动态换肤之从SD卡中的xml中获取ColorStateList

ColorStateList value = new ColorStateList(states, colors);

看到ColorStateList的构造方法，我们知道要想获得一个ColorStateList，需要有一个

int[][]

和一个存放ColorRes的

int[]

先看看一个很常用selector结构的color.xml

<?xml version="1.0" encoding="utf-8"?>
<selector
    xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:color="#ffffff" android:state_enabled="true" android:state_pressed="true"/>
    <item android:color="#000000"/>
</selector>

要想解析这么一个xml文档，要用到xml解析库，我用的是jsoup，在AndroidStudio中的gradle添加

compile 'org.jsoup:jsoup:1.8.2'

就可以使用这个库了。

final File colorDir = new File(skinDirectory, "color");//指定SD卡目录下的color文件夹，这个目录由外部传入
                if (colorDir.exists()) {
                    final File[] files = colorDir.listFiles(mXmlFilter);
                    for (File file : files) {
                        final Document parse = Jsoup.parse(file, "UTF-8");//将xml文件解析成Document对象
                        final Elements selectors = parse.getElementsByTag("selector");//拿到selector节点列表，实际上列表中只有一个selector
                        if (selectors.isEmpty()) {
                            continue;
                        }
                        final Element selector = selectors.get(0);
                        final Elements children = selector.children();
                        int[][] states = new int[children.size()][];
                        int[] colors = new int[children.size()];
                        for (int i = 0; i < children.size(); i++) {
                            Element child = children.get(i);
                            if ("item".equals(child.tagName())) {//拿到item节点
                                final Attributes attributes = child.attributes();//item节点的属性集
                                String value = attributes.get("android:color");
                                final int parseColor = Color.parseColor(value);
                                states[i] = getStatesArr(attributes);
                                colors[i] = parseColor;
                            }
                        }
                        ColorStateList value = new ColorStateList(states, colors);

这段代码里主要是将每个item的属性取出来，比如android:color 就是item的一个属性，取到color的值，通过Color.parseColor转换成ColorInt。

private int[] getStatesArr(Attributes attributes) {
        List<Integer> stateList = new ArrayList<>();
        String attributePress = attributes.get("android:state_pressed");
        if (!TextUtils.isEmpty(attributePress)) {
            boolean isPressed = Boolean.parseBoolean(attributePress);
            stateList.add((isPressed ? 1 : -1) * android.R.attr.state_pressed);
        }
        String attributeFocus = attributes.get("android:state_focused");
        if (!TextUtils.isEmpty(attributeFocus)) {
            boolean isPressed = Boolean.parseBoolean(attributeFocus);
            stateList.add((isPressed ? 1 : -1) * android.R.attr.state_focused);
        }
        String attributeSelect = attributes.get("android:state_selected");
        if (!TextUtils.isEmpty(attributeSelect)) {
            boolean isPressed = Boolean.parseBoolean(attributeSelect);
            stateList.add((isPressed ? 1 : -1) * android.R.attr.state_selected);
        }
        String attributeActive = attributes.get("android:state_active");
        if (!TextUtils.isEmpty(attributeActive)) {
            boolean isPressed = Boolean.parseBoolean(attributeActive);
            stateList.add((isPressed ? 1 : -1) * android.R.attr.state_active);
        }
        String attributeCheckable = attributes.get("android:state_checkable");
        if (!TextUtils.isEmpty(attributeCheckable)) {
            boolean isPressed = Boolean.parseBoolean(attributeCheckable);
            stateList.add((isPressed ? 1 : -1) * android.R.attr.state_checkable);
        }
        String attributeChecked = attributes.get("android:state_checked");
        if (!TextUtils.isEmpty(attributeChecked)) {
            boolean isPressed = Boolean.parseBoolean(attributeChecked);
            stateList.add((isPressed ? 1 : -1) * android.R.attr.state_checked);
        }
        String attributeEnable = attributes.get("android:state_enabled");
        if (!TextUtils.isEmpty(attributeEnable)) {
            boolean isPressed = Boolean.parseBoolean(attributeEnable);
            stateList.add((isPressed ? 1 : -1) * android.R.attr.state_enabled);
        }
        String attributeWindowFocus = attributes.get("android:state_window_focused");
        if (!TextUtils.isEmpty(attributeWindowFocus)) {
            boolean isPressed = Boolean.parseBoolean(attributeWindowFocus);
            stateList.add((isPressed ? 1 : -1) * android.R.attr.state_window_focused);
        }
        if(stateList.isEmpty()){
            return new int[]{};
        }else{
            int[] stateArr =new int[stateList.size()];
            for (int i=0;i<stateList.size();i++){
                stateArr[i] =stateList.get(i);
            }
            return stateArr;
        }
    }

这是取每个状态对应的int值，比如android:state_pressed为true，添加android.R.attr.state_pressed到数组中，如果为false添加 -android.R.attr.state_pressed，负的。