Android工具类整理：检查是否有网络、检查SD卡是否存在

import android.content.Context;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;

public class CommonUtils {

    /** 检查是否有网络 */
    public static boolean isNetworkAvailable(Context context) {
        NetworkInfo info = getNetworkInfo(context);
        if (info != null) {
            return info.isAvailable();
        }
        return false;
    }

    /** 检查是否是WIFI */
    public static boolean isWifi(Context context) {
        NetworkInfo info = getNetworkInfo(context);
        if (info != null) {
            if (info.getType() == ConnectivityManager.TYPE_WIFI)
                return true;
        }
        return false;
    }

    /** 检查是否是移动网络 */
    public static boolean isMobile(Context context) {
        NetworkInfo info = getNetworkInfo(context);
        if (info != null) {
            if (info.getType() == ConnectivityManager.TYPE_MOBILE)
                return true;
        }
        return false;
    }

    private static NetworkInfo getNetworkInfo(Context context) {

        ConnectivityManager cm = (ConnectivityManager) context
                .getSystemService(Context.CONNECTIVITY_SERVICE);
        return cm.getActiveNetworkInfo();
    }

    /** 检查SD卡是否存在 */
    public static boolean checkSdCard() {
        if (android.os.Environment.getExternalStorageState().equals(
                android.os.Environment.MEDIA_MOUNTED))
            return true;
        else
            return false;
    }

}