# View Flow for Android ViewFlow is an Android UI widget providing a horizontally scrollable [ViewGroup](http://developer.android.com/reference/android/view/ViewGroup.html) with items populated from an [Adapter](http://developer.android.com/reference/android/widget/Adapter.html). Scroll down to the bottom of the page for a screen shot. The component is a [Library Project](http://developer.android.com/guide/developing/eclipse-adt.html#libraryProject). This means that there's no need to copy-paste resources into your own project, simply add the viewflow component as a reference to any project. ## When to use This library might be suitable if you have an indeterminate number of views in your viewflow, if instead you have a static numbers of views you ought to look at Fragments and the ViewPager in the Compatibility Library instead. ## Usage ### In your layout <org.taptwo.android.widget.ViewFlow android:id="@+id/viewflow" app:sidebuffer="5" /> The use of `app:sidebuffer` is optional. It defines the number of Views to buffer on each side of the currently shown View. The default sidebuffer is 3, making up a grand total of 7 (3 * 2 + 1) Views loaded at a time (at max). To be able to use the more convenient `app:sidebuffer` attribute, the application namespace must be included in the same manner as the android namespace is. Please refer to the layout main.xml in the example project for a full example. Again, note that it's the application namespace and *not* the viewflow namespace that must be referred like `xmlns:app="http://schemas.android.com/apk/res/your.application.package.here"`. ### In your activity ViewFlow viewFlow = (ViewFlow) findViewById(R.id.viewflow); viewFlow.setAdapter(myAdapter); Setting a different initial position (0 being default) is as easy as: viewFlow.setAdapter(myAdapter, 8); Although possible, you should not call `setSelection(...)` immediately after calling `setAdapter(myAdapter)` as that might load unnecessary views giving you a decrease in performance. ### Listen on screen change events If you need to listen to screen change events you would want to implement your own `ViewFlow.ViewSwitchListener` and pass it to the `setOnViewSwitchListener()` method. viewFlow.setOnViewSwitchListener(new ViewSwitchListener() { public void onSwitched(View v, int position) { // Your code here } }); ### Listen on initialize view events If you need a lazy View initialization you would want to implement your own `ViewFlow.ViewLazyInitializeListener` and pass it to the `setOnViewLazyInitializeListener()` method. viewFlow.setOnViewLazyInitializeListener(new ViewLazyInitializeListener() { public void onViewLazyInitialize(View view, int position) { // Your code here e.g. ((MyAdapter)((AbsListView)view).getAdapter()).initializeData(); } }); ### Flow Indicator It is also possible to add a flow view indicator to your layout. The purpose of a `FlowIndicator` is to present a visual representation of where in the item list focus is at. You may either implement a `FlowIndicator` yourself or use an implementation provided by the View Flow library. The View Flow library currently supports the following indicators: #### Circle Flow Indicator #### This indicator shows a circle for each `View` in the adapter with a special circle representing the currently selected view (see screenshot below). <org.taptwo.android.widget.CircleFlowIndicator android:padding="10dip" android:layout_height="wrap_content" android:layout_width="wrap_content" android:id="@+id/viewflowindic" android:background="#00000000"/> And then you'll need to connect your `ViewFlow` with the `FlowIndicator`: CircleFlowIndicator indic = (CircleFlowIndicator) findViewById(R.id.viewflowindic); viewFlow.setFlowIndicator(indic); By default, the 'active' indicator moves smoothly from one 'inactive' indicator to the next, as the user scrolls. If you set the `snap` attribute to `true`, it will instead jump to the next position when the flow settles at the next page. The following attributes are supported: `activeColor`, `inactiveColor`, `activeType` (either fill or stroke), `inactiveType` (either fill or stroke), `fadeOut` (time in ms until indicator fades out, 0 = never), `radius`, `sync` (see above). #### Title Flow Indicator #### This indicator presents the title of the previous, current and next `View` in the adapter (see screenshot below). <org.taptwo.android.widget.TitleFlowIndicator android:id="@+id/viewflowindic" android:layout_height="wrap_content" android:layout_width="fill_parent" app:footerLineHeight="2dp" app:footerTriangleHeight="10dp" app:textColor="#FFFFFFFF" app:selectedColor="#FFFFC445" app:footerColor="#FFFFC445" app:titlePadding="10dp" app:textSize="11dp" app:selectedSize="12dp" android:layout_marginTop="10dip" app:clipPadding="5dp" /> And then you'll need to connect your `ViewFlow` with the `FlowIndicator`: TitleFlowIndicator indicator = (TitleFlowIndicator) findViewById(R.id.viewflowindic); indicator.setTitleProvider(myTitleProvider); viewFlow.setFlowIndicator(indicator); ## Building a jar file If you rather want a jar file instead of a including the project as an android library, run `ant jar` in the `android-viewflow/viewflow` folder, to build a jar file. ## Caveats ## The manifest states a min sdk version of 4, which is true. But in any case you want to support an api level < 8 you will have to forward an `onConfigurationChanged` event to the `ViewFlow` from your `Activity`. I know this isn't a very nice solution, feel free to propose better ones! @Override public void onConfigurationChanged(Configuration newConfig) { super.onConfigurationChanged(newConfig); viewFlow.onConfigurationChanged(newConfig); } ## Contributions The following persons deserves a mention for their contributions: * Eric Taix * Marc Reichelt, <http://marcreichelt.blogspot.com/> ### Want to contribute? GitHub has some great articles on [how to get started with Git and GitHub](http://help.github.com/) and how to [fork a project](http://help.github.com/forking/). Contributers are recommended to fork the app on GitHub (but don't have too). Create a feature branch, push the branch to git hub, press Pull Request and write a simple explanation. One fix per commit. If let's say a commit closes the open issue 12. Just add `closes #12` in your commit message to close that issue automagically. If you still feel uncomfortable contributing the project github-wise, don't hesistate to send a regular patch. All code that is contributed must be compliant with [Apache License 2.0](http://www.apache.org/licenses/LICENSE-2.0.html). ## License Copyright (c) 2011 [Patrik Åkerfeldt](http://about.me/pakerfeldt) Licensed under the [Apache License, Version 2.0](http://www.apache.org/licenses/LICENSE-2.0.html)  &nbsp;&nbsp;