情况是当我选择其中一个列表项时。它将在下一个 Activity 中显示该项目的详细信息。
我尝试使用 onItemClick
监听器从选定的 ListItem
获取值。我在点击该项目时遇到错误 [FATAL EXCEPTION]
。
请帮助我。
这是 ScheduleFragment.java 的一部分
public class ScheduleFragment extends Fragment {
/* other activity */
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
View rootView = inflater.inflate(R.layout.fragment_schedule, container, false);
myListView = (ListView) rootView.findViewById(R.id.list);
// on selecting single subject
myListView.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
// getting values from selected ListItem
String matrix_id = ((ListView) view.findViewById(R.id.list)).getText()
.toString();
// Starting new intent
Intent in = new Intent(getActivity().getApplicationContext(),
SingleSubject.class);
// sending matrix id to next activity
in.putExtra(TAG_MATRIX_ID, matrix_id);
// starting new activity and expecting some response back
startActivityForResult(in, 100);
}
});
这是 SingleSubject.java
public class SingleSubject extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.single_subject);
// getting subject details from intent
Intent i = getIntent();
// getting matrix_id from intent
matrix_id = i.getStringExtra(TAG_MATRIX_ID);
// Getting complete matrix_id details in background thread
new GetSubjectDetails().execute();
}
这个single_subject.xml
<!-- Name Label -->
<TextView android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Name"
android:paddingLeft="10dip"
android:paddingRight="10dip"
android:paddingTop="10dip"
android:textSize="17dip"/>
<!-- Input Name -->
<EditText android:id="@+id/inputName"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_margin="5dip"
android:layout_marginBottom="15dip"
android:singleLine="true"/>
<!-- Email Label -->
<TextView android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Email"
android:paddingLeft="10dip"
android:paddingRight="10dip"
android:paddingTop="10dip"
android:textSize="17dip"/>
<!-- Input Email -->
<EditText android:id="@+id/inputEmail"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_margin="5dip"
android:layout_marginBottom="15dip"
android:singleLine="true"/>
这是fragment_schedule.xml
<ListView
android:id="@+id/list"
android:layout_width="fill_parent"
android:layout_height="wrap_content"/>
这是日志错误。
03-25 14:40:49.808: W/dalvikvm(10182): threadid=1: thread exiting with uncaught exception (group=0x40d09930)
03-25 14:40:49.854: E/AndroidRuntime(10182): FATAL EXCEPTION: main
03-25 14:40:49.854: E/AndroidRuntime(10182): java.lang.NullPointerException
03-25 14:40:49.854: E/AndroidRuntime(10182): at com.ultra.esc.ScheduleFragment$1.onItemClick(ScheduleFragment.java:95)
03-25 14:40:49.854: E/AndroidRuntime(10182): at android.widget.AdapterView.performItemClick(AdapterView.java:298)
03-25 14:40:49.854: E/AndroidRuntime(10182): at android.widget.AbsListView.performItemClick(AbsListView.java:1100)
03-25 14:40:49.854: E/AndroidRuntime(10182): at android.widget.AbsListView$PerformClick.run(AbsListView.java:2749)
03-25 14:40:49.854: E/AndroidRuntime(10182): at android.widget.AbsListView$1.run(AbsListView.java:3423)
03-25 14:40:49.854: E/AndroidRuntime(10182): at android.os.Handler.handleCallback(Handler.java:725)
03-25 14:40:49.854: E/AndroidRuntime(10182): at android.os.Handler.dispatchMessage(Handler.java:92)
03-25 14:40:49.854: E/AndroidRuntime(10182): at android.os.Looper.loop(Looper.java:137)
03-25 14:40:49.854: E/AndroidRuntime(10182): at android.app.ActivityThread.main(ActivityThread.java:5039)
03-25 14:40:49.854: E/AndroidRuntime(10182): at java.lang.reflect.Method.invokeNative(Native Method)
03-25 14:40:49.854: E/AndroidRuntime(10182): at java.lang.reflect.Method.invoke(Method.java:511)
03-25 14:40:49.854: E/AndroidRuntime(10182): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
03-25 14:40:49.854: E/AndroidRuntime(10182): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
03-25 14:40:49.854: E/AndroidRuntime(10182): at dalvik.system.NativeStart.main(Native Method)
最佳答案
您在为适配器扩展的布局中没有 ListView
String matrix_id = ((ListView) view.findViewById(R.id.list)).getText()
.toString();
因此,上述初始化为您提供了 NullpointerExcpetion
。
猜测工作:
我可以从我回答的上一个问题中猜出你的问题( ClassCastException: android.widget.TextView cannot be cast to android.widget.ListView )。您在适配器中使用 id R.id.matrix_id
和 R.id.name
膨胀的布局具有 TextView。但为了确认您可以发布您的适配器代码。
复制您之前的问题
ListAdapter adapter = new SimpleAdapter(
getActivity(), subjectList,
R.layout.all_subject, new String[] { TAG_MATRIX_ID,
TAG_NAME},
new int[] { R.id.matrix_id, R.id.name });
您可以使用 getTag
和 setTag
来避免按照 laalto 的建议再次初始化 View
String matrix_id = ((TextView) view.findViewById(R.id.matrix_id)).getText()
.toString();
String name = ((TextView) view.findViewById(R.id.name)).getText()
.toString();
关于java - 致命异常 onItemClick 监听器,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/22627436/