android动态加载外部资源文件

package com.lonelypluto.loadresourcedemo.utils; import android.content.Context; import android.content.pm.PackageInfo; import android.content.pm.PackageManager; import android.content.res.AssetManager; import android.content.res.Resources; import android.graphics.drawable.Drawable; import android.util.Log; import com.lonelypluto.loadresourcedemo.bean.LoadResourceBean; import com.lonelypluto.loadresourcedemo.constants.SPConsts; import java.io.File; import java.lang.reflect.Method; import dalvik.system.DexClassLoader; /** * @Description: 资源加载工具类 * @author: ZhangYW * @time: 2018/9/17 11:16 */ public class LoadResourceUtil { private static final String TAG = LoadResourceUtil.class.getSimpleName(); private static final String RESOURCE_TYPE_DRAWABLE = "drawable";// 图片 private static final String RESOURCE_TYPE_STRING = "string";// 文字 private static final String RESOURCE_TYPE_COLOR = "color";// 颜色 private Context mContext; private String mDexDir;// 资源路径 private static LoadResourceBean mResourceLoadBean;// 资源对象 /** * 静态内部类 */ private static class LoadResourceUtilHolder { private static final LoadResourceUtil INSTANCE = new LoadResourceUtil(); } /** * 单例模式 * @return */ public static final LoadResourceUtil getInstance() { return LoadResourceUtilHolder.INSTANCE; } /** * 初始化 * * @param context * @param resourcePath 本地资源路径 */ public void init(Context context, String resourcePath) { Log.e(TAG, "init"); mContext = context.getApplicationContext(); File dexDir = mContext.getDir("dex", Context.MODE_PRIVATE); if (!dexDir.exists()) { dexDir.mkdir(); } mDexDir = dexDir.getAbsolutePath(); mResourceLoadBean = getResourceLoad(resourcePath); } /** * 加载未安装资源包 * * @param resourcePath 未安装资源包 * @return */ public LoadResourceBean getResourceLoad(String resourcePath) { Log.e(TAG, "getLoadResource"); LoadResourceBean resourceLoadBean = null; // 获取未安装APK的PackageInfo PackageInfo info = queryPackageInfo(resourcePath); if (info != null) { // 获取成功 try { // 创建AssetManager实例 AssetManager assetManager = AssetManager.class.newInstance(); Class cls = AssetManager.class; Method method = cls.getMethod("addAssetPath", String.class); // 反射设置资源加载路径 method.invoke(assetManager, resourcePath); // 构造出正确的Resource Resources resources = new Resources(assetManager, mContext.getResources().getDisplayMetrics(), mContext.getResources().getConfiguration()); resourceLoadBean = new LoadResourceBean(); resourceLoadBean.setResources(resources); resourceLoadBean.setPackageName(info.packageName); // 设置正确的类加载器, 因为需要去加载R文件 resourceLoadBean.setClassLoader(new DexClassLoader(resourcePath, mDexDir, null, mContext.getClassLoader())); } catch (Exception e) { e.printStackTrace(); } } return resourceLoadBean; } /** * 重新加载未安装应用资源包 * * @param resourcePath 未安装资源包路径 * @return */ public void setLoadResource(String resourcePath) { // 保存资源包路径 下次进入程序默认加载 SharedPreferencesUtil.put(SPConsts.SP_RESOURCE_PATH, resourcePath); mResourceLoadBean = getResourceLoad(resourcePath); } /** * 获取未安装资源包信息 * * @param resourcePath 未安装资源包路径 * @return */ private PackageInfo queryPackageInfo(String resourcePath) { return mContext.getPackageManager().getPackageArchiveInfo(resourcePath, PackageManager.GET_ACTIVITIES); } /** * 获取未安装资源Drawable * * @param fieldName 资源名 * @return */ public Drawable getDrawable(String fieldName) { Drawable drawable = null; int resourceID = getResourceID(mResourceLoadBean.getPackageName(), RESOURCE_TYPE_DRAWABLE, fieldName); if (mResourceLoadBean != null) { drawable = mResourceLoadBean.getResources().getDrawable(resourceID); } return drawable; } /** * 获取未安装资源String * * @param fieldName 资源名 * @return */ public String getString(String fieldName) { String string = null; int resourceID = getResourceID(mResourceLoadBean.getPackageName(), RESOURCE_TYPE_STRING, fieldName); if (mResourceLoadBean != null) { string = mResourceLoadBean.getResources().getString(resourceID); } return string; } /** * 获取未安装资源color * * @param fieldName 资源名 * @return */ public int getColor(String fieldName) { int color = 0; int resourceID = getResourceID(mResourceLoadBean.getPackageName(), RESOURCE_TYPE_COLOR, fieldName); if (mResourceLoadBean != null) { color = mResourceLoadBean.getResources().getColor(resourceID); } return color; } /** * 获取未安装资源的ID * * @param packageName 包名 * @param type 资源类型 * @param fieldName 资源名 * @return */ public int getResourceID(String packageName, String type, String fieldName) { int resID = 0; String rClassName = packageName + ".R$" + type; try { Class cls = mResourceLoadBean.getClassLoader().loadClass(rClassName); resID = (Integer) cls.getField(fieldName).get(null); } catch (Exception e) { e.printStackTrace(); } return resID; } }