Develop Reference

Android Studio - Return error msg when sql query search record does not exist

I have created an android application with a built in sqlite database, the user makes a search and the data is shown. Everything works wonderfully however i am totally stuck on getting an error message to popup when what the user searches for does not exist.
Rather than returning nothing i would like to have a popup message saying "Record does not exist!"
This may be simple but every IF statement i try has errors, would appreciate any pointers.
My query code:
public String getProduct(String userInput){
c=db.rawQuery("select productname from Inventory where productname ='"+userInput+"'", new String[]{});
StringBuffer buffer = new StringBuffer();
while(c.moveToNext()){
String product = c.getString(0);
buffer.append(""+product);
}
return buffer.toString();
}
Thank you for any assistance.

Before your while loop you can check if the query returned any data and if not just return an empty String
if(!c.moveToFirst()) return ""
When you use getProduct you could check if it is empty or not
String dbResult = getProduct(userInput);
if(dbResult.isEmpty) {
// Display "Record does not exist!"
}

Cannot parse file using JDBC

Im trying to parse a pipe delimited file and insert fields into a table. when i start the application nothing happens in my DB. My DB has 4 columns (account_name, command_name, and system_name, CreateDt). The file i am parsing has the date in the first row then extra data. The rows following i only need the first 3 fields in each the rest is extra data. the last row is the row count. i skipped the inserting date because for now but want to get back to it after at least able to insert the first 3 fields. I have little experience with parsing a file and storing data in a DB and have looked through jdbc examples to get to this point but im struggling and am sure there is a better way.
File Example
20200310|extra|extra|extra||
Mn1223|01192|windows|extra|extra|extra||
Sd1223|02390|linux|extra|extra|extra||
2
table format
account_name command_name system_name createDt
Mn1223 01192 windows 20200310
Sd1223 02390 linux 20200310
Code to parse and insert into DB
public List insertZygateData (List<ZygateEntity> parseData) throws Exception {
String filePath = "C:\\DEV\\Test_file.xlsx";
List<String> lines = Files.readAllLines(Paths.get(filePath));
// remove date and amount
lines.remove(0);
lines.remove(lines.size() - 1);
for (ZygateEntity zygateInfo : parseData){
new MapSqlParameterSource("account_name", zygateInfo.getAccountName())
.addValue("command_name", zygateInfo.getCommandName())
.addValue("system_name", zygateInfo.getSystemName())
.getValues();
}
return lines.stream()
.map(s -> s.split("[|]")).map(val -> new ZygateEntity(val[0],val[1],val[2])).collect(Collectors.toList());
}
public boolean cleantheTable() throws SQLException {
String sql = "INSERT INTO Landing.midrange_xygate_load (account_name,command_name,system_name)"+
"VALUES (:account_name,:command_name,:system_name)";
boolean truncated = false;
Statement stmt = null;
try {
String sqlTruncate = "truncate table Landing.midrange_xygate_load";
jdbcTemplate.execute(sqlTruncate);
truncated = true;
} catch (Exception e) {
e.printStackTrace();
truncated = false;
return truncated;
} finally {
if (stmt != null) {
jdbcTemplate.execute(sql);
stmt.close();
}
}
log.info("Clean the table return value :" + truncated);
return truncated;
}
}
Entity/Model
public ZygateEntity(String accountName, String commandName, String systemName){
this.accountName=accountName;
this.commandName=commandName;
this.systemName=systemName;
}
//getters and setters
#Override
public String toString() {
return "ZygateEntity [accountName=" + accountName + ", commandName=" + commandName + ", systemName=" + systemName + ", createDt=" + createDt +"]";
}
}

