optionally show BACK button in the first page of the wizard (issue #18)…

… (#22)

- updated library version to 1.1.0

README.md

@@ -11,7 +11,7 @@ Quoting the [documentation](https://www.google.com/design/spec/components/steppe
 
 ## Download (from JCenter)
 ```groovy
-compile 'com.stepstone.stepper:material-stepper:1.0.3'
+compile 'com.stepstone.stepper:material-stepper:1.1.0'
 ```
 
 ## Supported steppers
@@ -158,6 +158,11 @@ public class StepperActivity extends AppCompatActivity implements StepperLayout.
         Toast.makeText(this, "onStepSelected! -> " + newStepPosition, Toast.LENGTH_SHORT).show();
     }
 
+    @Override
+    public void onReturn() {
+        finish();
+    }
+
 }
 ```
 
@@ -265,6 +270,21 @@ and declare that style in the XML you keep your styles at, e.g.
     </style>
 ```
 
+### Showing a Back button on first step
+By default if the user is on the first step then the Back button in the bottom navigation is hidden. 
+This behaviour can be changed by setting ```ms_showBackButtonOnFirstStep``` to ```true```, e.g.
+```xml
+    <?xml version="1.0" encoding="utf-8"?>
+    <com.stepstone.stepper.StepperLayout xmlns:android="http://schemas.android.com/apk/res/android"
+        xmlns:app="http://schemas.android.com/apk/res-auto"
+        android:id="@+id/stepperLayout"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        app:ms_showBackButtonOnFirstStep="true"
+        app:ms_stepperType="dots" />
+```
+To get a callback when this button was pressed you need set a ```StepperListener``` and write your own custom return logic in the ```onReturn()``` method to e.g. close the Activity.
+
 ### Advanced usage
 For other examples, e.g. persisting state on rotation, displaying errors, changing whether the user can go to the next step, etc. check out the sample app.
 
@@ -285,6 +305,7 @@ For other examples, e.g. persisting state on rotation, displaying errors, changi
 | *ms_nextButtonText*             | string or reference                       | NEXT button's text            |
 | *ms_completeButtonText*         | string or reference                       | COMPLETE button's text            |
 | *ms_tabStepDividerWidth*        | dimension or reference                    | The width of the horizontal tab divider used in tabs stepper type            |
+| *ms_showBackButtonOnFirstStep*  | boolean                                   | Flag indicating if the Back (Previous step) button should be shown on the first step. False by default.            |
 
 ## Missing features
   - support for non-linear steppers

gradle.properties

@@ -19,4 +19,4 @@
 
 POM_GROUP_ID=com.stepstone.stepper
 POM_ARTIFACT_ID=material-stepper
-POM_VERSION=1.0.3
+POM_VERSION=1.1.0

material-stepper/src/main/java/com/stepstone/stepper/StepperLayout.java

@@ -85,6 +85,12 @@ public interface StepperListener {
          */
         void onStepSelected(int newStepPosition);
 
+        /**
+         * Called when the Previous step button was pressed while on the first step
+         * (the button is not present by default on first step).
+         */
+        void onReturn();
+
         StepperListener NULL = new StepperListener() {
             @Override
             public void onCompleted(View completeButton) {
@@ -97,6 +103,10 @@ public void onError(VerificationError verificationError) {
             @Override
             public void onStepSelected(int newStepPosition) {
             }
+
+            @Override
+            public void onReturn() {
+            }
         };
     }
 
@@ -163,6 +173,8 @@ public final void goToNextStep() {
 
     private String mCompleteButtonText;
 
+    private boolean mShowBackButtonOnFirstStep;
+
     private int mTypeIdentifier = AbstractStepperType.PROGRESS_BAR;
 
     private AbstractStepAdapter mStepAdapter;
@@ -413,6 +425,8 @@ private void extractValuesFromAttributes(AttributeSet attrs, @AttrRes int defSty
                 mTabStepDividerWidth = a.getDimensionPixelOffset(R.styleable.StepperLayout_ms_tabStepDividerWidth, -1);
             }
 
