Develop Reference

Open/Close SQL Database on the same thread

I'm developing a recipe book and I'm implementing this method to insert my Recipe in the Database. In the for cycle I get the ingredient's name and quantity from multiples EditText, saving each of them in an Ingredient.class instance (newIngredient). Then I insert the instance into the DB and add it to an ArrayList. The followings "if conditions" are for the title, time and other Recipe's attributes. Finally, I also insert Recipe and Tag instances in the relatives DB's tables and I close DB.
public void saveRecipe() {
dbHelper = new DatabaseHelper(context);
// creating new recipe from user input
Ingredient newIngredient;
String title, childIngredient, instruction, tag;
int target, time, childQuantity, calories;
int countIngredients = parentIngredientLayout.getChildCount();
int countTags = chipGroup.getChildCount();
ArrayList<Ingredient> ingredients = null;
ArrayList<Tag> tags = null;
View childViewIng = null;
EditText childTextViewI = null;
EditText childTextViewQ = null;
// ingredients fields settings
for (int d=0; d<countIngredients; d++) {
childViewIng = parentIngredientLayout.getChildAt(d);
childTextViewI = childViewIng.findViewById(R.id.ingredientsField);
childTextViewQ = childViewIng.findViewById(R.id.quantityField);
childIngredient = childTextViewI.getText().toString();
childQuantity = Integer.parseInt(childTextViewQ.getText().toString());
newIngredient = new Ingredient(childIngredient, childQuantity);
dbHelper.insertIngredient(newIngredient);
ingredients.add(newIngredient);
}
//recipe fields settings
if (photoPath1 == null)
photoPath1 = "";
if (photoPath2 == null)
photoPath2 = "";
if (photoPath3 == null)
photoPath3 = "";
if (titleText.getText().toString().isEmpty()) {
title = "";
} else {
title = titleText.getText().toString();
}
if (targetNumber.getText().toString().isEmpty()) {
target = 0;
} else {
target = Integer.parseInt(targetNumber.getText().toString());
}
if (timeNumber.getText().toString().isEmpty()) {
time = 0;
} else {
time = Integer.parseInt(timeNumber.getText().toString());
}
if (instructionText.getText().toString().isEmpty()) {
instruction = "";
} else {
instruction = instructionText.getText().toString();
}
if (caloriesNumber.getText().toString().isEmpty()) {
calories = 0;
} else {
calories = Integer.parseInt(caloriesNumber.getText().toString());
}
if (tagName.getText().toString().isEmpty()) {
tag = "";
} else {
tag = tagName.getText().toString();
}
Recipe newRecipe = new Recipe(title, photoPath1, photoPath2, photoPath3, instruction, target, time, calories, ingredients);
Tag newTag = new Tag(tag);
dbHelper.insertRecipe(newRecipe);
dbHelper.insertTag(newTag);
dbHelper.close(); }
I found out by debugging that in this case is inserted only the first ingredient. I tried to move the FOR until the end of code, but in that case, are inserted both recipe and tag and always only the first ingredient. I think the problem is relative to the opening/closing of the DB. Can somebody help me?
Ingredient constructor:
public Ingredient(String ingredient_name, int quantity) {
this.ingredient_name = ingredient_name;
this.quantity = quantity;
}
dbHelper.insertIngredient(newIngredient) method:
public boolean insertIngredient(Ingredient ingredient) {
db = this.getWritableDatabase();
ContentValues contentValues = new ContentValues();
contentValues.put(INGREDIENT_NAME, ingredient.getIngredient_name());
contentValues.put(QUANTITY, ingredient.getQuantity());
contentValues.put(KEY_CREATED_AT, time.getTime().toString());
long result = db.insert(TBL_INGREDIENTS, null, contentValues);
//db.close();
Log.e(TAG, "Ingredient inserted!");
if (result == -1) {
return false;
} else {
return true;
}
}

Ok, thanks to your comment we got the problem :)
You are calling .add(newIngredient) on a list that you initialized with ArrayList<Ingredient> ingredients = null;
Change it to
ArrayList<Ingredient> ingredients = new ArrayList<Ingredient>();
and it will work :)
Good luck!

