Question

我有一个片段类，它是viewpager中其他几个类的一部分。我想创建一个ListView通过和数组适配器，并在其中一个片段上显示listview中的内容。这里的问题是当我实现MyLogs.add(new actlog("String","String");程序崩溃时，但当我添加删除这行代码时，应用程序运行但片段为空。这通常是我在活动类上设置和显示ListView的方式，但它对片段类的工作方式不同。

片段类

package com.example.swipeview;

import java.util.ArrayList;
import java.util.List;

import android.content.Context;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.TextView;

public class FragmentOne extends Fragment {
Context context;
public List<actlog> MyLogs = new ArrayList<actlog>();


@Override 
public View onCreateView(LayoutInflater inflater, ViewGroup container,
    Bundle savedInstanceState){

View view= inflater.inflate(R.layout.fragment_one_layout,container, false);


MyLogs.add(new actlog("12:00 AM",""));
MyLogs.add(new actlog("12:30 AM",""));  
MyLogs.add(new actlog("1:00 AM",""));
MyLogs.add(new actlog("1:30 AM",""));
MyLogs.add(new actlog("2:00 AM",""));
MyLogs.add(new actlog("2:30 AM",""));
MyLogs.add(new actlog("3:00 AM",""));


ArrayAdapter<actlog> adapter = new MyListAdapter();

ListView list = (ListView) view.findViewById(R.id.fragmentonelistview);
list.setAdapter(adapter);

return view;

}



@Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);


}

public class MyListAdapter extends ArrayAdapter<actlog>{
public MyListAdapter(){
super(getActivity(),R.layout.item_view, MyLogs);
}

@Override
public View getView(int position, View convertView, ViewGroup parent){

LayoutInflater inflater = (LayoutInflater) context.getSystemService(    Context.LAYOUT_INFLATER_SERVICE);
convertView = inflater.inflate(R.layout.item_view, parent, false);

actlog currentlog = MyLogs.get(position);
TextView textview = (TextView) convertView.findViewById(R.id.timeView);
textview.setText(currentlog.getTime());

return convertView;
}

}//end of listadapter class




}//end of class

actlog class

package com.example.swipeview;

import java.io.Serializable;

public class actlog implements Serializable{


public String time;
public String log;
public actlog(String time, String log) {
    super();
    this.time = time;
    this.setLog(log);
}

public String getTime(){
    return time;
}


public String getLog(){
    return log;
}

public void setLog(String log){
    this.log = log;

}


}

logcat的

09-03 19:50:39.989: W/dalvikvm(1548): threadid=1: thread exiting with uncaught exception       (group=0xb1aa4ba8)
09-03 19:50:40.019: E/AndroidRuntime(1548): FATAL   EXCEPTION: main
09-03 19:50:40.019: E/AndroidRuntime(1548): Process: com.example.swipeview, PID: 1548
09-03 19:50:40.019: E/AndroidRuntime(1548):     java.lang.NullPointerException
09-03 19:50:40.019: E/AndroidRuntime(1548):     at     com.example.swipeview.FragmentOne$MyListAdapter.getView  (FragmentOne.java:63)
09-03 19:50:40.019: E/AndroidRuntime(1548):     at   android.widget.AbsListView.obtainView(AbsListView.java:2263)
09-03 19:50:40.019:     E/AndroidRuntime(1548):     at android.widget.ListView.measureHeightOfChildren(ListView.java:1263)
09-03 19:50:40.019: E/AndroidRuntime(1548):     at  android.widget.ListView.onMeasure(ListView.java:1175)
09-03 19:50:40.019: E/AndroidRuntime(1548):     at android.view.View.measure(View.java:16497)
09-03   19:50:40.019: E/AndroidRuntime(1548):   at android.widget.RelativeLayout.measureChild(RelativeLayout.java:689)
09-03 19:50:40.019: E/AndroidRuntime(1548):         at android.widget.RelativeLayout.onMeasure(RelativeLayout.java:473)
09-03 19:50:40.019: E/AndroidRuntime(1548):     at android.view.View.measure(View.java:16497)
09-03 19:50:40.019: E/AndroidRuntime(1548):     at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125)
09-03 19:50:40.019: E/AndroidRuntime

Answer 1

在你的适配器的getView（）中你喜欢这个

LayoutInflater inflater = (LayoutInflater) getActivity().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
                   OR 
LayoutInflater inflater = LayoutInflater.from(getActivity());

或在适配器的构造函数中初始化Context变量，如

public MyListAdapter(){
 super(getActivity(),R.layout.item_view, MyLogs);
 Context context = getactivity();
}

我认为这可以解决您的问题。

ListView没有出现在Fragment类中

1 个答案: