我已经使用BaseAdapter显示自定义列表。现在我有一个按钮，但我得到空指针异常。我不知道为什么会发生这种情况，即使我已经初始化了按钮。
代码
public class ContactListAdapter extends BaseAdapter {
private Context context;
private ArrayList<ContactModel> data;
DbHandler dbHandler;
public ContactListAdapter(Context context, ArrayList<ContactModel> data) {
this.context = context;
this.data = data;
}
@Override
public int getCount() {
return data.size();
}
@Override
public Object getItem(int i) {
return null;
}
@Override
public long getItemId(int i) {
return 0;
}
@Override
public View getView(final int i, View view, ViewGroup viewGroup) {
final ViewHolder holder;
dbHandler = new DbHandler(context);
if (view == null) {
holder = new ViewHolder();
view = LayoutInflater.from(context).inflate(R.layout.contact_custom_list, viewGroup, false);
holder.tvContact = (TextView) view.findViewById(R.id.tv_contact_name);
holder.checkBox = (CheckBox) view.findViewById(R.id.cb_contact_checkbox);
holder.btSend = (Button) view.findViewById(R.id.bt_sharecontact_send);
view.setTag(holder);
} else {
holder = (ViewHolder) view.getTag();
}
holder.checkBox.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(CompoundButton compoundButton, boolean b) {
if (compoundButton == holder.checkBox) {
if (b) {
dbHandler.updateContactList(data.get(i).getUserID(), 1);
} else {
dbHandler.updateContactList(data.get(i).getUserID(), 0);
}
}
}
});
holder.tvContact.setText(data.get(i).getContactName());
holder.btSend.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
StringBuilder values = new StringBuilder();
values = dbHandler.getCheckedContact();
}
});
return view;
}
private class ViewHolder {
TextView tvContact;
CheckBox checkBox;
Button btSend;
}
}
logcat的
FATAL EXCEPTION: main
java.lang.NullPointerException
at example.com.pocketdocs.Group.ContactListAdapter.getView(ContactListAdapter.java:82)
at android.widget.AbsListView.obtainView(AbsListView.java:2271)
at android.widget.ListView.measureHeightOfChildren(ListView.java:1270)
at android.widget.ListView.onMeasure(ListView.java:1182)
at android.view.View.measure(View.java:15367)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4924)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1420)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:697)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:578)
at android.view.View.measure(View.java:15367)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4924)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:314)
at android.view.View.measure(View.java:15367)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4924)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1420)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:697)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:578)
at android.view.View.measure(View.java:15367)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4924)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1420)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:697)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:578)
at android.view.View.measure(View.java:15367)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4924)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:314)
at android.view.View.measure(View.java:15367)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4924)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1420)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:697)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:578)
at android.view.View.measure(View.java:15367)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4924)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1420)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:697)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:578)
at android.view.View.measure(View.java:15367)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4924)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:314)
at android.view.View.measure(View.java:15367)
at net.simonvt.menudrawer.OverlayDrawer.onMeasure(OverlayDrawer.java:335)
at android.view.View.measure(View.java:15367)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4924)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:314)
at android.view.View.measure(View.java:15367)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4924)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1420)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:697)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:578)
at android.view.View.measure(View.java:15367)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4924)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:314)
at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2154)
at android.view.View.measure(View.java:15367)
at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:1858)
at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1106)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1279)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1004)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:4223)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:725)
at android.view.Choreographer.doCallbacks(Choreographer.java:555)
at android.view.Choreographer.doFrame(Ch
在该按钮上单击我从数据库中获取一些值
答案 0 :(得分：0)
NPE in：
holder.btSend.setOnClickListener(...)
由于holder不为null（之前会崩溃），btSend必须为null。这里的NPE没有其他办法了。 btSend初始化为：
holder.btSend = (Button) view.findViewById(R.id.bt_sharecontact_send);
您的contact_custom_list布局不包含ID为bt_sharecontact_send的视图，findViewById()返回null。