我怎样才能在 android 中解决这个问题？
07-07 14:44:58.122: E/CursorWindow(12281): Could not allocate CursorWindow '/storage/emulated/0/Android/data/com.example.mytestlistview/Mafatih/Mafatih.db' of size 2097152 due to error -12.
我在 10MB 的数据库上创建了一个 SearchBox 。它显示了 ListView 上的搜索结果，但出现了这个错误。
我的 StructNote.java :
public class StructNote {
public String Title;
public String Comment;
public StructNote(String Title,String Comment)
{
super();
this.Title = Title;
this.Comment = Comment;
}
public String getTitle()
{
return Title;
}
public String getComment()
{
return Comment;
}
}
我的 MainActivity.java :
public class MainActivity extends ActionBarActivity {
public static final String DIR_SDCARD = Environment
.getExternalStorageDirectory().getAbsolutePath();
public static final String DIR_DATABASE = DIR_SDCARD + "/Android/data/";
public ArrayList<StructNote> notes = new ArrayList<StructNote>();
public ArrayAdapter adapter;
public String Titel_Drawer;
public Integer titleID;
public Cursor cursorid;
public ArrayList<String> array;
public static String PACKAGE_NAME;
EditText editText;
DB db = new DB(MainActivity.this);
public Cursor cursor;
public SQLiteDatabase sql;
public ListView lstContent;
int selectedId;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
PACKAGE_NAME = getApplicationContext().getPackageName();
File file = new File(DIR_DATABASE + PACKAGE_NAME + "/Mafatih");
file.mkdirs();
db.GetPackageName(PACKAGE_NAME);
db.CreateFile();
try {
db.CreateandOpenDataBase();
} catch (IOException e) {
e.printStackTrace();
}
sql = db.openDataBase();
final ListView lstContent = (ListView) findViewById(R.id.lstContent);
adapter = new AdapterNote(notes);
lstContent.setAdapter(adapter);
editText = (EditText) findViewById(R.id.search);
editText.setOnKeyListener(new OnKeyListener() {
@Override
public boolean onKey(View v, int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_ENTER) {
if (editText.getText().length() < 2) {
Toast.makeText(MainActivity.this, "Please enter more text !", Toast.LENGTH_SHORT).show();
return true;
}
else
{
populateListView(editText.getText());
return true;
}
}
else if(keyCode == KeyEvent.KEYCODE_DEL) {
adapter.clear();
return false;
}
return false;
}
});
final RadioGroup radioGroup = (RadioGroup) findViewById(R.id.Language);
radioGroup.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(RadioGroup arg0, int arg1) {
selectedId = radioGroup.getCheckedRadioButtonId();
Log.i("xxx", String.valueOf(selectedId));
}
});
}
public void populateListView(Editable editable) {
if(selectedId == 2131034177)
{
try {
cursor = sql.rawQuery(
"SELECT * FROM WebSite_MetaDataDBBack WHERE Comment LIKE '"
+"%"+ editable + "%'", null);
array = new ArrayList<String>();
if (cursor != null) {
if (cursor.moveToFirst()) {
do {
StructNote note = new StructNote(Titel_Drawer, Titel_Drawer);
note.Comment = cursor.getString(cursor
.getColumnIndex("Comment"));
titleID = cursor.getInt(cursor
.getColumnIndex("CategoryID"));
cursorid = sql.rawQuery(
"SELECT Title FROM WebSite_CategoryBack WHERE CategoryID ="
+ titleID, null);
if (cursorid != null) {
do {
cursorid.moveToFirst();
note.Title = cursorid.getString(cursorid
.getColumnIndex("Title"));
} while (cursorid.moveToNext());
}
notes.add(note);
} while (cursor.moveToNext());
}
adapter.notifyDataSetChanged();
cursor.close();
}
} catch (Exception e) {
Log.i("xxx", "You have an error");
}
}
else if(selectedId == 2131034176)
{
try {
cursor = sql.rawQuery(
"SELECT Tafsir,CategoryID FROM WebSite_MetaDataDBBack WHERE Tafsir LIKE '"
+"%"+ editable + "%'", null);
array = new ArrayList<String>();
if (cursor != null) {
if (cursor.moveToFirst()) {
do {
StructNote note = new StructNote(Titel_Drawer, Titel_Drawer);
note.Comment = cursor.getString(cursor
.getColumnIndex("Tafsir"));
titleID = cursor.getInt(cursor
.getColumnIndex("CategoryID"));
cursorid = sql.rawQuery(
"SELECT Title FROM WebSite_CategoryBack WHERE CategoryID ="
+ titleID, null);
if (cursorid != null) {
do {
cursorid.moveToFirst();
note.Title = cursorid.getString(cursorid
.getColumnIndex("Title"));
} while (cursorid.moveToNext());
}
notes.add(note);
} while (cursor.moveToNext());
}
adapter.notifyDataSetChanged();
cursor.close();
}
} catch (Exception e) {
