Zoom-in and zoom-out of android Images

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All the code. <喎?http: www.bkjia.com kf ware vc " target="_blank" class="keylink"> VcD4KPHA + PHByZSBjbGFzcz0 = "brush: java;"> public class MainActivity extends Activity {private ImageView imageView; @ Override public void onCreate (Bundle savedInstanceState) {super. onCreate (savedInstanceState); setContentView (R. layout. activity_main); imageView = (ImageView) findViewById (R. id. imageView); imageView. setOnTouchListener (new OnTouchListener () {// set the start point private PointF startPoint = new PointF (); // set the conversion Matrix private matrix Matrix = new Matrix () of the image position (); // set the transformation Matrix private Matrix currentMatrix = new Matrix () for the current position of the image; // The initialization mode parameter private int mode = 0; // non-mode private static final int NONE = 0; // DRAG mode private static final int DRAG = 1; // scaling mode private static final int ZOOM = 2; // enable the threshold for scaling effect: private static final float ZOOM_THRESHOLD = 10.0f; // start from private float startDistance; // center point private PointF middlePoint; @ Override public boolean onTouch (View v, motionEvent) {switch (event. getAction () & MotionEvent. ACTION_MASK) {case MotionEvent. ACTION_DOWN: mode = DRAG; // record the current position of the image currentMatrix. set (imageView. getImageMatrix (); // record the start coordinate startPoint. set (event. getX (), event. getY (); break; // This event case MotionEvent is triggered when there are contacts (fingers) on the screen and another finger is pressed. ACTION_POINTER_DOWN: mode = ZOOM; // get the distance between two points: startDistance = getDistance (event); // if it is greater than if (startDistance> ZOOM_THRESHOLD) {// obtain the middle point of the two points middlePoint = getMiddlePoint (event); // record the current scaling ratio of the image currentMatrix. set (imageView. getImageMatrix ();} break; case MotionEvent. ACTION_MOVE: if (mode = DRAG) {// obtain the moving distance from the X axis to float distanceX = event. getX ()-startPoint. x; // obtain the moving distance from the Y axis to float distanceY = event. getY ()-startPoint. y; // move the matrix based on the last stop position. set (currentMatrix); // moves the matrix to the image position. postTranslate (distanceX, distanceY);} else if (mode = ZOOM) {// The end distance from float endDistance = getDistance (event); if (endDistance> ZOOM_THRESHOLD) {// float scale = endDistance/startDistance; matrix. set (currentMatrix); matrix. postScale (scale, scale, middlePoint. x, middlePoint. y) ;}} break; case MotionEvent. ACTION_UP: // This event case MotionEvent is triggered when the finger leaves the screen but there are other contacts on the screen. ACTION_POINTER_UP: mode = 0; break;} imageView. setImageMatrix (matrix); return true ;}});}/*** calculate the distance between two points */public static float getDistance (MotionEvent event) {// The second vertex x and y minus the first vertex x and y coordinate float disX = event. getX (1)-event. getX (0); float disY = event. getY (1)-event. getY (0); return FloatMath. sqrt (disX * disX + disY * disY);}/*** calculate the intermediate point between two points */public static PointF getMiddlePoint (MotionEvent event) {float midX = (event. getX (0) + event. getX (1)/2; float midY = (event. getY (0) + event. getY (1)/2; return new PointF (midX, midY );}}