我正在使用以下代码来生成图像，该图像将会旋转，并通过捏合放大。用户可以通过拖动来定位。
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，通过捏合动作缩小图像。但根本没有轮换。如何获得旋转动作并获得旋转角度？
答案 0 :(得分：4)
尝试使用以下代码为我工作。
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;
}
//用于多点触控旋转图像。
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);
}