android - 从 ListView 获取选中的 View

Question

我正在使用 CursorAdapter 来处理我的 ListActivity:

public class Mclass extends ListActivity{
...
TheAdapter mAdapter;
public static HashMap<Long, Boolean> shown = new HashMap<Long, Boolean>();
...

@Override
protected void onListItemClick(ListView l, View v, int position, long id) {
    super.onListItemClick(l, v, position, id);
         Boolean tmp = shown.get(id); 
        if (tmp == null) { // if null we don't have this key in the hashmap so we added with the value true
            shown.put(id, true);
        } else {
            shown.put(id, !tmp.booleanValue()); // if the value exists in the map then inverse it's value
        }
    mAdapter.notifyDataSetChanged();
         }

}

和我扩展 CursorAdapter 并覆盖 bindView 的适配器类:

@Override
public void bindView(View view, Context context, Cursor cursor) {
    String listText= cursor
            .getString(cursor
                    .getColumnIndexOrThrow(DataHandler.MY_TEXT));

long id = cursor.getLong(cursor.getColumnIndexOrThrow(DataHandler.ROW_ID)); 
    if (Mclass.shown.get(id) != null) {
        TextView m_text = (TextView) view
                .findViewById(R.id.my_text);
        if (m_text != null) {
            m_text.setVisibility(Mclass.shown.get(id)? View.VISIBLE:
                     View.GONE);

            if (m_text.isShown())
                m_text.setText("STRING");
   }
}

我的列表项布局在 xml 文件 list_item.xml 中定义:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:background="#DDDDDD"
android:orientation="horizontal" >

<LinearLayout
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:orientation="vertical" >

    <ImageView
        android:id="@+id/my_image"
        android:layout_width="wrap_content"
        android:layout_height="0dip"
        android:layout_weight="1"
        android:paddingRight="1dip"
        android:paddingTop="1dip"
</LinearLayout>

/*
 *I want to toggle this text view's visibility
 */
<TextView
    android:id="@+id/my_text"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:visibility="gone"//VISIBILITY defined here
    android:paddingBottom="2dip"
    android:paddingLeft="4dip"
    android:paddingRight="4dip"
    android:paddingTop="5dip" />
 </LinearLayout>

如何在 onListItemClick 中切换布局中 TextView 的可见性？ 我试过:

TextView mTextView = (TextView) v.findViewById(R.id.my_text);
mTextView.setVisibility(mTextView.isShown()? View.GONE: View.VISIBLE);
mAdapter.notifyDataSetChanged();

但它似乎是在随机选择要切换的列表项，而不管我点击的是哪个。

Answer 1

您必须存储要隐藏的行的 ID。您可以在 Activity 中创建一个字段来存储这些 ID:

HashMap<Long, Boolean> positionHide = new HashMap<Long, Boolean>();

其中键是行的长 id， bool 对象表示 TextView 的状态(false - 它消失了，true 它可见)。在 onListItemClick() 中，将点击行的 ID 添加到该字段:

    @Override
    protected void onListItemClick(ListView l, View v, int position, long id) {
         Boolean tmp = positionHide.get(id); 
        if (tmp == null) { // if null we don't have this key in the hashmap so we added with the value true
            status.put(id, true);
        } else {
            status.put(id, !tmp.booleanValue()); // if the value exists in the map then inverse it's value
        }
        mAdapter.notifyDataSetChanged();
    }

同时修改bindView()方法:

@Override
public void bindView(View view, Context context, Cursor cursor) {
    String listText = cursor.getString(cursor
            .getColumnIndexOrThrow(DataHandler.MY_TEXT));
    long pos = cursor.getLong(cursor.getColumnIndex(DataHandler.ID)); // DataHandler.ID will point to the column _id
TextView m_text = (TextView) view.findViewById(R.id.my_text);

    if(status.get(pos) == null) {
//id is not yet in the hashmap so the value is 
//by default false, the TextView is invisible
    m_text.setVisibility(View.GONE);

    } else {
        // we have the value in the
        // Hashmap so see what it is and set the
    // textview visibility from this value

        if (tmp.booleanValue()) {
          m_text.setVisibility(View.VISIBLE);
             } else {
                 m_text.setVisibility(View.GONE);
                   }
          }
    if (m_text != null)
     m_text.setText(listText);  

}

为此，您需要在数据库中包含 _id INTEGER PRIMARY KEY AUTOINCREMENT 列(并添加到查询中)。