java - 从数据库获取文件名并使用它来填充 ImageView

Question

我正在创建一个应用程序，此时需要从 sqlite 数据库获取文件名，获取具有该文件名的图像并将其插入 ImageView 中，我现在已经创建了此代码，但我认为我'我在这里做的一切都错了......

Database db = new Database(getApplicationContext());
SQLiteDatabase readableDatabase = db.getReadableDatabase();
final Cursor curFileName = readableDatabase.rawQuery("select filename from data order by id asc", null);
image = (ImageView) findViewById(R.id.image);
int filename = curFileName.getColumnIndex("filename");
String filenameString = curFileName.getString(filename);
d = Drawable.createFromPath(Environment.getExternalStorageDirectory().toString()+filenameString);
Toast.makeText(getApplicationContext(), filenameString, Toast.LENGTH_SHORT).show();
handleDrawable(d);

是的，抱歉，这是异常(exception):

04-09 13:48:16.950: E/AndroidRuntime(30802): FATAL EXCEPTION: main
04-09 13:48:16.950: E/AndroidRuntime(30802): java.lang.RuntimeException: Unable to start activity ComponentInfo{g.d.filer/g.d.filer.Favorites}: android.database.CursorIndexOutOfBoundsException: Index -1 requested, with a size of 33

Answer 1

您必须先定位光标才能阅读

 int filename = curFileName.getColumnIndex("filename");
 if (cur.moveToFirst()) { // position cursor to first item. false: empty resultset
     String filenameString = curFileName.getString(filename);
     d = Drawable.createFromPath(Environment.getExternalStorageDirectory().toString()+filenameString);
     Toast.makeText(getApplicationContext(), filenameString, Toast.LENGTH_SHORT).show();
     handleDrawable(d);
     ...
 }