Database Users

[Q] AlertDialog (-> list with a lot of elements) how to handle orientation-change

Hi,
A few weeks ago I started developing an Android app but I've gut one problem
If the user changed the orientation of his phone the Activity is of course newly created. If there is ProgressDialog opened, I simply open a new one and the user does not realize it, but if I show an AlertDialog containing a few hundred elements and the user scrolls a bit he/she will realize it after I recreate the AlertDialog because the dialog will start again with the first element and the user has to scroll newly to the element he wants.
How I handle the "ListDialog":
At first I have two classes which simplify the ListDialog because I use it a few times...
ListDialog class:
Code:
public class ListDialog {
public static int CHOOSE_MODE_ONLINE = 0x01;
public static int CHOOSE_MODE_BOOKMARK = 0x02;
public static int CHOOSE_MODE_LOCAL = 0x03;
public static int CHOOSE_CHAPTER_ONLINE_DOWNLOAD = 0x04;
public static int CHOOSE_CHAPTER_BOOKMARK_DOWNLOAD = 0x05;
public static int CHOOSE_CHAPTER_ONLINE_READ = 0x06;
public static int CHOOSE_CHAPTER_BOOKMARK_READ = 0x07;
public static int CHOOSE_CHAPTER_LOCAL_READ = 0x08;
public static int CHOOSE_CHAPTER_LOCAL_DELETE = 0x09;
public static int GOTO_PAGE = 0x0A;
public static void show(Context context, String title, CharSequence[] elems, final ListMethodInvoker invoker)
{
AlertDialog.Builder builder = new AlertDialog.Builder(context);
builder.setTitle(title);
builder.setItems(elems, new DialogInterface.OnClickListener() {
%mail%Override
public void onClick(DialogInterface dialog, int which) {
invoker.invoke(which);
}
});
builder.setOnCancelListener(new OnCancelListener() {
%mail%Override
public void onCancel(DialogInterface dialog) {
invoker.cancel();
}
});
AlertDialog dialog = builder.create();
dialog.show();
}
}
ListMethodInvoker class:
Code:
public class ListMethodInvoker {
public void invoke(int id)
{
}
public void cancel()
{
}
}
and now I create the dialog:
Code:
ApplicationController.get().addOpenedDialog(ListDialog.CHOOSE_MODE_ONLINE);
ListDialog.show(OnlineActivity.this,
mangaController.getManga().getMangaName(),
new CharSequence[]{"Add to Bookmarks", "Download a Chapter", "Read a Chapter"},
new ListMethodInvoker()
{
%mail%Override
public void invoke(int id)
{
ApplicationController.get().removeOpenedDialog(ListDialog.CHOOSE_MODE_ONLINE);
switch(id)
{
case 0: addBookmark(mangaController.getManga()); break;
case 1:
ApplicationController.get().addOpenedDialog(ListDialog.CHOOSE_CHAPTER_ONLINE_DOWNLOAD);
handleChapter(ChapterMode.Download);
break;
case 2:
ApplicationController.get().addOpenedDialog(ListDialog.CHOOSE_CHAPTER_ONLINE_READ);
handleChapter(ChapterMode.Read);
break;
}
}
%mail%Override
public void cancel()
{
ApplicationController.get().removeOpenedDialog(ListDialog.CHOOSE_MODE_ONLINE);
}
});
I also add the ID of the dialog to my ApplicationController which allows me to remember if a dialog has been openend and I can recreate it when onCreate(...) is called again.
(The ApplicationController uses the singleton design pattern which always allows me to retrieve the same instance of the ApplicationController.)
Thanks in advance
best regards
mike
btw: If you wonder why I write %mail% instead of the correct symbol, I get the following exception message if I use it: To prevent spam to the forums, new users are not permitted to post outside links in their messages. All new user accounts will be verified by moderators before this restriction is removed.

Why is Sample Notepad app inserting blank lines?

