[置顶] 判断Adndroid手机的网络连接状态

        判断手机的网络状态，需要使用ConnectivityManager。ConnectivityManager主要管理和网络连接相关的操作 。 相关的TelephonyManager则管理和手机、运营商等的相关信息；WifiManager则管理和wifi相关的信息。NetworkInfo类包含了对wifi和mobile两种网络模式连接的详细描述，通过其getState()方法获取的State对象则代表着连接成功与否等状态。 

Java代码：

package com.lenovo.test.network;

import android.app.Activity;
import android.app.AlertDialog;
import android.app.AlertDialog.Builder;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.net.ConnectivityManager;
import android.net.NetworkInfo.State;
import android.os.Bundle;
import android.provider.Settings;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

public class JudgeNetworkActivity extends Activity {
	/** Called when the activity is first created. */
	private Button mButton = null;
	private TextView mTextView = null;

	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);

		mButton = (Button) findViewById(R.id.mbutton);
		mTextView = (TextView) findViewById(R.id.mtv);
		final Builder builder = new AlertDialog.Builder(this);
		mButton.setOnClickListener(new View.OnClickListener() {
			public void onClick(View v) {
				// TODO Auto-generated method stub
				ConnectivityManager conMan = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);

				// mobile 3G Data Network
				State mobile = conMan.getNetworkInfo(
						ConnectivityManager.TYPE_MOBILE).getState();

				// wifi
				State wifi = conMan.getNetworkInfo(
						ConnectivityManager.TYPE_WIFI).getState();
				mTextView.setText("Moble Network:" + mobile.toString() + "\n"
						+ "WIFI Network:" + wifi.toString());
				// 如果3G网络和wifi网络都未连接，且不是处于正在连接状态 则进入Network Setting界面 由用户配置网络连接
				if (!(mobile == State.CONNECTED || mobile == State.CONNECTING
						|| wifi == State.CONNECTED || wifi == State.CONNECTING)) {
					builder.setTitle("Message")
							.setMessage("没有可用的网络，请设置有效的网络连接！")
							.setNegativeButton("确定",
									new DialogInterface.OnClickListener() {
										public void onClick(
												DialogInterface dialog,
												int which) {
											startActivity(new Intent(
													Settings.ACTION_WIRELESS_SETTINGS));// 进入无线网络配置界面
											// startActivity(new
											// Intent(Settings.ACTION_WIFI_SETTINGS));
											// 进入手机中的wifi网络设置界面
										}
									}).show();
				}
			}
		});
	}
}

在AndroidManifest.xml里添加权限：

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

运行结果：