我使用此视图错误了吗？我在第165行得到一份NPE。有一个明显的原因导致我失踪吗？如果我使用expandablelistview，是否需要组视图和子视图？我标记了第165行，试图让眼睛更容易。
非常感谢
我的expandablelistview正在获得NPE：
public class MyExpandableListAdapter extends BaseExpandableListAdapter {
private Context mContext;
private ArrayList<ContactNameItems> mListDataHeader;
private ArrayList<Boolean> phoneNumberCheckStates;
private ArrayList<String> selectedNumbers;
private HashMap<String, List<ContactPhoneItems>> mListDataChild;
private ViewHolder mViewHolder;
public MyExpandableListAdapter(Context context,
ArrayList<ContactNameItems> listDataHeader,
HashMap<String, List<ContactPhoneItems>> listDataChild,
ArrayList<String> listOfNumbers) {
mContext = context;
mListDataHeader = listDataHeader;
mListDataChild = listDataChild;
selectedNumbers = listOfNumbers;
}
@Override
public int getGroupCount() {
return mListDataHeader.size();
}
@Override
public ContactNameItems getGroup(int groupPosition) {
return mListDataHeader.get(groupPosition);
}
@Override
public long getGroupId(int groupPosition) {
return groupPosition;
}
@Override
public View getGroupView(int groupPosition, boolean isExpanded,
View convertView, ViewGroup parent) {
String contactName = getGroup(groupPosition).getName();
Bitmap contactImage = getGroup(groupPosition).getImage();
if (convertView == null) {
LayoutInflater inflater = (LayoutInflater) mContext
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
convertView = inflater.inflate(R.layout.contact_name_item, null);
mViewHolder = new ViewHolder();
mViewHolder.mContactName = (TextView) convertView
.findViewById(R.id.lblListHeader);
mViewHolder.mContactImage = (ImageView) convertView
.findViewById(R.id.ivContactPhoto);
convertView.setTag(mViewHolder);
} else {
mViewHolder = (ViewHolder) convertView.getTag();
}
if (contactImage != null) {
mViewHolder.mContactImage.setImageBitmap(contactImage);
} else {
mViewHolder.mContactImage.setImageResource(R.drawable.default_contact);
}
mViewHolder.mContactName.setText(contactName);
return convertView;
}
@Override
public int getChildrenCount(int groupPosition) {
return mListDataChild.get(mListDataHeader.get(groupPosition).getName())
.size();
}
@Override
public ContactPhoneItems getChild(int groupPosition, int childPosition) {
return mListDataChild.get(mListDataHeader.get(groupPosition).getName())
.get(childPosition);
}
@Override
public long getChildId(int groupPosition, int childPosition) {
return childPosition;
}
@Override
public View getChildView(int groupPosition, final int childPosition,
boolean isLastChild, View convertView, ViewGroup parent) {
String numberText = getChild(groupPosition, childPosition).getNumber();
String typeText = getChild(groupPosition, childPosition).getPhoneType();
final int mGroupPosition = groupPosition;
if (convertView == null) {
LayoutInflater inflater = (LayoutInflater) this.mContext
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
convertView = inflater.inflate(R.layout.contact_detail_item, null);
mViewHolder = new ViewHolder();
mViewHolder.mPhoneNumber = (TextView) convertView
.findViewById(R.id.tv_phone_number);
mViewHolder.mPhoneType = (TextView) convertView
.findViewById(R.id.tv_phone_type);
mViewHolder.mCheckBox = (CheckBox) convertView
.findViewById(R.id.checkBox);
convertView.setTag(mViewHolder);
} else {
mViewHolder = (ViewHolder) convertView.getTag();
}
mViewHolder.mPhoneNumber.setText(numberText);
mViewHolder.mPhoneType.setText(typeText);
phoneNumberCheckStates = new ArrayList<Boolean>();
for (int i = 0; i < mListDataChild.size(); i++) {
phoneNumberCheckStates.add(false);
}
if (phoneNumberCheckStates.get(childPosition)) {
mViewHolder.mCheckBox.setChecked(true);
} else {
mViewHolder.mCheckBox.setChecked(false);
}
mViewHolder.mCheckBox.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
/*this is line 165*/ if (mViewHolder.mCheckBox.isChecked()) { /*this is line 165*/
