【发布时间】：2016-05-16 12:08:19
【问题描述】：
我尝试在我的饼图中使用 MarkView。关注了这个文档https://github.com/PhilJay/MPAndroidChart/wiki/MarkerView
不幸的是，当我单击任何值时它会出错。
我的活动看起来像这样
mChart = (PieChart) findViewById(R.id.chart1);
mChart.setDescription("");
typeface = Typeface.createFromAsset(getAssets(), "OpenSans-Light.ttf");
mChart.setCenterTextTypeface(typeface);
mChart.setCenterText(generateCenterText());
mChart.setCenterTextSize(15f);
mChart.setCenterTextTypeface(typeface);
// radius of the center hole in percent of maximum radius
mChart.setHoleRadius(45f);
mChart.setTransparentCircleRadius(50f);
mChart.getLegend().setEnabled(false);
mChart.setData(generatePieData());
mChart.animateX(1500, Easing.EasingOption.EaseOutBounce);
//mChart.animateY(1500, Easing.EasingOption.EaseInOutQuad);
mChart.setTouchEnabled(true);
CustomMarkerView mv = new CustomMarkerView (this, R.layout.custom_marker_view_layout);
mChart.setMarkerView(mv);
这是我的标记类
public class CustomMarkerView extends MarkerView {
private TextView tvContent;
public CustomMarkerView (Context context, int layoutResource) {
super(context, layoutResource);
// this markerview only displays a textview
tvContent = (TextView) findViewById(R.id.tvContent);
}
// callbacks everytime the MarkerView is redrawn, can be used to update the
// content (user-interface)
@Override
public void refreshContent(Entry e, Highlight highlight) {
tvContent.setText("" + e.getVal()); // set the entry-value as the display text
}
@Override
public int getXOffset(float xpos) {
// this will center the marker-view horizontally
return -(getWidth() / 2);
}
@Override
public int getYOffset(float ypos) {
// this will cause the marker-view to be above the selected value
return -getHeight();
}
}
这是我的布局
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="40dp"
android:background="@drawable/marker" >
<TextView
android:id="@+id/tvContent"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:layout_marginTop="7dp"
android:layout_marginLeft="5dp"
android:layout_marginRight="5dp"
android:text=""
android:textSize="12dp"
android:textColor="@android:color/white"
android:ellipsize="end"
android:singleLine="true"
android:textAppearance="?android:attr/textAppearanceSmall" />
</RelativeLayout>
但我总是得到这个错误......
05-16 07:50:06.321 23967-23967/com.anwarhossainbd.bdelectricbillcalculator E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.anwarhossainbd.bdelectricbillcalculator, PID: 23967
java.lang.NullPointerException: Attempt to read from field 'float com.github.mikephil.charting.components.AxisBase.mAxisRange' on a null object reference
at com.github.mikephil.charting.charts.Chart.drawMarkers(Chart.java:673)
at com.github.mikephil.charting.charts.PieChart.onDraw(PieChart.java:136)
at android.view.View.draw(View.java:16178)
at android.view.View.updateDisplayListIfDirty(View.java:15174)
at android.view.ViewGroup.recreateChildDisplayList(ViewGroup.java:3593)
at android.view.ViewGroup.dispatchGetDisplayList(ViewGroup.java:3573)
at android.view.View.updateDisplayListIfDirty(View.java:15134)
at android.view.ViewGroup.recreateChildDisplayList(ViewGroup.java:3593)
at android.view.ViewGroup.dispatchGetDisplayList(ViewGroup.java:3573)
at android.view.View.updateDisplayListIfDirty(View.java:15134)
at android.view.ViewGroup.recreateChildDisplayList(ViewGroup.java:3593)
at android.view.ViewGroup.dispatchGetDisplayList(ViewGroup.java:3573)
at android.view.View.updateDisplayListIfDirty(View.java:15134)
at android.view.ViewGroup.recreateChildDisplayList(ViewGroup.java:3593)
at android.view.ViewGroup.dispatchGetDisplayList(ViewGroup.java:3573)
at android.view.View.updateDisplayListIfDirty(View.java:15134)
at android.view.ViewGroup.recreateChildDisplayList(ViewGroup.java:3593)
at android.view.ViewGroup.dispatchGetDisplayList(ViewGroup.java:3573)
at android.view.View.updateDisplayListIfDirty(View.java:15134)
at android.view.ViewGroup.recreateChildDisplayList(ViewGroup.java:3593)
at android.view.ViewGroup.dispatchGetDisplayList(ViewGroup.java:3573)
at android.view.View.updateDisplayListIfDirty(View.java:15134)
at android.view.ViewGroup.recreateChildDisplayList(ViewGroup.java:3593)
at android.view.ViewGroup.dispatchGetDisplayList(ViewGroup.java:3573)
at android.view.View.updateDisplayListIfDirty(View.java:15134)
at android.view.ViewGroup.recreateChildDisplayList(ViewGroup.java:3593)
at android.view.ViewGroup.dispatchGetDisplayList(ViewGroup.java:3573)
at android.view.View.updateDisplayListIfDirty(View.java:15134)
at android.view.ThreadedRenderer.updateViewTreeDisplayList(ThreadedRenderer.java:281)
at android.view.ThreadedRenderer.updateRootDisplayList(ThreadedRenderer.java:287)
at android.view.ThreadedRenderer.draw(ThreadedRenderer.java:322)
at android.view.ViewRootImpl.draw(ViewRootImpl.java:2615)
at android.view.ViewRootImpl.performDraw(ViewRootImpl.java:2434)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2067)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1107)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:6013)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:858)
at android.view.Choreographer.doCallbacks(Choreographer.java:670)
at android.view.Choreographer.doFrame(Choreographer.java:606)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:844)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5417)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
有什么帮助吗？
【问题讨论】：