Get app label by launched package

- Activity#getCallingPackage will return null in some special cases, use the launched package instead.

Bug: 194709435
Test: manual test
make RunSettingsRoboTests ROBOTEST_FILTER=WifiScanModeActivityTest

Change-Id: I4f22bab7592dedf75dd36daf5e18dbc934bc8655

src/com/android/settings/wifi/WifiScanModeActivity.java

@@ -20,26 +20,30 @@ import android.app.Dialog;
 import android.app.settings.SettingsEnums;
 import android.content.DialogInterface;
 import android.content.Intent;
-import android.content.pm.ApplicationInfo;
-import android.content.pm.PackageManager;
 import android.net.wifi.WifiManager;
 import android.os.Bundle;
 import android.text.TextUtils;
 import android.view.WindowManager;
 
+import androidx.annotation.VisibleForTesting;
 import androidx.appcompat.app.AlertDialog;
 import androidx.fragment.app.DialogFragment;
 import androidx.fragment.app.FragmentActivity;
 
 import com.android.settings.R;
+import com.android.settings.Utils;
 import com.android.settings.core.instrumentation.InstrumentedDialogFragment;
+import com.android.settingslib.wifi.WifiPermissionChecker;
 
 /**
  * This activity requests users permission to allow scanning even when Wi-Fi is turned off
  */
 public class WifiScanModeActivity extends FragmentActivity {
     private DialogFragment mDialog;
-    private String mApp;
+    @VisibleForTesting
+    String mApp;
+    @VisibleForTesting
+    WifiPermissionChecker mWifiPermissionChecker;
 
     @Override
     protected void onCreate(Bundle savedInstanceState) {
@@ -50,13 +54,7 @@ public class WifiScanModeActivity extends FragmentActivity {
         if (savedInstanceState == null) {
             if (intent != null && WifiManager.ACTION_REQUEST_SCAN_ALWAYS_AVAILABLE
                     .equals(intent.getAction())) {
-                ApplicationInfo ai;
-                mApp = getCallingPackage();
-                try {
-                    PackageManager pm = getPackageManager();
-                    ai = pm.getApplicationInfo(mApp, 0);
-                    mApp = (String)pm.getApplicationLabel(ai);
-                } catch (PackageManager.NameNotFoundException e) { }
+                refreshAppLabel();
             } else {
                 finish();
                 return;
@@ -67,6 +65,19 @@ public class WifiScanModeActivity extends FragmentActivity {
         createDialog();
     }
 
+    @VisibleForTesting
+    void refreshAppLabel() {
+        if (mWifiPermissionChecker == null) {
+            mWifiPermissionChecker = new WifiPermissionChecker(this);
+        }
+        String packageName = mWifiPermissionChecker.getLaunchedPackage();
+        if (TextUtils.isEmpty(packageName)) {
+            mApp = null;
+            return;
+        }
+        mApp = Utils.getApplicationLabel(getApplicationContext(), packageName).toString();
+    }
+
     private void createDialog() {
         if (mDialog == null) {
             mDialog = AlertDialogFragment.newInstance(mApp);