Question

我收到了这些错误，

The method setContentView(int) is undefined for the type DataEdit

The method getApplicationContext() is undefined for the type DataEdit

The method findViewById(int) is undefined for the type DataEdit

代码如下：

    public class DataEdit extends Fragment {
SQLiteDatabase db;
SQLiteDatabase d;
Cursor queryAll;

@Override
public void onCreate(Bundle savedInstanceState) {  
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.dataedit); 
    DBAdapter msdb= new DBAdapter(getApplicationContext(),"adfg", null);        
    db=msdb.getWritableDatabase(); 
    ((EditText)findViewById(R.id.edSpecies)).requestFocus();
}}

我在这里缺少什么？提前感谢您的耐心和智慧。

这是修改后的代码......

    public class DataEdit extends Fragment {
SQLiteDatabase db;
SQLiteDatabase d;
Cursor queryAll;

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    View view = inflater.inflate(R.layout.dataedit, container, false);
    DBAdapter msdb= new DBAdapter(view.getApplicationContext(),"adfg", null);        
    db=msdb.getWritableDatabase(); 
    ((EditText)view.findViewById(R.id.edSpecies)).requestFocus();
    return view;
}

Answer 1

Fragments的行为与Activities不同。片段中的视图层次结构在onCreateView中创建，必须重写并返回View对象。然后在膨胀的视图本身上调用findByViewId()。请参阅文档here

在onCreateView()中，您会像这样夸大视图：

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

    // your layout
    View view = inflater.inflate(R.layout.dataedit, container, false);

    // find the element in the inflated view
    ((EditText) view.findViewById(R.id.edSpecies)).requestFocus();

    // get the context from the holding activity
    DBAdapter msdb= new DBAdapter(getActivity().getApplicationContext(),"adfg", null);
    ...

    return view;

}

带有标签的Android ActionBar，获取多个与片段相关的错误消息

1 个答案: