CODEWITHSUNDEEP
javaandroidondraw
AdriSer
AdriSer

Reputation: 1

Invalidate() method on onDraw in android

I'm doing a project in android studio. I just want to do a flashing light point using onDraw() and invalidate() but something is wrong.

This is the first class

public class flashingPoint extends View {

    private ShapeDrawable mParteDibujable;

    public flashingPoint(Context context){

        super(context);

        final Handler bridge = new Handler();

        Thread time = new Thread() {

            public void run() {

                bridge.postDelayed(this, 1000);
                invalidate();

            }

        };
        time.start();

        }
    @Override
    protected void onDraw(Canvas canvas) {
        mParteDibujable = new ShapeDrawable(new OvalShape());
        mParteDibujable.getPaint().setColor(0xff74AC23);
        mParteDibujable.setBounds(10, 20, 80, 80);

        mParteDibujable.draw(canvas);
        //invalidate();

    }

And then the main class:

public class MainActivity extends AppCompatActivity {

    private ShapeDrawable mParteDibujable;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        LinearLayout mLinearLayout = new LinearLayout(this);

        flashingPoint myView = new flashingpoint(this);
        mLinearLayout.addView(myView);

        setContentView(mLinearLayout);

    }
}

Upvotes: 0

Views: 636

Answers (1)

Gabe Sechan
Gabe Sechan

Reputation: 93551

If you have the timer, you neither need nor want the invalidate in onDraw. Invalidating in onDraw is both logically weird and will lead to poor results- it would either be ignored, or it would cause an immediate redraw. Neither is desired.

Also, you can't invalidate on a Thread, you'd need to use postInvalidate. And your thread is wrong- either don't use a thread, use a Runnable and post it to the Handler, or the thread should infinitely loop, not return. Preferably the first, there's no reason to have a thread here at all.

Upvotes: 3

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