Question

I want to implement chart like structure.

For bar graph I’m using no. of buttons in my main activity and hence the output is as following :

---

Then I’m creating new class which extends View in order to draw x and y axes for graph using canvas as following:

public class Draw extends View {

Paint paint = new Paint();

public Draw(Context context) {
    super(context);
    paint.setColor(Color.BLACK);
  }

@Override
public void onDraw(Canvas canvas) {

    canvas.drawLine(20, 50, 20, 200, paint);
    canvas.drawLine(20, 200, 200, 200, paint);
  }
}

But the problem is, after I use following lines of code in my main activity:

Draw draw = new Draw(this);
setContentView(draw);

I get following output as I’m setting the ContentView again:

---

So my question is how do I integrate both these views in order to get below output:

Is there any other way for doing the same?
ANY HELP APPRECIATED.

EDIT

Based on various suggestions, I removed

Draw draw = new Draw(this);
setContentView(draw);

from my activity class and instead put these lines in main xml layout.

<com.example.calci.Draw 
    android:id="@+id/draw" 
    android:layout_width="fill_parent" 
    android:layout_height="fill_parent" />

But I’m getting following EXCEPTION:

java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.calci/com.example.calci.CalciActivity}: android.view.InflateException: Binary XML file line #468: Error inflating class com.example.calci.Draw

Caused by: java.lang.NoSuchMethodException: Draw(Context,AttributeSet)
at java.lang.Class.getMatchingConstructor(Class.java:643)
at java.lang.Class.getConstructor(Class.java:472)
at android.view.LayoutInflater.createView(LayoutInflater.java:480)

EDIT 2

By adding AttributeSet attributeSet to constructor, I got the desired result.

But can anyone suggest whether I should use buttons or rectangles from canvas to draw bar graph.

Please note that I need to modify the height of the bar graphs dynamically based on seekbar value.

Answer 1

If you are using xml for bar graph layout, you can include there your new created view like this:

<view
    class="your.package.name.ProjectName$NameOfYourClass" 
    id="@+id/draw"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent" />

More about using custom components: http://developer.android.com/guide/topics/ui/custom-components.html