CODEWITHSUNDEEP
android
pankajagarwal
pankajagarwal

Reputation: 13582

Android onDraw called a large number of times

In the following snippet the onDraw method is called around 10-15 times. Can anyone explain this behaviour

LinearLayout ll = new LinearLayout(this);
        View v = new View(this) {
            @Override
            protected void onDraw(Canvas canvas) {
                // TODO Auto-generated method stub
                System.out.println("large view on draw called");
                super.onDraw(canvas);
            }
        };
        v.setLayoutParams(new LayoutParams(LayoutParams.FILL_PARENT, 2000));
        LinearLayout ll2 = new LinearLayout(this);
        ll2.addView(v);
        ScrollView sv = new ScrollView(this);
        sv.addView(ll2);
        ll.addView(sv);
        LinearLayout ll1 = new LinearLayout(this);
        ll1.addView(ll);

Upvotes: 2

Views: 3610

Answers (1)

CommonsWare
CommonsWare

Reputation: 1006604

Every time you do something that might affect a widget, the widget will be redrawn. Putting the widget in a container might affect it. Putting the container in another container might affect it.

You should be making no assumptions about how many times onDraw() will be called, other than that it will be called a lot and therefore needs to be fast.

Upvotes: 3

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