当我尝试创建自定义列表视图片段时，我的应用程序崩溃了 我没有看到这方面的问题，但没有一个有帮助 这是我的HomeFragment.java：
public class HomeFragment extends Fragment implements AdapterView.OnItemClickListener {
ArrayList<Questions> arrayQues;
ListView listViewQues;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.custom_list_layout_home, container, false);
arrayQues = new ArrayList<Questions>();
//new LoadInbox().execute();
Questions q1 = new Questions( "This is a sample question 1", 789456123, "28/06/2015");
Questions q2 = new Questions( "This is a sample question 2", 789456123, "28/06/2015");
Questions q3 = new Questions( "This is a sample question 3", 789456123, "28/06/2015");
Questions q4 = new Questions( "This is a sample question 4", 789456123, "28/06/2015");
Questions q5 = new Questions( "This is a sample question 5", 789456123, "28/06/2015");
Questions q6 = new Questions( "This is a sample question 6", 789456123, "28/06/2015");
Questions q7 = new Questions( "This is a sample question 7", 789456123, "28/06/2015");
Questions q8 = new Questions( "This is a sample question 8", 789456123, "28/06/2015");
Questions q9 = new Questions( "This is a sample question 9", 789456123, "28/06/2015");
Questions q10 = new Questions( "This is a sample question 10", 789456123, "28/06/2015");
Questions q11 = new Questions( "This is a sample question 11", 789456123, "28/06/2015");
Questions q12 = new Questions( "This is a sample question 12", 789456123, "28/06/2015");
Questions q13 = new Questions( "This is a sample question 13", 789456123, "28/06/2015");
Questions q14 = new Questions( "This is a sample question 14", 789456123, "28/06/2015");
arrayQues.add(q1);
arrayQues.add(q2);
arrayQues.add(q3);
arrayQues.add(q4);
arrayQues.add(q5);
arrayQues.add(q6);
arrayQues.add(q7);
arrayQues.add(q8);
arrayQues.add(q9);
arrayQues.add(q10);
arrayQues.add(q11);
arrayQues.add(q12);
arrayQues.add(q13);
arrayQues.add(q14);
perform(rootView);
return rootView;
}
public void perform(View v) {
listViewQues = (ListView)v.findViewById(R.id.list_ques);
QuestionListAdapter adapter = new QuestionListAdapter(getActivity(), arrayQues);
listViewQues.setAdapter(adapter);
// Set the onItemClickListener on the ListView to listen for items clicks
listViewQues.setOnItemClickListener( this);
listViewQues.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
// ListView Clicked item index
int itemPosition = position;
// ListView Clicked item value
String itemValue = (String) listViewQues.getItemAtPosition(position);
// Show Alert
Toast.makeText(getActivity().getApplicationContext(),
"Position :" + itemPosition + " ListItem : " + itemValue, Toast.LENGTH_LONG)
.show();
}
});
}
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
}
给出了nullPoint异常
这是我的QuestionListAdapter.java
package wolverine.example.com.btp_scientist;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.TextView;
import java.util.ArrayList;
import java.util.List;
/**
* Created by Wolverine on 28-06-2015.
