Question

我是Android编程新手。我正在制作一个需要＆＃34; OnlineMode＆＃34;以及＆＃34; OfflineMode＆＃34;。我研究了很多关于这个主题的内容，第一步是不断检查互联网连接。就像＃34; WhatsApp＆＃34;等大型应用程序一样。＆＃34;徒步＆＃34;等使用。现在我尝试创建一个将在后台运行的线程，它已创建但无法生成输出结果。我尝试了各种方法。这就是我想要的东西

1。线程应该在整个应用程序的后台连续运行，检查网络连接。

2。用户打开应用程序后应立即创建线程

以下是我的MainActivity.java文件

import android.content.Context;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;    


public class MainActivity extends ActionBarActivity{

    // flag for Internet connection status
    Boolean isInternetPresent = false;

    // Connection detector class
    ConnectionDetector cd;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
       runInBackground();

       Button btnStatus = (Button) findViewById(R.id.btn_check);

        btnStatus.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Toast.makeText(MainActivity.this, "Button Clicked.", Toast.LENGTH_LONG).show();
            }
        });
    }

   void runInBackground() {
        new Thread(new Runnable() {
            @Override
            public void run() {
                ConnectivityManager cm =
                        (ConnectivityManager)getApplicationContext().getSystemService(Context.CONNECTIVITY_SERVICE);
                NetworkInfo activeNetwork = cm.getActiveNetworkInfo();
                boolean isConnected = activeNetwork != null &&
                        activeNetwork.isConnectedOrConnecting();
                if (!isConnected) {
                    runOnUiThread(new Runnable() {
                        @Override
                        public void run() {
                            Thread t1 = new Thread(this);
                            t1.start();
                            Toast.makeText(MainActivity.this, "You are online.", Toast.LENGTH_LONG).show();
                            runInBackground();
                        }
                    });
                } else{
                    Toast.makeText(MainActivity.this, "You have gone offline.", Toast.LENGTH_LONG).show();
                    try {
                        Thread.sleep(6000);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                    runInBackground();
                }
            }
        });
    }                

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();
        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }

编辑：
这是我的最终代码，我收到错误

的AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.xyz.broadcastreciever" >

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name=".MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <receiver android:name=".NetworkChangeReceiver" >
            <intent-filter>
                <action android:name="android.net.conn.CONNECTIVITY_CHANGE" />
                <action android:name="android.net.wifi.WIFI_STATE_CHANGED" />
            </intent-filter>
        </receiver>
        <!-- Internet Permissions -->
        <uses-permission android:name="android.permission.INTERNET" />

        <!-- Network State Permissions -->
        <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
    </application>

</manifest>

MainActivity.java

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.net.ConnectivityManager;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;


public class MainActivity extends ActionBarActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Intent intent = new Intent();
        NetworkChangeReceiver network = new NetworkChangeReceiver();
        network.onReceive(this,intent);
    }


    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }
}

NetworkChangeReceiver.java

公共类NetworkChangeReceiver扩展了BroadcastReceiver {

@Override
public void onReceive(final Context context, final Intent intent) {
    final ConnectivityManager connMgr = (ConnectivityManager) context
            .getSystemService(Context.CONNECTIVITY_SERVICE);

    final android.net.NetworkInfo wifi = connMgr
            .getNetworkInfo(ConnectivityManager.TYPE_WIFI);

    final android.net.NetworkInfo mobile = connMgr
            .getNetworkInfo(ConnectivityManager.TYPE_MOBILE);

    if (wifi.isAvailable() || mobile.isAvailable()) {

        Log.d("Netowk Available ", "Flag No 1");
    }
}

}

以下是我的日志显示错误：

02-19 12:10:21.321  30369-30369/com.aubergine.broadcastreciever E/AndroidRuntime﹕ FATAL EXCEPTION: main
    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.aubergine.broadcastreciever/com.aubergine.broadcastreciever.MainActivity}: java.lang.SecurityException: ConnectivityService: Neither user 10208 nor current process has android.permission.ACCESS_NETWORK_STATE.
            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2245)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2299)
            at android.app.ActivityThread.access$700(ActivityThread.java:150)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1280)
            at android.os.Handler.dispatchMessage(Handler.java:99)
            at android.os.Looper.loop(Looper.java:137)
            at android.app.ActivityThread.main(ActivityThread.java:5283)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:511)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1102)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:869)
            at dalvik.system.NativeStart.main(Native Method)
     Caused by: java.lang.SecurityException: ConnectivityService: Neither user 10208 nor current process has android.permission.ACCESS_NETWORK_STATE.
            at android.os.Parcel.readException(Parcel.java:1425)
            at android.os.Parcel.readException(Parcel.java:1379)
            at android.net.IConnectivityManager$Stub$Proxy.getNetworkInfo(IConnectivityManager.java:1123)
            at android.net.ConnectivityManager.getNetworkInfo(ConnectivityManager.java:636)
            at com.aubergine.broadcastreciever.NetworkChangeReceiver.onReceive(NetworkChangeReceiver.java:19)
            at com.aubergine.broadcastreciever.MainActivity.onCreate(MainActivity.java:22)
            at android.app.Activity.performCreate(Activity.java:5283)
            at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1097)
            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2209)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2299)
            at android.app.ActivityThread.access$700(ActivityThread.java:150)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1280)
            at android.os.Handler.dispatchMessage(Handler.java:99)
            at android.os.Looper.loop(Looper.java:137)
            at android.app.ActivityThread.main(ActivityThread.java:5283)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:511)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1102)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:869)
            at dalvik.system.NativeStart.main(Native Method)

Answer 1

要检查互联网连接，您不应该按照以下步骤启动新线程：

一旦您输入应用程序，请检查互联网连接。
添加一个BroadCastREceiver，继续监听网络开/关，即状态更改更新，添加一个IntentFilter <action android:name="android.net.conn.CONNECTIVITY_CHANGE" />
现在无论何时连接或断开互联网，您都会收到关于BroadcastReceiver onReceive的更新。

这是清单中的接收者

<receiver android:name=".NetworkChangeReceiver" >
            <intent-filter>
                <action android:name="android.net.conn.CONNECTIVITY_CHANGE" />

            </intent-filter>
        </receiver>

这是接收器的java类：

public class NetworkChangeReceiver extends BroadcastReceiver {

    @Override
    public void onReceive(final Context context, final Intent intent) {
        final ConnectivityManager connMgr = (ConnectivityManager) context
                .getSystemService(Context.CONNECTIVITY_SERVICE);

        final android.net.NetworkInfo wifi = connMgr
                .getNetworkInfo(ConnectivityManager.TYPE_WIFI);

        final android.net.NetworkInfo mobile = connMgr
                .getNetworkInfo(ConnectivityManager.TYPE_MOBILE);

        if (wifi.isAvailable() || mobile.isAvailable()) {
            // Do something

            Log.d("Netowk Available ", "Flag No 1");
        }
    }
}

如果您遇到上述任何一种情况，请发表评论。

创建活动时运行后台线程

1 个答案: