我在适配器视图中显示MPAndroidChart时有空对象引用，如果任何人可以协助，我使用单独的适配器，因为在一个布局中使用不同的视图，
这是适配器：
public class VerticalListAdapter extends RecyclerView.Adapter<VerticalListAdapter.ViewHolder> {
private Activity activity;
BarChart chart ;
ArrayList<BarEntry> BARENTRY = new ArrayList<BarEntry>();
ArrayList<String> BarEntryLabels = new ArrayList<String>(); ;
BarDataSet Bardataset ;
BarData BARDATA ;
public VerticalListAdapter(Activity activity) {
this.activity = activity;
}
@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
LayoutInflater inflater = activity.getLayoutInflater();
View view = inflater.inflate(R.layout.item_recycler_view, parent, false);
BARENTRY = new ArrayList<BarEntry>();
BarEntryLabels = new ArrayList<String>();
AddValuesToBARENTRY();
AddValuesToBarEntryLabels();
Bardataset = new BarDataSet(BARENTRY, "Projects");
BARDATA = new BarData(BarEntryLabels, Bardataset);
Bardataset.setColors(ColorTemplate.COLORFUL_COLORS);
chart.setData(BARDATA);
chart.animateY(3000);
return new ViewHolder(view);
}
private void AddValuesToBarEntryLabels() {
BarEntryLabels.add("January");
BarEntryLabels.add("February");
BarEntryLabels.add("March");
BarEntryLabels.add("April");
BarEntryLabels.add("May");
BarEntryLabels.add("June");
}
private void AddValuesToBARENTRY() {
BARENTRY.add(new BarEntry(2f, 0));
BARENTRY.add(new BarEntry(4f, 1));
BARENTRY.add(new BarEntry(6f, 2));
BARENTRY.add(new BarEntry(8f, 3));
BARENTRY.add(new BarEntry(7f, 4));
BARENTRY.add(new BarEntry(3f, 5));
}
@Override
public void onBindViewHolder(ViewHolder viewHolder, final int position) {
viewHolder.BarChart.setData(BARDATA);
}
@Override
public int getItemCount() {
return 1;
}
/**
* View holder to display each RecylerView item
*/
protected class ViewHolder extends RecyclerView.ViewHolder {
BarChart BarChart;
public ViewHolder(View view) {
super(view);
BarChart = (BarChart) view.findViewById(R.id.chart1);
}
}
}
和XML
<android.support.v7.widget.CardView xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:layout_marginBottom="5dp"
android:layout_marginLeft="5dp"
android:layout_marginRight="5dp"
android:layout_marginTop="5dp">
<com.github.mikephil.charting.charts.BarChart
android:id="@+id/chart1"
android:layout_width="match_parent"
android:layout_height="200dp" />
这是LogCaT：
java.lang.NullPointerException: Attempt to invoke virtual method 'void com.github.mikephil.charting.charts.BarChart.setData(com.github.mikephil.charting.data.ChartData)' on a null object reference
at info.devexchanges.recyclerview.VerticalListAdapter.onCreateViewHolder(VerticalListAdapter.java:32)
at info.devexchanges.recyclerview.VerticalListAdapter.onCreateViewHolder(VerticalListAdapter.java:18)
at android.support.v7.widget.RecyclerView$Adapter.createViewHolder(RecyclerView.java:5482)
at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:4707)
at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:4617)
at android.support.v7.widget.LinearLayoutManager$LayoutState.next(LinearLayoutManager.java:1994)
at android.support.v7.widget.LinearLayoutManager.layoutChunk(LinearLayoutManager.java:1390)
at android.support.v7.widget.LinearLayoutManager.fill(LinearLayoutManager.java:1353)
at android.support.v7.widget.LinearLayoutManager.onLayoutChildren(LinearLayoutManager.java:574)
at android.support.v7.widget.RecyclerView.dispatchLayoutStep2(RecyclerView.java:3028)
at android.support.v7.widget.RecyclerView.onMeasure(RecyclerView.java:2625)
at android.view.View.measure(View.java:18788)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5951)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1465)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:748)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:630)
at android.view.View.measure(View.java:18788)
at android.widget.ScrollView.measureChildWithMargins(ScrollView.java:1283)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:194)
at android.widget.ScrollView.onMeasure(ScrollView.java:340)
at android.view.View.measure(View.java:18788)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5951)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:194)
at android.support.v7.widget.ContentFrameLayout.onMeasure(ContentFrameLayout.java:135)
at android.view.View.measure(View.java:18788)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5951)
at android.support.v7.widget.ActionBarOverlayLayout.onMeasure(ActionBarOverlayLayout.java:391)
at android.view.View.measure(View.java:18788)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5951)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:194)
at android.view.View.measure(View.java:18788)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5951)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1465)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:748)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:630)
at android.view.View.measure(View.java:18788)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5951)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:194)
at com.android.internal.policy.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2643)
at android.view.View.measure(View.java:18788)
at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:2100)
at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1216)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1452)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1107)
at android.view.ViewRootImpl$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)
1 回答
我已经解决了这个问题，想要发布代码，我有空引用，因为我没有在onCreateViewHolder中启动布局，在我的布局中添加这两行后，在卡片视图中显示图形视图（图形在列表视图中使用动态视图类型）
在onCreateViewHolder中