In Googles sample Notepad app (the final version using NotepadV3Solution), if you select Add Note (launching the NoteEdit activity), then just hit the back button, a blank line is then inserted into the Notepad activity, and it cannot be deleted. Does anyone know why? Below is the java code for this activity...
package com.android.demo.notepad3;
import android.app.Activity;
import android.database.Cursor;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
public class NoteEdit extends Activity {
private EditText mTitleText;
private EditText mBodyText;
private Long mRowId;
private NotesDbAdapter mDbHelper;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mDbHelper = new NotesDbAdapter(this);
mDbHelper.open();
setContentView(R.layout.note_edit);
mTitleText = (EditText) findViewById(R.id.title);
mBodyText = (EditText) findViewById(R.id.body);
Button confirmButton = (Button) findViewById(R.id.confirm);
mRowId = savedInstanceState != null ? savedInstanceState.getLong(NotesDbAdapter.KEY_ROWID)
: null;
if (mRowId == null) {
Bundle extras = getIntent().getExtras();
mRowId = extras != null ? extras.getLong(NotesDbAdapter.KEY_ROWID)
: null;
}
populateFields();
confirmButton.setOnClickListener(new View.OnClickListener() {
public void onClick(View view) {
setResult(RESULT_OK);
finish();
}
});
}
private void populateFields() {
if (mRowId != null) {
Cursor note = mDbHelper.fetchNote(mRowId);
startManagingCursor(note);
mTitleText.setText(note.getString(
note.getColumnIndexOrThrow(NotesDbAdapter.KEY_TITLE)));
mBodyText.setText(note.getString(
note.getColumnIndexOrThrow(NotesDbAdapter.KEY_BODY)));
}
}
@Override
protected void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
outState.putLong(NotesDbAdapter.KEY_ROWID, mRowId);
}
@Override
protected void onPause() {
super.onPause();
saveState();
}
@Override
protected void onResume() {
super.onResume();
populateFields();
}
private void saveState() {
String title = mTitleText.getText().toString();
String body = mBodyText.getText().toString();
if (mRowId == null) {
long id = mDbHelper.createNote(title, body);
if (id > 0) {
mRowId = id;
}
} else {
mDbHelper.updateNote(mRowId, title, body);
}
}
}

When you hit the back button the onpause function is called which calls savestate. In savestate it doesn't check to see it fields title and body are blank. So it writes a record with blank or null values.
________________________________
http://ron-droid.blogspot.com

I'm still trying to figure all this java out. Any chance you could tell me specifically what I need to add to fix it?

greydarrah said:
I'm still trying to figure all this java out. Any chance you could tell me specifically what I need to add to fix it?
Click to expand...
Click to collapse
Modify the saveState() function to check to see if the body or titles are empty.
You can do something like:
Code:
if (title.isEmpty() || body.isEmpty())
return;
Which will make the save state not needlessly update or add to the db if a field is blank. This disallows you to add blank notes though (ie. notes with only a title, no body). Though I'm OK with that. But the save-state is where you want to start, because that's what's happening.
And for the love of Christ please wrap your code in code tags (select the code, hit the # sign in the top menu bar).

I'd do something like this;
private void saveState() {
String title = mTitleText.getText().toString();
String body = mBodyText.getText().toString();
If (title == null || title == "") return;
________________________________
http://ron-droid.blogspot.com

rigman said:
I'd do something like this;
private void saveState() {
String title = mTitleText.getText().toString();
String body = mBodyText.getText().toString();
If (title == null || title == "") return;
________________________________
http://ron-droid.blogspot.com
Click to expand...
Click to collapse
I'm sorry for being such an idiot, but when I put:
If (title == null || title == "") return;
in saveState, I get red mark right after the closing paren (just before return. If I hold my cursor over the red mark, it says syntax error, insert ";" to complete statement. Any idea why Eclipse doesn't like this?
Edit...A little more to the story:
The first error I got was this...
The method fi(boolean) is undefined fo rthe type NoteEdit
Quick fix: create method If(boolean)
So I did the quick fix. Now I'm thinking that I should add a ";" at the end if the if statement and put the return; in the new If(boolean) mentod. It would look like this:
Code:
private void saveState() {
String title = mTitleText.getText().toString();
String body = mBodyText.getText().toString();
If (title == null || title == "");
if (mRowId == null) {
long id = mDbHelper.createNote(title, body);
if (id > 0) {
mRowId = id;
}
} else {
mDbHelper.updateNote(mRowId, title, body);
}
}
private void If(boolean b) {
// TODO Auto-generated method stub
return;
}
Is that correct, or am I totally retarded?

