android - 结合 StateListDrawable 和 LevelListDrawable

Question

有没有办法结合 StateListDrawable 和 LevelListDrawable 的效果？

我写了这个资源文件，但是在使用时什么也没有出现:

<?xml version="1.0" encoding="utf-8"?>
<level-list xmlns:android="http://schemas.android.com/apk/res/android">
        <selector
                android:constantSize="true"
                android:variablePadding="false"
                android:maxLevel="0"
                >
                <item android:state_pressed="true">
                        <layer-list>
                                <item android:drawable="@drawable/btu_color_standard" />
                                <item android:drawable="@drawable/btu_shade_pressed" />
                        </layer-list>
                </item>
                <item android:state_focused="true">
                        <layer-list>
                                <item android:drawable="@drawable/btu_color_standard" />
                                <item android:drawable="@drawable/btu_shade_selected" />
                        </layer-list>
                </item>
                <item>
                        <layer-list>
                                <item android:drawable="@drawable/btu_color_standard" />
                                <item android:drawable="@drawable/btu_shade_normal" />
                        </layer-list>
                </item>
        </selector>
        <selector
                android:constantSize="true"
                android:variablePadding="false"
                android:maxLevel="1"
                >
                <item android:state_pressed="true">
                        <layer-list>
                                <item android:drawable="@drawable/btu_color_standard" />
                                <item android:drawable="@drawable/btu_lighted" />
                                <item android:drawable="@drawable/btu_shade_pressed" />
                        </layer-list>
                </item>
                <item android:state_focused="true">
                        <layer-list>
                                <item android:drawable="@drawable/btu_color_standard" />
                                <item android:drawable="@drawable/btu_lighted" />
                                <item android:drawable="@drawable/btu_shade_selected" />
                        </layer-list>
                </item>
                <item>
                        <layer-list>
                                <item android:drawable="@drawable/btu_color_standard" />
                                <item android:drawable="@drawable/btu_lighted" />
                                <item android:drawable="@drawable/btu_shade_normal" />
                        </layer-list>
                </item>
        </selector>
</level-list>

然后我打电话

_btn.getBackground().setLevel(level); //level is either 0 or 1

更改可绘制对象的级别(顺便说一句，_btn 是一个按钮)。

为什么它不起作用？

提前致谢。

Answer 1

自己找到解决方案: 元素必须包含在 元素中:

<?xml version="1.0" encoding="utf-8"?>
<level-list xmlns:android="http://schemas.android.com/apk/res/android">
        <item
                android:maxLevel="0"
                >
                <selector
                        android:constantSize="true"
                        android:variablePadding="false"
                        >
                        <item android:state_pressed="true">
                                <layer-list>
                                        <item android:drawable="@drawable/btu_color_standard" />
                                        <item android:drawable="@drawable/btu_shade_pressed" />
                                </layer-list>
                        </item>
                        <item android:state_focused="true">
                                <layer-list>
                                        <item android:drawable="@drawable/btu_color_standard" />
                                        <item android:drawable="@drawable/btu_shade_selected" />
                                </layer-list>
                        </item>
                        <item>
                                <layer-list>
                                        <item android:drawable="@drawable/btu_color_standard" />
                                        <item android:drawable="@drawable/btu_shade_normal" />
                                </layer-list>
                        </item>
                </selector>
        </item>
        <item
                android:maxLevel="1"
                >
                <selector
                        android:constantSize="true"
                        android:variablePadding="false"
                        >
                        <item android:state_pressed="true">
                                <layer-list>
                                        <item android:drawable="@drawable/btu_color_standard" />
                                        <item android:drawable="@drawable/btu_lighted" />
                                        <item android:drawable="@drawable/btu_shade_pressed" />
                                </layer-list>
                        </item>
                        <item android:state_focused="true">
                                <layer-list>
                                        <item android:drawable="@drawable/btu_color_standard" />
                                        <item android:drawable="@drawable/btu_lighted" />
                                        <item android:drawable="@drawable/btu_shade_selected" />
                                </layer-list>
                        </item>
                        <item>
                                <layer-list>
                                        <item android:drawable="@drawable/btu_color_standard" />
                                        <item android:drawable="@drawable/btu_lighted" />
                                        <item android:drawable="@drawable/btu_shade_normal" />
                                </layer-list>
                        </item>
                </selector>
        </item>
</level-list>