Android连接网络问题

一、检查网络是否连接

 

方法一、

 

public void CheckNetworkState() {
  boolean flag = false;
  ConnectivityManager manager = (ConnectivityManager) getSystemService    (Context.CONNECTIVITY_SERVICE);
  State mobile = manager.getNetworkInfo(ConnectivityManager.TYPE_MOBILE)
    .getState();
  State wifi = manager.getNetworkInfo(ConnectivityManager.TYPE_WIFI)
    .getState();
  // 如果3G、wifi、2G等网络状态是连接的，则退出，否则显示提示信息进入网络设置界面
  if (mobile == State.CONNECTED || mobile == State.CONNECTING)
   return;
  if (wifi == State.CONNECTED || wifi == State.CONNECTING)
   return;

   //如果不可用,弹出对话框

 }

 

方法二：

 

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

}

 

 

方法三、

 

1. 首先先看一下Android 判断网络是否已打开(如果直接写在Activity里面,则可以不需要参数)


    /*
     * 判断网络连接是否已开
     * 2012-08-20
     *true 已打开  false 未打开
     * */
    public static boolean isConn(Context context){
        boolean bisConnFlag=false;
        ConnectivityManager conManager = (ConnectivityManager)context.getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo network = conManager.getActiveNetworkInfo();
        if(network!=null){
            bisConnFlag=conManager.getActiveNetworkInfo().isAvailable();
        }
        return bisConnFlag;
    }


 
  2. 如果未开启网络调用打开设置界面(如果不写在Activity里面则不需要参数)


    /*
     * 打开设置网络界面
     * */
    public static void setNetworkMethod(final Context context){
        //提示对话框
        AlertDialog.Builder builder=new Builder(context);
        builder.setTitle("网络设置提示").setMessage("网络连接不可用,是否进行设置?").setPositiveButton("设置", new DialogInterface.OnClickListener() {
            
            @Override
            public void onClick(DialogInterface dialog, int which) {
                // TODO Auto-generated method stub
                Intent intent=null;
                //判断手机系统的版本  即API大于10 就是3.0或以上版本 
                if(android.os.Build.VERSION.SDK_INT>10){
                    intent = new Intent(android.provider.Settings.ACTION_WIRELESS_SETTINGS);
                }else{
                    intent = new Intent();
                    ComponentName component = new ComponentName("com.android.settings","com.android.settings.WirelessSettings");
                    intent.setComponent(component);
                    intent.setAction("android.intent.action.VIEW");
                }
                context.startActivity(intent);
            }
        }).setNegativeButton("取消", new DialogInterface.OnClickListener() {
            
            @Override
            public void onClick(DialogInterface dialog, int which) {
                // TODO Auto-generated method stub
                dialog.dismiss();
            }
        }).show();
    }


3.  在 AndroidManifest.xml中设置权限

    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
    <uses-permission android:name="android.permission.INTERNET"/>

4. 在相应的位置调用即可

if(!ConnectionUtil.isConn(getApplicationContext())){
            ConnectionUtil.setNetworkMethod(MainActivity.this);
        }