Fix an NPE in WifiSettings.

Under stressful conditions, like the Monkey tests, getActivity() can
return null. We assume this occurs when the fragment has shut down but
asynchronous commands are returning results. This change adds appropriate
null checks but assumes during normal operation the checks are not needed.

Bug: 7152711
Change-Id: I7a3736ccead33738dab1a36e78ae1d8042db6e94

1 files changed, 33 insertions, 15 deletions

diff --git a/src/com/android/settings/wifi/WifiSettings.java b/src/com/android/settings/wifi/WifiSettings.java
index b28aef334..61f8dcf25 100644
--- a/src/com/android/settings/wifi/WifiSettings.java
+++ b/src/com/android/settings/wifi/WifiSettings.java
@@ -246,9 +246,12 @@ public class WifiSettings extends SettingsPreferenceFragment
                                    public void onSuccess() {
                                    }
                                    public void onFailure(int reason) {
-                                        Toast.makeText(getActivity(),
-                                            R.string.wifi_failed_connect_message,
-                                            Toast.LENGTH_SHORT).show();
+                                       Activity activity = getActivity();
+                                       if (activity != null) {
+                                           Toast.makeText(activity,
+                                                R.string.wifi_failed_connect_message,
+                                                Toast.LENGTH_SHORT).show();
+                                       }
                                    }
                                };
 
@@ -256,9 +259,12 @@ public class WifiSettings extends SettingsPreferenceFragment
                                 public void onSuccess() {
                                 }
                                 public void onFailure(int reason) {
-                                    Toast.makeText(getActivity(),
-                                        R.string.wifi_failed_save_message,
-                                        Toast.LENGTH_SHORT).show();
+                                    Activity activity = getActivity();
+                                    if (activity != null) {
+                                        Toast.makeText(activity,
+                                            R.string.wifi_failed_save_message,
+                                            Toast.LENGTH_SHORT).show();
+                                    }
                                 }
                             };
 
@@ -266,9 +272,12 @@ public class WifiSettings extends SettingsPreferenceFragment
                                    public void onSuccess() {
                                    }
                                    public void onFailure(int reason) {
-                                        Toast.makeText(getActivity(),
-                                            R.string.wifi_failed_forget_message,
-                                            Toast.LENGTH_SHORT).show();
+                                       Activity activity = getActivity();
+                                       if (activity != null) {
+                                           Toast.makeText(activity,
+                                               R.string.wifi_failed_forget_message,
+                                               Toast.LENGTH_SHORT).show();
+                                       }
                                    }
                                };
 
@@ -291,7 +300,7 @@ public class WifiSettings extends SettingsPreferenceFragment
             }
 
             final ConnectivityManager connectivity = (ConnectivityManager)
-                    getActivity().getSystemService(Context.CONNECTIVITY_SERVICE);
+                    activity.getSystemService(Context.CONNECTIVITY_SERVICE);
             if (connectivity != null
                     && connectivity.getNetworkInfo(ConnectivityManager.TYPE_WIFI).isConnected()) {
                 super.onActivityCreated(savedInstanceState);
@@ -307,7 +316,7 @@ public class WifiSettings extends SettingsPreferenceFragment
         if (mEnableNextOnConnection) {
             if (hasNextButton()) {
                 final ConnectivityManager connectivity = (ConnectivityManager)
-                        getActivity().getSystemService(Context.CONNECTIVITY_SERVICE);
+                        activity.getSystemService(Context.CONNECTIVITY_SERVICE);
                 if (connectivity != null) {
                     NetworkInfo info = connectivity.getNetworkInfo(
                             ConnectivityManager.TYPE_WIFI);
@@ -742,7 +751,10 @@ public class WifiSettings extends SettingsPreferenceFragment
             updateAccessPoints();
             updateConnectionState(info.getDetailedState());
             if (mAutoFinishOnConnection && info.isConnected()) {
-                getActivity().finish();
+                Activity activity = getActivity();
+                if (activity != null) {
+                    activity.finish();
+                }
                 return;
             }
         } else if (WifiManager.RSSI_CHANGED_ACTION.equals(action)) {
@@ -779,7 +791,10 @@ public class WifiSettings extends SettingsPreferenceFragment
     }
 
     private void updateWifiState(int state) {
-        getActivity().invalidateOptionsMenu();
+        Activity activity = getActivity();
+        if (activity != null) {
+            activity.invalidateOptionsMenu();
+        }
 
         switch (state) {
             case WifiManager.WIFI_STATE_ENABLED:
@@ -825,8 +840,11 @@ public class WifiSettings extends SettingsPreferenceFragment
                 mRetry = 0;
             } else if (++mRetry >= 3) {
                 mRetry = 0;
-                Toast.makeText(getActivity(), R.string.wifi_fail_to_scan,
-                        Toast.LENGTH_LONG).show();
+                Activity activity = getActivity();
+                if (activity != null) {
+                    Toast.makeText(activity, R.string.wifi_fail_to_scan,
+                            Toast.LENGTH_LONG).show();
+                }
                 return;
             }
             sendEmptyMessageDelayed(0, WIFI_RESCAN_INTERVAL_MS);