Complex branching with Conditionals

library/src/main/java/com/tech/freak/wizardpager/model/Conditional.java

@@ -0,0 +1,78 @@
+/*
+ * Copyright 2013 str4d
+ *
+ * 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.tech.freak.wizardpager.model;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+public class Conditional implements ModelCallbacks {
+    private Object mData = null;
+    private List<Page> mConditionalPages = new ArrayList<Page>();
+
+    public void onPageDataChanged(Page page) {
+        mData = page.getData().get(Page.SIMPLE_DATA_KEY);
+        for (Page p : mConditionalPages)
+            p.isSatisfied();
+    }
+
+    public void onPageTreeChanged() {
+    }
+
+    public interface Condition {
+        public boolean isSatisfied();
+    }
+
+    public class EqualCondition<T> implements Condition {
+        private T mCompValue;
+
+        public EqualCondition(Page page, T compValue) {
+            mCompValue = compValue;
+            mConditionalPages.add(page);
+        }
+
+        public boolean isSatisfied() {
+            return mCompValue.equals(mData);
+        }
+    }
+
+    public class NotEqualCondition<T> implements Condition {
+        private T mCompValue;
+
+        public NotEqualCondition(Page page, T compValue) {
+            mCompValue = compValue;
+            mConditionalPages.add(page);
+        }
+
+        public boolean isSatisfied() {
+            return !(mCompValue.equals(mData));
+        }
+    }
+
+    public class EqualAnyCondition<T> implements Condition {
+        private ArrayList<T> mChoices = new ArrayList<T>();
+
+        public EqualAnyCondition(Page page, T... choices) {
+            mChoices.addAll(Arrays.asList(choices));
+            mConditionalPages.add(page);
+        }
+
+        public boolean isSatisfied() {
+            return mChoices.contains(mData);
+        }
+    }
+}

library/src/main/java/com/tech/freak/wizardpager/model/Page.java

@@ -1,4 +1,5 @@
 /*
+ * Copyright 2013 str4d
  * Copyright 2012 Roman Nurik
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
@@ -20,6 +21,7 @@
 import android.support.v4.app.Fragment;
 
 import java.util.ArrayList;
+import java.util.List;
 
 /**
  * Represents a single page in the wizard.
@@ -32,6 +34,24 @@ public abstract class Page implements PageTreeNode {
 
     protected ModelCallbacks mCallbacks;
 
+    /**
+     * Conditionals that rely on this page.
+     */
+    protected List<ModelCallbacks> mConditionals = new ArrayList<ModelCallbacks>();
+
+    /**
+     * Conditions on whether this page should be used.
+     */
+    protected List<Conditional.Condition> mConditions = new ArrayList<Conditional.Condition>();
+    /**
+     * Should all conditions be satisfied, or any of them?
+     */
+    protected boolean mConditionAnd = false;
+    /**
+     * The last condition status.
+     */
+    protected boolean mSatisfied = true;
+
     /**
      * Current wizard values/selections.
      */
@@ -53,22 +73,43 @@ public String getTitle() {
         return mTitle;
     }
 
+    public boolean isSatisfied() {
+        boolean ret = true;
+        if (mConditions.size() > 0) {
+            ret = false;
+            for (Conditional.Condition c : mConditions) {
+                if (c.isSatisfied()) {
+                    ret = true;
+                    if (!mConditionAnd) break;
+                } else if (mConditionAnd) {
+                    ret = false;
+                    break;
+                }
+            }
+        }
+        // If the conditions have changed, update the page tree.
+        if (!(mSatisfied == ret)) {
+            mSatisfied = ret;
+            mCallbacks.onPageTreeChanged();
+        }
+        return mSatisfied;
+    }
+
     public boolean isRequired() {
-        return mRequired;
+        return isSatisfied() && mRequired;
     }
 
     void setParentKey(String parentKey) {
         mParentKey = parentKey;
     }
 
-    @Override
     public Page findByKey(String key) {
         return getKey().equals(key) ? this : null;
     }
 
-    @Override
     public void flattenCurrentPageSequence(ArrayList<Page> dest) {
-        dest.add(this);
+        if (isSatisfied())
+            dest.add(this);
     }
 
     public abstract Fragment createFragment();
@@ -89,11 +130,42 @@ public void resetData(Bundle data) {
     }
 
     public void notifyDataChanged() {
+        for (ModelCallbacks c : mConditionals) {
+            c.onPageDataChanged(this);
+        }
         mCallbacks.onPageDataChanged(this);
     }
 
     public Page setRequired(boolean required) {
         mRequired = required;
         return this;
     }
+
+    public Page makeConditional(Conditional conditional) {
+        mConditionals.add(conditional);
+        return this;
+    }
+
+    public <T> Page setEqualCondition(Conditional conditional, T comp) {
+        Conditional.Condition c = conditional.new EqualCondition<T>(this, comp);
+        mConditions.add(c);
+        return this;
+    }
+
+    public <T> Page setNotEqualCondition(Conditional conditional, T comp) {
+        Conditional.Condition c = conditional.new NotEqualCondition<T>(this, comp);
+        mConditions.add(c);
+        return this;
+    }
+
+    public <T> Page setEqualAnyCondition(Conditional conditional, T... choices) {
+        Conditional.Condition c = conditional.new EqualAnyCondition<T>(this, choices);
+        mConditions.add(c);
+        return this;
+    }
+
+    public Page satisfyAllConditions(boolean conditionAnd) {
+        mConditionAnd = conditionAnd;
+        return this;
+    }
 }