如何检查Android网络连接状态

如何检查Android网络连接状态 在送任何发发发发HTTP发发发发发发发发发发发发发发发发发发发发发发发发发发发发求前最好下网接状,可以避免异常。个将会介 怎在你的用中网接状。发发发发发发发发发发发发发发发发 发发发建新的目 1.在Eclipse IDE发发发发发发发发发发发发发发发发发发 中建一个新的目并把填入必的信息。 File->;New->;Android Project 2.发发发发发建新目后的第一是要在步AndroidManifest.xml发发发文件中添加必要的限。 发发发发发发发发发 了网我需要INTERNET 发 限 发发发发发发发发发发发 了网状我需要ACCESS_NETWORK_STATE 发 限 AndroidManifest.xml 01 <;?xml version=";1.0"; encoding=";utf-8";?>; 02 <;manifest xmlns:android=";;; 03 package=";com.example.detectinternetconnection"; 04 android:versionCode=";1"; 05 android:versionName=";1.0"; >; 06 07 <;uses-sdk android:minSdkVersion=";8"; />; 08 09 <;application 10 android:icon=";@drawable/ic_launcher"; 11 android:label=";@string/app_name"; >; 12 <;activity 13 android:name=";.AndroidDetectInternetConnectionActivity"; 14 android:label=";@string/app_name"; >; 15 <;intent-filter>; 16 <;action android:name=";android.intent.action.MAIN"; />; 17 18 <;category android:name=";android.intent.category.LAUNCHER"; />; 19 <;/intent-filter>; 20 <;/activity>; 21 <;/application>; 22 23 <;!-- Internet Permissions -->; 24 <;uses-permission android:name=";android.permission.INTERNET"; />; 25 26 <;!-- Network State Permissions -->; 27 <;uses-permission android:name=";android.permission.ACCESS_NETWORK_STATE"; />; 28 29 <;/manifest>; 3.发发发发发建一个新的,名ConnectionDetector.java发发发发发发发,并入以下代。 ConnectionDetector.java 01 package com.example.detectinternetconnection; 02 03 import android.content.Context; 04 import android.net.ConnectivityManager; 05 import android.net.NetworkInfo; 06 07 public class ConnectionDetector { 08 09 private Context _context; 10 11 public ConnectionDetector(Context context){ 12 this._context = context; 13 } 14 15 public boolean isConnectingToInternet(){ 16 ConnectivityManager connectivity = (ConnectivityManager) _context.getSystemService(Context.CONNECTIVITY_SERVICE); 17 if (connectivity != null) 18 { 19 NetworkInfo[] info = connectivity.getAllNetworkInfo(); 20 if (info != null) 21 for (int i = 0; i <; info.length; i++) 22 if (info[i].getState() == NetworkInfo.State.CONNECTED) 23 { 24 return true; 25 } 26 27 } 28 return false; 29 } 30 } 4.发发发发发发发发发发发发当你需要在你的用中网状用isConnectingToInternet()函数,它会返回true或 false 。 1 ConnectionDetector cd = new ConnectionDetector(getApplicationContext()); 2 3 Boolean isInternetPresent = cd.isConnectingToInternet(); // true or false 5.发发发发发发发发发发发发发发发发发发发发发发发发发发发发发发发发发发发在个教程中了我的放置了一个按。只要按下个按就会出 一个 alert dialog 发发发发发发发示网接状。 6.发 打res/layout 发发发 目下的main.xml 发发发发发发发并建一个按。 main.xml 01 <;?xml version=";1.0"; encoding=";utf-8";?>; 02 <;RelativeLayout xmlns:android=";;; 03 android:layout_width=";fill_parent"; 04 android:layout_height=";fill_parent"; 05 android:orientation=";vertical"; >; 06 07 <;TextView 08 android:layout_width=";fill_parent"; 09 android:layout_height=";wrap_content"; 10 android:text=";Detect Internet Status"; />; 11 12 <;Button android:id=";@+id/btn_check"; 13 android:layout_height=";wrap_content"; 14 android:layout_width=";wrap_content"; 15 android:text=";Check Internet Status"; 16 android:layout_centerInParent=";true";/>; 17 18 <;/RelativeLayout>; 7.发发发 最后打你的MainActivity 发发发发发发发发发发发发发发发发发发文件并粘下面的代。在下面的代中我用一个 alert dialog 发发发发发发发发发发 来示期的状信息。 01 package com.example.detectinternetconnection; 02 03 import android.app.Activity; 04 import android.app.AlertDialog; 05 import android.content.Context; 06 import android.content.DialogInterface; 07 import android.os.Bundle; 08 import android.view.View; 09 import android.widget.Button; 10 11 public class AndroidDetectInternetConnectionActivity extends Activity { 12 13 // flag for Internet connection status 14 Boolean isInternetPresent = false; 15 16 // Connection detector class 17 ConnectionDetector cd; 18 19 @Override 20 public void onCreate(Bundle savedInstanceState) { 21 super.onCreate(savedInstanceState); 22 setContentView(R.layout.main); 23 24 Button btnStatus = (Button) findViewById(R.id.btn_check); 25 26 // creating connection detector class instance 27 cd = new ConnectionDetector(getApplicationContext()); 28 29 /** 30 * Check Internet status button click event 31 * */ 32 btnStatus.setOnClickListener(new View.OnClickListener() { 33 34 @Override 35 public void onClick(View v) { 36 37 // get Internet status 38 isInternetPresent = cd.isConnectingToInternet(); 39 40 // check for Internet status 41 if (isInternetPresent) { 42 // Internet Connection is Present 43 // make HTTP requests 44 showAlertDialog(AndroidDetectInternetConnectionActi vity.this,";Internet Connection";, 45 ";You have internet connection";, true); 46 } else { 47 // Internet connection is not present 48 // Ask user to connect to Internet 49 showAlertDialog(AndroidDetectInternetConnectionActivity.this, ";No Internet Connection";, 50 ";You don't have internet connection.";, false); 51 } 52 } 53 54 }); 55 56 } 57 58 /** 59 * Function to display simple Alert Dialog 60 * @param context - application context 61 * @param title - alert dialog title 62 * @param message - alert message 63 * @param status - success/failure (used to set icon) 64 * */ 65 public void showAlertDialog(Context context, String title, String message, Boolean status) { 66 AlertDialog alertDialog = new AlertDialog.Builder(context).create(); 67 68 // Setting Dialog Title 69 alertDialog.setTitle(title); 70 71 // Setting Dialog Message 72 alertDialog.setMessage(message); 73 74 // Setting alert dialog icon 75 alertDialog.setIcon((status) ? R.drawable.success : R.drawable.fail); 76 77 // Setting OK Button 78 alertDialog.setButton(";OK";, new DialogInterface.OnClickListener() { 79 public void onClick(DialogInterface dialog, int which) { 80 } 81 }); 82 83 // Showing Alert Message 84 alertDialog.show(); 85 } 86 } 发发发发发发发发发发发发发发发发发发发发发发运行并下你的程序吧:你将会得到似下面的果。