android - setViewBinder/setViewValue 和 getView/LayoutInflater 的用法有什么区别？

Question

看起来有两种可能的方法来更改ListView行中的某些内容：

1. 使用setViewBinder/ setViewValue：

   myCursor.setViewBinder(new SimpleCursorAdapter.ViewBinder() {

     @Override
     public boolean setViewValue(View view, Cursor cursor, int columnIndex) {
       int viewId = view.getId();
       switch(viewId) {
       case R.id.icon:
           // change something related to the icon here
   

2. 使用getView/ LayoutInflater：

   public View getView(int position, View convertView, ViewGroup parent) {

       View itemView = null;
   
       if (convertView == null) {
           LayoutInflater inflater = (LayoutInflater) parent.getContext()
                   .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
           itemView = inflater.inflate(R.layout.list_row, null);
       } else {
           itemView = convertView;
       }
   
       ImageView imgViewChecked = (ImageView) itemView
               .findViewById(R.id.icon);
       // change something related to the icon here
   

这两种方法有什么区别？

Answer 1

您可以同时使用它们来完成相同的任务。ViewBinder 系统是由 SimpleCursorAdapter 添加的，让您更轻松，因此您不必编写整个 getView 代码。事实上，SimpleCursorAdapter 只是通过调用 setViewValue 方法来实现 getView（以及标准的样板错误检查和膨胀）

我在 SimpleCursorAdapter 中附上了 Android 源代码用于 getView 的实现：

public View getView(int position, View convertView, ViewGroup parent) {
  if (!mDataValid) {
    throw new IllegalStateException(
        "this should only be called when the cursor is valid");
  }
  if (!mCursor.moveToPosition(position)) {
    throw new IllegalStateException("couldn't move cursor to position "
        + position);
  }
  View v;
  if (convertView == null) {
    v = newView(mContext, mCursor, parent);
  } else {
    v = convertView;
  }
  bindView(v, mContext, mCursor);
  return v;
}


public void bindView(View view, Context context, Cursor cursor) {
  final ViewBinder binder = mViewBinder;
  final int count = mTo.length;
  final int[] from = mFrom;
  final int[] to = mTo;

  for (int i = 0; i < count; i++) {
    final View v = view.findViewById(to[i]);
    if (v != null) {
      boolean bound = false;
      if (binder != null) {
        bound = binder.setViewValue(v, cursor, from[i]);
      }

      if (!bound) {
        String text = cursor.getString(from[i]);
        if (text == null) {
          text = "";
        }

        if (v instanceof TextView) {
          setViewText((TextView) v, text);
        } else if (v instanceof ImageView) {
          setViewImage((ImageView) v, text);
        } else {
          throw new IllegalStateException(
              v.getClass().getName()
                  + " is not a "
                  + " view that can be bounds by this SimpleCursorAdapter");
        }
      }
    }
  }
}