Well, I'm not sure what's going on in the code above, but it doesn't work...still inserts blank lines. I wish I knew more about what I'm doing.
If anyone can help me figure this out, I'm ONLY concerned with the note title (if it equals "", don't save the blank line). I don't care if the body has text in it or not.

greydarrah said:
Well, I'm not sure what's going on in the code above, but it doesn't work...still inserts blank lines. I wish I knew more about what I'm doing.
If anyone can help me figure this out, I'm ONLY concerned with the note title (if it equals "", don't save the blank line). I don't care if the body has text in it or not.
Click to expand...
Click to collapse
I'm sorry, I thought isEmpty() was a standard function of the String library in Java.
Aside from that, can I ask what your issue is with my solution?
If you don't want to check to see if the body is empty, don't. If you are only concerned with whether or not the title is empty, use Java's built in string functionality. So in your saveState function, put this after:
Code:
String title = mTitleText.getText().toString();
String body = mBodyText.getText().toString();
if (title.length() == 0) // if string length is 0
{
return;
}
What this will do, is if the title is empty (ie. == "") it will return from the saveState function, without updating or adding the note to the database. You CANNOT use the "==" operator, as that will run a comparison of the objects (to see if they're the same string instance), ie.:
Code:
String a = "hi";
String b = "hi";
if (a == b); // false
if (a.equals(b)); // true ([I]this calls the comparison operator on the strings, which is built into the String class[/I])
if (a == a); // true (they're the same object)
If you're checking to see if a string is empty, you can do:
Code:
if (a.equals("")) ... // checks if it's the equivalent of the empty string
OR
if (a.length() == 0) ... // Checks if size of string is 0
Either will work. Hopefully that clears it up for you, you can check if the String is empty, or you can see if it equals the empty string.
It sounds like you're new to programming in general, is this the case? Or are you just new to Android? If you are more accustomed to another language I can possibly (probably) give you better analogies from there...unless it's some weird language .

Syndacate said:
I'm sorry, I thought isEmpty() was a standard function of the String library in Java.
Aside from that, can I ask what your issue is with my solution?
If you don't want to check to see if the body is empty, don't. If you are only concerned with whether or not the title is empty, use Java's built in string functionality. So in your saveState function, put this after:
Code:
String title = mTitleText.getText().toString();
String body = mBodyText.getText().toString();
if (title.length() == 0) // if string length is 0
{
return;
}
Click to expand...
Click to collapse
Thanks so much. This worked perfectly. As to my programming, I'm a long time VB programmer (since VB 3), but brand new to java. In these early stages, I'm having issues getting my mind wrapped around it, but I'll get there.
I'm thankful to everyone that responded to this thread. This is how a forum should work.

greydarrah said:
As to my programming, I'm a long time VB programmer (since VB 3), but brand new to java.
Click to expand...
Click to collapse
That explains your syntax error problems above. Unlike VB, Java is case-sensitive, and you used an upper-case "If" instead of the correct lower-case "if". The compiler did not recognize this as a keyword and assumed you wanted to use a method called "If(boolean)" but forgot to define it.
So, change all capital letters in all keywords to lower case, and remove the auto-generated "If(boolean)" method again.
Cheers
tadzio

greydarrah said:
Thanks so much. This worked perfectly. As to my programming, I'm a long time VB programmer (since VB 3), but brand new to java. In these early stages, I'm having issues getting my mind wrapped around it, but I'll get there.
I'm thankful to everyone that responded to this thread. This is how a forum should work.
Click to expand...
Click to collapse
Ah, I see. Haven't used VB in forever, barely remember it, haha. Glad it works for you, though.

Help writing something with setOnItemClickListener

In my Android app, I have a sound that I want to play when a certain selection has been made from a spinner, but I want it to play the when the user actually makes the proper selection (or just after). My problem is that although the sound does play when they make the correct selection, as long as that selection stays chosen, it also plays every time the app starts up, when it should ONLY play at the time it's chosen. I think I need to change my setOnItemSelectedListener to setOnItemClickListener, but I'm not sure how (still pretty new to java). Can any generous soul out there show me how to change this up (assuming that's how to best solve this problem)?
Here is the code I have now:
Code:
fitnessSpinner = (Spinner) findViewById(R.id.fitness_spinner);
ArrayAdapter adapter4 = ArrayAdapter.createFromResource(
this, R.array.fitness_array, android.R.layout.simple_spinner_item);
adapter4.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
fitnessSpinner.setAdapter(adapter4);
fitnessSpinner.setOnItemSelectedListener(new OnItemSelectedListener()
{
@Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long i) {
Log.d("test", "p: " + position + " " + i);
if(position == 0) {
//First Entry
MediaPlayer mp = MediaPlayer.create(mContext, R.raw.bowchica);
mp.start();
} if(position == 4) {
MediaPlayer mp = MediaPlayer.create(mContext, R.raw.debbie2);
mp.start();
}
}
@Override
public void onNothingSelected(AdapterView<?> arg0) {
}
});

I haven't try the below code but you can try it on your own and tell us.
In onCreate() declare MediaPlayer mp;
In every if statement that you use for check insert this code:
Code:
if(mp!=null){mp.release();}
int resid = R.raw.yoursound;
mp = MediaPlayer.create(this, resid);
After that override the methods onPause() and onResume() and insert this:
if(mp!=null){mp.release();}
If it is still playing a sound when you start your app, then you should check your code again if you have set as default option any of your selection options.