Taking a look at what you've provided, it seems you have a jumbled collection of bits of code, and while most of it is there, it's not all there and not quite all in the right order.
To get some kind of clarity, try to break down what it is you're doing into separate steps, and have a method that focuses on each step. In particular, you write
Im trying to parse a pipe delimited file and insert fields into a table
This naturally breaks down into two parts:
parsing the pipe-delimited file, and
inserting fields into a table.
For the first part, you seem to have most of the parts already in your insertZygateData method. In particular, this line reads all the lines of a file into a list:
List<String> lines = Files.readAllLines(Paths.get(filePath));
These lines then remove the first and last lines from the list of lines read:
// remove date and amount
lines.remove(0);
lines.remove(lines.size() - 1);
You then have some code that looks a bit out of place: this seems to be something to do with inserting into the database, but we haven't created our list of ZygateEntity objects as we haven't yet finished reading the file. Let's put this for loop to one side for the moment.
Finally, we take the list of lines we read, split them using pipes, create ZygateEntity objects from the parts and create a List of these objects, which we then return.
return lines.stream()
.map(s -> s.split("[|]")).map(val -> new ZygateEntity(val[0],val[1],val[2])).collect(Collectors.toList());
Putting this lot together, we have a useful method that parses the file, completing the first part of the task:
private List<ZygateEntity> parseZygateData() throws IOException {
String filePath = "C:\\DEV\\Test_file.xlsx";
List<String> lines = Files.readAllLines(Paths.get(filePath));
// remove date and amount
lines.remove(0);
lines.remove(lines.size() - 1);
return lines.stream()
.map(s -> s.split("[|]")).map(val -> new ZygateEntity(val[0],val[1],val[2])).collect(Collectors.toList());
}
(Of course, we could add a parameter for the file path to read, but in the interest of getting something working, it's OK to stick with the current hard-coded file path.)
So, we've got our list of ZygateEntity objects. How do we write a method to insert them into the database?
We can find a couple of the ingredients we need in your code sample. First, we need the SQL statement to insert the data. This is in your cleanThetable method:
String sql = "INSERT INTO Landing.midrange_xygate_load (account_name,command_name,system_name)"+
"VALUES (:account_name,:command_name,:system_name)";
We then have this loop:
for (ZygateEntity zygateInfo : parseData){
new MapSqlParameterSource("account_name", zygateInfo.getAccountName())
.addValue("command_name", zygateInfo.getCommandName())
.addValue("system_name", zygateInfo.getSystemName())
.getValues();
}
This loop creates a MapSqlParameterSource out of each ZygateEntity object, and then converts it to a Map<String, Object> by calling the getValues() method. But then it does nothing with this value. Effectively you're creating these objects and getting rid of them again without doing anything with them. This isn't ideal.
A MapSqlParameterSource is used with a Spring NamedParameterJdbcTemplate. Your code mentions a jdbcTemplate, which appears to be a field within the class that parses data and inserts into the database, but you don't show the full code of this class. I'm going to have to assume it's a NamedParameterJdbcTemplate rather than a 'plain' JdbcTemplate.
A NamedParameterJdbcTemplate contains a method update that takes a SQL string and a SqlParameterSource. We have a SQL string, and we're creating MapSqlParameterSource objects, so we can use these to carry out the insert. There's not a lot of point in creating one of these MapSqlParameterSource objects only to convert it to a map, so let's remove the call to getValues().
So, we now have a method to insert the data into the database:
public void insertZygateData(List<ZygateEntity> parseData) {
String sql = "INSERT INTO Landing.midrange_xygate_load (account_name,command_name,system_name)"+
"VALUES (:account_name,:command_name,:system_name)";
for (ZygateEntity zygateInfo : parseData){
SqlParameterSource source = new MapSqlParameterSource("account_name", zygateInfo.getAccountName())
.addValue("command_name", zygateInfo.getCommandName())
.addValue("system_name", zygateInfo.getSystemName());
jdbcTemplate.update(sql, source);
}
}
Finally, let's take a look at your cleanThetable method. As with the others, let's keep it focused on one task: it looks like at the moment you're trying to delete the data out of the table and then insert it in the same method, but let's have it just focus on deleting the data as we've now got a method to insert the data.
We can't immediately get rid of the String sql = ... line, because the finally block in your code uses it. If stmt is not null, then you attempt to run the INSERT statement and then close stmt.
However, stmt is never assigned any value other than null, so it remains null. stmt != null is therefore always false, so the INSERT statement never runs. Your finally block never does anything, so you would be best off removing it altogether. With your finally block gone, you can also get rid of your local variable stmt and the sql string, leaving us with a method whose focus is to truncate the table:
public boolean cleantheTable() throws SQLException {
boolean truncated = false;
try {
String sqlTruncate = "truncate table Landing.midrange_xygate_load";
jdbcTemplate.execute(sqlTruncate);
truncated = true;
} catch (Exception e) {
e.printStackTrace();
truncated = false;
return truncated;
}
log.info("Clean the table return value :" + truncated);
return truncated;
}
I'll leave it up to you to write the code that calls these methods. I wrote some code for this purpose, and it ran successfully and inserted into a database.
So, in summary, no data was being written to your database because you were never making a call to the database to insert any. In your insertZygateData method you were creating the parameter-source objects but not doing anything useful with them, and in your cleanThetable method, it looked like you were trying to insert data, but your line jdbcTemplate.execute(sql) that attempted to do this never ran. Even if stmt wasn't null, this line wouldn't work as you didn't pass the parameter values in anywhere: you would get an exception from the database as it would be expecting values for the parameters but you never gave it any.
Hopefully my explanation gives you a way of getting your code working and helps you understand why it wasn't.

