Add support for default credentials

src/main/java/com/owncloud/android/authentication/PassCodeManager.java

@@ -95,6 +95,14 @@ public class PassCodeManager {
             activity.startActivityForResult(i, PASSCODE_ACTIVITY);
         }
 
+        if (!sExemptOfPasscodeActivites.contains(activity.getClass()) && Build.VERSION.SDK_INT >=
+                Build.VERSION_CODES.M && deviceCredentialsShouldBeRequested() &&
+                !DeviceCredentialUtils.tryEncrypt()) {
+            Intent i = new Intent(MainApp.getAppContext(), RequestCredentialsActivity.class);
+            i.setFlags(Intent.FLAG_ACTIVITY_REORDER_TO_FRONT);
+            activity.startActivity(i);
+        }
+
         visibleActivitiesCounter++;    // keep it AFTER passCodeShouldBeRequested was checked
     }
 
@@ -134,4 +142,10 @@ public class PassCodeManager {
                         (PreferenceManager.isUseFingerprint(MainApp.getAppContext())
                                 && DeviceCredentialUtils.areCredentialsAvailable(activity));
     }
+
+    private boolean deviceCredentialsShouldBeRequested() {
+        SharedPreferences appPrefs = PreferenceManager
+                .getDefaultSharedPreferences(MainApp.getAppContext());
+        return (appPrefs.getBoolean(Preferences.PREFERENCE_USE_DEVICE_CREDENTIALS, false));
+    }
 }

src/main/java/com/owncloud/android/ui/activity/Preferences.java

@@ -93,6 +93,9 @@ public class Preferences extends PreferenceActivity
     public static final String LOCK_DEVICE_CREDENTIALS = "device_credentials";
 
     public final static String PREFERENCE_USE_FINGERPRINT = "use_fingerprint";
+
+    public final static String PREFERENCE_USE_DEVICE_CREDENTIALS= "use_device_credentials";
+
     public static final String PREFERENCE_EXPERT_MODE = "expert_mode";
 
     private static final int ACTION_REQUEST_PASSCODE = 5;
@@ -520,6 +523,8 @@ public class Preferences extends PreferenceActivity
 
         setupLockPreference(preferenceCategoryDetails, fPassCodeEnabled, fDeviceCredentialsEnabled);
 
+        setupDeviceCredentialsPreference(preferenceCategoryDetails, fDeviceCredentialsEnabled);
+
         setupHiddenFilesPreference(preferenceCategoryDetails, fShowHiddenFilesEnabled);
 
         setupExpertModePreference(preferenceCategoryDetails, fSyncedFolderLightEnabled);

src/main/res/xml/preferences.xml

@@ -44,6 +44,9 @@
 			android:key="lock"
 			android:dialogTitle="@string/prefs_lock_title"
 			android:defaultValue="none"/>
+		<com.owncloud.android.ui.ThemeableSwitchPreference
+			android:title="@string/prefs_use_device_credentials"
+			android:key="use_device_credentials"/>
 		<com.owncloud.android.ui.ThemeableSwitchPreference
 			android:title="@string/prefs_show_hidden_files"
 			android:key="show_hidden_files"/>