How do i fix this error, System.NotSupportedException: Could not activate JNI Handle 0x7fec3e5620

I have tried searching for the error but i can't seem to link the results i find to my application.
Here is the error i get whenever i run my program.
Unhandled Exception:
System.NotSupportedException: Could not activate JNI Handle
0x7fec3e5620 (key_handle 0xe1ccda9) of Java
type 'md5ca0dbb1ec41706184e899fc3d5b0057e/MainActivity'
as managed type 'PowerCellShipping3.MainActivity'. occurred
Here is my c# code. I am unsure what is actually causing the error as i have never come across this error(obviously.)
protected override void OnCreate(Bundle savedInstanceState)
{
base.OnCreate(savedInstanceState);
// Set our view from the "main" layout resource
SetContentView(Resource.Layout.activity_main);
scan = FindViewById<Button>(Resource.Id.btnScan);
lbviewScan = FindViewById<ListView>(Resource.Id.lvbScanned);
lbviewReject = FindViewById<ListView>(Resource.Id.lbRejected);
tvscanned = FindViewById<TextView>(Resource.Id.textView4);
tvreject = FindViewById<TextView>(Resource.Id.textView5);
etLot = FindViewById<EditText>(Resource.Id.etLotNumber);
scan.Click += delegate {
//Call Your Method When User Clicks The Button
btnClick();
};
}
/**************************************************************************************************************************************************************/
public class ToDoTasks
{
[PrimaryKey, AutoIncrement, Column("#Lot_Number")]
public int Id { get; set; }
[MaxLength(100)]
public string Task { get; set; }
}
public List<string> GetData()
{
var db = new SQLiteConnection("Data Source = obdbnsql3; Persist Security Info=True;User ID = sa" + "Password=P0w3r1T");
List<string> data = new List<string>();
foreach (var item in db.Table<ToDoTasks>())
{
var objectItem = item.Task.ToString();
data.Add(objectItem);
}
return data;
}
/***************************************************************************************************************************************************************/
public void btnClick()
{
sql1 = "update [Otto_Internal_Apps].[dbo].[Shipping_Detail] set [Box_Scanned] = 1, [Shipment_Scan_Date] = GETDATE(), [Box_Rejected] = 0 " +
"where [Lot_No] = #Lot_Number and ([Box_Rejected] != 1 or [Box_Rejected] is null)";
SQLiteCommand sqlCommand = new SQLiteCommand(connection);
sqlCommand.CommandText.Replace(sql1,sql1);
string attempt = sql1;
int iCount = Convert.ToInt32(attempt);
sqlCommand.CommandText.Remove(iCount,iCount);
/********************************************************************************************************************************/
string attempt2 = "#Lot_Number";
int iCount2 = Convert.ToInt32(attempt2);
//sqlCommand.Parameters.AddWithValue("#Lot_number", etLot.Text);
sqlCommand.CommandText.Insert(iCount2, etLot.Text);
/********************************************************************************************************************************/
try
{ // Execute the query and return the rows affected
sql2 = "select top 1 * from [Otto_Internal_Apps].[dbo].[Shipping_Detail] where [Lot_No] = #Lot_Number and [Box_Rejected] = 1";
int iRowsAffected = sqlCommand.ExecuteNonQuery();
// if the rows affected is zero then the lot no. does not exist and must be inserted as a rejected scan
if (iRowsAffected == 0)
{
sqlCommand.CommandText = sql2;
sql3 = "INSERT INTO [Otto_Internal_Apps].[dbo].[Shipping_Detail] ([Lot_No],[Box_Rejected]) VALUES(#Lot_Number, 1) ";
//lbviewScan.Load(sqlCommand.ExecuteQuery);
var items = GetData();
var listView = FindViewById<ListView>(Resource.Id.lvbScanned);
listView.Adapter = new ArrayAdapter<string>(this, Android.Resource.Layout.SimpleListItem1, items);
if (lbviewScan.Count == 0)
{
sqlCommand.CommandText = sql3;
string attempt3 = sql3;
int iCount3 = Convert.ToInt32(attempt3);
sqlCommand.CommandText.Remove(iCount3, iCount3);
string attempt4 = "#Lot_Number";
int iCount4 = Convert.ToInt32(attempt4);
sqlCommand.CommandText.Insert(iCount4, etLot.Text);
sqlCommand.ExecuteNonQuery();
}
//int iItemFound = lbviewReject.Items.IndexOf(etLot.Text);
int iItemFound = itemList.IndexOf(etLot.Text);
if (iItemFound == -1)
{
//lbviewReject.Items.Add(etLot.Text);
itemList.Add(etLot.Text);
}
}
else
{
//int iItemFound = lbviewScan.Items.IndexOf(etLot.Text);
int iItemFound = itemList.IndexOf(etLot.Text);
if (iItemFound == -1)
{
//lbviewScan.Items.Add(etLot.Text);
itemList.Add(etLot.Text);
}
Console.Beep(800, 200);
}
}
catch (SQLException sqle)
{
Toast.MakeText(ApplicationContext, sqle.Message, ToastLength.Long).Show();
Console.Beep(2000, 1600);
return;
}
The other posts that I saw on the Xamarin site seemed to be similar errors but like i said before, I still can't find a solution.
I think that the error could be caused due to one of the listboxes but i am unsure about that.
Any help would be greatly appreciated. Thanks

