自定义视图中未调用onDraw（）

Question

I've already searched on Stackoverflow for a suitable answer but couldn't find anything that would help me.

I've got a Fragment which contains a ListView. This ListView should display an array of custom views. The problem is, that the custom views' onDraw() method won't be called. They get initialized but not drawn. Even forcing them to draw via invalidate() doesn't change anything. I've already tried to set

this.setWillNotDraw(true);

in the constructor, which didn't help. Any help would be appreciated.

Fragment

public static class CustomFragment extends Fragment {

        private ListView list;

        @Override
        public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
            final View rootView = inflater.inflate(R.layout.fragment, container, false);
            list = (ListView)rootView.findViewById(R.id.fragment_list);
            list.setAdapter(new CustomAdapter(getActivity(), R.layout.list_item, somevalues));
            return rootView;
        }
    }

Custom View

    public class CustomView extends View {

    public static final String TAG = "CustomView";

    public CustomView(Context context) {
        super(context);
        init();
    }

    public CustomView(Context context, AttributeSet attrs) {
        super(context, attrs);
        init();
    }

    public CustomView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        init();
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        Log.d(TAG, "Measuring and storing dimensions");
    }

    public void init() {
        Log.d(TAG, "Initializing CustomView");
        this.setWillNotDraw(false);
        invalidate();
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        Log.d(TAG, "OnDraw called");
    }
}

Custom Adapter

public static class CustomAdapter extends ArrayAdapter<String> {
        private String[] values;
        private Context context;
        private int resource;

        public CustomAdapter(Context context, int resource, String[] values) {
            super(context, resource, values);
            this.values = values;
            this.context = context;
            this.resource = resource;
        }

        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            LayoutInflater inflater = (LayoutInflater)context.getSystemService(LAYOUT_INFLATER_SERVICE);
            View rowView = inflater.inflate(resource, parent, false);
            CustomView cView = (CustomView)rowView.findViewById(R.id.cview);
            cView.setColors(values);
            return rowView;
        }
    }

Answer 1

您应该在init方法中设置setWillNotDraw（false）。