*/
public class QuestionListAdapter extends BaseAdapter {
Context context;
protected List<Questions> listQuestions;
LayoutInflater inflater;
public QuestionListAdapter(Context context, ArrayList<Questions> listQues) {
this.listQuestions = listQuestions;
this.inflater = LayoutInflater.from(context);
this.context = context;
}
public int getCount() {
return listQuestions.size();
}
public Questions getItem(int position) {
return listQuestions.get(position);
}
@Override
public long getItemId(int position) {
return listQuestions.indexOf(getItem(position));
}
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder holder;
if (convertView == null) {
holder = new ViewHolder();
convertView = this.inflater.inflate(R.layout.custom_list_layout_home,
parent, false);
holder.txtQues = (TextView) convertView
.findViewById(R.id.txt_questions);
holder.txtDate = (TextView) convertView
.findViewById(R.id.txt_date);
holder.txtNum = (TextView) convertView
.findViewById(R.id.txt_asked_by);
convertView.setTag(holder);
} else {
holder = (ViewHolder) convertView.getTag();
}
Questions question = listQuestions.get(position);
holder.txtQues.setText(question.getQues());
holder.txtNum.setText((int) question.getNumber());
holder.txtQues.setText(question.getQues());
return convertView;
}
private class ViewHolder {
TextView txtQues;
TextView txtNum;
TextView txtDate;
}
}
Logcat：
06-29 09:06:58.659 19195-19297/? E/Babel﹕ Network error while getting auth token
06-29 09:06:58.679 19195-19297/? E/Babel﹕ bfm: Cannot get auth token
at f.a(Unknown Source)
at bff.a(SourceFile:88)
at bff.a(SourceFile:128)
at bzp.a(SourceFile:289)
at bzp.a(SourceFile:115)
at bui.a(SourceFile:626)
at bui.a(SourceFile:491)
at bfq.a(SourceFile:39)
at bfr.run(SourceFile:88)
Caused by: java.io.IOException: NetworkError
at dcr.a(Unknown Source)
at f.a(Unknown Source)
at bff.a(SourceFile:88)
at bff.a(SourceFile:128)
at bzp.a(SourceFile:289)
at bzp.a(SourceFile:115)
at bui.a(SourceFile:626)
at bui.a(SourceFile:491)
at bfq.a(SourceFile:39)
at bfr.run(SourceFile:88)
06-29 09:06:59.309 19330-19330/? E/Trace﹕ error opening trace file: No such file or directory (2)
06-29 09:06:59.409 16174-19328/? E/dalvikvm﹕ Could not find class 'android.security.KeyPairGeneratorSpec$Builder', referenced from method com.google.android.gms.auth.e.c.a
06-29 09:06:59.979 19195-19297/? E/Babel﹕ Network error while getting auth token
06-29 09:06:59.979 19195-19297/? E/Babel﹕ bfm: Cannot get auth token
at f.a(Unknown Source)
at bff.a(SourceFile:88)
at bff.a(SourceFile:128)
at bzp.a(SourceFile:289)
at bzp.a(SourceFile:115)
at bui.a(SourceFile:626)
at bui.a(SourceFile:491)
at bfq.a(SourceFile:39)
at bfr.run(SourceFile:88)
Caused by: java.io.IOException: NetworkError
at dcr.a(Unknown Source)
at f.a(Unknown Source)
at bff.a(SourceFile:88)
at bff.a(SourceFile:128)
at bzp.a(SourceFile:289)
at bzp.a(SourceFile:115)
at bui.a(SourceFile:626)
at bui.a(SourceFile:491)
at bfq.a(SourceFile:39)
at bfr.run(SourceFile:88)
06-29 09:07:00.389 16174-19348/? E/dalvikvm﹕ Could not find class 'android.os.UserHandle', referenced from method com.google.android.gms.icing.b.g.a
06-29 09:07:00.469 28484-19357/? E/SQLiteLog﹕ (5) statement aborts at 1: [PRAGMA journal_mode=TRUNCATE;]
06-29 09:07:00.559 156-495/? E/AudioHardwareMSM8660﹕ value of device and enable is 23 0 ALSA dev id:20
06-29 09:07:00.729 19330-19330/? E/dalvikvm﹕ Could not find class 'android.app.Notification$Action$Builder', referenced from method b.a
06-29 09:07:00.839 19330-19330/? E/dalvikvm﹕ Could not find class 'android.graphics.drawable.RippleDrawable', referenced from method b.a
06-29 09:07:00.909 19039-19039/? E/AndroidRuntime﹕ FATAL EXCEPTION: main
java.lang.RuntimeException: Unable to start activity ComponentInfo{wolverine.example.com.btp_scientist/wolverine.example.com.btp_scientist.FinalScreen}: java.lang.NullPointerException
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2071)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2096)
at android.app.ActivityThread.access$600(ActivityThread.java:138)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1207)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:213)
at android.app.ActivityThread.main(ActivityThread.java:4787)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:789)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:556)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at wolverine.example.com.btp_scientist.HomeFragment.perform(HomeFragment.java:110)
at wolverine.example.com.btp_scientist.HomeFragment.onCreateView(HomeFragment.java:100)
at android.support.v4.app.Fragment.performCreateView(Fragment.java:1789)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:955)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1138)
at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:740)
