Question

我正在尝试使用CursorLoader获取设备中包含电话号码的联系人列表，如下所示：

@Override
public Loader<Cursor> onCreateLoader(int id, Bundle args) {
    return new CursorLoader(getActivity(), ContactsContract.CommonDataKinds.Phone.CONTENT_URI, new String[] {
            Contacts._ID, Contacts.DISPLAY_NAME }, null, null, Contacts.DISPLAY_NAME);
}

@Override
public void onLoadFinished(Loader<Cursor> loader, Cursor cursor) {
    mAdapter.swapCursor(cursor);
}

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

这完全有时，有时不工作。它从一个应用程序启动变为另一个。我得到的异常的堆栈跟踪发布在下面。我将光标传递给IndexedNameAdapter这是SimpleCursorAdapter的扩展名，其中包含AlphabetIndexer以便快速滚动：

import android.content.Context;
import android.database.Cursor;
import android.support.v4.widget.SimpleCursorAdapter;
import android.widget.AlphabetIndexer;
import android.widget.SectionIndexer;

public class IndexedNameAdapter extends SimpleCursorAdapter implements SectionIndexer {

private AlphabetIndexer mAlphabetIndexer;
private String[] from;

public IndexedNameAdapter(Context context, int layout, Cursor c, String[] from, int[] to) {
    this(context, layout, c, from, to, 0);
}

public IndexedNameAdapter(Context context, int layout, Cursor c, String[] from, int[] to, int flags) {
    super(context, layout, c, from, to, flags);

    this.from = from;
    setAlphabetIndexerCursor(c, from);
}

@Override
public Cursor swapCursor(Cursor c) {
    setAlphabetIndexerCursor(c, from);

            // error occurs here:
    return super.swapCursor(c);
}

private void setAlphabetIndexerCursor(Cursor c, String[] columns) {
    if (c != null) {
        mAlphabetIndexer = new AlphabetIndexer(c, c.getColumnIndex(columns[0]), "ABCDEFGHIJKLMNOPQRSTUVWXYZ");
        mAlphabetIndexer.setCursor(c);
    }
}

@Override
public int getPositionForSection(int section) {
    return mAlphabetIndexer.getPositionForSection(section);
}

@Override
public int getSectionForPosition(int position) {
    return mAlphabetIndexer.getSectionForPosition(position);
}

@Override
public Object[] getSections() {
    return mAlphabetIndexer.getSections();
}

}

以下是我看到的错误：

 java.lang.IllegalArgumentException: column 'display_name' does not exist
    at android.database.AbstractCursor.getColumnIndexOrThrow(AbstractCursor.java:303)
    at android.database.CursorWrapper.getColumnIndexOrThrow(CursorWrapper.java:78)
    at android.support.v4.widget.SimpleCursorAdapter.findColumns(SimpleCursorAdapter.java:317)
    at android.support.v4.widget.SimpleCursorAdapter.swapCursor(SimpleCursorAdapter.java:328)
    at com.mypackage.myprofile.IndexedNameAdapter.swapCursor(IndexedNameAdapter.java:29)
    at com.mypackage.myprofile.ProfileUserFragment.onLoadFinished(ProfileUserFragment.java:52)
    at com.mypackage.myprofile.ProfileUserFragment.onLoadFinished(ProfileUserFragment.java:1)
    at android.support.v4.app.LoaderManagerImpl$LoaderInfo.callOnLoadFinished(LoaderManager.java:427)
    at android.support.v4.app.LoaderManagerImpl$LoaderInfo.onLoadComplete(LoaderManager.java:395)
    at android.support.v4.content.Loader.deliverResult(Loader.java:103)
    at android.support.v4.content.CursorLoader.deliverResult(CursorLoader.java:81)
    at android.support.v4.content.CursorLoader.deliverResult(CursorLoader.java:35)
    at android.support.v4.content.AsyncTaskLoader.dispatchOnLoadComplete(AsyncTaskLoader.java:221)
    at android.support.v4.content.AsyncTaskLoader$LoadTask.onPostExecute(AsyncTaskLoader.java:61)
    at android.support.v4.content.ModernAsyncTask.finish(ModernAsyncTask.java:461)
    at android.support.v4.content.ModernAsyncTask.access$500(ModernAsyncTask.java:47)
    at android.support.v4.content.ModernAsyncTask$InternalHandler.handleMessage(ModernAsyncTask.java:474)
    at android.os.Handler.dispatchMessage(Handler.java:99)
    at android.os.Looper.loop(Looper.java:137)
    at android.app.ActivityThread.main(ActivityThread.java:5039)
    at java.lang.reflect.Method.invokeNative(Native Method)
    at java.lang.reflect.Method.invoke(Method.java:511)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
    at dalvik.system.NativeStart.main(Native Method)

Answer 1

我通常不喜欢回答我自己的问题，但我最终找到了解决问题的方法。

我在同一个活动中有另一个片段也实现了LoaderCallbacks<Cursor>，并且我没有两个游标的唯一ID。我正在为这个片段中的错误加载器获取一个游标。

我认为，因为它们是两个不同的片段，在同一时间永远不可见，我不需要一个唯一的ID，但这是不正确的。

ContactsContract查询列'display_name'不存在

1 个答案: