检测哪个选定项(在ListView中)产生了ContextMenu(Android)

Question

我有一个ListView,允许用户长按项目以获取上下文菜单.我遇到的问题是确定ListItem他们长期压迫的问题.我试过这样做:

myListView.setOnCreateContextMenuListener(new OnCreateContextMenuListener() {
  @Override public void onCreateContextMenu(ContextMenu menu, final View v, ContextMenuInfo menuInfo) {
   menu.add("Make Toast")
    .setOnMenuItemClickListener(new OnMenuItemClickListener() {
     @Override public boolean onMenuItemClick(MenuItem item) {
      String toastText = "You clicked position " + ((ListView)v).getSelectedItemPosition();
      Toast.makeText(DisplayScheduleActivity.this, toastText, Toast.LENGTH_SHORT).show();
      return true;
     }
    });
  } 
 });

但它只是挂起,直到ANR弹出.我怀疑创建菜单后ListItem不再选择.

看起来您可以监控点击或长按,然后在那里记录点击的项目:

 mArrivalsList.setOnItemLongClickListener(new OnItemLongClickListener() {
  @Override public boolean onItemLongClick(AdapterView<?> parent, View v, int position, long id) {
   // record position/id/whatever here
   return false;
  }
 });

但这对我来说感觉很重要.有没有人有更好的解决方案呢？

Answer 1

我这样做.在我的onCreateContextMenu(...)方法中,我将其转换ContextMenu.ContextMenuInfo为AdapterView.AdapterContextMenuInfo.从那里,您可以获得targetView,再次将其投射到窗口小部件.完整的代码在HomeActivity.java中可用,查找onCreateContextMenu(...)方法.

@Override
public void onCreateContextMenu(ContextMenu contextMenu,
                                View v,
                                ContextMenu.ContextMenuInfo menuInfo) {
    AdapterView.AdapterContextMenuInfo info =
            (AdapterView.AdapterContextMenuInfo) menuInfo;
    selectedWord = ((TextView) info.targetView).getText().toString();
    selectedWordId = info.id;

    contextMenu.setHeaderTitle(selectedWord);
    contextMenu.add(0, CONTEXT_MENU_EDIT_ITEM, 0, R.string.edit);
    contextMenu.add(0, CONTEXT_MENU_DELETE_ITEM, 1, R.string.delete);
}

请注意,我将所选文本以及选择ID存储在私有字段中.由于UI是线程限制的,我知道selectedWord和selectedWordId字段对于以后的操作是正确的.

Answer 2

首先,我想知道你是否通过使用使事情变得过于复杂View.setOnCreateContextMenuListener().如果您使用Activity.registerForContextMenu(),事情会变得更加容易,因为您可以使用Activity.onCreateContextMenu()和Activity.onContextItemSelected()处理所有菜单事件.它基本上意味着您不必定义所有这些匿名内部类来处理每个事件; 您只需要覆盖一些Activity方法来处理这些上下文菜单事件.

其次,检索当前所选项目的方法肯定更简单.您需要做的就是保持ListView对Adapter用于填充它的或使用的引用.您可以使用ContextMenuInfo作为AdapterContextMenuInfo来获取项目的位置; 然后你可以使用ListView.getItemAtPosition()或Adapter.getItem()检索Object专门链接到被点击的内容.例如,假设我正在使用Activity.onCreateContextMenu(),我可以这样做:

@Override
public void onCreateContextMenu(ContextMenu menu, View v, ContextMenuInfo menuInfo) {
    super.onCreateContextMenu(menu, v, menuInfo);

    // Get the info on which item was selected
    AdapterContextMenuInfo info = (AdapterContextMenuInfo) menuInfo;

    // Get the Adapter behind your ListView (this assumes you're using
    // a ListActivity; if you're not, you'll have to store the Adapter yourself
    // in some way that can be accessed here.)
    Adapter adapter = getListAdapter();

    // Retrieve the item that was clicked on
    Object item = adapter.getItem(info.position);
}

@Override
public boolean onContextItemSelected(MenuItem item) {
    // Here's how you can get the correct item in onContextItemSelected()
    AdapterContextMenuInfo info = (AdapterContextMenuInfo) item.getMenuInfo();
    Object item = getListAdapter().getItem(info.position);
}