Draw Text inside an Arc using canvas

android, android-canvas

Solution

Try this:

private String[] STRINGS = { "Yellow", "GREEN", "WHITE", "CYAN", "RED" }; // Array of strings, just for the sample

    @Override
    protected void onDraw(Canvas canvas) 
    {           
        super.onDraw(canvas);

        temp = 0;

        int centerX = (rect.left + rect.right) / 2;
        int centerY = (rect.top + rect.bottom) / 2;
        int radius = (rect.right - rect.left) / 2;

        radius *= 0.5; // 1 will put the text in the border, 0 will put the text in the center. Play with this to set the distance of your text.

        for (int i = 0; i < data.length; i++) 
        {
            if (i > 0) 
                temp += (int) data[i - 1]; // rewrote your code here a bit, to avoid duplicate code.

            paint.setColor(COLORS[i]);
            canvas.drawArc(rectf, temp, data[i], true, paint);

            paint.setColor(Color.BLACK); // set this to the text color.
            float medianAngle = (temp + (data[i] / 2f)) * (float)Math.PI / 180f; // this angle will place the text in the center of the arc.
            canvas.drawText(STRINGS[i], (float)(centerX + (radius * Math.cos(medianAngle))), (float)(centerY + (radius * Math.sin(medianAngle))), paint);
        }
    }

Also, for nicer results, make sure to set the Align.CENTER property in the paint before drawing any text:

paint.setTextSize(16);
paint.setTextAlign(Align.CENTER);

Hope this helps :)

Problem

I am working in an android application to draw a circle and divide them equally and bind text inside the divided portion in the circle(like pichart). I have drawn a circle and divided them equally, but I want to bind text inside the divided portion. Please look into my code and give a solution. Thanks in advance. ``` public class MainActivity extends Activity { /** Called when the activity is first created. */ float values[] = { 130, 130, 130, 130, 130 }; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); LinearLayout linear = (LinearLayout) findViewById(R.id.linearlay); values = calculateData(values); linear.addView(new MyGraphview(this, values)); } private float[] calculateData(float[] data) { float total = 0; for (int i = 0; i < data.length; i++) { total += data[i]; } for (int i = 0; i < data.length; i++) { data[i] = 360 * (data[i] / total); } return data; } public class MyGraphview extends View { private Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG); private float[] value_degree; private int[] COLORS = { Color.YELLOW, Color.GREEN, Color.WHITE, Color.CYAN, Color.RED }; RectF rectf = new RectF(10, 10, 300, 300); Rect rect = new Rect(10, 10, 300, 300); int temp = 0; String rotatedtext; Path path; public MyGraphview(Context context, float[] values) { super(context); path = new Path(); value_degree = new float[values.length]; for (int i = 0; i < values.length; i++) { value_degree[i] = values[i]; } paint.setTextSize(16); rotatedtext = "Rotated :)"; } @Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); for (int i = 0; i < value_degree.length; i++) { if (i == 0) { paint.setColor(COLORS[i]); canvas.drawArc(rectf, 0, value_degree[i], true, paint); } else { temp += (int) value_degree[i - 1]; paint.setColor(COLORS[i]); canvas.drawArc(rectf, temp, value_degree[i], true, paint); // } } } } } ```

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