at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1501)
at android.support.v4.app.FragmentActivity.onStart(FragmentActivity.java:551)
at android.app.Instrumentation.callActivityOnStart(Instrumentation.java:1163)
at android.app.Activity.performStart(Activity.java:5018)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2044)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2096)
at android.app.ActivityThread.access$600(ActivityThread.java:138)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1207)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:213)
at android.app.ActivityThread.main(ActivityThread.java:4787)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:789)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:556)
at dalvik.system.NativeStart.main(Native Method)
06-29 09:07:01.089 19330-19330/? E/dalvikvm﹕ Could not find class 'android.app.Notification$Action$Builder', referenced from method b.a
06-29 09:07:01.139 19330-19330/? E/dalvikvm﹕ Could not find class 'android.transition.Transition', referenced from method b.a
06-29 09:07:01.139 19330-19330/? E/dalvikvm﹕ Could not find class 'android.transition.Transition', referenced from method b.a
06-29 09:07:01.139 19330-19330/? E/dalvikvm﹕ Could not find class 'android.transition.Transition', referenced from method b.a
06-29 09:07:01.199 19330-19330/? E/dalvikvm﹕ Could not find class 'android.app.RemoteInput[]', referenced from method b.a
06-29 09:07:01.229 19330-19330/? E/dalvikvm﹕ Could not find class 'android.transition.Transition', referenced from method b.b
06-29 09:07:01.769 19383-19383/? E/Trace﹕ error opening trace file: No such file or directory (2)
06-29 09:07:02.049 19398-19398/? E/Trace﹕ error opening trace file: No such file or directory (2)
06-29 09:07:02.229 19412-19412/? E/Trace﹕ error opening trace file: No such file or directory (2)
06-29 09:07:02.569 28484-19435/? E/SQLiteLog﹕ (5) statement aborts at 1: [PRAGMA journal_mode=TRUNCATE;]
06-29 09:07:02.639 19436-19436/? E/Trace﹕ error opening trace file: No such file or directory (2)
06-29 09:07:02.909 19452-19452/? E/Trace﹕ error opening trace file: No such file or directory (2)
06-29 09:07:02.989 156-495/? E/AudioHardwareMSM8660﹕ write(): dec_id = 1 cur_rx = 23
06-29 09:07:02.989 156-495/? E/AudioHardwareMSM8660﹕ cur_rx for pcm playback = 23
06-29 09:07:02.989 156-495/? E/AudioHardwareMSM8660﹕ value of device and enable is 23 1 ALSA dev id:20
06-29 09:07:03.199 421-544/? E/InputDispatcher﹕ channel '435759e0 wolverine.example.com.btp_scientist/wolverine.example.com.btp_scientist.MainActivity (server)' ~ Channel is unrecoverably broken and will be disposed!
06-29 09:07:03.199 421-544/? E/InputDispatcher﹕ channel '43548c20 wolverine.example.com.btp_scientist/wolverine.example.com.btp_scientist.Registration (server)' ~ Channel is unrecoverably broken and will be disposed!
06-29 09:07:03.199 421-544/? E/InputDispatcher﹕ channel '418895f0 wolverine.example.com.btp_scientist/wolverine.example.com.btp_scientist.Register2ndStep (server)' ~ Channel is unrecoverably broken and will be disposed!
06-29 09:07:03.309 19465-19465/wolverine.example.com.btp_scientist E/Trace﹕ error opening trace file: No such file or directory (2)
06-29 09:07:03.389 19195-19297/? E/Babel﹕ Network error while getting auth token
06-29 09:07:03.389 19195-19297/? E/Babel﹕ bfm: Cannot get auth token
at f.a(Unknown Source)
at bff.a(SourceFile:88)
at bff.a(SourceFile:128)
at bzp.a(SourceFile:289)
at bzp.a(SourceFile:115)
at bui.a(SourceFile:626)
at bui.a(SourceFile:491)
at bfq.a(SourceFile:39)
at bfr.run(SourceFile:88)
Caused by: java.io.IOException: NetworkError
at dcr.a(Unknown Source)
at f.a(Unknown Source)
at bff.a(SourceFile:88)
at bff.a(SourceFile:128)
at bzp.a(SourceFile:289)
at bzp.a(SourceFile:115)
at bui.a(SourceFile:626)
at bui.a(SourceFile:491)
at bfq.a(SourceFile:39)
at bfr.run(SourceFile:88)
06-29 09:07:03.599 19482-19482/? E/Trace﹕ error opening trace file: No such file or directory (2)
06-29 09:07:04.259 19436-19436/? E/dalvikvm﹕ Could not find class 'android.app.AppOpsManager', referenced from method com.google.android.gms.common.GooglePlayServicesUtil.zza
06-29 09:07:05.229 808-808/? E/libEGL﹕ eglSetBlobCacheFuncsANDROID resulted in an error: 0x300c
06-29 09:07:06.079 156-495/? E/AudioHardwareMSM8660﹕ value of device and enable is 23 0 ALSA dev id:20
06-29 09:07:06.509 28484-19546/? E/SQLiteLog﹕ (5) statement aborts at 1: [PRAGMA journal_mode=TRUNCATE;]
06-29 09:07:07.549 19592-19592/? E/Trace﹕ error opening trace file: No such file or directory (2)
06-29 09:07:07.679 421-544/? E/InputDispatcher﹕ channel '42ba5a30 wolverine.example.com.btp_scientist/wolverine.example.com.btp_scientist.MainActivity (server)' ~ Channel is unrecoverably broken and will be disposed!
