Links to the original text: https://www.cnblogs.com/huolongluo/p/5988644.html

Thank you guys: https://www.cnblogs.com/huolongluo/p/5988644.html

<lecho.lib.hellocharts.view.LineChartView
           android:id="@+id/line_chart"
            android:layout_width="fill_parent"
           android:layout_height="300dp"/>

Then one is the abscissa and the other is the array of data points.

private LineChartView lineChart;

    String[] date = {"10-22","11-22","12-22","1-22","6-22","5-23","5-22","6-22","5-23","5-22"};//Marking of X-axis
    int[] score= {50,42,90,33,10,74,22,18,79,20};//Data Points of Charts
    private List<PointValue> mPointValues = new ArrayList<PointValue>();
    private List<AxisValue> mAxisXValues = new ArrayList<AxisValue>();

There are three methods in oncreate:

protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        lineChart = (LineChartView)findViewById(R.id.line_chart);
        getAxisXLables();//Get the label of the x-axis
        getAxisPoints();//Getting coordinate points
        initLineChart();//Initialization
    }

/**
     * Set up X-axis display
     */
    private void getAxisXLables() {
        for (int i = 0; i < date.length; i++) {
            mAxisXValues.add(new AxisValue(i).setLabel(date[i]));
        }
    }

    /**
     * Display of each point in the chart
     */
    private void getAxisPoints() {
        for (int i = 0; i < score.length; i++) {
            mPointValues.add(new PointValue(i, score[i]));
        }
    }

private void initLineChart() {
        Line line = new Line(mPointValues).setColor(Color.parseColor("#FFCD41"));  //The color of the broken line (orange)
        List<Line> lines = new ArrayList<Line>();
        line.setShape(ValueShape.CIRCLE);//The shape of each data point on a broken line chart is circular here (there are three kinds: ValueShape. SQUARE ValueShape. CIRCLE ValueShape. DIAMOND)
        line.setCubic(false);//Whether the curve is smooth, that is, whether it is a curve or a broken line
        line.setFilled(false);//Whether or not to fill the area of the curve
        line.setHasLabels(true);//Whether to add notes to the data coordinates of curves
//      Line. setHasLabels OnlyForSelected (true); // Click on the data coordinates to prompt the data (set this line.setHasLabels(true); invalid)
        line.setHasLines(true);//Whether to display with line or not. If it is false, there is no curve but point display
        line.setHasPoints(true);//Whether to display a dot if it is false, there is no origin but only a dot (each data point is a large dot)
        lines.add(line);
        LineChartData data = new LineChartData();
        data.setLines(lines);

        //Axis of coordinates
        Axis axisX = new Axis(); //X axis
        axisX.setHasTiltedLabels(true);  //Is the font on the X axis oblique or straight, and true oblique?
        axisX.setTextColor(Color.GRAY);  //Setting font color
        //axisX.setName("date"); // table name
        axisX.setTextSize(10);//Set font size
        axisX.setMaxLabelChars(8); //Up to a few X-axis coordinates, which means that your scaling allows the number of data on the X-axis to be 7<=x<=mAxisXValues.length.
        axisX.setValues(mAxisXValues);  //Fill in the coordinate name of the X-axis
        data.setAxisXBottom(axisX); //The x-axis is at the bottom.
        //Data. setAxisXTop (axisX); //x axis at top
        axisX.setHasLines(true); //x-axis dividing line

        // The Y-axis automatically sets the Y-axis limit according to the size of the data (below I will give a solution for fixing the number of Y-axis data)
        Axis axisY = new Axis();  //Y axis
        axisY.setName("");//y axis annotation
        axisY.setTextSize(10);//Set font size
        data.setAxisYLeft(axisY);  //The Y-axis is set on the left
        //Data. setAxisYRight (axisY); the // Y axis is set to the right


        //Setting behavioral properties to support zooming, sliding, and Translation
        lineChart.setInteractive(true);
        lineChart.setZoomType(ZoomType.HORIZONTAL);
        lineChart.setMaxZoom((float) 2);//Maximum method ratio
        lineChart.setContainerScrollEnabled(true, ContainerScrollType.HORIZONTAL);
        lineChart.setLineChartData(data);
        lineChart.setVisibility(View.VISIBLE);
        /**Note: The following 7, 10 just represent a number to analogize.
         * At that time, it was to solve the fixed number of X-axis data. See (http://forum.xda-developers.com/tools/programming/library-hellocharts-charting-library-t2904456/page2);
         */
        Viewport v = new Viewport(lineChart.getMaximumViewport());
        v.left = 0;
        v.right = 7;
        lineChart.setCurrentViewport(v);
    }

See the following picture:

These four codes can set the number of X-axis data display (x-axis 0-7 data).
1 When the number of data points is less than (29), shrink to the extreme hellochart by default is all display.
When the number of data points is greater than (29).
2.1 If the sentence axisX.setMaxLabelChars(int count) is not set, the number of data that the X-axis can display will be automatically adapted to the most appropriate number.
2.2 If you set axisX. setMax LabelChars (int count), 33 data points will be tested.
2.2.1 If axisX.setMax LabelChars (10); the inside 10 is greater than v.right= 7; the inside 7, the X-axis displays seven data at the beginning, and then the number of X-axis is guaranteed to be greater than 7 and less than 10 when zooming in.
2.2.2 If it is less than v.right= 7; 7 in the middle, anyway, I feel that these two sentences seem to be invalid - - if v.right= 7 is not set here, then the chart will display all the data as far as possible at the beginning, and the interaction is too poor.

Let's look at a solution for fixing the number of Y-axes:
Example: Want to fix Y-axis data from 0-100

Axis axisY = new Axis().setHasLines(true);
axisY.setMaxLabelChars(6);//max label length, for example 60
List<AxisValue> values = new ArrayList<>();
for(int i = 0; i < 100; i+= 10){
    AxisValue value = new AxisValue(i);
    String label = "";
    value.setLabel(label);
    values.add(value);
}
axisY.setValues(values);

Obviously, as long as you divide the data proportionally.
Okay, that's basically it.

Source GitHub address: https://github.com/qht1003077897/hellocharts-line.git
CSDN download address: http://download.csdn.net/detail/u012534831/9531702

Supplement: Common charts