ViewFlow is an Android UI widget providing a horizontally scrollable ViewGroup with items populated from an Adapter. Scroll down to the bottom of the page for a screen shot.

The component is a Library Project. 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.

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.

<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".

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.

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
    }
});

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();
    }
});

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:

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);

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.

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);

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.

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);
	}

The following persons deserves a mention for their contributions:

• Eric Taix
• Marc Reichelt, http://marcreichelt.blogspot.com/

GitHub has some great articles on how to get started with Git and GitHub and how to fork a project.

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.

Copyright (c) 2011 Patrik Åkerfeldt

Licensed under the Apache License, Version 2.0