06-29 09:07:07.839 28484-19605/? E/SQLiteLog﹕ (5) statement aborts at 1: [PRAGMA journal_mode=TRUNCATE;]
06-29 09:07:08.089 19482-19608/? E/dalvikvm﹕ Could not find class 'android.os.UserHandle', referenced from method com.amazon.identity.auth.device.framework.AndroidUser.<init>
06-29 09:07:08.199 19195-19297/? E/Babel﹕ Network error while getting auth token
06-29 09:07:08.209 19195-19297/? E/Babel﹕ bfm: Cannot get auth token
at f.a(Unknown Source)
at bff.a(SourceFile:88)
at bff.a(SourceFile:128)
at bzp.a(SourceFile:289)
at bzp.a(SourceFile:115)
at bui.a(SourceFile:626)
at bui.a(SourceFile:491)
at bfq.a(SourceFile:39)
at bfr.run(SourceFile:88)
Caused by: java.io.IOException: NetworkError
at dcr.a(Unknown Source)
at f.a(Unknown Source)
at bff.a(SourceFile:88)
at bff.a(SourceFile:128)
at bzp.a(SourceFile:289)
at bzp.a(SourceFile:115)
at bui.a(SourceFile:626)
at bui.a(SourceFile:491)
at bfq.a(SourceFile:39)
at bfr.run(SourceFile:88)
custom_list_layout_home.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:padding="8dp"
android:background="#ffffff">
<RelativeLayout
android:id="@+id/layout_item_car"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1" >
<LinearLayout
android:id="@+id/layout_questions"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:orientation="horizontal" >
<TextView
android:id="@+id/txt_questions"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceMedium"
android:textStyle="normal" />
</LinearLayout>
<LinearLayout
android:id="@+id/layout_car_color"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_below="@+id/layout_questions"
android:orientation="horizontal"
android:layout_marginTop="5dp">
<TextView
android:id="@+id/lbl_asked_by"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Asked By-"
android:textAppearance="?android:attr/textAppearanceMedium"
android:textStyle="bold" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/txt_asked_by"/>
<TextView
android:id="@+id/txt_date"
android:layout_width="wrap_content"
android:layout_gravity="right"
android:layout_marginLeft="100dp"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceMedium"
android:textStyle="normal" />
</LinearLayout>
</RelativeLayout>
</LinearLayout>
fragment_home.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<ListView
android:id="@+id/list_ques"
android:layout_width="fill_parent"
android:divider="@color/list_divider"
android:dividerHeight="5dp"
android:layout_height="wrap_content"
android:listSelector="@drawable/list_row_selector"></ListView>
</RelativeLayout>
请帮助。提前致谢
答案 0 :(得分：1)
使用
而不是
holder.txtNum.setText((int) question.getNumber());
你应该使用
holder.txtNum.setText(String.valueOf(question.getNumber()));
它将彻底解决你的崩溃!!
答案 1 :(得分：0)
您需要更改视图，
View rootView = inflater.inflate(R.layout.fragment_home, container, false);
请用 -
替换您的适配器方法public QuestionListAdapter(Context context, ArrayList<Questions> listQues) {
this.listQuestions = listQues;
this.inflater = LayoutInflater.from(context);
this.context = context;
}
请使用getView()方法更改此内容，
holder.txtNum.setText(""+question.getNumber());