Improve UX of Wi-Fi QR code scanner enrollee flow

1. Do not start WifiSettings after enrollee success
2. Return WifiConfiguration to the calling object after enrollee success
3. In WifiDialog, do not show scan button if Save button is not visible to users
4. Fix scanner button may not respond problem by setting listener for scanner
   button of ssid field and password field
5. If SSID is assigned, only allow to enrollee for the network of assigned SSID

Bug: 124416152
Test: manual test
Change-Id: Ic5241c4767eaa8ea01782817d8302d8b0572ab36

src/com/android/settings/wifi/dpp/WifiDppQrCodeScannerFragment.java

@@ -31,7 +31,6 @@ import android.net.wifi.WifiManager;
 import android.os.Bundle;
 import android.os.Handler;
 import android.os.Message;
-import android.provider.Settings;
 import android.text.TextUtils;
 import android.util.Log;
 import android.util.Size;
@@ -47,6 +46,7 @@ import android.widget.TextView;
 import androidx.lifecycle.ViewModelProviders;
 
 import com.android.settings.R;
+import com.android.settings.wifi.WifiDialogActivity;
 import com.android.settings.wifi.qrcode.QrCamera;
 import com.android.settings.wifi.qrcode.QrDecorateView;
 
@@ -76,6 +76,7 @@ public class WifiDppQrCodeScannerFragment extends WifiDppQrCodeBaseFragment impl
     // Key for Bundle usage
     private static final String KEY_IS_CONFIGURATOR_MODE = "key_is_configurator_mode";
     private static final String KEY_LATEST_ERROR_CODE = "key_latest_error_code";
+    private static final String KEY_WIFI_CONFIGURATION = "key_wifi_configuration";
 
     private QrCamera mCamera;
     private TextureView mTextureView;
@@ -91,6 +92,9 @@ public class WifiDppQrCodeScannerFragment extends WifiDppQrCodeBaseFragment impl
     /** QR code data scanned by camera */
     private WifiQrCode mWifiQrCode;
 
+    /** The WifiConfiguration connecting for enrollee usage */
+    private WifiConfiguration mWifiConfiguration;
+
     private int mLatestStatusCode = WifiDppUtils.EASY_CONNECT_EVENT_FAILURE_NONE;
 
     @Override
@@ -100,6 +104,7 @@ public class WifiDppQrCodeScannerFragment extends WifiDppQrCodeBaseFragment impl
         if (savedInstanceState != null) {
             mIsConfiguratorMode = savedInstanceState.getBoolean(KEY_IS_CONFIGURATOR_MODE);
             mLatestStatusCode = savedInstanceState.getInt(KEY_LATEST_ERROR_CODE);
+            mWifiConfiguration = savedInstanceState.getParcelable(KEY_WIFI_CONFIGURATION);
         }
 
         final WifiDppInitiatorViewModel model =
@@ -410,6 +415,7 @@ public class WifiDppQrCodeScannerFragment extends WifiDppQrCodeBaseFragment impl
                     mErrorMessage.setVisibility(View.INVISIBLE);
 
                     final WifiNetworkConfig wifiNetworkConfig = (WifiNetworkConfig)msg.obj;
+                    mWifiConfiguration = wifiNetworkConfig.getWifiConfigurationOrNull();
                     wifiNetworkConfig.connect(getContext(),
                             /* listener */ WifiDppQrCodeScannerFragment.this);
                     break;
@@ -424,6 +430,7 @@ public class WifiDppQrCodeScannerFragment extends WifiDppQrCodeBaseFragment impl
     public void onSaveInstanceState(Bundle outState) {
         outState.putBoolean(KEY_IS_CONFIGURATOR_MODE, mIsConfiguratorMode);
         outState.putInt(KEY_LATEST_ERROR_CODE, mLatestStatusCode);
+        outState.putParcelable(KEY_WIFI_CONFIGURATION, mWifiConfiguration);
 
         super.onSaveInstanceState(outState);
     }
@@ -439,6 +446,7 @@ public class WifiDppQrCodeScannerFragment extends WifiDppQrCodeBaseFragment impl
             for (WifiConfiguration wifiConfig : wifiConfigs) {
                 if (wifiConfig.networkId == newNetworkId) {
                     mLatestStatusCode = WifiDppUtils.EASY_CONNECT_EVENT_SUCCESS;
+                    mWifiConfiguration = wifiConfig;
                     wifiManager.connect(wifiConfig, WifiDppQrCodeScannerFragment.this);
                     return;
                 }
@@ -530,9 +538,11 @@ public class WifiDppQrCodeScannerFragment extends WifiDppQrCodeBaseFragment impl
 
     @Override
     public void onSuccess() {
-        startActivity(new Intent(Settings.ACTION_WIFI_SETTINGS));
+        final Intent resultIntent = new Intent();
+        resultIntent.putExtra(WifiDialogActivity.KEY_WIFI_CONFIGURATION, mWifiConfiguration);
+
         final Activity hostActivity = getActivity();
-        hostActivity.setResult(Activity.RESULT_OK);
+        hostActivity.setResult(Activity.RESULT_OK, resultIntent);
         hostActivity.finish();
     }
 

src/com/android/settings/wifi/dpp/WifiDppUtils.java

@@ -95,6 +95,11 @@ public class WifiDppUtils {
     /**
      * Returns an intent to launch QR code scanner for Wi-Fi DPP enrollee.
      *
+     * After enrollee success, the callee activity will return connecting WifiConfiguration by
+     * putExtra {@code WifiDialogActivity.KEY_WIFI_CONFIGURATION} for
+     * {@code Activity#setResult(int resultCode, Intent data)}. The calling object should check
+     * if it's available before using it.
+     *
      * @param ssid The data corresponding to {@code WifiConfiguration} SSID
      * @return Intent for launching QR code scanner
      */

src/com/android/settings/wifi/dpp/WifiNetworkConfig.java

@@ -228,7 +228,7 @@ public class WifiNetworkConfig {
     /**
      * This is a simplified method from {@code WifiConfigController.getConfig()}
      */
-    private WifiConfiguration getWifiConfigurationOrNull() {
+    WifiConfiguration getWifiConfigurationOrNull() {
         if (!isValidConfig(this)) {
             return null;
         }