android开发分享Android使用反射设置外部资源（SDK中使用居多）

1、在开发SDK的过程中会发现通常是以jar和资源结合。而资源是提供给外部接入方使用的，在调用的时候为了防止编译的错误，要么使用反射，要么将资源放到jar工程当前，只是最后打包的时候不打资源包，将资源外放。这里提供下使用反射在sdk中调用外部资源的方法。

2、ReflectResourcesUtil类。调用前先调用init方法，当然如果你不想调用的话我也有备用的初始化方法，使用反射获取当前应用的Application来进行初始化。

import android.app.Application; import android.content.Context; import android.content.res.Resources; import android.text.TextUtils; import android.util.Log;  import java.lang.reflect.Method;  public class ReflectResourcesUtil {     private static final String TAG = "ReflectResourcesUtil";     private static String mPackageName;     private static Resources mResources;      /**      * 先调用初始化，然后再调用其他方法      *      * @param context      */     public static void init(Context context) {         mPackageName = context.getApplicationContext().getPackageName();         mResources = context.getApplicationContext().getResources();     }      /**      * 防止没有调用初始化，使用备用初始化方法      */     private static void retryInit() {         if (!TextUtils.isEmpty(mPackageName) || mResources != null) {             //已经初始化过，无需要再初始化             return;         }         Application application = getCurApplication();         if (application == null)             return;         init(application.getApplicationContext());     }      public static int getLayout(String resName) {         retryInit();         if (mResources == null || TextUtils.isEmpty(mPackageName)) {             return -1;         }         return mResources.getIdentifier(resName, "layout", mPackageName);     }      public static int getDrawable(String resName) {         retryInit();         if (mResources == null || TextUtils.isEmpty(mPackageName)) {             return -1;         }         return mResources.getIdentifier(resName, "drawable", mPackageName);     }      public static int getString(String resName) {         retryInit();         if (mResources == null || TextUtils.isEmpty(mPackageName)) {             return -1;         }         return mResources.getIdentifier(resName, "string", mPackageName);     }      public static int getId(String resName) {         retryInit();         if (mResources == null || TextUtils.isEmpty(mPackageName)) {             return -1;         }         return mResources.getIdentifier(resName, "id", mPackageName);     }      public static int getStyle(String resName) {         retryInit();         if (mResources == null || TextUtils.isEmpty(mPackageName)) {             return -1;         }         return mResources.getIdentifier(resName, "style", mPackageName);     }      public static int getArray(String resName) {         retryInit();         if (mResources == null || TextUtils.isEmpty(mPackageName)) {             return -1;         }         return mResources.getIdentifier(resName, "array", mPackageName);     }      public static int getColor(String resName) {         retryInit();         if (mResources == null || TextUtils.isEmpty(mPackageName)) {             return -1;         }         return mResources.getIdentifier(resName, "color", mPackageName);     }      public static int getDimen(String resName) {         retryInit();         if (mResources == null || TextUtils.isEmpty(mPackageName)) {             return -1;         }         return mResources.getIdentifier(resName, "dimen", mPackageName);     }      public static int getAnim(String resName) {         retryInit();         if (mResources == null || TextUtils.isEmpty(mPackageName)) {             return -1;         }         return mResources.getIdentifier(resName, "anim", mPackageName);     }      public static int getRaw(String resName) {         retryInit();         if (mResources == null || TextUtils.isEmpty(mPackageName)) {             return -1;         }         return mResources.getIdentifier(resName, "raw", mPackageName);     }      public static int getStyleable(String resName) {         retryInit();         if (mResources == null || TextUtils.isEmpty(mPackageName)) {             return -1;         }         return mResources.getIdentifier(resName, "styleable", mPackageName);     }      public static int[] getStyleableArray(String resName) {         retryInit();         if (mResources == null || TextUtils.isEmpty(mPackageName)) {             return null;         }         return getResourceIDsByName(resName, "styleable", mPackageName);     }      /**      * 利用反射，获取int数组格式的资源ID，例如styleable      */     private static int[] getResourceIDsByName(String resName, String resType, String packageName) {         Class clsR = null;         int[] ids = null;         try {             clsR = Class.forName(packageName + ".R");             Class[] classes = clsR.getClasses();             Class desClass = null;             for (int i = 0; i < classes.length; i++) {                 String[] temp = classes[i].getName().split("\$");                 if (temp.length >= 2) {                     if (temp[1].equals(resType)) {                         desClass = classes[i];                         break;                     }                 }             }             if (desClass != null) {                 ids = (int[]) desClass.getField(resName).get(resName);             }         } catch (Exception e) {             Log.e("ReflectResources", e.toString());         }         return ids;     }      /**      * 获取当前应用的Application      * 先使用ActivityThread里获取Application的方法，如果没有获取到，      * 再使用AppGlobals里面的获取Application的方法      *      * @return      */     private static Application getCurApplication() {         Application application = null;         try {             Class atClass = Class.forName("android.app.ActivityThread");             Method currentApplicationMethod = atClass.getDeclaredMethod("currentApplication");             currentApplicationMethod.setAccessible(true);             application = (Application) currentApplicationMethod.invoke(null);             Log.d(TAG, "curApp class1:" + application);         } catch (Exception e) {             Log.d(TAG, "e:" + e.toString());         }          if (application != null)             return application;          try {             Class atClass = Class.forName("android.app.AppGlobals");             Method currentApplicationMethod = atClass.getDeclaredMethod("getInitialApplication");             currentApplicationMethod.setAccessible(true);             application = (Application) currentApplicationMethod.invoke(null);             Log.d(TAG, "curApp class2:" + application);         } catch (Exception e) {             Log.d(TAG, "e:" + e.toString());         }          return application;     } }