如何将颜色过滤器应用于StateListDrawable中的特定drawable？

Question

似乎StateListDrawable将忽略应用于它们包含的drawable的颜色过滤器.例如:

StateListDrawable sld = new StateListDrawable();
Drawable pressedState = Context.getResources().getDrawable(R.drawable.solid_green);

pressedState.setColorFilter(Color.RED, PorterDuff.Mode.SRC);

sld.addState(new int[] {android.R.attr.state_pressed}, pressedState);
// Other states...

如果应用于sld视图的背景,则可以预期视图的背景在按下时会变为红色.相反,它会变成绿色 - pressedState没有应用过滤器的颜色.

Answer 1

要解决此问题,您必须StateListDrawable根据drawable所处的状态将颜色过滤器应用于自身.以下扩展将StateListDrawable完成此操作.

public class SelectorDrawable extends StateListDrawable {

    public SelectorDrawable(Context c) {
        super();

        addState(new int[] {android.R.attr.state_pressed}, c.getResources().getDrawable(R.drawable.solid_green));
        // Other states...
    }

    @Override
    protected boolean onStateChange(int[] states) {
        boolean isClicked = false;
        for (int state : states) {
            if (state == android.R.attr.state_pressed) {
                isClicked = true;
            }
        }

        if (isClicked)
            setColorFilter(Color.RED, PorterDuff.Mode.SRC);
        else
            clearColorFilter();

        return super.onStateChange(states);
    }
}

逻辑输入onStateChange(int[] states)可以进一步扩展以测试不仅仅是按下状态,并且可以相应地应用不同的滤色器.