Hi,
I am reading a book on Android development. In one of the source code examples the author uses the construct:
String tt = **;
I assume he is initializing his new string to empty, but I have never seen this before and just want to be sure. There is probably a more detailed meaning.
Google search doesn't find anything like this. Can someone confirm what this means?
Thanks for any info or pointers to the definition.
Barry.
Uh, that's an error.
// Initialize String, 2 ways
String tt = null; // I always use this
String tt = ""; // empty string can be unpredictable
Hello all! I'm somewhat new to Android development, I'm using eclipse to do all of my development. Right now I am working on an "away message text" application. I am having trouble with database query returning a string of the first index of data. Here is my code where i am trying to pull data from the database. This is being done inside my ReceiveText class, which extends BroadcastReceiver.
mDbHelper = new TextsDbAdapter(context);
mDbHelper.open();
getText = mDbHelper.fetchText(0);
message = getText.getString(getText.getColumnIndex(mDbHelper.KEY_BODY)).toString();
The error that I am getting is Cursor index out of bounds...any recommendations? Thanks!
you always start out of bounds.... you have to moveToFirst() first...
Thanks. Would I moveToFirst() before I fetchText()?
you're probably going to have to change how the fetchText method is implemented.
you'll probably want something like
Code:
public String fetchText(int id){
Cursor c = getContentResolver().query( uri,
new String[] { <name_of_text_column> } ,
"_id == " + id, null, null);
String text = null;
if( c != null ){
if( c.moveToFirst() ){
text = c.getString( c.getColumnIndex( <name_of_text_column> ) );
}
c.close();
}
return text;
}
Thanks. The method I have for fetchText returns a Cursor, however I made another method that returns a string, similar to what you recommended. For some reason, there is something wrong with the rowid sending in, I want to just get the first one, if I'm not mistaken, wouldn't it be 0? I have a seperate ReceiveText.java class, which extends Broadcast Receiver. The part where the messages are stored into the database is very similar to androids notepad demo. When a text is received, I want the ReceiveText class to query the database and just pull the first text that was actually stored into the database. I have 3 columns, KEY_ROWID, KEY_TITLE, and KEY_BODY. For some reason there is an issue when trying to query the database from the ReceiveText class. Any ideas that would make better sense or be easier to implement? Any help is much appreciated.
oh, right. I wasn't paying attention and for some reason I thought it was returning a string. I see now that it's obviously a cursor..
what you are doing sounds fine but you sure really look at the database on the phone/emulator.
open up adb and type
Code:
sqlite3 /data/data/<name_of_app>/databases/<name_of_db>
then you can do
Code:
select * from <name_of_table>
personally, I find it way easier to read if you change the mode with a ".mode line" command(the dot is important).
that should give you a good idea of why it is not working properly.
How do I open up the adb? I looked online, and it says i can run it through command line, or terminal since I use ubuntu, but I'm not sure exactly how to open it. Apologies for my noobness with android development i'm trying to learn!
if you're running it on a phone/tablet, you'll have to set up the adb drivers
but if you're just using the emulator, you're fine
Code:
cd /<path_to_sdk>/platform-tools/
./adb devices ##this should list the device. if not you have a problem.
./adb shell
and now you can execute commands on the device, like sqlite3
Awesome, I got that to work, and i can see the three "texts" that i've added to the database...looks like this...
1|Sleeping|Sleeping...text you when I wake up.
2|Driving|Driving right now...text you when I'm done.
3|Xbox|Playing xbox...text you later.
So this means that my database works. The numbers 1,2, and 3 are the KEY_ROWID, sleeping, driving, and xbox are the KEY_TITLE, and the third part is the KEY_BODY.
For some reason the ReceiveText class is having trouble pulling this information from the database, I really think it has something to do with when i Query the database, it asks for a columnindex, and i am putting a 0 as the parameter. Any ideas? Thanks again for all your help. It's a great learning process.
yeah, there doesn't seem to be a column with _id == 0
that is strange. when you defined it did you use "integer primary key autoincrement"? This should start at 0, I believe.. maybe you deleted your first entry at some point?
try it with 1 and see if that works.
Man, thanks so much for your help...it works! Here is how I did it from the ReceiveText class.
mDbHelper = new TextsDbAdapter(context);
mDbHelper.open();
getText = mDbHelper.fetchText(1);
message = getText.getString(2).toString();
getText is a Cursor type, and message is a String type.
I really appreciate the help, I understand a lot more now. My next step is to set the text to use without having to specify from the ReceiveText class...any suggestions? I was thinking adding another column in the database that would hold either a 1 or 0, and if it is selected, it updates the database and changes that field to a 1, then the ReceiveText class will query the database to return the field that has the 1...make sense? lol
Just to clear this up a bit for those still a little fuzzy:
Code:
Cursor c = db.query(TABLE_NAME3, new String[] {NAMESHORT, LAPTIME, LAPNUMBER}, null ,null, null, null, orderBy);
The column indexes are what you have in the "new String[]" area whether you have 1 or 50 items. So, NAMESHORT is index 0, LAPTIME is index 1 and LAPNUMPER is index 2. It's NOT the column number of where it is in the table
Just a personal preference of mine, but I code all this in the database methods and return what I need from there. Seeing hard-coded numbers in a program always bothers me. Instead of returning cursors I'll return a StringBuilder or ArrayList or whatever. Just sayn'
I have an EditText object (et_travel) on my screen that's asking for miles traveled. I grab that data like this:
Code:
float travel = Float.parseFloat(et_travel.getText().toString());
if(travel > 40000){
I just discover that if someone puts 40000 in the EditText, everything works fine, but if they put 40,000 (adding a comma to the number), I force close on the float travel = ...statement.
