Note: This library is in an early stage of development. There will be breaking changes to the public API until the first stable version is released.

GraphView

Android GraphView is used to display data in graph structures.

Overview

The library is designed to support different algorithms. Currently, only the algorithms from Walker (with the runtime improvements from Buchheim) and Fruchterman&Reingold (for small graphs) have been implemented.

Download

dependencies {
    implementation 'de.blox:graphview:0.4.2'
}

Usage

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    <de.blox.graphview.GraphView
     android:id="@+id/graph"
     android:layout_width="match_parent"
     android:layout_height="match_parent">
    </de.blox.graphview.GraphView>
</LinearLayout>

You can make the node Layout how you like. Just define a layout file, e.g. node.xml ...

<android.support.v7.widget.CardView xmlns:android="http://schemas.android.com/apk/res/android"
                                    xmlns:card_view="http://schemas.android.com/apk/res-auto"
                                    android:id="@+id/card_view"
                                    android:layout_width="match_parent"
                                    android:layout_height="wrap_content"
                                    android:layout_gravity="center"
                                    android:layout_margin="5dp"
                                    card_view:cardBackgroundColor="@android:color/holo_blue_dark"
                                    card_view:cardElevation="16dp"
                                    card_view:contentPadding="10dp">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical">

        <TextView
            android:id="@+id/textView"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textColor="@android:color/white"
            android:textStyle="bold"/>

    </LinearLayout>
</android.support.v7.widget.CardView>

... and use it with the adapter

public class MainActivity extends AppCompatActivity {
    private int nodeCount = 1;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        GraphView graphView = findViewById(R.id.graph);

        // example tree
        final Graph graph = new Graph();
        final Node node1 = new Node(getNodeText());
        final Node node2 = new Node(getNodeText());
        final Node node3 = new Node(getNodeText());
        final Node node4 = new Node(getNodeText());
        final Node node5 = new Node(getNodeText());
        final Node node6 = new Node(getNodeText());
        final Node node8 = new Node(getNodeText());
        final Node node7 = new Node(getNodeText());
        final Node node9 = new Node(getNodeText());
        final Node node10 = new Node(getNodeText());
        final Node node11 = new Node(getNodeText());
        final Node node12 = new Node(getNodeText());

        graph.addEdge(node1, node2);
        graph.addEdge(node1, node3);
        graph.addEdge(node1, node4);
        graph.addEdge(node2, node5);
        graph.addEdge(node2, node6);
        graph.addEdge(node6, node7);
        graph.addEdge(node6, node8);
        graph.addEdge(node4, node9);
        graph.addEdge(node4, node10);
        graph.addEdge(node4, node11);
        graph.addEdge(node11, node12);

        // you can set the graph via the constructor or use the adapter.setGraph(Graph) method
        final BaseGraphAdapter<ViewHolder> adapter = new BaseGraphAdapter<ViewHolder>(this, R.layout.node, graph) {
            @NonNull
            @Override
            public ViewHolder onCreateViewHolder(View view) {
                return new ViewHolder(view);
            }

            @Override
            public void onBindViewHolder(ViewHolder viewHolder, Object data, int position) {
                viewHolder.mTextView.setText(data.toString());
            }
        };
        graphView.setAdapter(adapter);
        
        // set the algorithm here
        final BuchheimWalkerConfiguration configuration = new BuchheimWalkerConfiguration.Builder()
                .setSiblingSeparation(100)
                .setLevelSeparation(300)
                .setSubtreeSeparation(300)
                .setOrientation(BuchheimWalkerConfiguration.ORIENTATION_TOP_BOTTOM)
                .build();
        adapter.setAlgorithm(new BuchheimWalkerAlgorithm(configuration));
    }
    
    private String getNodeText() {
        return "Node " + nodeCount++;
    }
}

ViewHolder class:

    private class ViewHolder {
        TextView mTextView;
        ViewHolder(View view) {
            mTextView = view.findViewById(R.id.textView);
        }
    }

Customization

To use the custom attributes you have to add the namespace first: xmlns:app="http://schemas.android.com/apk/res-auto"

Attribute	Format	Example	Explanation
lineThickness	Dimension	10dp	Set how thick the connection lines should be
lineColor	Color	"@android:color/holo_red_dark"	Set the color of the connection lines
useMaxSize	Boolean	true	Use the same size for each node

Each of the attributes has a corresponding setter in the GraphView class, if you want to use it programmatically.

GraphView internally uses ZoomLayout for its zoom feature. To change the zoom values just use the different attributes described in the ZoomLayout project site.

Examples

Rooted Tree

Directed Graph

License

Copyright 2018 Team-Blox

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.