我在NullPointerException
上获得tv.setMovementMethod(new ScrollingMovementMethod());
,但我完全不明白为什么!我在XML文件中声明了textView并在onCreateView中初始化了它。任何帮助,将不胜感激。
以下是java代码的相关部分:
public class TestConnection extends Fragment {
public TestConnection() {
}
JSONParser jParser = new JSONParser();
//button pressed to get the items
Button getAllItems;
//declare list view
TextView tv;
//Progress dialog
private ProgressDialog pDialog;
//Make an arrayList containing all items
ArrayList<HashMap<String, String>> itemsList;
//url to get items
private static String urlAllItems = "http://jamesalfei.netne.net/php/get_all_items.php";
//JSON node/tag names
private static final String TAG_SUCCESS = "success";
private static final String TAG_ITEMS = "items";
private static final String TAG_PID = "pid";
private static final String TAG_NAME = "name";
//items array
JSONArray items = null;
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.sql_layout,
container, false);
getAllItems = (Button) getActivity().findViewById(R.id.SQLGetItems);
//listview
tv = (TextView) getActivity().findViewById(R.id.sqltv);
tv.setMovementMethod(new ScrollingMovementMethod());
getAllItems.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// Launching All products Activity
retreiveProducts();
}
});
return view;
}
这是xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent" >
<Button
android:id="@+id/SQLGetItems"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentRight="true"
android:layout_alignParentTop="true"
android:text="@string/getSQL" />
<TextView
android:id="@+id/sqltv"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentLeft="true"
android:layout_alignParentRight="true"
android:layout_below="@+id/SQLGetItems"
android:text="@string/sqlLabel" />
</RelativeLayout>
如果我使用了任何不良的编码习惯,我会道歉,但我对Android编程非常陌生!
答案 0 :(得分:5)
您正在错误的视图中查找TextView。您应该搜索夸大的视图,而不是父母的视图,主要是因为您未在onCreateView()
中添加。所以替换:
tv = (TextView) getActivity().findViewById(R.id.sqltv);
用这个
tv = (TextView) view.findViewById(R.id.sqltv);
答案 1 :(得分:3)
视图未附加到任何内容,因为您使用false
作为inflate()
中的第三个参数。因此,您需要将findViewById()
范围限定为具有TextView的布局。使用:
tv = (TextView) view.findViewById(R.id.sqltv);