java - 连接改变时显示 toast

Question

我构建了一个使用 WebView 流式传输音频的应用程序。现在我添加了一个检查是否有连接(或没有)。使用 toast 我显示一 strip 有“真”或“假”的消息，但我只想在连接发生变化时显示 toast 。我该怎么办？

protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

update();

private void update() {
        new Thread() {
            public void run() {
                while (true) {
                    runOnUiThread(new Runnable() {
                         @Override
                         public void run() {
                             isOnline();
                         }
                    });
                    try {
                        Thread.sleep(5000);
                    } catch (InterruptedException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }
                } 
            }
        }.start();
        }


    public boolean isOnline() {
        ConnectivityManager cm = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo netInfo = cm.getActiveNetworkInfo();
        if (netInfo != null && netInfo.isConnectedOrConnecting()) {

            Toast.makeText(getApplicationContext(), "true",Toast.LENGTH_LONG).show();   
            return true;
        }
        Toast.makeText(getApplicationContext(), "false",Toast.LENGTH_LONG).show();
        return false;

Answer 1

试试这个:

public class BroadCastSampleActivity extends Activity {
        /** Called when the activity is first created. */
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            // TODO Auto-generated method stub
            super.onCreate(savedInstanceState);
            this.registerReceiver(this.mConnReceiver,
                    new IntentFilter(ConnectivityManager.CONNECTIVITY_ACTION));
        }
        private BroadcastReceiver mConnReceiver = new BroadcastReceiver() {
            public void onReceive(Context context, Intent intent) {
                boolean noConnectivity = intent.getBooleanExtra(ConnectivityManager.EXTRA_NO_CONNECTIVITY, false);
                String reason = intent.getStringExtra(ConnectivityManager.EXTRA_REASON);
                boolean isFailover = intent.getBooleanExtra(ConnectivityManager.EXTRA_IS_FAILOVER, false);

                NetworkInfo currentNetworkInfo = (NetworkInfo) intent.getParcelableExtra(ConnectivityManager.EXTRA_NETWORK_INFO);
                NetworkInfo otherNetworkInfo = (NetworkInfo) intent.getParcelableExtra(ConnectivityManager.EXTRA_OTHER_NETWORK_INFO);

                if(currentNetworkInfo.isConnected()){
                    Toast.makeText(getApplicationContext(), "Connected", Toast.LENGTH_LONG).show();
                }else{
                    Toast.makeText(getApplicationContext(), "Not Connected", Toast.LENGTH_LONG).show();
                }
            }
        };
}

在您的 list 中添加此权限:

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