Android camera autofocus with touch focus implementation

1. Auto Focus

In the Param set before and after the preview Setfocusmode (); for Camera.Parameters.FOCUS_MODE_CONTINUOUS_VIDEO or Camera.Parameters.FOCUS_MODE_AUTO , it is recommended that the latter be used. Note When this method is called, calling Camera.autofocus () again causes the focus to fail

Refer to this article http://blog.csdn.net/yanzi1225627/article/details/8577682

2. Touch Focus

Touch focus needs to cancel the previously set focus before setting the focus.

Reference article http://stackoverflow.com/a/19272166

    /** * On each tap event we'll calculate focus area and metering area.     * <p/> * Metering area are slightly larger as it should contain more info for exposure calculation. * As it is very easy to over/under expose */public void Focusontouch (Motionevent event) {if (Camera_! = Nu            LL) {//cancel previous Actions camera_.cancelautofocus ();            Rect focusrect = Calculatetaparea (Event.getx (), Event.gety (), 1f);            Rect meteringrect = Calculatetaparea (Event.getx (), Event.gety (), 1.5f);            Camera.parameters Parameters = null;            try {parameters = Camera_.getparameters ();            } catch (Exception e) {e.printstacktrace ();            }//Check if parameters is set (handle Runtimeexception:getparameters failed (empty parameters))                if (Parameters! = null) {Parameters.setfocusmode (Camera.Parameters.FOCUS_MODE_AUTO); IF (Build.VERSION.SDK_INT >= build.version_codes.                    Ice_cream_sandwich) {list<camera.area> focus = new arraylist<> ();                    Focus.add (New Camera.area (Focusrect, 1000));                    Parameters.setfocusareas (focus); if (Parameters.getmaxnummeteringareas () > 0) {list<camera.area> metering = new arraylist&                        Lt;> ();                        Metering.add (New Camera.area (Focusrect, 1000));                    Parameters.setmeteringareas (metering);                    }} try {camera_.setparameters (parameters); Camera_.autofocus (New Camera.autofocuscallback () {@Override public void OnA                Utofocus (Boolean success, Camera camera) {}});                } catch (Exception e) {e.printstacktrace ();          }  }}} private int focusareasize = 300;     /** * Convert Touch position x:y to {@link Camera.area} position-1000:-1000 to 1000:1000. * <p/> * Rotate, scale and translate touch rectangle using the matrix configured in * {@link surfaceholder.callb Ack#surfacechanged (android.view.SurfaceHolder, int, int, int)} */Private Rect Calculatetaparea (float x, float y, F        Loat coefficient) {int areasize = float.valueof (focusareasize * coefficient). Intvalue ();        int left = clamp ((int) X-AREASIZE/2, 0, Surfaceview_.getwidth ()-areasize);        int top = clamp ((int) Y-AREASIZE/2, 0, Surfaceview_.getheight ()-areasize);        RECTF RECTF = new RECTF (left, top, left + areasize, top + areasize);        (New Matrix ()). Maprect (RECTF);    return new Rect (Math.Round (Rectf.left), Math.Round (Rectf.top), Math.Round (Rectf.right), Math.Round (Rectf.bottom)); } private int clamp (int x, int min, int max) {if (x > Max) {reTurn Max;        } if (x < min) {return min;    } return x; }

　　

Android camera autofocus with touch focus implementation