android - I want to follow the path of drawing dynamic curve,how to solve it? -

1、here chart:

2、here code:

private void drawcircle( canvas canvas, string content ){     mpath.addcircle(getwidth() / 2, getheight() / 2, mradius, direction.ccw);     canvas.rotate(180, getwidth() / 2, getheight() / 2);     canvas.drawtextonpath(content, mpath, 0, 0, mpaint); } 

3、my problem how let circle 1 point 1 point display，not one-time display。i'm try use handler/thread/timer draw dynamic chart drawtextonpath , drawpath method, there show nothing.

you need use postdelayed() , add new character each time.

public class myview extends view {      private path mpath = new path();     private float mradius = 100;     private paint mpaint = new paint();     private string thewholetext = "abcdefghijklmnopqrstuvwxyz";     private string thecurrenttext = "";     private int = 0;     private long frequency = 150;     private runnable addcharacter = new runnable() {         @override         public void run() {             thecurrenttext = thewholetext.substring(0, ++i);             invalidate();         }     };      public myview(context context, attributeset attrs, int defstyleattr) {         super(context, attrs, defstyleattr);         mpaint.setcolor(color.red);         mpaint.settextsize(20);     }      public myview(context context, attributeset attrs) {         this(context, attrs, 0);     }      public myview(context context) {         this(context, null, 0);     }      private void drawcircle(canvas canvas, string content) {         mpath.addcircle(getwidth() / 2, getheight() / 2, mradius, path.direction.ccw);         canvas.rotate(180, getwidth() / 2, getheight() / 2);         canvas.drawtextonpath(content, mpath, 0, 0, mpaint);     }      @override     protected void ondraw(canvas canvas) {         drawcircle(canvas, thecurrenttext);         if (thecurrenttext.length() < thewholetext.length())             postdelayed(addcharacter, frequency);     } } 

please mark correct answer if works out you!