phoneNumberCheckStates.set(childPosition, true);
selectedNumbers.add(mListDataChild
.get(mListDataHeader.get(mGroupPosition).getName())
.get(childPosition).getNumber());
} else {
phoneNumberCheckStates.set(childPosition, false);
selectedNumbers.remove(mListDataChild
.get(mListDataHeader.get(mGroupPosition).getName())
.get(childPosition).getNumber());
}
}
});
return convertView;
}
@Override
public boolean isChildSelectable(int groupPosition, int childPosition) {
return false;
}
@Override
public boolean hasStableIds() {
return false;
}
public ArrayList<Boolean> getCheckedNumbers() {
return phoneNumberCheckStates;
}
public ArrayList<String> getSelectedNumbers() {
return selectedNumbers;
}
private class ViewHolder {
TextView mContactName;
TextView mPhoneNumber;
TextView mPhoneType;
ImageView mContactImage;
CheckBox mCheckBox;
}
}
如果有帮助，这是Log：
01-25 04:34:31.695: E/AndroidRuntime(7074): FATAL EXCEPTION: main
01-25 04:34:31.695: E/AndroidRuntime(7074): java.lang.NullPointerException
01-25 04:34:31.695: E/AndroidRuntime(7074): at com.psesto.journeysend.contactpicker.MyExpandableListAdapter$1.onClick(MyExpandableListAdapter.java:165)
01-25 04:34:31.695: E/AndroidRuntime(7074): at android.view.View.performClick(View.java:4204)
01-25 04:34:31.695: E/AndroidRuntime(7074): at android.widget.CompoundButton.performClick(CompoundButton.java:100)
01-25 04:34:31.695: E/AndroidRuntime(7074): at android.view.View$PerformClick.run(View.java:17355)
01-25 04:34:31.695: E/AndroidRuntime(7074): at android.os.Handler.handleCallback(Handler.java:725)
01-25 04:34:31.695: E/AndroidRuntime(7074): at android.os.Handler.dispatchMessage(Handler.java:92)
01-25 04:34:31.695: E/AndroidRuntime(7074): at android.os.Looper.loop(Looper.java:137)
01-25 04:34:31.695: E/AndroidRuntime(7074): at android.app.ActivityThread.main(ActivityThread.java:5041)
01-25 04:34:31.695: E/AndroidRuntime(7074): at java.lang.reflect.Method.invokeNative(Native Method)
01-25 04:34:31.695: E/AndroidRuntime(7074): at java.lang.reflect.Method.invoke(Method.java:511)
01-25 04:34:31.695: E/AndroidRuntime(7074): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
01-25 04:34:31.695: E/AndroidRuntime(7074): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
01-25 04:34:31.695: E/AndroidRuntime(7074): at dalvik.system.NativeStart.main(Native Method)
答案 0 :(得分：6)
我接受了Towlie288的答案，因为它指出了我正确的方向。以下是使一切正常的代码更改：
public class MyExpandableListAdapter extends BaseExpandableListAdapter {
private Context mContext;
private ArrayList<ContactNameItems> mListDataHeader;
private ArrayList<String> selectedNumbers;
private HashMap<String, List<ContactPhoneItems>> mListDataChild;
private ChildViewHolder childViewHolder;
private GroupViewHolder groupViewHolder;
public MyExpandableListAdapter(Context context,
ArrayList<ContactNameItems> listDataHeader,
HashMap<String, List<ContactPhoneItems>> listDataChild,
ArrayList<String> listOfNumbers) {
mContext = context;
mListDataHeader = listDataHeader;
mListDataChild = listDataChild;
selectedNumbers = listOfNumbers;
}
@Override
public int getGroupCount() {
return mListDataHeader.size();
}
@Override
public ContactNameItems getGroup(int groupPosition) {
return mListDataHeader.get(groupPosition);
}
@Override
public long getGroupId(int groupPosition) {
return groupPosition;
}
@Override
public View getGroupView(int groupPosition, boolean isExpanded,
View convertView, ViewGroup parent) {
String contactName = getGroup(groupPosition).getName();
Bitmap contactImage = getGroup(groupPosition).getImage();
if (convertView == null) {
LayoutInflater inflater = (LayoutInflater) mContext
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
convertView = inflater.inflate(R.layout.contact_name_item, null);
groupViewHolder = new GroupViewHolder();
groupViewHolder.mContactName = (TextView) convertView
.findViewById(R.id.lblListHeader);
groupViewHolder.mContactImage = (ImageView) convertView
.findViewById(R.id.ivContactPhoto);
convertView.setTag(groupViewHolder);
} else {
groupViewHolder = (GroupViewHolder) convertView.getTag();
}
if (contactImage != null) {
groupViewHolder.mContactImage.setImageBitmap(contactImage);
} else {
groupViewHolder.mContactImage
.setImageResource(R.drawable.default_contact);
}
groupViewHolder.mContactName.setText(contactName);
return convertView;
}
@Override
public int getChildrenCount(int groupPosition) {
return mListDataChild.get(mListDataHeader.get(groupPosition).getName())
.size();
}
@Override
public ContactPhoneItems getChild(int groupPosition, int childPosition) {
return mListDataChild.get(mListDataHeader.get(groupPosition).getName())
.get(childPosition);
}
@Override
public long getChildId(int groupPosition, int childPosition) {
return childPosition;
}
@Override
public View getChildView(int groupPosition, final int childPosition,
boolean isLastChild, View convertView, ViewGroup parent) {
String numberText = getChild(groupPosition, childPosition).getNumber();
String typeText = getChild(groupPosition, childPosition).getPhoneType();
final int mGroupPosition = groupPosition;
if (convertView == null) {
LayoutInflater inflater = (LayoutInflater) this.mContext
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
convertView = inflater.inflate(R.layout.contact_detail_item, null);
childViewHolder = new ChildViewHolder();
childViewHolder.mPhoneNumber = (TextView) convertView
.findViewById(R.id.tv_phone_number);
childViewHolder.mPhoneType = (TextView) convertView
.findViewById(R.id.tv_phone_type);
childViewHolder.mCheckBox = (CheckBox) convertView
.findViewById(R.id.checkBox);
childViewHolder.mCheckBox.setOnCheckedChangeListener(checkListener);
convertView.setTag(childViewHolder);
} else {
childViewHolder = (ChildViewHolder) convertView.getTag();
}
childViewHolder.mPhoneNumber.setText(numberText);
childViewHolder.mPhoneType.setText(typeText);
ContactPhoneItems cpi = getChild(mGroupPosition, childPosition);
childViewHolder.mCheckBox.setTag(cpi);
childViewHolder.mCheckBox.setChecked(cpi.getSelected());
// for managing the state of the boolean
// array according to the state of the
// CheckBox
childViewHolder.mCheckBox
.setOnClickListener(new View.OnClickListener() {
String contactNumber = mListDataChild
.get(mListDataHeader.get(mGroupPosition).getName())
.get(childPosition).getNumber();
public void onClick(View v) {
boolean isChecked = ((CheckBox) v).isChecked();
if (isChecked) {
selectedNumbers.add(contactNumber);
} else {
selectedNumbers.remove(contactNumber);
}
getChild(mGroupPosition, childPosition).setSelected(isChecked);
notifyDataSetChanged();
}
});
return convertView;
}
@Override
public boolean isChildSelectable(int groupPosition, int childPosition) {
return false;
}
@Override
public boolean hasStableIds() {
return false;
}
public ArrayList<String> getSelectedNumbers() {
return selectedNumbers;
}
public final class GroupViewHolder {
TextView mContactName;
ImageView mContactImage;
}
public final class ChildViewHolder {
TextView mPhoneNumber;
TextView mPhoneType;
CheckBox mCheckBox;
}
OnCheckedChangeListener checkListener = new OnCheckedChangeListener() {
@Override
public void onCheckedChanged(CompoundButton buttonView,
boolean isChecked) {
ContactPhoneItems c = (ContactPhoneItems) buttonView.getTag();
c.setSelected(isChecked);
}
};
}
答案 1 :(得分：2)
ViewHolder为Adapter提供了一个Views引用。这没有任何意义，因为列表中的每个视图都有自己ViewHolder的{{1}}实例。
您可以将View.getTag()设置为int[]
CheckBox并在 int[] positions = new int[2];
positions[0] = childPosition;
positions[1] = groupPosition;
mViewHolder.mCheckBox.setTag(positions);
onClick()然后你有状态的CheckBox和其余的位置
答案 2 :(得分：-1)
如果Child的视图正在重复使用Group的视图，以及ViewHolder的视图，则会发生这种情况。显然，它在第165行找不到mCheckBox，因为它尚未设置
只需在ViewHolder中添加一个标记，以检查它是Child的{{1}}就可以解决您的问题。这里不需要两种ViewHolder
希望是有帮助的