Loading Artists from Android MediaStore along with Artwork

I am aware that media artwork is stored under albums and to get them you need to have the album id to access it. I have been able to get the images for tracks and albums using the album id.
However for artists table doesn't have the album id field. Other apps such as Play Music and Poweramp are somehow able to get the track artwork and add them to the respective artists.
How do i achieve this?

The way I do it is to get all albums for an artist and then use the rnd function to return an albumid:
String artist_id = c.getString(c.getColumnIndex(MediaStore.Audio.Artists._ID));
Cursor crs = album.getArtistsAlbumcursor(mContext, artist_id);
if(crs!=null && crs.moveToFirst()) {
Random rn = new Random();
int rnd = rn.nextInt( crs.getCount());
crs.moveToPosition(rnd);
album_id = crs.getLong(crs.getColumnIndex(MediaStore.Audio.Media.ALBUM_ID));
crs.close();
}
where getArtistsAlbumcursor is:
public Cursor getArtistsAlbumcursor(Context context, String artistId) {
ContentResolver cr = context.getContentResolver();
final String _id = MediaStore.Audio.Media._ID;
final String album_id = MediaStore.Audio.Media.ALBUM_ID;
final String artistid = MediaStore.Audio.Media.ARTIST_ID;
final String[] columns = { _id, album_id, artistid };
String where = artistid +" =?";
String[] aId = {artistId};
return cr.query(uri, columns, where, aId, null);
}
Once you have an albumid you can get your albumart using your original method.
Or
if you want to get the albumart from the mp3 track itself, you will need to implement a libary such as jaudiotagger or org.blinkenlights.jid3.v2.
Life gets a little more complicated but below how to get albumart from the mp3 tag using the JID3 library:
try {
bmp = getmp3AlbumArt(sourceFile);
} catch (Exception e) {
e.printStackTrace();
}
where getmp3Albumart is:
public Bitmap getmp3AlbumArt(File SourceFile) throws Exception {
Bitmap bmp = null;
arrayByte = null;
APICID3V2Frame frames[];
MediaFile MediaFile = new MP3File(SourceFile);
try {
Object obj = null;
obj = MediaFile.getID3V2Tag();
if (obj != null) {
tagImage = (org.blinkenlights.jid3.v2.ID3V2_3_0Tag) obj;
if ((tagImage != null) && (arrayByte == null) && (tagImage.getAPICFrames() != null) && (tagImage.getAPICFrames().length > 0)) {
frames = tagImage.getAPICFrames();
for (int i = 0; i < tagImage.getAPICFrames().length; i++) {
if (frames[i] != null) {
arrayByte = frames[i].getPictureData();
break;
}
}
}
}
} catch (ID3Exception | OutOfMemoryError e) {
e.printStackTrace();
}
if (arrayByte != null) {
try {
bmp = BitmapFactory.decodeByteArray(arrayByte, 0, arrayByte.length);
} catch (Exception|OutOfMemoryError e) {
e.printStackTrace();
}
}
return bmp;
}

txtt.setText(getString(R.string.("i" + j++)));

What's wrong with this code? I want to use id automatically. I think after R.string there is a mistake. What can ı do

Do it like this
public static int getStringIDFromName(String stringName)
{
int stringID= 0;
if(stringName == null
|| stringName.equalsIgnoreCase(""))
{
return 0;
}
try
{
#SuppressWarnings("rawtypes")
Class res = R.string.class;
Field field = res.getField(stringName);
stringID = field.getInt(null);
}
catch(Exception e)
{
// Error
}
return stringID;
}
Set your value like this
int stringVal = getStringIDFromName("i" + j++);
if( stringVal != 0)
txtt.setText(getResource().getString(stringVal));
This would work only if you are doing everything else right.

// initialization for TextView
TextView txtt = (TextView) findViewById(R.id.myTextViewId);
// set the text
txtt.setText(getResources().getString(R.string.mystring));

Compare contents of two files line by line

public class MainActivity extends Activity {
FileOutputStream fos;
FileInputStream fOne, fTwo;
ArrayList<String> arr1 = new ArrayList<String>();
ArrayList<String> arr2 = new ArrayList<String>();
ArrayList<String> words = new ArrayList<String>();
ArrayList<String> wordsTwo = new ArrayList<String>();
int count = 0;
int countTwo = 0;
int countThree = 0;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button fileOne = (Button)findViewById(R.id.file1);
Button fileTwo = (Button)findViewById(R.id.file2);
Button compare = (Button)findViewById(R.id.compare);
arr1.add("1");
arr1.add("2");
arr1.add("3");
arr1.add("4");
//arr1.add("3");
arr2.add("1");
arr2.add("2");
fileOne.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
// TODO Auto-generated method stub
try
{
fos = openFileOutput("File1", Context.MODE_PRIVATE);
for(int temp = 0; temp< arr1.size(); temp++)
{
fos.write((arr1.get(temp).getBytes()) );
fos.write(System.getProperty("line.separator").getBytes());
}
fos.close();
fos.flush();
}
catch(Exception e)
{
}
}
});
fileTwo.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
// TODO Auto-generated method stub
try
{
fos = openFileOutput("File2", Context.MODE_PRIVATE);
for(int temp = 0; temp< arr2.size(); temp++)
{
fos.write((arr2.get(temp).getBytes()) );
fos.write(System.getProperty("line.separator").getBytes());
}
fos.close();
fos.flush();
}
catch(Exception e)
{
}
}
});
compare.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
// TODO Auto-generated method stub
try
{
fOne = openFileInput("File1");
fTwo = openFileInput("File2");
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
Scanner scanFile = new Scanner(new DataInputStream(fOne));
Scanner scanFileT = new Scanner(new DataInputStream(fTwo));
words = new ArrayList<String>();
wordsTwo = new ArrayList<String>();
while (scanFile.hasNextLine())
{
if(scanFile.nextLine()!=null)
{
count++;
}
while(scanFileT.hasNextLine())
{
if(scanFileT.nextLine()!=null)
{
countTwo++;
}
}
}
try
{
fOne.close();
fTwo.close();
scanFile.close();
scanFileT.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
Toast.makeText(getBaseContext(), "One : " + count, 1000).show();
Toast.makeText(getBaseContext(), "Two : " + countTwo, 1000).show();
Toast.makeText(getBaseContext(), "Three : " + countThree, 1000).show();
count = 0 ;
countTwo = 0;
countThree = 0;
}
});
}
}
Above is the code to write and read the file. What I did here, write two files and read the contents..Now I have to compare contents of files line by line. What needs to be done?

