android - 外部APIを使用せずにAndroidでグラフを描画するにはどうすればよいですか？

Question

キャンバスを使用して線を描画する方法は理解していますが、キャンバスを使用して同じ線を使用してグラフを描画するにはどうすればよいですか？

問題は座標にあります。（0,0）は、デバイスの左上隅から始まります。マージンとして（0,0）を設定し、マージンに対して特定の線を引くにはどうすればよいですか？

Answer 1

1）アクティビティを作成します。

public class GraphView1 extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    float[] values = new float[] { "your values"};
    String[] verlabels = new String[] { "your values" };
    String[] horlabels = new String[] { "your values"
    GraphView graphView = new GraphView(this, values,"GraphView",horlabels, verlabels, GraphView.BAR);
    setContentView(graphView);
}
} 

2）次に、Viewを拡張する別のクラスを作成します。

public class GraphView2 extends View{


public static boolean LINE = true;

private Paint paint;
private float[] values;
private String[] str;
private String[] verlabels;
private String title;
private boolean type;
Context context;


public GraphView(Context context, float[] values, String title, String[] str,String[] verlabels, boolean type) {

    super(context);
    if (values == null)
        values = new float[0];
    else
        this.values = values;
    if (title == null)
        title = "";
    else
        this.title = title;
    if (str == null)
        this.str = new String[0];
    else
        this.str = str;
    if (verlabels == null)
        this.verlabels = new String[0];
    else
        this.verlabels = verlabels;
    this.type = type;
    paint = new Paint();
}

@Override
protected void onDraw(final Canvas canvas) {
    context=getContext();
    float border = 15;
    float horstart = border * 2;
    float height = getHeight();
    float width = getWidth();
    float max = getMax();
    Log.w("max", ""+max);
    float min = getMin();
    Log.w("min", ""+min);
    float diff = max - min;
    float graphheight = height - (2 * border);
    float graphwidth = width - (2 * border);

    paint.setTextAlign(Align.LEFT);
    int vers = verlabels.length;
    for (int i = 0; i < verlabels.length; i++) {
        paint.setColor(Color.DKGRAY);
        float y = ((graphheight / vers) * i) + border;
        canvas.drawLine(horstart, y, width, y, paint);
        paint.setColor(Color.WHITE);
        paint.setTextSize(10);
        canvas.drawText(verlabels[i], 0, y, paint);
    }
    int hors = values.length;
    for (int i = 0; i < str.length; i++) {
        paint.setColor(Color.DKGRAY);
        float x = ((graphwidth / hors) * i) + horstart;
        canvas.drawLine(x, height - border, x, border, paint);
        paint.setTextAlign(Align.LEFT);
        if (i==str.length)
            paint.setTextAlign(Align.RIGHT);
        if (i==0)
            paint.setTextAlign(Align.LEFT);
        paint.setColor(Color.WHITE);
        paint.setTextSize(9);
        canvas.drawText( str[i], x, height - 4, paint);
    }

    paint.setTextAlign(Align.CENTER);
    canvas.drawText(title, (graphwidth / 2) + horstart, border - 4, paint);



    if (max != min) {
        paint.setColor(Color.BLUE);
        paint.setStyle(Paint.Style.FILL);

        if (type == BAR) {
            float datalength = values.length;
            float colwidth = (width - (2 * border)) / datalength;
            for (int i = 0; i < values.length; i++) {
            //  float val = values[i] - min;

            //  float rat = val / diff;
            //  float h = graphheight * rat;
            //  canvas.drawRect((i * colwidth) + horstart, (border - h) + graphheight, ((i * colwidth) + horstart) + (colwidth - 1), height - (border - 1), paint);                     
                float graph_h = getHeight()-(border*2); 
                 // Log.e("", "graph_h > "+graph_h);

                float ind_h = graph_h/7; 
                  //Log.e("", "ind_h > "+ind_h);

                float t = values[i]/5;

                float top = (graph_h - ind_h*(t)); 
                 // Log.e("", " > "+i+1);
                 // Log.e("", "top > "+top);

                //for values between 0 and 5 ,vice versa
                //Log.e("", " values[i] > "+values[i]);
                float acc = ind_h/5;
                acc = acc * (values[i]%5);

              //  Log.e("", " acc > "+acc);

                canvas.drawRect((i * colwidth) + horstart, top+border-acc , ((i * colwidth) + horstart) + (colwidth - 1), graph_h+border, paint);                       
            }
        } else {
            float datalength = values.length;
            float colwidth = (width - (2 * border)) / datalength;
            float halfcol = colwidth / 2;
            float lasth = 0;
            for (int i = 0; i < values.length; i++) {
                float val = values[i] - min;
                float rat = val / diff;
                float h = graphheight * rat;
                if (i > 0)
                    canvas.drawLine(((i - 1) * colwidth) + (horstart + 1) + halfcol, (border - lasth) + graphheight, (i * colwidth) + (horstart + 1) + halfcol, (border - h) + graphheight, paint);
                lasth = h;
            }
        }
    }
}



private float getMax() {
    float largest = Integer.MIN_VALUE;
    for (int i = 0; i < values.length; i++)
        if (values[i] > largest)
            largest = values[i];
    return largest;
}

private float getMin() {
    float smallest = Integer.MAX_VALUE;
    for (int i = 0; i < values.length; i++)
        if (values[i] < smallest)
            smallest = values[i];
    return smallest;
}


}