+            mShowBackButtonOnFirstStep = a.getBoolean(R.styleable.StepperLayout_ms_showBackButtonOnFirstStep, false);
+
             if (a.hasValue(R.styleable.StepperLayout_ms_stepperType)) {
                 mTypeIdentifier = a.getInt(R.styleable.StepperLayout_ms_stepperType, DEFAULT_TAB_DIVIDER_WIDTH);
             }
@@ -441,9 +455,12 @@ private Step findCurrentStep() {
     }
 
     private void onPrevious() {
-        if (mCurrentStepPosition <= 0)
+        if (mCurrentStepPosition <= 0) {
+            if (mShowBackButtonOnFirstStep) {
+                mListener.onReturn();
+            }
             return;
-
+        }
         mCurrentStepPosition--;
         onUpdate(mCurrentStepPosition);
     }
@@ -494,7 +511,7 @@ private void onUpdate(int newStepPosition) {
         boolean isFirst = newStepPosition == 0;
         mNextNavigationButton.setVisibility(isLast ? View.GONE : View.VISIBLE);
         mCompleteNavigationButton.setVisibility(!isLast ? View.GONE : View.VISIBLE);
-        mBackNavigationButton.setVisibility(isFirst ? View.GONE : View.VISIBLE);
+        mBackNavigationButton.setVisibility(isFirst && !mShowBackButtonOnFirstStep ? View.GONE : View.VISIBLE);
 
         if (!isLast) {
             int nextButtonTextForStep = mStepAdapter.getNextButtonText(newStepPosition);

material-stepper/src/main/res/values/attrs.xml

@@ -46,6 +46,9 @@ limitations under the License.
 
         <!-- The width of the horizontal tab divider used in tabs stepper type -->
         <attr name="ms_tabStepDividerWidth" format="dimension|reference" />
+
+        <!-- Flag indicating if the Back (Previous step) button should be shown on the first step. False by default. -->
+        <attr name="ms_showBackButtonOnFirstStep" format="boolean" />
 
         <!-- REQUIRED: Type of the stepper-->
         <attr name="ms_stepperType">

sample/src/main/AndroidManifest.xml

@@ -35,6 +35,8 @@
 
         <activity android:name=".DifferentNextButtonStepperActivity" />
 
+        <activity android:name=".ReturnButtonActivity" />
+
     </application>
 
 </manifest>

sample/src/main/java/com/stepstone/stepper/sample/AbstractStepperActivity.java

@@ -83,6 +83,11 @@ public void onStepSelected(int newStepPosition) {
         Toast.makeText(this, "onStepSelected! -> " + newStepPosition, Toast.LENGTH_SHORT).show();
     }
 
+    @Override
+    public void onReturn() {
+        finish();
+    }
+
     @Override
     public void onChangeEndButtonsEnabled(boolean enabled) {
         mStepperLayout.setNextButtonVerificationFailed(!enabled);

sample/src/main/java/com/stepstone/stepper/sample/MainActivity.java

@@ -88,4 +88,9 @@ public void onDifferentNextButtons(View view) {
         startActivity(new Intent(this, DifferentNextButtonStepperActivity.class));
     }
 
+    @OnClick(R.id.showReturnButtonOnFirstStep)
+    public void onShowReturnButton(View view) {
+        startActivity(new Intent(this, ReturnButtonActivity.class));
+    }
+
 }

sample/src/main/java/com/stepstone/stepper/sample/ReturnButtonActivity.java

@@ -0,0 +1,26 @@
+/*
+Copyright 2016 StepStone Services
+
+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.stepstone.stepper.sample;
+
+public class ReturnButtonActivity extends AbstractStepperActivity {
+
+    @Override
+    protected int getLayoutResId() {
+        return R.layout.activity_return_button;
+    }
+
+}

sample/src/main/res/layout/activity_main.xml

@@ -82,5 +82,11 @@
             android:layout_height="wrap_content"
             android:text="@string/different_next_buttons" />
 
+        <Button
+            android:id="@+id/showReturnButtonOnFirstStep"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:text="@string/show_back_button" />
+
     </LinearLayout>
 </ScrollView>

sample/src/main/res/layout/activity_return_button.xml

@@ -0,0 +1,9 @@
+<?xml version="1.0" encoding="utf-8"?>
+<com.stepstone.stepper.StepperLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    android:id="@+id/stepperLayout"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:orientation="vertical"
+    app:ms_showBackButtonOnFirstStep="true"
+    app:ms_stepperType="dots"/>

sample/src/main/res/values/strings.xml

@@ -11,6 +11,7 @@
     <string name="custom_page_transformer">Custom PageTransformer</string>
     <string name="delayed_transition">Delayed transition</string>
     <string name="different_next_buttons">Different next buttons</string>
+    <string name="show_back_button">Show Back button on first step</string>
 
     <string name="tab_title">Tab title</string>
     <string name="lorem_ipsum">Lorem ipsum dolor sit amet, sale viris intellegam usu eu, persius patrioque sea at. Ne salutandi repudiandae mei, cu mollis accusam mediocrem mea. Altera dolorem praesent at vis. Torquatos philosophia ad quo. Omnis adipiscing has ea, mel no hinc iudico percipit.</string>