java - Static Methods in Android -

im try create drawing app. in main activity have xml file contains drawing viewview

<app.color.drawingview     android:layout_width="match_parent"     android:layout_height="200dp"     android:id="@+id/drawing"     android:layout_marginleft="5dp"     android:layout_marginright="5dp"     android:background="#ffffffff"     android:layout_above="@+id/settings"     android:layout_alignparenttop="true" /> 

this based on drawing view class:

package app.color;  import android.content.context; import android.graphics.canvas; import android.graphics.color; import android.graphics.paint; import android.graphics.path; import android.util.attributeset; import android.view.motionevent; import android.view.view;  public class drawingview extends view {     private paint paint = new paint();     private path path = new path();      public drawingview(context context, attributeset attrs) {         super(context, attrs);          paint.setantialias(true);         paint.setstrokewidth(5f);         paint.setcolor(color.black);         paint.setstyle(paint.style.stroke);         paint.setstrokejoin(paint.join.round);     }      @override     protected void ondraw(canvas canvas) {         canvas.drawpath(path, paint);     }      @override     public boolean ontouchevent(motionevent event) {         // coordinates of touch event.         float eventx = event.getx();         float eventy = event.gety();          switch (event.getaction()) {             case motionevent.action_down:                 // set new starting point                 path.moveto(eventx,      return true;             case motionevent.action_move:                 // connect points                 path.lineto(eventx, eventy);                 break;             default:                 return false;         }          // makes our view repaint , call ondraw         invalidate();         return true;     }      public void setcolor(string newcolor){         invalidate();         int paintcolor = color.parsecolor(newcolor);         paint.setcolor(paintcolor);     } } 

then in activity on button click have method which want able call setcolor method in drawingview change color. wont let me because "non-static method cannot referenced static context"

public void toblack(view view) {     drawingview.setcolor("#00000");     intent intent = new intent(colors.this, mainactivity.class);     startactivity(intent); }  

create instance of drawingview.

thats ,

drawingview drawingview = new drawingview(); drawingview.setcolor("#00000"); 

setcolor instance method, meaning need instance of drawingview class in order call it. you're attempting call on drawingview type itself.

just make code to

drawingview dv = new drawingview();  dv.setcolor("#00000"); intent intent = new intent(colors.this, mainactivity.class); startactivity(intent); 

for example have

public drawingview(context context, attributeset attrs) {     super(context, attrs);      paint.setantialias(true);     paint.setstrokewidth(5f);     paint.setcolor(color.black);     paint.setstyle(paint.style.stroke);     paint.setstrokejoin(paint.join.round); } 

you can have empty constructor like

public drawingview() { }