如何在Mpandroid Pie图表内动态添加文本？

Question

我已遵循MpAndroid库进行图表创建。我想在饼图的中心设置动态文本。我正在创建一个BMI计算器，所以我想在饼图的中心内显示BMI值。 这是我用来在饼图中显示文本的代码。 `

        mChart.setDrawCenterText(true);
        mChart.setCenterTextTypeface(mTfLight);

        mChart.setCenterTextColor(Color.WHITE);
        mChart.setCenterTextSize(15f);
        mChart.setCenterText("BMI:"+bmi);

`

请看完整的代码。在Oncreate()方法中，我已经设置了上面的代码以将文本设置在中心，但这显示的是静态文本，如何在中心内部动态设置文本（即计算值） BMI）。

MainActivity.java

    public class MainActivity extends AppCompatActivity
        implements NavigationView.OnNavigationItemSelectedListener {

    private RadioGroup radioSexGroup;
    private RadioButton radioSexButton;
    private int selectedId;
    private EditText age;
    private EditText height;
    private EditText weight;
    private TextView result;
    private Spinner height_spinner;
    private Spinner weight_spinner;
    private Button calculate;
    private PieChart mChart;

    String spinner_height; //Height Spinner
    String spinner_weight; //Weight Spinner
    String selected_item1;
    String selected_item2;

    float bmi=0f;

    protected String[] BMIcategory = new String[]
            {
            "Very Severly Underweight", "Severly Underweight", "Underweight", "Normal",
                    "Overweight", "Obese Class I", "Obese Class II", "Obese Class III",
    };




    protected Typeface mTfRegular;
    protected Typeface mTfLight;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);
        setTitle("BMI Calculator");

        mTfRegular=Typeface.MONOSPACE;
        mTfLight = Typeface.MONOSPACE;
        radioSexGroup = (RadioGroup) findViewById(R.id.radioSex);
        selectedId = radioSexGroup.getCheckedRadioButtonId();
        radioSexButton = (RadioButton) findViewById(selectedId);
        mChart=(PieChart)findViewById(R.id.chart);
        age=(EditText) findViewById(R.id.age);
        height=(EditText) findViewById(R.id.height);
        weight=(EditText) findViewById(R.id.weight);
//        result=(TextView) findViewById(R.id.result);
        height_spinner=(Spinner) findViewById(R.id.height_spinner);
        weight_spinner=(Spinner) findViewById(R.id.weight_spinner);
        calculate=(Button) findViewById(R.id.calculate_button);

        mChart.setBackgroundColor(Color.rgb(76,0,0));
//        moveOffScreen();
        mChart.setUsePercentValues(false);
        mChart.getDescription().setEnabled(false);

        mChart.setDrawCenterText(true);
        mChart.setCenterTextTypeface(mTfLight);

        mChart.setCenterTextColor(Color.WHITE);
        mChart.setCenterTextSize(15f);
        mChart.setCenterText("BMI:"+bmi);

        mChart.setDrawHoleEnabled(true);
        mChart.setHoleColor(Color.rgb(76,0,0));

        mChart.setTransparentCircleColor(Color.rgb(76,0,0));
        mChart.setTransparentCircleAlpha(110);

        mChart.setHoleRadius(65f);
        mChart.setTransparentCircleRadius(68f);
        mChart.setDrawSliceText(false);
        mChart.setDrawEntryLabels(false);

        mChart.setRotationEnabled(false);
        mChart.setHighlightPerTapEnabled(false);

        mChart.setMaxAngle(270f); // HALF CHART
        mChart.setRotationAngle(135f);
//        mChart.setRotation(180f);


//        mChart.setCenterTextOffset(0, -20);

        setData(8, 80);

        mChart.animateY(1400, Easing.EasingOption.EaseInOutQuad);
        mChart.getLegend().setEnabled(false);

        calculate.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                calculate();
            }
        });


        set_spinner();

    }

    private void setData(int count, float range) {

        ArrayList<PieEntry> values = new ArrayList<>();

        values.add(new PieEntry(10f,BMIcategory[0]));
        values.add(new PieEntry(15f,BMIcategory[1]));
        values.add(new PieEntry(8f,BMIcategory[2]));
        values.add(new PieEntry(12f,BMIcategory[3]));
        values.add(new PieEntry(5f,BMIcategory[4]));
        values.add(new PieEntry(5f,BMIcategory[5]));
        values.add(new PieEntry(15f,BMIcategory[6]));
        values.add(new PieEntry(10f,BMIcategory[7]));


        PieDataSet dataSet = new PieDataSet(values, "BMI Category");
        dataSet.setSliceSpace(1f);
        dataSet.setSelectionShift(5f);

