SimpleCursorAdapter's old constructor deprecated.. really?

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春和景丽
春和景丽 2021-02-06 02:20

Here it says that SimpleCursorAdapter\'s API level 1 constructor is deprecated and the use of LoaderManager and CursorLoader is recommende

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  •  心在旅途
    2021-02-06 03:03

    I wrote a simple CursorLoader that does not need a content provider:

    import android.content.Context;
    import android.database.Cursor;
    import android.support.v4.content.AsyncTaskLoader;
    
    /**
     * Used to write apps that run on platforms prior to Android 3.0. When running
     * on Android 3.0 or above, this implementation is still used; it does not try
     * to switch to the framework's implementation. See the framework SDK
     * documentation for a class overview.
     *
     * This was based on the CursorLoader class
     */
    public abstract class SimpleCursorLoader extends AsyncTaskLoader {
        private Cursor mCursor;
    
        public SimpleCursorLoader(Context context) {
            super(context);
        }
    
        /* Runs on a worker thread */
        @Override
        public abstract Cursor loadInBackground();
    
        /* Runs on the UI thread */
        @Override
        public void deliverResult(Cursor cursor) {
            if (isReset()) {
                // An async query came in while the loader is stopped
                if (cursor != null) {
                    cursor.close();
                }
                return;
            }
            Cursor oldCursor = mCursor;
            mCursor = cursor;
    
            if (isStarted()) {
                super.deliverResult(cursor);
            }
    
            if (oldCursor != null && oldCursor != cursor && !oldCursor.isClosed()) {
                oldCursor.close();
            }
        }
    
        /**
         * Starts an asynchronous load of the contacts list data. When the result is ready the callbacks
         * will be called on the UI thread. If a previous load has been completed and is still valid
         * the result may be passed to the callbacks immediately.
         * 

    * Must be called from the UI thread */ @Override protected void onStartLoading() { if (mCursor != null) { deliverResult(mCursor); } if (takeContentChanged() || mCursor == null) { forceLoad(); } } /** * Must be called from the UI thread */ @Override protected void onStopLoading() { // Attempt to cancel the current load task if possible. cancelLoad(); } @Override public void onCanceled(Cursor cursor) { if (cursor != null && !cursor.isClosed()) { cursor.close(); } } @Override protected void onReset() { super.onReset(); // Ensure the loader is stopped onStopLoading(); if (mCursor != null && !mCursor.isClosed()) { mCursor.close(); } mCursor = null; } }

    It only needs the AsyncTaskLoader class. Either the one in Android 3.0 or higher, or the one that comes with the compatibility package.

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