如何在不使用任何外部API的情况下在Android上绘制图形？ [英] How do I draw a graph on Android without using any external API?

问题描述

我懂得如何使用画布绘制线条，但是如何使用画布绘制图形的相同线条？

问题出在坐标。 （0,0）从设备的左上角开始。我如何设置（0,0）作为边距，并相对于边距绘制特定的线？

解决方案

<1>创建一个活动。

  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 b）然后创建另一个类extends View： p> 
 
 
  public class GraphView2 extends View {
 
 
 public static boolean LINE = true; 
 
私人油漆; 
私人浮动[]值; 
 private String [] str; 
 private String [] verlabels; 
私有字符串标题; 
私有布尔类型; 
上下文上下文; 
 
 $ b public graphView（Context context，float [] values，String title，String [] str，String [] verlabels，boolean type）{
 
 super上下文）; 
 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），涂料）; 
 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）; 
 
 //对于0到5之间的值，反之亦然
 //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 maximum = Integer .MIN_VALUE; 
 for（int i = 0; i< values.length; i ++）
 if（values [i]> maximum）
 largest = values [i] 
回报最大; 
 
 
 private float getMin（）{
 float minimum = Integer.MAX_VALUE; 
 for（int i = 0; i  if（values [i] <最小）
最小=值[i]; 
回报最小; 
} 
 
 
} 
  
 
I understand how to draw lines using a canvas, but how can I use the same lines using a canvas to draw a graph?

The problem is with the coordinates.  (0,0) starts right at the top left corner of the device. How can I set (0,0) as the margin and draw the particular line with respect to the margin?
解决方案
1)Create an activity. 
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)Then create another class extends View:   
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;
}


}   


                        
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