New call log record not found in android broadcastreceiver

I am working on android application that needs phone calls to be logged on the server for personal use of course. I have broadcastreceiver registered for this purpose and I am able to detect all types of calls and their details. However, it is not possible to detect accurate outgoing call time i.e. we get to detect complete OFFHOOK time for outdoing call which is not exactly call duration talked. So only for outgoing call ended case I try to read records from the call log history. I am able to read call log history from broadcastreceiver for outgoing call ended but I don't see the entry of currently received call in the call log entry. I can see all the previous calls in the call history but not the one for which I received broadcastreceiver. I am using Gabe Sechan example from here in my code. And I try to read latest call history in outgoingcallended method like this,
ContentResolver crs = globalContext.getContentResolver();
Cursor cr = getAllCallLogs(crs);
if(cr.moveToFirst()){
duration = cr.getString(cr
.getColumnIndex(android.provider.CallLog.Calls.DURATION));
callNumber = cr.getString(cr
.getColumnIndex(android.provider.CallLog.Calls.NUMBER));
}
private Cursor getAllCallLogs(ContentResolver cr) {
// reading all data in descending order according to DATE
String strOrder = android.provider.CallLog.Calls.DATE + " DESC";
Uri callUri = Uri.parse("content://call_log/calls");
Cursor cur = cr.query(callUri, null, null, null, strOrder);
return cur;
}
But the callNumber is previous call number and not the one for which I received broadcastreciver and same is the case with the duration.
I understand that by the time I try to read call log it is not updated so how do I solve this? What am I missing?

You have to add some delay before getContentResolver(), so that table get updated. You can add either Thread.sleep() or can use handler.
public void loadCursorPostDelayed(){
final Handler handler = new Handler();
handler.postDelayed(new Runnable() {
#Override
public void run() {
ContentResolver crs = globalContext.getContentResolver();
...
}
}, 1500);
}
}

Android application exits without any exception

I'm building an application that shows in a WebView some remote data that is cached in SQLite db. The data is being requested by JavaScript function from WebView via JavaScript interface.
When user types into an input element on the page, JavaScript function requests search result by calling Java function, which in turn fires a sql query. Results are then packaged in suitable JSON format and returned.
Fetching data works OK unless you type very quickly. If you type quick enough after few key presses the app quits WITHOUT any exceptions being thrown, it just goes back to home screen.
I have managed to narrow down the cause - commenting out the call to .query method prevents crashing, but renders app useless.
Is there a way to check what caused application to quit, another log or tool that could help?
Java function code:
public Lot[] getLotList(String query, int limitCount) {
...
...
String[] resultColumns = new String[] { LotsSearch._ID };
String queryWhere = LotsSearch.TABLE_NAME + " MATCH ?";
String[] queryArgs = new String[] { query + "*" };
String sortOrder = LotsSearch.COLUMN_NAME_NUMBER + " ASC, " + LotsSearch.COLUMN_NAME_TITLE + " ASC";
String limit = null;
Cursor cursor = null;
if (limitCount != -1)
limit = "0," + limitCount;
try {
cursor = mDb.query(LotsSearch.TABLE_NAME, resultColumns, queryWhere, queryArgs, null, null, sortOrder, limit);
if (cursor != null && cursor.moveToFirst()) {
result = new Lot[cursor.getCount()];
try {
int idColumnIndex = cursor.getColumnIndexOrThrow(LotsSearch._ID);
int lotId;
Lot lot;
do {
lotId = cursor.getInt(idColumnIndex);
lot = mLots.get(lotId);
if (lot != null)
result[index++] = lot;
} while (cursor.moveToNext());
} catch (IllegalArgumentException e) {
e.printStackTrace();
}
}
} catch (SQLiteException e) {
e.printStackTrace();
} finally {
if (cursor != null)
cursor.close();
}
...
...
return result;
}
UPDATE:
I have discovered that there is another log that could be accessed by issuing
logcat -b events
when the app crashes there is just one entry
I/am_proc_died( 59): [11473,com.example.app]
and when the app exits gracefuly this log shows set of entries:
I/am_finish_activity( 59): [1157978656,22,com.example.app/.MainActivity,app-request]
I/am_pause_activity( 59): [1157978656,com.example.app/.MainActivity]
I/am_on_paused_called(11473): com.example.app.MainActivity
I/am_destroy_activity( 59): [1157978656,22,com.example.app/.MainActivity]

I'd make a change to my auto search function. Namely, only perform the search if the user hasn't pressed a key for about 1/2 a second.
If you are typing fast, then this function is being executed several times right on top of itself, before the results are even able to come back. Meanwhile you are probably have too many cursor resources going at once causing the app to just completely fail.
update. If you consider it, typing 10 keys fairly quickly in a row could potentially mean that you have 10 different queries executing and parsing results... There could certainly be some deadlocking issues with the code that actually calls the getLotList method if it's spun multiple threads to try and update the UI. This can lead to some programs simply giving up the ghost not knowing what to do or even what thread to report the issue on.
Of course, all of that's hard to tell from the small snippet we have.

Error on Updating Table in Sqlite

When trying to update a record for one of my records I am using this code
private void UpdateCattleRecord(UpdateCattleRecord updateRecord){
mDB.beginTransaction();
String where = "_ID=";
String[] RecordToUpdate = {Cattle._ID};
Toast.makeText(this,"Updating Animal "+ RecordToUpdate, Toast.LENGTH_LONG).show();
try {
ContentValues CattleFieldsToUpdate = new ContentValues();
CattleFieldsToUpdate.put(Cattle.CATTLE_ANIMALID,updateRecord.getCattleName());
CattleFieldsToUpdate.put(Cattle.CATTLE_TYPE, updateRecord.getCattleType());
CattleFieldsToUpdate.put(Cattle.CATTLE_LOCATION, updateRecord.getCattleLocation());
CattleFieldsToUpdate.put(Cattle.CATTLE_DOB, updateRecord.getCattleDob());
CattleFieldsToUpdate.put(Cattle.CATTLE_DAM, updateRecord.getCattleDam());
CattleFieldsToUpdate.put(Cattle.CATTLE_SEX, updateRecord.getCattleSex());
mDB.update(Cattle.CATTLE_TABLE_NAME,CattleFieldsToUpdate, where, RecordToUpdate);
mDB.setTransactionSuccessful();
} finally {
mDB.endTransaction();
}
}
My log shows
Tag Database sqlite returned: error code =1, msg = near "=": syntax error
After researching this, I think I have everything in the right place but obviously I don't,
when I look at the next error in the log it's of course in 'red' and it shows me all the correct data,
03-27 15:15:29.291: E/Database(12011): Error updating date_of_birth=March 27, 2012 animaltype=Calf sex=F location=Eastern dam=601 animal_id=601A using UPDATE cattle SET date_of_birth=?, animaltype=?, sex=?, location=?, dam=?, animal_id=? WHERE _ID=
I've obviously got a problem with the value for _ID but can't seem to locate it. Can someone please point out where my Syntax error is?
Update
The problem occurred because I was failing to pass the actual value of the record (_ID) that I wanted to update. Once I passed that as a parameter to my updaterecords function the update went as scheduled.
Thanks for the input, it helped me narrow down what I was doing wrong.

Check your database creation, your probably have a column named _id(although you refer to it by _ID, its name is _id) and not _ID:
String where = "_id= ?"; // ? represent the value from the selection arguments String array
or better:
String where = Cattle._ID + "= ?";
Edit:
In your where selection argument you put:
String[] RecordToUpdate = {Cattle._ID};
you probably want to put in there some id you get from somewhere(of the record you want to update, a long number), right now you're doing:
WHERE _ID = _ID (or _id)
and this will fail.

try:
mDB.update(Cattle.CATTLE_TABLE_NAME,CattleFieldsToUpdate, "_ID="+Cattle._ID, null);
try:
mDB.update(Cattle.CATTLE_TABLE_NAME,CattleFieldsToUpdate, "_ID="+updateRecord.getId(), null);