How can I evaluate the number without having a problem from the user adding a comma?
you should parse the string before you run it through Float.parseFloat() so that there are no bad characters in the string. use some of the String methods to find and remove bad characters.
Also that parsefloat method probably throws some sort of exception. You could catch it and let your user know that there value is invalid and to try again
Sent from my Desire HD using XDA App
Set the properties on the edittext so it accepts numbers only.
android:inputtype="numberDecimal|numberSigned"
________________________________
http://ron-droid.blogspot.com
Last day I opened my Strings.xml file with Notepad and added all my needed texts to it. Today I opened eclipse and wrote this code :
TextView title1 = (TextView) findViewById (R.string.myAddedTextName);
But the problem is that eclipse cannot find that. I restarted it but it didn't work again. I checked the strings.xml file by eclipse. Everything was corect but the R.String (gen) hasn't saved them. Now I can't accses the texts. Is there anyway I can access them?
Thanks in advance.
You can clean the project. That way it will build again. Just select Project > Clean... and then select your project.
I may be wrong but I don't think you can do this: TextView title1 = (TextView) findViewById (R.string.myAddedTextName);
TextView is a widget object. You are telling eclipse to find a TextView (by id) but are telling it to look for a stored string.
zalez said:
I may be wrong but I don't think you can do this: TextView title1 = (TextView) findViewById (R.string.myAddedTextName);
TextView is a widget object. You are telling eclipse to find a TextView (by id) but are telling it to look for a stored string.
Click to expand...
Click to collapse
That is right. Ids are integer values. I did not see that. :laugh:
Change it to
Code:
TextView title1 = (TextView) findViewById (R.id.myAddedId);
You set the id that way:
Code:
<Button ...
android:id="@+id/myAddedId"
... />
This is what I was thinking:
If title1 is indeed a TextView in your layout you would do this:
Code:
TextView title1 = (TextView) findViewById(R.id.myTextView);
title1.setText(R.string.myAddedTextName);
Thank you.
The strings are now OK.
Also the famous TextView = String which I wrote at the first post has no problem in eclipse.
torpedo mohammadi said:
Thank you.
The strings are now OK.
Also the famous TextView = String which I wrote at the first post has no problem in eclipse.
Click to expand...
Click to collapse
This is because R.id......
And R.string........ Point to int data type so compiler won't mind
Not to mention it will crash at runtime
Sent from my GT-S5302 using Tapatalk 2
So, suppose I have written a text in the strings.xml like :
<String name ="text">Hi there.</string>
Using which code can retreive the "Hi there."? I have something in my mind:
String s = getString(R.string.text);
Or
String s = getResources().getString(R.string.text);
Which one can give me the "Hi there."?
The first one. Not sure about the second one, but just use the first
Both of them will do the same job
Sent from my GT-S5302 using Tapatalk 2
I am trying to swap out characters from one string to those in another (like the simple alphabetic offset code people used as kids), the code I am using is
public void convertMe(){
//lets convert the text
rInput = etrInput.getText().toString();
//lets extract the input characters to a chararray
char[] inputArray = rInput.toCharArray();
//lets get the numbers and make them a string
rNumbers = etrNumbers.getText().toString();
//lets extract them and place them in an chararray
char[] numbersArray = rNumbers.toCharArray();
for (int i=0; i<inputArray.length; i++){
rResult = rNumbers.replace(numbersArray, inputArray);
}
}
Clarification of the behaviour of my code above:
If the string rInput is smaller than the rNumbers array then the app crashes. If not then the only character that is encoded is the last character looped through the array.
I would like to be able to 'encode' all characters in the array, and also be able to encode any number of characters, not be limited to matching the length of the numbersArray.
How can I deal with the arrays of different lengths to substitute the values?
rInput must be 10character word
rNumbers can be any length string but only containing numbers.
The result should be that the numbers are "coded" in simple terms using the letters from the rInput charArray:
ACHROMATIC
0123456789
So encoding 5501 should give the answer MMAC, or 5512345 should give MMCHROM.
User enters a 10character word with no 2 characters the same (like the example achromatic)
User can then enter a series of numbers. (5501)
The substitution should then take the int value of each digit entered by the user, look up that value from the first word and substitute that character:
The fifth letter in the word achromatic is m (assuming you count from 0). The result of 5501 being substituted should be MMAC.
Thanks;
Andy
Anyone able to give me a steer on how i should adjust my code for this to work?