        // add many colors
        ArrayList<Integer> colors = new ArrayList<Integer>();

        for (int c : ColorTemplate.VORDIPLOM_COLORS)
            colors.add(c);

        for (int c : ColorTemplate.JOYFUL_COLORS)
            colors.add(c);

        for (int c : ColorTemplate.COLORFUL_COLORS)
            colors.add(c);

        for (int c : ColorTemplate.LIBERTY_COLORS)
            colors.add(c);

        for (int c : ColorTemplate.PASTEL_COLORS)
            colors.add(c);

        colors.add(ColorTemplate.getHoloBlue());
        dataSet.setColors(colors);


        //dataSet.setSelectionShift(0f);

        PieData data = new PieData(dataSet);
        data.setDrawValues(false);

        mChart.setData(data);
        mChart.invalidate();
    }


    public void set_spinner(){

        ArrayAdapter<CharSequence> adapter1 = ArrayAdapter.createFromResource(this, R.array.height_spinner_array, android.R.layout.simple_spinner_item);
        adapter1.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        height_spinner.setAdapter(adapter1);

        height_spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
            @Override
            public void onItemSelected(AdapterView<?> parent, View view, int pos, long id) {
                int a = parent.getSelectedItemPosition();
                spinner_height = height_spinner.getSelectedItem().toString();
                if (a == 0) {
                    selected_item1="Meters";
                }
                if (a == 1) {
                    selected_item1="Inches";

                }
                if(a==2)
                {
                    selected_item1="Centimeters";
                }

            }

            @Override
            public void onNothingSelected(AdapterView<?> parent) {
                // Another interface callback
            }
        });


        ArrayAdapter<CharSequence> adapter2 = ArrayAdapter.createFromResource(this, R.array.weight_spinner_array, android.R.layout.simple_spinner_item);
        adapter2.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        weight_spinner.setAdapter(adapter2);
        weight_spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
            @Override
            public void onItemSelected(AdapterView<?> parent, View view, int pos, long id) {
                int b = parent.getSelectedItemPosition();
               spinner_weight = weight_spinner.getSelectedItem().toString();
                if(b==0)
                {
                    selected_item2="Kgs";
                }
                if(b==1)
                {
                    selected_item2="Lbs";
                }
            }
            @Override
            public void onNothingSelected(AdapterView<?> parent) {} } );


    }

    public void calculate() {

        float getHeight, getWeight;

        DecimalFormat df = new DecimalFormat("#0.00");
//        for height in m and weight in kgs

        if (height.getText().toString().equals("")) {
            getHeight = 0f;
        } else {
            getHeight = Float.parseFloat(height.getText().toString());
        }
        if (weight.getText().toString().equals("")) {
            getWeight = 0f;
        } else {
            getWeight = Float.parseFloat(weight.getText().toString());
        }
        if(height.getText().toString().equals("") || weight.getText().toString().equals("") || age.getText().toString().equals(""))
        {
            Toast.makeText(this,"Please Enter All the Values",Toast.LENGTH_SHORT).show();
            return;
        }

        if(selected_item1.equals("Meters"))
        {
            if(selected_item2.equals("Kgs"))
            {
                bmi = getWeight / (getHeight * getHeight);

            }
            if(selected_item2.equals("Lbs"))
            {
                 bmi = (getWeight*0.453592f) / (getHeight * getHeight);
            }
        }
        if(selected_item1.equals("Inches"))
        {
            if(selected_item2.equals("Kgs"))
            {
                bmi = (getWeight*318.87517f) / (getHeight * getHeight);

            }
            if(selected_item2.equals("Lbs"))
            {
                bmi = (getWeight*703f) / (getHeight * getHeight);
            }

        }
        if(selected_item1.equals("Centimeters"))
        {
            if(selected_item2.equals("Kgs"))
            {
                 bmi = (getWeight*10000) / (getHeight * getHeight);
            }
            if(selected_item2.equals("Lbs"))
            {
                bmi=(getWeight*0.453592f*10000) / (getHeight * getHeight);
            }
        }
//        result.setText("Your BMI is " + df.format((double)bmi));



    }


    @Override
    public void onBackPressed() {
        DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        if (drawer.isDrawerOpen(GravityCompat.START)) {
            drawer.closeDrawer(GravityCompat.START);
        } else {
            super.onBackPressed();
        }
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }



}

我想问的另一件事是，如何减小饼图切片的宽度。有一个选项可以调整内部圆的半径，但是如何调整切片的宽度。

任何帮助都是最欢迎的。谢谢！

Answer 1

您问了两个问题：

如何动态设置中心内的文字？

只需再次调用setCenterText ，然后invalidate Chart方法invalidate ：

mChart.setCenterText("BMI:" + bmi);
mChart.invalidate();

---

我如何减小饼图切片的宽度

有一种PieChart方法：

setHoleRadius

您使用不正确。 它的参数应为“ PieChart”半径的百分比。 因此调用：

mChart.setHoleRadius(0.65f);

表示孔应占图表半径的65％。