Question

我有一个ListView的问题，我不断得到一个意外的错误:( 当我试图在我的SamsungGalaxy s4 mini上运行它时我得到一个错误并且它崩溃了几秒后它就会关闭。我究竟做错了什么？这是我的代码：

public class FirstActivity extends Activity {

private ListView listview01;
private TextView TextView01;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_first);

    Student students_data[] = new Student[]
            {
                    new Student("Nikos", "Apostolakis", "2012", "03112023"),
                    new Student("Stavros", "Birbilis", "2012", "03112116")
            };


    StudentAdapter adapter = new StudentAdapter(this, R.layout.studentitemlayout, students_data);
    listview01 = (ListView) findViewById(R.id.ListView01);
    TextView01 = (TextView) findViewById(R.id.HelloWorld);
    TextView01.setText("BreakPointReached!");


    listview01.setAdapter(adapter);


}

}

我的班级是

public class Student {

public String  FirstName;
public String  LastName;
public String  JoinedYear;
public int     JoinedRank;

public Student() {
    super();
}

public Student(String FirstName , String LastName , String JoinedYear, String JoinedRank){
    this.FirstName  = FirstName;
    this.LastName   = LastName;
    this.JoinedYear = JoinedYear;
    this.JoinedRank = Integer.parseInt(JoinedRank);
}

}

和

public class StudentAdapter extends ArrayAdapter {

Context context;
int layoutResourceId;
Student data[] = null;

public StudentAdapter(Context context, int layoutResourceId, Student[] data) {
    super(context, layoutResourceId, data);
    this.layoutResourceId = layoutResourceId;
    this.context = context;
    this.data = data;
}

public View getView(int position, View convertView, ViewGroup parent) {
    View row = convertView;
     StudentHolder holder = null;

    if (row == null) {
        LayoutInflater inflater = ((Activity) context).getLayoutInflater();
        row = inflater.inflate(layoutResourceId, parent, false);

        holder = new StudentHolder();
        holder.FirstName = (TextView) row.findViewById(R.id.FirstName);
        holder.LastName = (TextView) row.findViewById(R.id.LastName);
        holder.JoinedYear = (TextView) row.findViewById(R.id.JoinedYear);
        holder.JoinedRank = (TextView) row.findViewById(R.id.JoinedRank);

        row.setTag(holder);
    } else {
        holder = (StudentHolder) row.getTag();
    }

    Student student = data[position];
    holder.FirstName.setText(student.FirstName);
    holder.LastName.setText(student.LastName);
    holder.JoinedYear.setText(student.JoinedYear);
    holder.JoinedRank.setText(student.JoinedRank);

    return row;
}

static class StudentHolder {
    TextView FirstName;
    TextView LastName;
    TextView JoinedYear;
    TextView JoinedRank;
}

}

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:padding="10dp">

<TextView
    android:id="@+id/FirstName"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:textStyle="bold"
    android:textSize="22dp"
    android:textColor="#000000" />

<TextView
    android:id="@+id/LastName"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content" />

<TextView
    android:id="@+id/JoinedYear"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content" />

<TextView
    android:id="@+id/JoinedRank"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content" />

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingBottom="@dimen/activity_vertical_margin"
tools:context=".FirstActivity">

<TextView
    android:id="@+id/HelloWorld"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="HelloWorld"/>



<ListView
    android:id="@+id/ListView01"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"></ListView>

Answer 1

确保所有资源都存在于相应的布局XML中。

<强> R.id.FirstName

<强> R.id.LastName

<强> R.id.JoinedYear

<强> R.id.JoinedRank

<强> R.id.HelloWorld

编辑：

您已从整数设置文本视图的文本。

替换

holder.JoinedRank.setText(student.JoinedRank);

用这个

holder.JoinedRank.setText(student.JoinedRank+"");

祝你好运。：）

Answer 2

Student student = data[position];
holder.FirstName.setText(student.FirstName);
holder.LastName.setText(student.LastName);
holder.JoinedYear.setText(student.JoinedYear);
holder.JoinedRank.setText(student.JoinedRank);

我想你的学生.JoinedRank是一个整数。这会调用setText(int resId)方法并导致异常，因为R类中的值不会是2010年的字符串常量等。

将行更改为

holder.JoinedRank.setText("" + student.JoinedRank);

它应该有用。

ListView出现意外错误

2 个答案: