我在我的应用程序之外的ListView中有一个惊人的异常。我已经读过它可能是由我的适配器引起的，它返回null。但我的适配器检查它：
public View getView(int position, View convertView, ViewGroup parent) {
View view = convertView;
SmsHolder v;
if(view == null) {
if(MainActivity.DEBUG) {
view = lInflater.inflate(R.layout.sms_list_item_debug, parent, false);
} else {
view = lInflater.inflate(R.layout.sms_list_item, parent, false);
}
}
v = (SmsHolder) view.getTag(R.id.screenHolder);
SMS sms = getSMS(position);
v.date.setText(ZenDate.format(ZenDate.FORMAT_RUS_DM, sms.time_stamp * 1000));
v.sender.setText(sms.sender + " ");
v.text.setText(sms.text + " ");
v.selector.setOnCheckedChangeListener(null);
v.selector.setChecked(checked.contains(sms._id));
v.status.setTag(sms);
v.selector.setTag(position);
boolean smsParsed = sms.parsed != null
&& sms.checkFlag(SMS.FLAG_SENDER_OK)
&& sms.checkFlag(SMS.FLAG_FORMAT_OK)
&& sms.checkFlag(SMS.FLAG_ACCOUNT_OK);
if(smsParsed) {
v.status_bg.setVisibility(View.GONE);
} else {
v.status_bg.setVisibility(View.VISIBLE);
if (sms.checkFlag(SMS.FLAG_FORMAT_OK)) {
v.status.setEnabled(false);
} else {
v.status.setEnabled(true);
}
v.status.setText(getSMSStatus(sms));
v.status.setEventListener(new ContextMenu.EventListener() {
@Override
public void onItemSelected(ContextMenu v, int index) {
SMS sms = (SMS) v.getTag();
if (index == 0) {
Intent i = new Intent(Intent.ACTION_SEND);
i.setType("message/rfc822");
i.putExtra(Intent.EXTRA_EMAIL , new String[]{"support@zenmoney.ru", ""});
String subj = getSMSStatus(sms) + "["+ ZenMoney.getVersionName()+"]";
i.putExtra(Intent.EXTRA_SUBJECT, subj);
String text = context.getString(R.string.sms_mail);
i.putExtra(Intent.EXTRA_TEXT, String.format(text, sms.sender, sms.text));
try {
i = Intent.createChooser(i, context.getString(R.string.sms_app_choose));
i.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
context.startActivity(i);
} catch (android.content.ActivityNotFoundException ex) {
Toast.makeText(context, context.getString(R.string.no_apps), Toast.LENGTH_SHORT).show();
}
} else if (MainActivity.DEBUG && index == 1) {
Intent i = new Intent(context, SmsTestActivity.class);
i.putExtra("sms_sender", sms.sender);
i.putExtra("sms_body", sms.text);
context.startActivity(i);
}
}
@Override
public void onClick(View view) {
//To change body of implemented methods use File | Settings | File Templates.
}
});
}
v.selector.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(CompoundButton v, boolean isChecked) {
// TODO Auto-generated method stub
Integer position = (Integer) v.getTag();
SMS sms = smsList.get(position);
Long id = sms._id;
if (!isChecked) {
checked.remove(id);
} else if (!checked.contains(id)) {
checked.add(id);
}
if (checked.size() > 0) {
SmsScreen.showBottomCAB();
} else {
SmsScreen.hideBottomCAB();
}
}
});
if (view == null) {
ZenMoney.uncaughtException(new NullPointerException());
}
return view;
}
这是错误日志：
ERROR/AndroidRuntime(4393): FATAL EXCEPTION: main
java.lang.NullPointerException
at android.widget.AbsListView.obtainView(AbsListView.java:1482)
at android.widget.ListView.makeAndAddView(ListView.java:1786)
at android.widget.ListView.fillDown(ListView.java:705)
at android.widget.ListView.fillFromTop(ListView.java:762)
at android.widget.ListView.layoutChildren(ListView.java:1639)
at android.widget.AbsListView.onLayout(AbsListView.java:1310)
at android.view.View.layout(View.java:7224)
at android.support.v4.view.ViewPager.onLayout(ViewPager.java:1528)
at android.view.View.layout(View.java:7224)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1290)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1166)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1083)
at android.view.View.layout(View.java:7224)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1290)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1166)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1083)
at android.view.View.layout(View.java:7224)
at android.widget.RelativeLayout.onLayout(RelativeLayout.java:943)
at android.view.View.layout(View.java:7224)
at android.widget.FrameLayout.onLayout(FrameLayout.java:369)
at android.view.View.layout(View.java:7224)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1290)
at android.widget.LinearLayout.layoutHorizontal(LinearLayout.java:1279)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1085)
at android.view.View.layout(View.java:7224)
at android.widget.FrameLayout.onLayout(FrameLayout.java:369)
at android.view.View.layout(View.java:7224)
at com.slidingmenu.lib.CustomViewAbove.onLayout(CustomViewAbove.java:426)
at android.view.View.layout(View.java:7224)
at android.widget.RelativeLayout.onLayout(RelativeLayout.java:943)
at android.view.View.layout(View.java:7224)
at android.widget.FrameLayout.onLayout(FrameLayout.java:369)
at android.view.View.layout(View.java:7224)
at android.view.ViewRoot.performTraversals(ViewRoot.java:1181)
at android.view.ViewRoot.handleMessage(ViewRoot.java:1913)
at android.os.Handler.dispatchMessage(Handler.java:130)
at android.os.Looper.loop(SourceFile:351)
at android.app.ActivityThread.main(ActivityThread.java:3820)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:538)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:969)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:727)
at dalvik.system.NativeStart.main(Native Method)
问题是：为什么会出现这种错误，我该如何避免呢？
更新：问题已解决。我刚刚在适配器中感到困惑并使用了另一个。对不起：）
答案 0 :(得分：2)
如果这是getView方法，它应该以这种方式实现......
public View getView(int position, View convertView, ViewGroup parent) {
View view = convertView;
if(view == null) {
//inflate
}
....
return view;
}
检查http://www.vogella.com/articles/AndroidListView/article.html
答案 1 :(得分：0)
这是因为您检查指针是否为空以及是否仍然抛出NullPointerException。对于指针为null而不是抛出NullPointerException的情况，您需要做一些合理的事情。否则你也可以不检查。