Question

我正在尝试将我的代码从使用游标转换为使用CursorLoaders。为了支持旧版本的Android，我安装了支持库，而不是导入android.content.CursorLoader，我正在导入android.support.v4.content.CursorLoader。现在编译好的代码会抛出两个错误。我实现它时，第一个错误是在LoaderManager上。错误是：LoaderManager无法解析为某种类型。第二个错误是对initLoader的调用。错误是：LoaderManager类型中的方法initLoader（int，Bundle，LoaderManager.LoaderCallbacks）不适用于参数（int，Bundle，MyList）。这是我的代码：

public class MyList extends ListActivity implements LoaderManager.LoaderCallbacks<Cursor> {

private static final String[] PROJECTION = new String[] { "_id", "fieldname" };
private static final int LOADER_ID = 0;
private static final String MYTABLE_BASEPATH = "MyTable_tbl";
private static final String AUTHORITY = "SQLData";
public static final Uri MY_URI = Uri.parse("content://" + AUTHORITY + "/" + MYTABLE_BASEPATH);
private SimpleCursorAdapter mAdapter;

@SuppressWarnings("deprecation")
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    Intent myData = getIntent();
    Bundle info = myData.getExtras();

    if (info != null){
        Cursor c;
        String[] dataColumns = { "fieldname" };
        int[] viewIDs = { R.id.mylist1 };

        SimpleCursorAdapter adapter;            
        adapter = new SimpleCursorAdapter(this, R.layout.mylist, null, dataColumns, viewIDs, CursorAdapter.FLAG_REGISTER_CONTENT_OBSERVER);
        setListAdapter(adapter);
        getLoaderManager().initLoader(0, info, this);
    }


}

public Loader<Cursor> onCreateLoader(int id, Bundle args) {
    String selection = "level = '" + args.getString("Level") + "'";
    return new CursorLoader(this, MY_URI,
            PROJECTION, selection, null, null); 
}

public void onLoadFinished(Loader<Cursor> loader, Cursor cursor) {
    switch (loader.getId()) {
      case LOADER_ID:
        mAdapter.swapCursor(cursor);
        break;
    }

}

public void onLoaderReset(Loader<Cursor> loader) {
    mAdapter.swapCursor(null);

}

}

Answer 1

要返回android.support.v4.app.LoaderManager，您需要使用getSupportLoaderManager()。不幸的是，ListActivity无法使用此方法。这可能会帮助你： How to get LoaderManager in a ListActivity

Answer 2

无法将LoaderManager解析为类型。可以解决添加导入：

import android.support.v4.app.LoaderManager;

和Marcelo一样指出，使用getSupportLoaderManager()代替getLoaderManager()

使用支持库时LoaderManager出错

2 个答案: