android:scaleType="matrix"
            android:src="@drawable/bone" />
    </FrameLayout>

ImgMatchActivity.java

    public class ImgMatchActivity extends Activity implements OnTouchListener {

    private static final String TAG = "Touch";
    // These matrices will be used to move and zoom image
    Matrix matrix = new Matrix();
    Matrix savedMatrix = new Matrix();
    Matrix savedMatrix2 = 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;
    private static final float MAX_ZOOM = 5.0f;
    private static final float MIN_ZOOM = 0.15f;
    int mode = NONE;

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

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_img_match);

        ImageView bonestruct = (ImageView) findViewById(R.id.bonestruct);
        bonestruct.setOnTouchListener(this);

    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.activity_img_match, menu);
        return true;
    }

    public boolean onTouch(View selectedView, MotionEvent event) {
        // TODO Auto-generated method stub
        ImageView view = (ImageView) selectedView;
        int rotation = 25;
        // Dump touch event to log
        dumpEvent(event);

        // Handle touch events here...
        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_UP:

            mode = NONE;
            Log.d(TAG, "mode=NONE");
            savedMatrix.set(matrix);
            //matrix.postRotate(90);

            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;
        }

        view.setImageMatrix(matrix);
        fixing();
        view.setImageMatrix(savedMatrix2);

        return true; // indicate event was handled

    }

    public void fixing() {

        float[] value = new float[9];
        matrix.getValues(value);

        float[] savedValue = new float[9];
        savedMatrix.getValues(savedValue);

        WindowManager mWinMgr = (WindowManager) getApplicationContext().getSystemService(Context.WINDOW_SERVICE);
        int width = mWinMgr.getDefaultDisplay().getWidth();
        int height = mWinMgr.getDefaultDisplay().getHeight();

        Drawable d = this.getResources().getDrawable(R.drawable.bone);
        if (d == null)
            return;
        int imageWidth = d.getIntrinsicWidth();
        int imageHeight = d.getIntrinsicHeight();
        int scaleWidth = (int) (imageWidth * value[0]);
        int scaleHeight = (int) (imageHeight * value[4]);

        // don't let the image go outside
        if (value[2] > width - 1)
            value[2] = width - 10;
        else if (value[5] > height - 1)
            value[5] = height - 10;
        else if (value[2] < -(scaleWidth - 1))
            value[2] = -(scaleWidth - 10);
        else if (value[5] < -(scaleHeight - 1))
            value[5] = -(scaleHeight - 10);

        //Log.d("value[0]", "value[0]: "+value[0]);
        //Log.d("value[4]", "value[4]: "+value[4]);

        // maximum zoom ratio: MAX
        if (value[0] > MAX_ZOOM || value[4] > MAX_ZOOM) {
            value[0] = MAX_ZOOM;
            value[4] = MAX_ZOOM;
            // value[2] = savedValue[2];
            // value[5] = savedValue[5];
        }

        // minimum zoom ratio: MIN
        /*if (value[0] < MIN_ZOOM || value[4] < MIN_ZOOM) {
            value[0] = MIN_ZOOM;
            value[4] = MIN_ZOOM;
            // value[2] = savedValue[2];
            // value[5] = savedValue[5];
        }*/

        matrix.setValues(value);
        savedMatrix2.set(matrix);
    }

    /** Show an event in the LogCat view, for debugging */
    private void dumpEvent(MotionEvent event) {
        String names[] = { "DOWN", "UP", "MOVE", "CANCEL", "OUTSIDE",
                "POINTER_DOWN", "POINTER_UP", "7?", "8?", "9?" };
        StringBuilder sb = new StringBuilder();
        int action = event.getAction();
        int actionCode = action & MotionEvent.ACTION_MASK;
        sb.append("event ACTION_").append(names[actionCode]);
        if (actionCode == MotionEvent.ACTION_POINTER_DOWN
                || actionCode == MotionEvent.ACTION_POINTER_UP) {
            sb.append("(pid ").append(
                    action >> MotionEvent.ACTION_POINTER_ID_SHIFT);
            sb.append(")");
        }
        sb.append("[");
        for (int i = 0; i < event.getPointerCount(); i++) {
            sb.append("#").append(i);
            sb.append("(pid ").append(event.getPointerId(i));
            sb.append(")=").append((int) event.getX(i));
            sb.append(",").append((int) event.getY(i));
            if (i + 1 < event.getPointerCount())
                sb.append(";");
        }
        sb.append("]");
        Log.d(TAG, sb.toString());
    }

    /** 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);
    }

}

现在我可以拖动图像，通过捏合操作将其缩小。但是根本没有旋转。如何获得旋转动作并获得旋转角度？

Answer 1

试试下面的代码，它对我有用。

float[] lastEvent = null;
float d = 0f;
float newRot = 0f;

 public boolean onTouch(View v, MotionEvent event) {
            ImageView view = (ImageView) v;

            // 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;
                lastEvent = null;
                break;
            case MotionEvent.ACTION_POINTER_DOWN:
                oldDist = spacing(event);
                if (oldDist > 10f) {
                    savedMatrix.set(matrix);
                    midPoint(mid, event);
                    mode = ZOOM;
                }
                lastEvent = new float[4];
                lastEvent[0] = event.getX(0);
                lastEvent[1] = event.getX(1);
                lastEvent[2] = event.getY(0);
                lastEvent[3] = event.getY(1);
                d = rotation(event);
                break;
            case MotionEvent.ACTION_UP:
            case MotionEvent.ACTION_POINTER_UP:
                mode = NONE;
                lastEvent = null;
                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 && event.getPointerCount() == 2) {
                    float newDist = spacing(event);
                    matrix.set(savedMatrix);
                    if (newDist > 10f) {
                        float scale = newDist / oldDist;
                        matrix.postScale(scale, scale, mid.x, mid.y);
                    }
                    if (lastEvent != null) {
                        newRot = rotation(event);
                        float r = newRot - d;
                        matrix.postRotate(r, view.getMeasuredWidth() / 2,
                                view.getMeasuredHeight() / 2);
                    }
                }
                break;
            }

            view.setImageMatrix(matrix);

            return true;
        }

//用于在多点触控时旋转图像。

private float rotation(MotionEvent event) {
        double delta_x = (event.getX(0) - event.getX(1));
        double delta_y = (event.getY(0) - event.getY(1));
        double radians = Math.atan2(delta_y, delta_x);

        return (float) Math.toDegrees(radians);
    }