XUtil学习笔记之ViewUtils（二）

**由于分离开讲解代码片段，读者看起来缺乏整体感，不容易记忆，
先提出要说的整段代码，方便查看。**

讲解会直接添加到代码的中，有需要重点说明的会在文章结尾详细说明。

public class ViewUtils {    //无参构造    private ViewUtils() {    }    //view注入的方法重载    public static void inject(View view) {        injectObject(view, new ViewFinder(view));    }    // Activity注入的方法重载    public static void inject(Activity activity) {        injectObject(activity, new ViewFinder(activity));    }// PreferenceActivity 注入的方法重载    public static void inject(PreferenceActivity preferenceActivity) {        injectObject(preferenceActivity, new ViewFinder(preferenceActivity));    }// handler，view注入的方法重载    public static void inject(Object handler, View view) {        injectObject(handler, new ViewFinder(view));    }// handler，Activity 注入的方法重载    public static void inject(Object handler, Activity activity) {        injectObject(handler, new ViewFinder(activity));    }// handler，PreferenceGroup 注入的方法重载    public static void inject(Object handler, PreferenceGroup preferenceGroup) {        injectObject(handler, new ViewFinder(preferenceGroup));    }// handler，PreferenceActivity 注入的方法重载    public static void inject(Object handler, PreferenceActivity preferenceActivity) {        injectObject(handler, new ViewFinder(preferenceActivity));    }    //核心的方法    @SuppressWarnings("ConstantConditions")    private static void injectObject(Object handler, ViewFinder finder) {        //使用到反射机制        Class<?> handlerType = handler.getClass();        // inject ContentView 注入ContentView         ContentView contentView = handlerType.getAnnotation(ContentView.class);        if (contentView != null) {            try {                Method setContentViewMethod = handlerType.getMethod("setContentView", int.class);                setContentViewMethod.invoke(handler, contentView.value());            } catch (Throwable e) {                LogUtils.e(e.getMessage(), e);            }        }        // inject view注入view        Field[] fields = handlerType.getDeclaredFields();        if (fields != null && fields.length > 0) {            for (Field field : fields) {                ViewInject viewInject = field.getAnnotation(ViewInject.class);                if (viewInject != null) {                    try {                        View view = finder.findViewById(viewInject.value(), viewInject.parentId());                        if (view != null) {                            field.setAccessible(true);                            field.set(handler, view);                        }                    } catch (Throwable e) {                        LogUtils.e(e.getMessage(), e);                    }                } else {                    ResInject resInject = field.getAnnotation(ResInject.class);                    if (resInject != null) {                        try {                            Object res = ResLoader.loadRes(                                    resInject.type(), finder.getContext(), resInject.id());                            if (res != null) {                                field.setAccessible(true);                                field.set(handler, res);                            }                        } catch (Throwable e) {                            LogUtils.e(e.getMessage(), e);                        }                    } else {                        PreferenceInject preferenceInject = field.getAnnotation(PreferenceInject.class);                        if (preferenceInject != null) {                            try {                                Preference preference = finder.findPreference(preferenceInject.value());                                if (preference != null) {                                    field.setAccessible(true);                                    field.set(handler, preference);                                }                            } catch (Throwable e) {                                LogUtils.e(e.getMessage(), e);                            }                        }                    }                }            }        }        // inject event注入事件        Method[] methods = handlerType.getDeclaredMethods();        if (methods != null && methods.length > 0) {            for (Method method : methods) {                Annotation[] annotations = method.getDeclaredAnnotations();                if (annotations != null && annotations.length > 0) {                    for (Annotation annotation : annotations) {                        Class<?> annType = annotation.annotationType();                        if (annType.getAnnotation(EventBase.class) != null) {                            method.setAccessible(true);                            try {                                // ProGuard：-keep class * extends java.lang.annotation.Annotation { *; }                                Method valueMethod = annType.getDeclaredMethod("value");                                Method parentIdMethod = null;                                try {                                    parentIdMethod = annType.getDeclaredMethod("parentId");                                } catch (Throwable e) {                                }                                Object values = valueMethod.invoke(annotation);                                Object parentIds = parentIdMethod == null ? null : parentIdMethod.invoke(annotation);                                int parentIdsLen = parentIds == null ? 0 : Array.getLength(parentIds);                                int len = Array.getLength(values);                                for (int i = 0; i < len; i++) {                                    ViewInjectInfo info = new ViewInjectInfo();                                    info.value = Array.get(values, i);                                    info.parentId = parentIdsLen > i ? (Integer) Array.get(parentIds, i) : 0;                                    EventListenerManager.addEventMethod(finder, info, annotation, handler, method);                                }                            } catch (Throwable e) {                                LogUtils.e(e.getMessage(), e);                            }                        }                    }                }            }        }    }