iOS uses Cgcontextref to draw a line chart dynamically

-(void) DrawRect: (cgrect) Rect {cgcontextref context = Uigraphicsgetcurrentcontext ();    Cgcontextclearrect (context, rect);                                 Cgcontextsetlinewidth (context, _linewidth);  Set Brush width cgcontextsetfillcolorwithcolor (context, [[self backgroundcolor] cgcolor]);                                           Sets the background fill color cgcontextfillrect (context, rect);              Fill background cgcontextsetstrokecolorwithcolor (context, _linecolor.cgcolor);            Sets the brush color//arr for real-time obtained Dynamic Data array for (int i = 0; i < _arr.count; i + +) {if (I < _arr.count-1) {            Cgpoint pp[2];            [_arr[i] getbytes:&pp[0] length:sizeof (cgpoint)];                        [_arr[i+1] getbytes:&pp[1] length:sizeof (cgpoint)];            Cgcontextmovetopoint (context, pp[0].x, pp[0].y);            Cgcontextaddlinetopoint (context, pp[1].x, pp[1].y);        Cgcontextstrokepath (context); }}}-(void) Adddatatoarr: (cgfloat) Data {if (!_arr) _arR = [[Nsmutablearray alloc] init];    Cgpoint Point; Max_x_count represents the maximum number displayed on the x-axis, moving the x-axis to the left, moving one unit at a time (_arr.count >= max_x_count) {//moving x-axis CGRect frame =        Self.frame;        Frame.origin.x-= (Self.frame.size.width/max_x_count);        Frame.size.width + = (self.frame.size.width/max_x_count);    Self.frame = frame;        } point.x = _arr.count * (self.frame.size.width/max_x_count); If the current value is greater than the maximum value represented by the y-axis, expand the y-axis maximum to twice times the current value if (Data > _maxypower) {//change the maximum value of y to currentpower _maxypower = data    * 2;        } point.y = data; Depositing data in real time into _arr [_arr addobject:[nsdata datawithbytes:&point length:sizeof (Cgpoint)]];}

Just call Adddatatoarr dynamically: Then call [Self.view Setneeddisplay] to

iOS uses Cgcontextref to draw a line chart dynamically