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https://github.com/robinhood/spark

A simple Android sparkline chart view.
https://github.com/robinhood/spark

android chart graph sparkline

Last synced: 5 days ago
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A simple Android sparkline chart view.

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README 

        
![](images/sample.png)



Spark

======



> Sparkline: a very small line chart, typically drawn without axes or coordinates. It presents the

> general shape of the variation (typically over time) in some measurement, such as temperature or

> stock market price, in a simple and highly condensed way.

>

> -- [en.wikipedia.org/wiki/Sparkline](https://en.wikipedia.org/wiki/Sparkline)



Spark is a simple Android library that takes a series of x,y points at any scale and draws them as a

sparkline chart.



Usage

-----



Spark is setup with reasonable default values out of the box. Just add a `SparkView` to your layout:



```xml



    



```



Then, just give it a `SparkAdapter` to graph your data:



```java

SparkView sparkView = (SparkView) findViewById(R.id.sparkview);

sparkView.setAdapter(new MyAdapter(data));

...

public class MyAdapter extends SparkAdapter {

    private float[] yData;



    public MyAdapter(float[] yData) {

      this.yData = yData;

    }



    @Override

    public int getCount() {

      return yData.length;

    }



    @Override

    public Object getItem(int index) {

      return yData[index];

    }



    @Override

    public float getY(int index) {

      return yData[index];

    }

}

```



See spark-sample for a complete sample app.



Theming

-------

Spark is very theme-friendly! It has default styles set for you, and welcomes any overrides:



In your `Activity`/`Fragment`/`View`:

```java

sparkView.setLineColor(getColor(R.color.brand_color_primary));

```



In your layout xml:

```xml

    

```



Set a default style for all `SparkView`s in your app's theme:

```xml



    

        <item name="spark_SparkViewStyle">@style/MySparkViewStyle</item>

    



    

        <item name="spark_lineColor">@color/line_color</item>

        <item name="spark_lineWidth">@dimen/line_width</item>

        <item name="spark_cornerRadius">@dimen/corner_radius</item>

        <item name="spark_fill">false</item>



        <item name="spark_baseLineColor">@color/base_line_color</item>

        <item name="spark_baseLineWidth">@dimen/base_line_width</item>



        <item name="spark_scrubLineColor">@color/scrub_line_color</item>

        <item name="spark_scrubLineWidth">@dimen/scrub_line_width</item>

        <item name="spark_scrubEnabled">true</item>



        <item name="spark_animateChanges">true</item>

    



```



Scrubbing

---------

Scrubbing is when the user taps and drags their finger along the sparkline chart. It is very useful

to display additional detail information about the point the user is currently scrubbing over.



Enable scrubbing via xml:

```xml



```



or programatically:

```java

sparkView.setScrubEnabled(true);

```

and then add a `SparkView.OnScrubListener` to get callbacks:

```java

sparkView.setScrubListener(new SparkView.OnScrubListener() {

        @Override

        public void onScrubbed(Object value) {

            scrubInfoTextView.setText(getString(R.string.scrub_format, value));

        }

    });

```



Base Line

---------

It's frequently useful to show a "base line" against which the rest of the sparkline chart will be

compared. In your `SparkAdapter`, override `hasBaseLine()` to return `true` and then return the

appropriate base line value in `getBaseline()`.



X Values

--------

Spark assumes that your graph's points are evenly distributed across the x-axis. If that's not true,

just override `getX(int index)` in your `SparkAdapter` to give `SparkView` the correct value.



Animation

---------

To animate sparkline changes, set an animator with `sparkView.setSparkAnimator(sparkAnimator)`.

There are two built-in animators: LineSparkAnimator (default) and MorphSparkAnimator. Pass your own

implementation to achieve custom effects.



Data Boundaries

---------------

By default, Spark will calculate the min and max of your data set, and draw the sparkline as large as

possible within the View boundaries. If you want different behavior, such as "zooming in" on a portion

of your data, or "zooming out" to leave space between the sparkline and the side of the view, you

can override `SparkAdapter.getDataBounds()`:



```java

public class MyAdapter extends SparkAdapter {

    ...



    @Override

    public RectF getDataBounds() {

        RectF bounds = super.getDataBounds();

        // will 'zoom in' to the middle portion of the graph

        bounds.inset(bounds.width() / 4, bounds.height() / 4);

        return bounds;

    }

}

```



Vision

-------

Spark is a very simple library and cannot possibly meet everyone's use-cases. A more robust charting

library (such as [MP Android Chart](https://github.com/PhilJay/MPAndroidChart)) may be a better fit

if you're looking for things like axes or advanced touch gestures. Spark aims to be lightweight

alternative for showing simple sparklines. Spark will prioritize simplicity over new use-cases the

vast majority of the time.



Download

--------



Gradle:



```groovy

implementation 'com.robinhood.spark:spark:1.2.0'

```



License

--------



    Copyright 2016 Robinhood Markets, Inc.



    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.