如何延迟文本视图输出

Question

我正在使用下面的代码连接到wifi网络。有没有办法可以延迟文本视图文本的输出，使其在连接到 wifi 之前不会显示？消息在实际连接之前就出现了。

import java.util.List;
import android.app.Activity;
import android.os.Bundle;
import android.content.Context;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.net.wifi.WifiConfiguration;
import android.net.wifi.WifiManager;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;
public class TestActivity extends Activity {
/** Called when the activity is first created. 
 * @return */

@Override
public void onCreate(Bundle savedInstanceState) {    
    super.onCreate(savedInstanceState);          

    setContentView(R.layout.main);
    Button OffWifi = (Button)findViewById(R.id.offwifi);
    OffWifi.setOnClickListener(new OnClickListener() { 
      public void onClick(View v) {   
          WifiManager wifiManager = (WifiManager)getBaseContext().getSystemService(Context.WIFI_SERVICE);
            wifiManager.setWifiEnabled(false);          
          }        
      });

    TextView tv= (TextView) findViewById(R.id.tv); 
    WifiManager wifi = (WifiManager) getSystemService(Context.WIFI_SERVICE); 
    WifiConfiguration wc = new WifiConfiguration();  
    wc.SSID = ""Test""; //IMP! This should be in Quotes!! 
    wc.hiddenSSID = true; 
    wc.status = WifiConfiguration.Status.ENABLED;      
    wc.priority = 10; 
    wc.allowedKeyManagement.set(WifiConfiguration.KeyMgmt.WPA_PSK); 
    wc.allowedProtocols.set(WifiConfiguration.Protocol.RSN);  
    wc.allowedProtocols.set(WifiConfiguration.Protocol.WPA); 
    wc.allowedAuthAlgorithms.set(WifiConfiguration.AuthAlgorithm.OPEN); 
    wc.allowedAuthAlgorithms.set(WifiConfiguration.AuthAlgorithm.SHARED); 
    wc.allowedPairwiseCiphers.set(WifiConfiguration.PairwiseCipher.CCMP); 
    wc.allowedPairwiseCiphers.set(WifiConfiguration.PairwiseCipher.TKIP); 
    wc.preSharedKey = ""Password""; 
    WifiManager  wifiManag = (WifiManager) this.getSystemService(WIFI_SERVICE); 
    boolean res1 = wifiManag.setWifiEnabled(true); 
    int res = wifi.addNetwork(checkPreviousConfiguration(wc)); 
    Log.d("WifiPreference", "add Network returned " + res ); 
    boolean es = wifi.saveConfiguration(); 
    Log.d("WifiPreference", "saveConfiguration returned " + es ); 
    boolean b = wifi.enableNetwork(res, true);    
    Log.d("WifiPreference", "enableNetwork returned " + b );   

         ConnectivityManager connec = (ConnectivityManager)getSystemService(Context.CONNECTIVITY_SERVICE); 
         if (connec != null && (connec.getNetworkInfo(1).getState() == NetworkInfo.State.CONNECTED) ||(connec.getNetworkInfo(0).getState() == NetworkInfo.State.CONNECTED)){  
             tv.setText("You are now connected!  " +  "Version 1.1"); 
            }else if (connec.getNetworkInfo(0).getState() == NetworkInfo.State.DISCONNECTED ||  connec.getNetworkInfo(1).getState() == NetworkInfo.State.DISCONNECTED ) {              
                tv.setText("The was an error connecting, please try again."); 
            }  
    }     


 public WifiConfiguration checkPreviousConfiguration(WifiConfiguration wc) {
WifiManager wifi = (WifiManager) getSystemService(Context.WIFI_SERVICE); 
 List<WifiConfiguration> configs = wifi.getConfiguredNetworks();     
    for(WifiConfiguration config : configs) {         
        if(config.SSID.equals(wc.SSID)) return config;     
        }     
    return wc; 
    } 
}

Answer 1

使用AsyncTask并将连接放在doInBackground中，setText放入onPostExecute

public class Connect extends AsyncTask<String, Void, Boolean> {
private Activity activity;
private Context context;
public LoadContacts(Activity activity){
    this.activity=activity;
    context = activity;
}
@Override
protected void onPreExecute() {
    // TODO Auto-generated method stub
    super.onPreExecute();
}
@Override
protected void onPostExecute(Boolean result) {
    TextView tv= (TextView) activity.findViewById(R.id.tv); 
    if (connec != null && (connec.getNetworkInfo(1).getState() == NetworkInfo.State.CONNECTED) ||(connec.getNetworkInfo(0).getState() == NetworkInfo.State.CONNECTED)){  
         tv.setText("You are now connected!  " +  "Version 1.1"); 
        }else if (connec.getNetworkInfo(0).getState() == NetworkInfo.State.DISCONNECTED ||  connec.getNetworkInfo(1).getState() == NetworkInfo.State.DISCONNECTED ) {              
            tv.setText("The was an error connecting, please try again."); 
        }
    super.onPostExecute();
}
@Override
protected Boolean doInBackground(String... params) {
    WifiManager wifi = (WifiManager) activity.getSystemService(Context.WIFI_SERVICE); 
WifiConfiguration wc = new WifiConfiguration();  
wc.SSID = ""Test""; //IMP! This should be in Quotes!! 
wc.hiddenSSID = true; 
wc.status = WifiConfiguration.Status.ENABLED;      
wc.priority = 10; 
wc.allowedKeyManagement.set(WifiConfiguration.KeyMgmt.WPA_PSK); 
wc.allowedProtocols.set(WifiConfiguration.Protocol.RSN);  
wc.allowedProtocols.set(WifiConfiguration.Protocol.WPA); 
wc.allowedAuthAlgorithms.set(WifiConfiguration.AuthAlgorithm.OPEN); 
wc.allowedAuthAlgorithms.set(WifiConfiguration.AuthAlgorithm.SHARED); 
wc.allowedPairwiseCiphers.set(WifiConfiguration.PairwiseCipher.CCMP); 
wc.allowedPairwiseCiphers.set(WifiConfiguration.PairwiseCipher.TKIP); 
wc.preSharedKey = ""Password""; 
WifiManager  wifiManag = (WifiManager) context.getSystemService(WIFI_SERVICE); 
boolean res1 = wifiManag.setWifiEnabled(true); 
int res = wifi.addNetwork(checkPreviousConfiguration(wc)); 
Log.d("WifiPreference", "add Network returned " + res ); 
boolean es = wifi.saveConfiguration(); 
Log.d("WifiPreference", "saveConfiguration returned " + es ); 
boolean b = wifi.enableNetwork(res, true);    
Log.d("WifiPreference", "enableNetwork returned " + b );   

     ConnectivityManager connec = (ConnectivityManager) activity.getSystemService(Context.CONNECTIVITY_SERVICE); 
    return true;
}
}

测试活动应如下所示：

public class TestActivity extends Activity {
/** Called when the activity is first created. 
 * @return */
@Override
public void onCreate(Bundle savedInstanceState) {    
super.onCreate(savedInstanceState);          

setContentView(R.layout.main);
new Connect(this).execute();
}

代码未经测试，可能会有一些错误，但我希望你明白这一点......

Answer 2

在我看来

，你需要一个BoadcastReceiver来监听NETWORK_STATE_CHANGED意图广播。