Log.i("xxx", "You have an error");
}
}
}
}
我的 AdapterNote.java :
public class AdapterNote extends ArrayAdapter<StructNote> {
public AdapterNote(ArrayList<StructNote> array) {
super(G.context, R.layout.dapter_notes, array);
}
public static class ViewHolder {
public TextView txtTitle;
public TextView txtDescription;
public ViewHolder(View view) {
txtTitle = (TextView) view.findViewById(R.id.txtTitle);
txtDescription = (TextView) view.findViewById(R.id.txtDescription);
}
public void fill(ArrayAdapter<StructNote> adapter, StructNote item,
int position) {
txtTitle.setText(item.Title);
txtDescription.setText(item.Comment);
}
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder holder;
StructNote item = getItem(position);
if (convertView == null) {
convertView = G.inflater.inflate(R.layout.dapter_notes, parent,
false);
holder = new ViewHolder(convertView);
convertView.setTag(holder);
} else {
holder = (ViewHolder) convertView.getTag();
}
holder.fill(this, item, position);
return convertView;
}
}
我的 G.java :
public class G extends Application{
public static Context context;
public static LayoutInflater inflater;
@Override
public void onCreate() {
super.onCreate();
context = getApplicationContext();
inflater = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}
}
这是我的数据库 Db.java :
public class DB extends SQLiteOpenHelper{
public static final String DIR_SDCARD =Environment.getExternalStorageDirectory().getAbsolutePath();
public static final String DIR_DATABASE = DIR_SDCARD +"/Android/data/";
private static String DB_NAME = "Mafatih.db";
private final Context myContext;
public static String PACKAGE_NAME;
public boolean flag = false;
private void copyDataBase() throws IOException{
//Open your local db as the input stream
InputStream myInput = myContext.getAssets().open(DB_NAME);
// Path to the just created empty db
String outFileName = DIR_DATABASE +PACKAGE_NAME+"/Mafatih/"+ DB_NAME;
//Open the empty db as the output stream
OutputStream myOutput = new FileOutputStream(outFileName);
//transfer bytes from the inputfile to the outputfile
byte[] buffer = new byte[1024];
int length;
try{
while ((length = myInput.read(buffer))>0){
myOutput.write(buffer, 0, length);
}
}
catch (IOException e) {
Log.e("Copy", e.toString());
}
//Close the streams
myOutput.flush();
myOutput.close();
myInput.close();
}
private boolean checkDataBase(){
SQLiteDatabase checkDB = null;
try{
checkDB = SQLiteDatabase.openDatabase(DIR_DATABASE +PACKAGE_NAME+ "/Mafatih/" + DB_NAME, null, 0);
}catch(SQLiteException e){
Log.e("asdf", "checkDataBase-->"+e.toString());
}
if(checkDB != null){
checkDB.close();
}
return checkDB != null ? true : false;
}
@Override
public synchronized SQLiteDatabase getReadableDatabase() {
return super.getReadableDatabase();
}
public DB(Context context) {
super(context, DB_NAME, null, 1);
this.myContext = context;
}
public void CreateandOpenDataBase() throws IOException{
boolean dbExist = checkDataBase();
if(dbExist){
}
else
{
try {
copyDataBase();
}
catch (IOException e) {
throw new Error("Error copying database --> "+e.toString());
}
}
}
public SQLiteDatabase openDataBase() throws SQLException{
return SQLiteDatabase.openOrCreateDatabase(DIR_DATABASE +PACKAGE_NAME+ "/Mafatih/" +DB_NAME, null);
}
public boolean CreateFile(){
if(flag == false)
{
File file= new File(DIR_DATABASE);
file.mkdirs();
return true;
}
else
{
return true;
}
}
public void GetPackageName(String res){
PACKAGE_NAME = res;
}
@Override
public void onCreate(SQLiteDatabase db) {
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
}
}
最佳答案
问题: 由于错误 -12，无法分配大小为 2097152 的 CursorWindow“.....”。
原因:大多数情况下，此问题是由于未关闭游标引起的。使用后必须关闭所有游标。
在您的代码中，如果 try block 中发生任何异常，游标将不会关闭，因为控制权将传递给 catch block 。因此修改您的代码如下:
try {....}
catch{
}
finally {
cursor.close();
}
在 finally block 中关闭 cursor 始终是一个好习惯。
您也没有关闭 cursorid。确保你也关闭了 cursorid。
更新 1:
Why and when does this exception occur?
为了处理SQLite语句，SQLite会创建一个内存区域，称为上下文区域，其中包含处理语句所需的所有信息，例如处理的行数等。 游标是指向此上下文区域的指针。 SQLite 通过游标控制上下文区域。游标保存 SQL 语句返回的行(一个或多个)。游标保存的行集称为 Activity 集。
Cursor.close()关闭游标，释放其所有资源并使其完全无效。
因此，如果您不关闭游标，则资源(最重要的是游标指向的内存)不会被释放，这会导致泄漏，进而导致分配问题。
希望对您有所帮助。
关于android - 如何在 android 中处理大数据？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/24608468/