判断android系统的版本和package是否存在

判断android系统的版本
参考网址：
http://rainhomepage.appspot.com/2010/03/how-to-determine-the-version-of-android-system

public static int getSDKVersionNumber() {
        int sdkVersion;
        try {
            sdkVersion = Integer.valueOf(android.os.Build.VERSION.SDK);
        } catch (NumberFormatException e) {
            sdkVersion = 0;
        }
        return sdkVersion;
    }

判断package是否存在
参考网址：http://ascii-iicsa.blogspot.tw/2011/04/package-app.html

方法一：

boolean bExists = false;
        final List<PackageInfo> packs = _service.getPackageManager()
                .getInstalledPackages(0);
        for (int i = 0; i < packs.size(); ++i) {
            final String packageName = packs.get(i).packageName;
            if (packageName != null
                    && packageName.startsWith("com.Ascii.Widget.AsciiApp")) {
                bExists = true;
                break;
            }
        }

        if (!bExists) {
            // 不存在
        }

方法二：

  PackageManager manager = _service.getPackageManager();
        Intent intent = new Intent().setPackage("com.Ascii.Widget.AsciiApp");
        List<ResolveInfo> infos = manager.queryIntentActivities(intent,
                PackageManager.GET_INTENT_FILTERS);

        if (infos == null || infos.size() < 1) {
            // 不存在
        }