java - 检查 Android 的互联网连接

Question

我的代码有问题，我想检查是否有互联网连接(wifi 或移动)，但是当我按下 vt 按钮时，应用程序停止工作，我得到“致命异常:主”。我是android的新手，也是新程序员。谢谢。

package com.example.josue.controles;
import android.content.Context;
import android.content.DialogInterface;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.View;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.Button;
import android.widget.TextView;
import android.app.AlertDialog;

public class controlespe extends AppCompatActivity
{

    Button vt;
    TextView et;


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

    }

    public void cambiarrr()

    {
        vt = (Button) findViewById(R.id.vt);    // "findViewById" Busca en el XML
        et = (TextView) findViewById(R.id.et);

        vt.setOnClickListener(new View.OnClickListener()

        {
            @Override
            public void onClick(View v) {
                if (!verificaConexion())
                {
                    AVISOsi();
                } else
                    AVISOno();
            }
        });
    }


    public void AVISOsi() {
        AlertDialog.Builder a_builder = new AlertDialog.Builder(controlespe.this);
        a_builder.setMessage("oie chy tines gauifai")
                .setCancelable(false)
                .setPositiveButton("Allhau Akbar", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
//                        finish();// con esto cierra la aplicacion
                        dialog.cancel();
                    }
                })
                .setNegativeButton(":3", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        dialog.cancel();
                    }
                });
        AlertDialog alert = a_builder.create();
        alert.setTitle("3stado");
        alert.show();
    }

    public void AVISOno() {
        AlertDialog.Builder a_builder = new AlertDialog.Builder(controlespe.this);
        a_builder.setMessage("oie no tines gauifai")
                .setCancelable(false)
                .setPositiveButton("maldita pobreza", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
//                        finish();// con esto cierra la aplicacion
                        dialog.cancel();
                    }
                })
                .setNegativeButton(":'v", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        dialog.cancel();
                    }
                });
        AlertDialog alert = a_builder.create();
        alert.setTitle("3stado");
        alert.show();
    }



    public boolean verificaConexion() {
        boolean bConectado = false;
        ConnectivityManager connec = (ConnectivityManager) this
                .getSystemService(Context.CONNECTIVITY_SERVICE);
        // No sólo wifi, también GPRS
        NetworkInfo[] redes = connec.getAllNetworkInfo();
        // este bucle debería no ser tan ñapa
        for (int i = 0; i < 2; i++) {
            // ¿Tenemos conexión? ponemos a true
            if (redes[i].getState() == NetworkInfo.State.CONNECTED) {
                bConectado = true;
            }
        }
        return bConectado;
    }



}

Answer 1

检查您是否有访问 list 中网络/wifi 状态的正确权限:

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