A single virtual joystick Development

Mainly primary des three parts, respectively is the calling class, touch handler class, utility class.

Touch handler class:Appsinglerocker

Package com. seuic;

Import com. seuic. util. mathutils;

Import Android. content. context;
Import Android. Graphics. Canvas;
Import Android. Graphics. color;
Import Android. Graphics. paint;
Import Android. Graphics. pixelformat;
Import Android. Graphics. Point;
Import Android. Graphics. porterduff. mode;
Import Android. View. motionevent;
Import Android. View. surfaceholder;
Import Android. View. surfaceview;
Import Android. View. surfaceholder. Callback;

Public class appsinglerocker extends surfaceview implements callback {

Private surfaceholder mholder;
Private paint mpaint;
Public point mrockerposition; // rocker position
Private point mctrlpoint = new point (80, 80); // rocker starting position
Private int mrudderradius = 20; // Rocker Arm radius
Private int mwheelradius = 60; // rocker range radius

Int ishide = 0;
Private singlerudderlistener listener = NULL; // Event Callback Interface
Public static final int action_rudder = 1, action_attack_devicemove = 2, action_stop = 3, action_attack_cameramove = 4;
Public javasinglerocker (context ){
Super (context );
This. setkeepscreenon (true );
Mholder = getholder ();
Mholder. addcallback (this );
Mpaint = new paint ();
Mpaint. setcolor (color. Green );
Mpaint. setantialias (true); // anti-aliasing
Mrockerposition = new point (mctrlpoint );
Setfocusable (true );
Setfocusableintouchmode (true );
Setzorderontop (true );
Mholder. setformat (pixelformat. Transparent); // sets the background transparency.
}

// Callback Interface
Public interface singlerudderlistener {
Void onsteeringwheelchanged (INT action, int angle );
}

// Set the callback Interface
Public void setsinglerudderlistener (singlerudderlistener rockerlistener ){
Listener = rockerlistener;
}

Int Len;
@ Override
Public Boolean ontouchevent (motionevent event ){
Try {
If (ishide = 0 ){
Switch (event. getaction ()){
Case motionevent. action_down:
Len = mathutils. getlength (mctrlpoint. X, mctrlpoint. Y, event. getx (), event. Gety ());
// If the screen contact point is not within the rocker wave range, do not process it
If (LEN> mwheelradius ){
Return true;
}
Break;
Case motionevent. action_move:
Len = mathutils. getlength (mctrlpoint. X, mctrlpoint. Y, event. getx (), event. Gety ());
If (LEN <= mwheelradius ){
// If the finger is in the active range of the joystick, the joystick is in the touch position of the finger
Mrockerposition. Set (INT) event. getx (), (INT) event. Gety ());

} Else {
// Set the joystick position so that it is at the edge of the Active range of the joystick in the direction of the finger touch
Mrockerposition = mathutils. getborderpoint (mctrlpoint, new point (INT) event. getx (), (INT) event. Gety (), mwheelradius );
}
If (listener! = NULL ){
Float radian = mathutils. getradian (mctrlpoint, new point (INT) event. getx (), (INT) event. Gety ()));
Listener. onsteeringwheelchanged (action_rudder, getanglecouvert (radian ));
}
Break;
Case motionevent. action_up:
Mrockerposition = new point (mctrlpoint );
Listener. onsteeringwheelchanged (action_stop, 0 );
Break;
}
Canvas_ OK ();
Thread. Sleep (60 );
} Else {
Thread. Sleep (200 );
}
} Catch (exception e ){

}
Return true;
}

// Obtain the joystick offset from 0 to °.
Private int getanglecouvert (float radian ){
Int TMP = (INT) math. Round (radian/Math. Pi * 180 );
If (TMP <0 ){
Return-TMP;
} Else {
Return 180 + (180-TMP );
}
}

Public void surfacecreated (surfaceholder holder ){
Canvas_ OK ();
}

Public void surfacechanged (surfaceholder holder, int format, int width,
Int height ){

}

Public void surfacedestroyed (surfaceholder holder ){

}
// Set whether to hide
Public void hided (int opt)
{
Ishide = OPT;
Canvas_ OK ();
}
 
// Draw the image
Public void canvas_ OK (){
Canvas canvas = NULL;
Try {
Canvas = mholder. lockcanvas ();
Canvas. drawcolor (color. Transparent, mode. Clear); // clear the screen
Mpaint. setcolor (color. Cyan );
Mpaint. setalpha (100 );
Canvas. drawcircle (mctrlpoint. X, mctrlpoint. Y, mwheelradius, mpaint); // draw range
Mpaint. setcolor (color. Red );
Mpaint. setalpha (100 );
Canvas. drawcircle (mrockerposition. X, mrockerposition. Y, mrudderradius, mpaint); // draw the joystick
} Catch (exception e ){
E. printstacktrace ();
} Finally {
If (canvas! = NULL ){
Mholder. unlockcanvasandpost (canvas );
}
}
}

}

 

Utility Class:Mathutils

Package com. seuic. util;

Import Android. Graphics. Point;
Public class mathutils {
// Obtain the linear distance between two points
Public static int getlength (float X1, float Y1, float X2, float Y2 ){
Return (INT) math. SQRT (math. Pow (x1-x2, 2) + math. Pow (y1-y2, 2 ));
}
/**
* Obtains the coordinates of a point on a line segment. The length is A. X-cutradius.
* @ Param A:
* @ Param B point B
* @ Param cutradius truncation distance
* @ Return truncation point
*/
Public static point getborderpoint (point a, point B, int cutradius ){
Float radian = getradian (A, B );
Return new point (. X + (INT) (cutradius * Math. cos (radian),. X + (INT) (cutradius * Math. sin (radian )));
}

// Obtain the angle radians of the horizontal line
Public static float getradian (point a, point B ){
Float Lena = B. x-a.x;
Float lenb = B. y-a.y;
Float lenc = (float) math. SQRT (Lena * Lena + lenb * lenb );
Float ang = (float) math. ACOs (Lena/lenc );
Ang = ang * (B. Y <A. Y? -1: 1 );
Return Ang;
}
}

Calling class:Singlerocker

Package com. seuic;

Import com. seuic. appsinglerocker. singlerudderlistener;

Import Android. OS. Bundle;
Import Android. util. log;
Import Android. widget. relativelayout;
Import Android. App. activity;

Public class singlerocker extends activity {
 
Relativelayout parent;
Appsinglerocker;
Public static final string main = "singlerocker ";
@ Override
Protected void oncreate (bundle savedinstancestate ){
Super. oncreate (savedinstancestate );
Parent = new relativelayout (this );
Relativelayout. layoutparams rockercanvasparams = new relativelayout. layoutparams (160,160 );
Rockercanvasparams. addrule (relativelayout. center_vertical );
Appsinglerocker = new appsinglerocker (this );
Parent. addview (appsinglerocker, rockercanvasparams );
Setcontentview (parent );
Appsinglerocker. setsinglerudderlistener (New singlerudderlistener (){

@ Override
Public void onsteeringwheelchanged (INT action, int angle ){
Log. E (main, angle + "");
}
});
}

}

 

 

Source Address:

Http://download.csdn.net/download/jwzhangjie/5184324