在代码中动态设置selector

class MyButton extends View {

public MyButton(Context context) {
super(context);
}

// 以下这个方法也可以把你的图片数组传过来，以StateListDrawable来设置图片状态，来表现button的各中状态。未选
// 中，按下，选中效果。
public StateListDrawable setbg(Integer[] mImageIds) {
StateListDrawable bg = new StateListDrawable();
Drawable normal = this.getResources().getDrawable(mImageIds[0]);
Drawable selected = this.getResources().getDrawable(mImageIds[1]);
Drawable pressed = this.getResources().getDrawable(mImageIds[2]);
bg.addState(View.PRESSED_ENABLED_STATE_SET, pressed);
bg.addState(View.ENABLED_FOCUSED_STATE_SET, selected);
bg.addState(View.ENABLED_STATE_SET, normal);
bg.addState(View.FOCUSED_STATE_SET, selected);
bg.addState(View.EMPTY_STATE_SET, normal);
return bg;
}
}

Integer[] mButtonState = { R.drawable.defaultbutton,
R.drawable.focusedpressed, R.drawable.pressed };
Button mButton = (Button) findViewById(R.id.button);
MyButton myButton = new MyButton(this);
mButton.setBackgroundDrawable(myButton.setbg(mButtonState));