Try following code. This will give you desired output. I took files from asset directory. So you need to replace that line of code if you are taking files from other directory.
private void compareFiles() throws Exception {
String s1 = "";
String s2 = "", s3 = "", s4 = "";
String y = "", z = "";
// Reading the contents of the files
BufferedReader br = new BufferedReader(new InputStreamReader(
getAssets().open("first.txt")));
BufferedReader br1 = new BufferedReader(new InputStreamReader(
getAssets().open("second.txt")));
while ((z = br1.readLine()) != null) {
s3 += z;
s3 += System.getProperty("line.separator");
}
while ((y = br.readLine()) != null) {
s1 += y;
s1 += System.getProperty("line.separator");
}
// String tokenizing
StringTokenizer st = new StringTokenizer(s1);
String[] a = new String[10000];
for (int l = 0; l < 10000; l++) {
a[l] = "";
}
int i = 0;
while (st.hasMoreTokens()) {
s2 = st.nextToken();
a[i] = s2;
i++;
}
StringTokenizer st1 = new StringTokenizer(s3);
String[] b = new String[10000];
for (int k = 0; k < 10000; k++) {
b[k] = "";
}
int j = 0;
while (st1.hasMoreTokens()) {
s4 = st1.nextToken();
b[j] = s4;
j++;
}
// comparing the contents of the files and printing the differences, if
// any.
int x = 0;
for (int m = 0; m < a.length; m++) {
if (a[m].equals(b[m])) {
} else {
x++;
Log.d("Home", a[m] + " -- " + b[m]);
}
}
Log.d("Home", "No. of differences : " + x);
if (x > 0) {
Log.d("Home", "Files are not equal");
} else {
Log.d("Home", "Files are equal. No difference found");
}
}
Input File 1
Hi
Hello
Chintan
Rathod
Input File 2
Hi
HellO
Chintan
RathoD
Output
08-26 12:07:58.219: DEBUG/Home(2350): Hello3. -- HellO3.
08-26 12:07:58.219: DEBUG/Home(2350): Rathod -- RathoD
08-26 12:07:58.229: DEBUG/Home(2350): No. of differences : 2
08-26 12:07:58.229: DEBUG/Home(2350): Files are not equal
Edit
To get Difference between two files
Use StringUtils library which is provide by Apache and check this Documentation for more about that library.
And modify following lines of code.
int x = 0;
for (int m = 0; m < a.length; m++) {
if (a[m].equals(b[m])) {
} else {
x++;
Log.d("Home", a[m] + " -- " + b[m]);
//to print difference
if (a[m].length() < b[m].length())
Log.d("Home", "" + StringUtils.difference(a[m], b[m]));
else
Log.d("Home", "" + StringUtils.difference(b[m], a[m]));
}
}
Output
08-26 17:51:26.949: DEBUG/Home(17900): 12 -- 123
08-26 17:51:26.949: DEBUG/Home(17900): Difference String : 3
08-26 17:51:26.949: DEBUG/Home(17900): No. of differences : 1
08-26 17:51:26.949: DEBUG/Home(17900): Files are not equal

Try using java.util.Scanner
while (sc1.hasNext() && sc2.hasNext()) {
String str1 = sc1.next();
String str2 = sc2.next();
if (!str1.equals(str2))
System.out.println(str1 + " != " + str2);
}

Change your while loop to the following:
while (scanFile.hasNextLine() && scanFileT.hasNextLine())
{
if(scanFileT.nextLine().equals(scanFile.nextLine()))
{
// The lines are equal.
} else {
// The lines are not equal.
}
}
if(scanFile.hasNextLine() || scanFileT.hasNextLine())
{
// If more lines remain in one of the files, they are not equal.
} else {
// If no content remains in both files, they are equal.
}
Depending on the size of your file, I would recommend some optimisation like checking the file sizes before you go through them line by line.
The overall logic reads as follows; if both have another line, compare it to see if it is equal. If they don't have another line, check if one of them has lines remaining, if so, they are not equal.
Update
After clarifying the objective of the comparison in chat, see the comments to this question, I have come to the conclusion that another comparison would be more effective and, as a matter of fact, correct. The comparison algorithm above works great if comparing the structure of text but not if comparing a data vector which may or may not be sorted. After some discussion, we came to the conclusion that data needs to be sorted or the comparison will blow the complexity to at least O(n^2)which could be done in O(2n) if the data is sorted. Here the algorithm's skeleton:
if(! scanGroupFriends.hasNextLine())
{
//simple sanity check to see if we need to compare at all. In this case, add all friends.
} else {
String nextFriend = scanGroupFriends.nextLine();
while(scanAllFriends.hasNextLine())
{
if(scanAllFriends.nextLine().equals(nextFriend))
{
// Friend already figures, do not add him and advance the list of group friends.
if(scanGroupFriends.hasNextLine())
{
nextFriend = scanGroupFriends.nextLine();
} else {
// There are no more friends in the group, add all remaining friends to list to show.
break; // Terminate the `while` loop.
}
}
}
}
However, I personally think it is bad to make to many assumptions. What I would suggest is that the friends be saved in a Set, a TreeSet for example. Then, serialize the object rather than manually writing it to file. Sets are neat because they hold several interesting objects. For example, you could easily use the following code to remove all friends in a group from the set of all friends:
allFriends.removeAll(groupFriends);
However, be aware that this removes it from the set completely so you should make a copy beforehand.