java代码：android获取apk包的MD5值

	public static String getSign() {
		PackageManager pm = Cocos2dxActivity.getContext().getPackageManager();
		List<PackageInfo> apps = pm
				.getInstalledPackages(PackageManager.GET_SIGNATURES);
		Iterator<PackageInfo> iter = apps.iterator();
		while (iter.hasNext()) {
			PackageInfo packageinfo = iter.next();
			String packageName = packageinfo.packageName;
			if (packageName.equals(Cocos2dxActivity.getContext()
					.getPackageName())) {
				return packageinfo.signatures[0].toCharsString();
			}
		}
		return "";
	}

// MD5值
	std::string chStr = env->GetStringUTFChars( jStr, NULL );
	std::string	chStr1 = "获取到的md5值放在这";	
	// 判断2个MD5值是否相同
	if( chStr != chStr1 ) {
		// 不相同，退出游戏
		CCDirector::sharedDirector()->end();
	}