判断网络状态

1.创建Android程序

2.编写代码

MainActity：

package com.example.network;

import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.Button;


public class MainActivity extends Activity {
    private Button netWrkBtn;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        //获取控件
        netWrkBtn = (Button)findViewById(R.id.netBtn1);
        //绑定单击事件
        netWrkBtn.setOnClickListener(new netWrkService(this));
    }

}

绑定单击事件的类:

package com.example.network;

import android.app.Activity;
import android.content.Context;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.TextView;



public class netWrkService implements OnClickListener{
    private Context context;
    private TextView tv1;
    public netWrkService(Context context){
        this.context = context;
    }
    @Override
    public void onClick(View v) {
        Activity c = (Activity)context;
        tv1 = (TextView)c.findViewById(R.id.textView1);
        String netStatus;
        int color;
        try {
            //查看有无网络
            ConnectivityManager cm = (ConnectivityManager)c.getSystemService(c.CONNECTIVITY_SERVICE);
            //查看连接是否成功
            NetworkInfo netWrkInfo = cm.getActiveNetworkInfo();
            //判断连接给出相应的结果
            if(netWrkInfo==null){
                netStatus = c.getResources().getString(R.string.net_status1);
                color = c.getResources().getColor(R.color.red);
            }else{
                netStatus = c.getResources().getString(R.string.net_status0);
                color = c.getResources().getColor(R.color.green);
            }
        } catch (Exception e) {
            //发生异常时给出的结果
            netStatus = c.getResources().getString(R.string.net_status3);
            color = c.getResources().getColor(R.color.yellow);
        }
        tv1.setText(netStatus);
        tv1.setBackgroundColor(color);
    }
    
}

string.xml资源文件

<?xml version="1.0" encoding="utf-8"?>
<resources>

    <string name="app_name">netWork</string>
    <string name="net_test">网络测试</string>
    <string name="net_btn1">测试</string>
    <string name="net_status0">网络通过</string>
    <string name="net_status1">网络异常</string>
    <string name="net_status3">权限不足</string>
    <string name="action_settings">Settings</string>

</resources>

3.测试