我想创建一个使用互联网的应用程序,我试图创建一个功能,检查连接是否可用,如果它不是,去到一个活动,有一个重试按钮和解释。

附件是我的代码到目前为止,但我得到的错误语法错误,插入“}”来完成MethodBody。

现在我已经把这些放在试图让它工作,但到目前为止没有运气…任何帮助都将不胜感激。

public class TheEvoStikLeagueActivity extends Activity {
    private final int SPLASH_DISPLAY_LENGHT = 3000;

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle icicle) {
        super.onCreate(icicle);
        setContentView(R.layout.main);

        private boolean checkInternetConnection() {
            ConnectivityManager conMgr = (ConnectivityManager) getSystemService (Context.CONNECTIVITY_SERVICE);
            // ARE WE CONNECTED TO THE NET
            if (conMgr.getActiveNetworkInfo() != null
                    && conMgr.getActiveNetworkInfo().isAvailable()
                    && conMgr.getActiveNetworkInfo().isConnected()) {

                return true;

                /* New Handler to start the Menu-Activity
                 * and close this Splash-Screen after some seconds.*/
                new Handler().postDelayed(new Runnable() {
                    public void run() {
                        /* Create an Intent that will start the Menu-Activity. */
                        Intent mainIntent = new Intent(TheEvoStikLeagueActivity.this, IntroActivity.class);
                        TheEvoStikLeagueActivity.this.startActivity(mainIntent);
                        TheEvoStikLeagueActivity.this.finish();
                    }
                }, SPLASH_DISPLAY_LENGHT);
            } else {
                return false;

                Intent connectionIntent = new Intent(TheEvoStikLeagueActivity.this, HomeActivity.class);
                TheEvoStikLeagueActivity.this.startActivity(connectionIntent);
                TheEvoStikLeagueActivity.this.finish();
            }
        }
    }

当前回答

在“return”语句之后,您不能编写任何代码(不包括try-finally块)。 将新的活动代码移到“return”语句之前。

其他回答

你不能在另一个方法中创建一个方法,将私有布尔checkInternetConnection(){方法移出onCreate

接受的答案的EDIT显示了如何检查internet上的某些内容是否可以到达。我不得不等了很长时间才得到答案,但事实并非如此(使用的是没有互联网连接的wifi)。不幸的是InetAddress。getByName没有超时参数,所以下面的代码围绕它工作:

private boolean internetConnectionAvailable(int timeOut) {
    InetAddress inetAddress = null;
    try {
        Future<InetAddress> future = Executors.newSingleThreadExecutor().submit(new Callable<InetAddress>() {
            @Override
            public InetAddress call() {
                try {
                    return InetAddress.getByName("google.com");
                } catch (UnknownHostException e) {
                    return null;
                }
            }
        });
        inetAddress = future.get(timeOut, TimeUnit.MILLISECONDS);
        future.cancel(true);
    } catch (InterruptedException e) {
    } catch (ExecutionException e) {
    } catch (TimeoutException e) {
    } 
    return inetAddress!=null && !inetAddress.equals("");
}
public boolean checkInternetConnection(Context context) {
    ConnectivityManager connectivity = (ConnectivityManager) context
        .getSystemService(Context.CONNECTIVITY_SERVICE);
    if (connectivity == null) {
        return false;
    } else {
        NetworkInfo[] info = connectivity.getAllNetworkInfo();
        if (info != null) {
            for (int i = 0; i < info.length; i++){
                if (info[i].getState()==NetworkInfo.State.CONNECTED){
                    return true;
                }
            }
        }
    }
    return false;
}

1-创建新的Java文件(右键单击包。新建>类>,命名为文件ConnectionDetector.java

2-在文件中添加以下代码

package <add you package name> example com.example.example;

import android.content.Context;
import android.net.ConnectivityManager;

public class ConnectionDetector {

    private Context mContext;

    public ConnectionDetector(Context context){
        this.mContext = context;
    }

    public boolean isConnectingToInternet(){

        ConnectivityManager cm = (ConnectivityManager)mContext.getSystemService(Context.CONNECTIVITY_SERVICE);
        if(cm.getActiveNetworkInfo() != null && cm.getActiveNetworkInfo().isConnected() == true)
        {
            return true; 
        }

        return false;

    }
}

3-打开MainActivity.java -要检查连接的活动,并执行以下操作

创建并定义函数。

ConnectionDetector mConnectionDetector;</pre>

在“OnCreate”中添加以下内容

mConnectionDetector = new ConnectionDetector(getApplicationContext());

C -检查连接使用以下步骤

if (mConnectionDetector.isConnectingToInternet() == false) {
//no connection- do something
} else {
//there is connection
}

在清单

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

在代码中,

public static boolean isOnline(Context ctx) {
    if (ctx == null)
        return false;

    ConnectivityManager cm =
            (ConnectivityManager) ctx.getSystemService(Context.CONNECTIVITY_SERVICE);
    NetworkInfo netInfo = cm.getActiveNetworkInfo();
    if (netInfo != null && netInfo.isConnectedOrConnecting()) {
        return true;
    }
    return false;
}