android检测网络是否正常
按照惯例，先上图后代码
在实际开发中，尤其是在网络应用开发中，时常要判断网络是否处在联网状态，以及给用户友好的提示，由于需要在每个界面中有需要对其进行检测，所以我们把它封转成一个方法，让每个activity公用。
首先是工具类
import android.app.Activity;import android.app.AlertDialog;import android.content.Context;import android.content.DialogInterface;import android.content.Intent;import android.net.ConnectivityManager;import android.net.NetworkInfo;public class CheckHttpUtil {public static boolean isNetworkAvailable(Activity mActivity){Context context = mActivity.getApplicationContext();ConnectivityManager connectivity = (ConnectivityManager)context.getSystemService(Context.CONNECTIVITY_SERVICE);if(connectivity == null){return false;}else {NetworkInfo[] info = connectivity.getAllNetworkInfo();if(info != null ){for(int i=0; i<info.length; i++){if(info[i].getState() == NetworkInfo.State.CONNECTED){return true;}}}}return false;}public static void checkhttp(final Activity activity){if(!isNetworkAvailable(activity)){AlertDialog.Builder builder = new AlertDialog.Builder(activity);builder.setTitle("网络错误，请检查网络设置");builder.setPositiveButton("确定", new DialogInterface.OnClickListener() {@Overridepublic void onClick(DialogInterface dialog, int which) { Intent intent = new Intent("android.settings.WIRELESS_SETTINGS"); activity.startActivity(intent); activity.finish();}});builder.show();}}}