饼图未显示在片段中（Android）

Question

我正在开发一个 andorid 应用程序，在这个应用程序中，我试图在一个带选项卡的片段中显示一个饼图。但是它显示"No chart data available"。当我尝试在 activity 中做同样的事情时，它显示得很完美。我使用 "MPAndroidChart" 作为参考。请帮忙。提前致谢！

这是我的fragment.class

import android.graphics.Color;
 import android.graphics.Typeface;
 import android.net.Uri;

import android.os.Bundle;
import android.text.SpannableString;
import android.text.style.ForegroundColorSpan;
import android.text.style.RelativeSizeSpan;
import android.text.style.StyleSpan;
import android.util.Log;
import android.view.InflateException;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.SeekBar;
import android.widget.TextView;
import com.github.mikephil.charting.charts.PieChart;
import com.github.mikephil.charting.components.Legend;
import com.github.mikephil.charting.data.Entry;


import com.github.mikephil.charting.data.PieData;
import com.github.mikephil.charting.data.PieDataSet;


 import com.github.mikephil.charting.utils.ColorTemplate;

 import java.util.ArrayList;






public class overview extends android.support.v4.app.Fragment {
private static final String ARG_PARAM1 = "param1";
private static final String ARG_PARAM2 = "param2";
private static View rootView;
private OnFragmentInteractionListener mListener;
private SeekBar mSeekBarX, mSeekBarY;
private TextView tvX, tvY;
private PieChart mChart;

private Typeface tf;



public overview() {
    // Required empty public constructor
}

//String param1, String param2
public static overview newInstance() {
    overview fragment = new overview();
    Bundle args = new Bundle();
    // args.putString(ARG_PARAM1, param1);
    //args.putString(ARG_PARAM2, param2);
    fragment.setArguments(args);
    return fragment;
}

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    if (getArguments() != null) {

    }
}
public View onCreateView(LayoutInflater inflater, final ViewGroup container,
                         Bundle savedInstanceState) {
    // Inflate the layout for this fragment
    View view = inflater.inflate(R.layout.overview, container, false);

     PieChart pieChart = (PieChart) findViewById(R.id.chart);

    ArrayList<Entry> entries = new ArrayList<>();
    entries.add(new Entry(4f, 0));
    entries.add(new Entry(8f, 1));
    entries.add(new Entry(6f, 2));
    entries.add(new Entry(12f, 3));
    entries.add(new Entry(18f, 4));
    entries.add(new Entry(9f, 5));

    PieDataSet dataset = new PieDataSet(entries, "# of Calls");

    ArrayList<String> labels = new ArrayList<String>();
    labels.add("January");
    labels.add("February");
    labels.add("March");
    labels.add("April");
    labels.add("May");
    labels.add("June");

    PieData data = new PieData(labels, dataset);
    dataset.setColors(ColorTemplate.COLORFUL_COLORS); //
    pieChart.setDescription("Description");
    pieChart.setData(data);

    pieChart.animateY(5000);

    pieChart.saveToGallery("/sd/mychart.jpg", 85); // 85 is the quality of 
   the image




    if (rootView != null) {
        ViewGroup parent = (ViewGroup) rootView.getParent();
        if (parent != null)
            parent.removeView(rootView);
    }
    try {
        rootView = inflater.inflate(R.layout.overview, container, false);

    } catch (InflateException e) {
    /* map is already there, just return view as it is  */
    }
    return rootView;
}

private SpannableString generateCenterText() {
    SpannableString s = new SpannableString("Revenues\nQuarters 2015");
    s.setSpan(new RelativeSizeSpan(2f), 0, 8, 0);
    s.setSpan(new ForegroundColorSpan(Color.GRAY), 8, s.length(), 0);
    return s;
}


@Override
public void onDetach() {
    super.onDetach();
    mListener = null;
}

public interface OnFragmentInteractionListener {
    // TODO: Update argument type and name
    void onFragmentInteraction(Uri uri);
}

}

这是我的 xml 文件：

     <com.github.mikephil.charting.charts.PieChart
            android:id="@+id/chart"
            android:layout_width="300dp"
            android:layout_height="300dp" />

Answer 1

实际上你的声明是错误的PiChart.Declare它是这样的;

 View view = inflater.inflate(R.layout.overview, container, false);

 PieChart pieChart = (PieChart)view.findViewById(R.id.chart);

Answer 2

因为你初始化错了。像这样

 PieChart pieChart = (PieChart) findViewById(R.id.chart);

将此行更改为

 PieChart pieChart = (PieChart) view.findViewById(R.id.chart);

饼图未显示在片段中（Android）

Pie Chart not displaying in a fragment(Android)

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pie-chart

mpandroidchart