场景：

1.统一设计Activity风格

2.加载外部资源，替换应用风格

3.不重启Activity的情况下，替换应用风格

4.应用使用系统默认View，开发者进行代码重构，想要增加view的功能，使用自定义View代替，却不想更改布局文件。例如：AppcomptActivity在factory使用新的View替换，实现风格的变换

原理：

1.拦截view创建

1.1创建自定义View

1.2穿件默认View，加载新的资源文件，设置View的属性

class SkinFactory implements LayoutInflater.Factory {    private Context context;    Resources resources;    ArrayList
    
     
      > skinAttrs = new ArrayList
      
       
        >();    public SkinFactory(Context context, Resources resources) {        this.resources = resources;        this.context = context;    }    @Override    public View onCreateView(String name, Context context, AttributeSet attrs) {// 创建View-----------------------start        View view = null;        try {            if (-1 == name.indexOf('.')) {                if ("View".equals(name)) {                    view = LayoutInflater.from(context).createView(name,                            "android.view.", attrs);                }                if (view == null) {                    view = LayoutInflater.from(context).createView(name,                            "android.widget.", attrs);                }                if (view == null) {                    view = LayoutInflater.from(context).createView(name,                            "android.webkit.", attrs);                }            } else {                view = LayoutInflater.from(context).createView(name, null,                        attrs);            }        } catch (Exception e) {            e.printStackTrace();            view = null;        }// 创建View-----------------------end        if (view == null) {            return null;        }        for (int i = 0; i < attrs.getAttributeCount(); i++) {            String attributeName = attrs.getAttributeName(i);            String attributeValue = attrs.getAttributeValue(i);             TODO: 2/17/2017 find attr that can be change and set new attr            if (resources != null)                applyResource(resources, new SkinAttr(view, attributeName, attributeValue));        }        return view;    }    public void resotreDefault() {        for (WeakReference
        
          skinAttrWeakReference : skinAttrs) {            SkinAttr skinAttr = skinAttrWeakReference.get();            if (skinAttr != null && skinAttr.getView() != null) {                applyResource(context.getResources(), skinAttr);            }        }    }    public void applyResource(Resources resource,  SkinAttr skinAttr) {    }    class SkinAttr {        View view;        String attributeName;        String attributeValue;        public SkinAttr(View view, String attributeName, String attributeValue) {            this.view = view;            this.attributeName = attributeName;            this.attributeValue = attributeValue;        }        public String getAttributeName() {            return attributeName;        }        public View getView() {            return view;        }        public String getAttributeValue() {            return attributeValue;        }        public String getAttributeValueType() {            return attributeValue.split("/")[0];        }        public String getAttributeValueName() {            return attributeValue.split("/")[1];        }    }}