I would LOVE to try this out...Unfortunately, I'm way too dumb at this point point ot figure out exactly where those code snippets would go inside of what I already have.
Does anyone have a couple of minutes to show me where it would go?

Below is a sample code. Since i don't know your code I give you a snippet that you should adjust it to your code.
Code:
public class SampleSound extends Activity{
private Spinner fitnessSpinner;
private MediaPlayer mp;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);//here goes your layout
setViews();//here you will set all your views(spinners buttons textviews etc..)
setAdapters();//set your adapters here
setListeners();//
}
private void setListeners() {
fitnessSpinner.setOnItemSelectedListener(new OnItemSelectedListener(){
@Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long i) {
Log.d("test", "p: " + position + " " + i);
if(position == 0) {
//First Entry
if(mp!=null){mp.release();}
int resid = R.raw.bowchica;
mp = MediaPlayer.create(this, resid);
mp.start();
} if(position == 4) {
if(mp!=null){mp.release();}
int resid = R.raw.debbie2;
mp = MediaPlayer.create(this, resid);
mp.start();
}
}
@Override
public void onNothingSelected(AdapterView<?> arg0) {
}
});
}
private void setAdapters() {
ArrayAdapter adapter4 = ArrayAdapter.createFromResource(this, R.array.fitness_array, android.R.layout.simple_spinner_item);
adapter4.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
fitnessSpinner.setAdapter(adapter4);
}
private void setViews() {
fitnessSpinner = (Spinner) findViewById(R.id.fitness_spinner);
}
public void onResume(){
super.onResume();
if(mp!=null){mp.release();}
}
public void onPause(){
super.onPause();
if(mp!=null){mp.release();}
}
}

I really appreciate the help. I put the code in my routine, but it still plays the sound every time the activity is loaded (as long as the selection in the spinner is correct). It should only play the sound when the correct selection is made.
Any other ideas?

I am sure that your Spinner is set to some value (since you have values to display). Because your Spinner points to a selection (doesn't matter if you have selected or it is selected by default) your sound plays (even when you start the app).
A way to stop the sound playing at start is to declare and an other Item like you did with the previous 4 and set it as default selection of your Spinner.
To sum up:
1.You have to append in R.array.fitness_array an Item (like you did with the previous Items) and give it a name.
2.At the end of method setAdapters() insert this:
Code:
fitnessSpiner.setSelection(5);// or whatever is your selection number
Now it should work but you should know that this is not a good practice and you should try make a ListView or something else.

I'd be happy to change this out to a listview, or whatever would work. I just have to give my user a choice of 4 or 5 items, from which they can choose only one. Something like a drop down box, but in Android, I thought my only option was a spinner. But whatever I use, I have to be able to play a sound when certain items are chosen, but ONLY when those items are chosen, NOT whenever the activity is called up.
Any specific ideas of what I might change to?

What if I had another control like a textview or an edittext (with it's visibility property set to false) that I programatically populated with the users selection (when it's the selection that I want) and then have an OnItemClcickListener set to play the sound?
Could that work?

I will answer from the last to the top of your questions.
1.You can do whatever you want with android. You want TextViews and EditTexts with complex and nested Layouts you can do it. Write services that will communicate with your contacts through a content provider? You can do it.
Write, read and test code. Only this way you will actually learn.
2.Read developer.android.com. Read the android tutorials from there and specifically the Notepad example. You will learn a lot.
A good resource with small examples for ListViews is this.
3.Have you tried the changes I told you from the last post? Did it worked?
Since you just started with android and programming you must first be happy if you have the expected result and then read more to make your code better

Your suggested changes (fitnessSpiner.setSelection(5);// or whatever is your selection number) would stop the sound from playing, but defeat the apps purpose. Every time this activity is loaded, the spinners hit preferences to load the previously stored data. So if I force the spinner to a different selection to NOT play sound when the activity loads, then I would be displaying the wrong data for the user.

Yes you are right. So it is better to make a ListActivity. Read developer.android.com and the link i gave you before. You will be ok with this!

