AppUtil工具类：

import java.io.File;
import java.util.ArrayList;
import java.util.List;
 
import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.content.pm.ApplicationInfo;
import android.content.pm.PackageInfo;
import android.content.pm.PackageManager;
import android.content.pm.PackageManager.NameNotFoundException;
import android.graphics.drawable.Drawable;
import android.net.Uri;
 
/**
 * 常用APP的工具类，包含版本号、版本名称、安装的应用程序ICON
 */
public class AppUtil {
	private AppUtil(){}
 
	/**
	 * 获取包名
	 * @param context
	 * @return
	 */
	public static String getPackageName(Context context){
		return context.getPackageName();
	}
	
	/**
	 * 获取VersionName(版本名称)
	 * @param context
	 * @return
	 * 失败时返回""
	 */
	public static String getVersionName(Context context){
		PackageManager packageManager = getPackageManager(context);
		try {
			PackageInfo packageInfo = packageManager.getPackageInfo(getPackageName(context), 0);
			return packageInfo.versionName;
		} catch (NameNotFoundException e) {
			e.printStackTrace();
		}
		return "";
	}
	
	/**
	 * 获取VersionCode(版本号)
	 * @param context
	 * @return
	 * 失败时返回-1
	 */
	public static int getVersionCode(Context context){
		PackageManager packageManager = getPackageManager(context);
		try {
			PackageInfo packageInfo = packageManager.getPackageInfo(getPackageName(context), 0);
			return packageInfo.versionCode;
		} catch (NameNotFoundException e) {
			e.printStackTrace();
		}
		return -1;
	}
	
	/**
	 * 获取所有安装的应用程序,不包含系统应用
	 * @param context
	 * @return
	 */
	public static List getInstalledPackages(Context context){
		PackageManager packageManager = getPackageManager(context);
		List packageInfos = packageManager.getInstalledPackages(0);
		List packageInfoList  = new ArrayList();
		for(int i=0; i < packageInfos.size();i++){
			if ((packageInfos.get(i).applicationInfo.flags & ApplicationInfo.FLAG_SYSTEM) == 0) {
				packageInfoList.add(packageInfos.get(i));
			}
		}
		return packageInfoList;
	}
	
	/**
	 * 获取应用程序的icon图标
	 * @param context
	 * @return
	 * 当包名错误时，返回null
	 */
	public static Drawable getApplicationIcon(Context context){
		PackageManager packageManager = getPackageManager(context);
		try {
			PackageInfo packageInfo = packageManager.getPackageInfo(getPackageName(context), 0);
			return packageInfo.applicationInfo.loadIcon(packageManager);
		} catch (NameNotFoundException e) {
			e.printStackTrace();
		}
		return null;
	}
	
	/**
	 * 启动安装应用程序
	 * @param activity
	 * @param path	应用程序路径
	 */
	public static void installApk(Activity activity, String path){
		Intent intent = new Intent(Intent.ACTION_VIEW);
		intent.setDataAndType(Uri.fromFile(new File(path)),
                "application/vnd.android.package-archive");
        activity.startActivity(intent);
	}
	
	/**
	 * 获取PackageManager对象
	 * @param context
	 * @return
	 */
	private static PackageManager getPackageManager(Context context){
		return context.getPackageManager();
	}
}