Add pattern protection

app/src/main/java/com/hippo/widget/lockpattern/LockPatternUtils.java

@@ -0,0 +1,75 @@
+/*
+ * Copyright (C) 2007 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.hippo.widget.lockpattern;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Utilities for the lock pattern and its settings.
+ */
+public class LockPatternUtils {
+
+    /**
+     * Deserialize a pattern.
+     * @param string The pattern serialized with {@link #patternToString}
+     * @return The pattern.
+     */
+    public static List<LockPatternView.Cell> stringToPattern(String string) {
+        List<LockPatternView.Cell> result = new ArrayList<>();
+
+        final byte[] bytes = string.getBytes();
+        for (int i = 0; i < bytes.length; i++) {
+            byte b = bytes[i];
+            result.add(LockPatternView.Cell.of(b / 3, b % 3));
+        }
+        return result;
+    }
+
+    /**
+     * Serialize a pattern.
+     * @param pattern The pattern.
+     * @return The pattern in string form.
+     */
+    public static String patternToString(List<LockPatternView.Cell> pattern) {
+        if (pattern == null) {
+            return "";
+        }
+        final int patternSize = pattern.size();
+
+        byte[] res = new byte[patternSize];
+        for (int i = 0; i < patternSize; i++) {
+            LockPatternView.Cell cell = pattern.get(i);
+            res[i] = (byte) (cell.getRow() * 3 + cell.getColumn());
+        }
+        return new String(res);
+    }
+
+    public static boolean isPatternVaild(String pattern) {
+        byte[] bytes = pattern.getBytes();
+        if (bytes.length <= 9 && bytes.length >= 2) {
+            for (byte b : bytes) {
+                if (b >= 9 || b < 0) {
+                    return false;
+                }
+            }
+            return true;
+        } else {
+            return false;
+        }
+    }
+}