You're using "setOnItemSelectedListener", which sounds like when the app starts, its getting "selected" again.
Have you tried using "setOnItemClickListener" instead?
fitnessSpinner.setOnItemClickListener(new AdapterView.OnItemClickListener () {
public void onItemClicked() {}
};

Lakers16 said:
You're using "setOnItemSelectedListener", which sounds like when the app starts, its getting "selected" again.
Have you tried using "setOnItemClickListener" instead?
fitnessSpinner.setOnItemClickListener(new AdapterView.OnItemClickListener () {
public void onItemClicked() {}
};
Click to expand...
Click to collapse
onClickListener doesn't work for the spinner...I wish it did.
I REALLY need the drop down functionality of teh spinner, so I guess I'm going to try and figure out a way to have an invisible edittext that I set to the spinner selection and then use onClickListener or onChange...

[Q] Repeat Button Action

Hello. New here and I hope this post is okay. The "Is this a question?" checkbox says it not the QA forum but it is?
Working on an app that all it's supposed to do is repeat taking a picture every 5 seconds after pressing a button. Now, I've looked at handler, timer, etc but I can't figure out the right way to do it. This is the code currently, and the onCameraClick of course runs when the button on the screen is pressed. I want that button to activate some kind of repeater so the picture gets taken every 5000ms.
Code:
public class CameraImage extends Activity {
public static int cameraID = 0;
public static ImageView image;
[user=439709]@override[/user]
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.cameraimage);
image = (ImageView) findViewById(R.id.imgView);
}
public void onCameraClick(View v)
{
cameraID = 1;
Intent i = new Intent(CameraImage.this, CameraView.class);
startActivityForResult(i, 9999);
}
}
Now, this is something I'd definitely like to use but I'm not sure how to implement this correctly into the code above. Been trying trial and error for past few hours and nothing. Tried out a timer example someone put on another website, 10792454/image-capture-in-android-automatically but not much there.
At the same time however though, I'm not sure if the code should go in the other class with all the functions to run the camera. Any suggestions/tip or help I'd greatly appreciate it.

Try a loop. I'm not sure if you have tried this or if it will work with launching an activity, but it sounds like that is what you want to do. I don't know how you determine when to stop taking pictures but you can use a "for loop" or a "while loop".
example "for loop":
Code:
for (int i; i > someNumber; i++){
//Your code here
}
someNumber would be perhaps the number of pictures you want to take and you can use i to number each picture.
example "while loop":
Code:
Boolean buttonClick = false;
onCreate(){
OnButtonClick(){
OnClick(){
if(buttonClick == true){
buttonClick = false;
}else{
buttonClick = true;
}
onCameraStart(buttonClick);
}
public void onCameraStart(boolean runCamera){
while (runCamera == true){
//Your code here
}
}
This example I showed you how you would be able to start the camera on the first click and stop it when clicked again. The OnButtonClick would be the OnClickListener for your button.
Both these examples may need a little refinement but this should point you in the right direction. Hope this helps. You can put these in threads and pause the thread at the end of the loop for 5 secs so it will wait (I think).

It's simple use a timer and invoke it on first click
Sent from my GT-S5302 using Tapatalk 2

[Q] onSaveInstanceState

I'm new to android app development
Facing an issue:
Data (String values) lost while changing screen orientation
I googled about it and found it can be handled by onSaveInstanceState()
But didn't get how to use that in the java file
Can someone clear it to me?

static final String STATE_SCORE = "playerScore";
static final String STATE_LEVEL = "playerLevel";
...
@override
public void onSaveInstanceState(Bundle savedInstanceState) {
// Save the user's current game state
savedInstanceState.putInt(STATE_SCORE, mCurrentScore);
savedInstanceState.putInt(STATE_LEVEL, mCurrentLevel);
// Always call the superclass so it can save the view hierarchy state
super.onSaveInstanceState(savedInstanceState);
}
 @override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState); // Always call the superclass first
// Check whether we're recreating a previously destroyed instance
if (savedInstanceState != null) {
// Restore value of members from saved state
mCurrentScore = savedInstanceState.getInt(STATE_SCORE);
mCurrentLevel = savedInstanceState.getInt(STATE_LEVEL);
} else {
// Probably initialize members with default values for a new instance
}
...
}

ChahatGupta said:
I'm new to android app development
Facing an issue:
Data (String values) lost while changing screen orientation
I googled about it and found it can be handled by onSaveInstanceState()
But didn't get how to use that in the java file
Can someone clear it to me?
Click to expand...
Click to collapse
If It s so important then save it as file
Or save it as temporary data to Bundle
Code:
Bundle.putExtra("name", Data);
:good: