get the apk icon.

GetAPKIcon.java

public Drawable getAPKDrawable(String filePath) {  
        Drawable dr = null;  
        if (filePath != null) {  
  
            String PATH_PackageParser = "android.content.pm.PackageParser";  
            String PATH_AssetManager = "android.content.res.AssetManager";  
            try {  
  
                Class pkgParserCls = Class.forName(PATH_PackageParser);  
                Class[] typeArgs = new Class[1];  
                typeArgs[0] = String.class;  
                Constructor pkgParserCt = pkgParserCls.getConstructor(typeArgs);  
                Object[] valueArgs = new Object[1];  
                valueArgs[0] = filePath;  
                Object pkgParser = pkgParserCt.newInstance(valueArgs);  
  
                DisplayMetrics metrics = new DisplayMetrics();  
                metrics.setToDefaults();  
  
                typeArgs = new Class[4];  
                typeArgs[0] = File.class;  
                typeArgs[1] = String.class;  
                typeArgs[2] = DisplayMetrics.class;  
                typeArgs[3] = Integer.TYPE;  
                Method pkgParser_parsePackageMtd = pkgParserCls.getDeclaredMethod("parsePackage", typeArgs);  
                valueArgs = new Object[4];  
                valueArgs[0] = new File(filePath);  
                valueArgs[1] = filePath;  
                valueArgs[2] = metrics;  
                valueArgs[3] = 0;  
                Object pkgParserPkg = pkgParser_parsePackageMtd.invoke(pkgParser, valueArgs);  
  
                Field appInfoFld = pkgParserPkg.getClass().getDeclaredField("applicationInfo");  
                ApplicationInfo info = (ApplicationInfo) appInfoFld.get(pkgParserPkg);  
  
                Class assetMagCls = Class.forName(PATH_AssetManager);  
                Constructor assetMagCt = assetMagCls.getConstructor((Class[]) null);  
                Object assetMag = assetMagCt.newInstance((Object[]) null);  
                typeArgs = new Class[1];  
                typeArgs[0] = String.class;  
                Method assetMag_addAssetPathMtd = assetMagCls.getDeclaredMethod("addAssetPath", typeArgs);  
                valueArgs = new Object[1];  
                valueArgs[0] = filePath;  
                assetMag_addAssetPathMtd.invoke(assetMag, valueArgs);  
                // 具体的activityy实例  
                Resources res = ManagerActivity.this.getResources();  
                typeArgs = new Class[3];  
                typeArgs[0] = assetMag.getClass();  
                typeArgs[1] = res.getDisplayMetrics().getClass();  
                typeArgs[2] = res.getConfiguration().getClass();  
                Constructor resCt = Resources.class.getConstructor(typeArgs);  
                valueArgs = new Object[3];  
                valueArgs[0] = assetMag;  
                valueArgs[1] = res.getDisplayMetrics();  
                valueArgs[2] = res.getConfiguration();  
                res = (Resources) resCt.newInstance(valueArgs);  
                CharSequence label = null;  
                if (info.labelRes != 0) {  
                    label = res.getText(info.labelRes);  
                }  
  
                if (info.icon != 0) {  
                    dr = res.getDrawable(info.icon);  
                }  
            } catch (Exception e) {  
                e.printStackTrace();  
            }  
        }  
        return dr;  
    }