Develop Reference

How to know which button user clicked and its text and id in Android Studio?

Through out the whole android application I want to capture button click, radio button clicks, link click etc... basically a user interaction in whole android application. Is there any common method to detect which element user click and its values.?

Try using onCickListener() on the buttons.

In Kotlin:
Add id to button in .xml files with android:id="#+id/nameOfButton". Every button needs an unique name.
In .kt file, use setOnClickListener with the id to set up the action when user click the button.
If there are several buttons, just follow step 1 and 2.
Example:
step 1
<Button
android:id="#+id/buttonSave"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Save" />
step 2
buttonSave.setOnclickListenter {
//TODO: your code goes here
}

Its very simple you just need to get the text and id of button from the onclick method. Here is java and xml code for it:
XML:
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/button"
android:onclick="getid"
android:text="Save" />
JAVA:
public void getid(View v){
int id = v.getId();
String text = v.getText();
}

As #Muthukumar Lenin asked here is listview in xml and java
XML:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/rl"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:padding="10dp"
tools:context=".MainActivity">
<TextView
android:id="#+id/textview"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:textStyle="italic"
android:textColor="#5f65ff"
android:padding="5dp"
android:text="Choose is the best football player?"/>
<ListView
android:id="#+id/listview"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="#id/textview" />
</RelativeLayout>
JAVA:
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.TextView;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ListView listView = (ListView) findViewById(R.id.listview);
final TextView textView = (TextView) findViewById(R.id.textview);
String[] players = new String[] {"CR7", "Messi", "Hazard", "Neymar"};
List<String> Players_list = new ArrayList<String>(Arrays.asList(players));
ArrayAdapter<String> arrayAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, Players_list);
listView.setAdapter(arrayAdapter);
listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
String selectedItem = (String) parent.getItemAtPosition(position);
textView.setText("The best football player is : " + selectedItem);
}
});
}
}
Some of these code are from tutorialspoint and some are edited by me.

Access string_array from activity and send selected item to another activity in android

hello friends today my question is about string_array.On my activity i created two buttons.Now on (strings.xml) i created string array name with two items and i have inserted some text as shown below.On each button click i would like to access each item individually.for example on button1 click show me first item and on button 2 click give me the 2nd item on.Can you please give me the code for button click as i have little idea on how to access item.I have created a textview activity to display my item with every click.my code is working fine till now but i need help with extra code that i have to add.Please help me .
// Button activity page
android:layout_height="match_parent">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical" />
</ScrollView>
<Button
android:layout_height="wrap_content"
android:layout_marginTop="90dp"
android:layout_marginEnd="60dp"
android:layout_marginRight="50dp"
android:id="#+id/btn1"
android:layout_width="wrap_content"
android:text="#string/OKILA"
android:textSize="18sp"
android:textStyle="bold" />
<Button
android:id="#+id/button1"
android:layout_width="50dp"
android:layout_height="wrap_content"
android:layout_marginTop="160dp"
android:layout_marginRight="50dp"
android:text="1"
android:textSize="18sp"
android:textStyle="bold" />
</RelativeLayout>
//strings.xml
<string-array name="chapters">
<item>this is tes1</item>
<item>this is test2</item>
</string-array>
//main
import android.content.Intent;
import android.graphics.Color;
import android.os.Bundle;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
import org.w3c.dom.Text;
public class Lipok extends AppCompatActivity implements View.OnClickListener {
Toolbar mActionBarToolbar;
Button btnOne;
Button btnTwo;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_lipok);
mActionBarToolbar=(Toolbar)findViewById(R.id.CHAPTERS);
setSupportActionBar(mActionBarToolbar);
getSupportActionBar().setTitle("CHAPTERS");
String[] chapters=getResources().getStringArray(R.array.chapters);
btnOne = findViewById(R.id.btn1);
btnTwo = findViewById(R.id.button1);
btnOne.setOnClickListener(this);
btnTwo.setOnClickListener(this);
}
#Override
public void onClick(View v) {
String text="";
switch(v.getId()){
case R.id.btn1 : {
text = getResources().getStringArray(R.array.chapters)[0];
break;
}
case R.id.button1 : {
text = getResources().getStringArray(R.array.chapters)[1];
break;
}
}
Intent intent = new Intent(Lipok.this,lipokchapters.class);
intent.putExtra("DATA", text);
startActivity(intent);
}
}
//textview activity page
package com.Aolai.temeshilai;
import androidx.appcompat.app.AppCompatActivity;
import android.content.Intent;
import android.os.Bundle;
import android.widget.TextView;
public class lipokchapters extends AppCompatActivity {
TextView textView;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_lipokchapters);
textView=findViewById(R.id.textv);
String text= getIntent().getStringExtra("Data");
textView.setText(text);
}
}

Try this :
xml file
android:layout_height="match_parent">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical" />
</ScrollView>
<Button
android:layout_height="wrap_content"
android:layout_marginTop="90dp"
android:layout_marginEnd="60dp"
android:layout_marginRight="50dp"
android:id="#+id/OKILA"
android:layout_width="wrap_content"
android:text="#string/OKILA"
android:textSize="18sp"
android:textStyle="bold" />
<Button
android:id="#+id/button1"
android:layout_width="50dp"
android:layout_height="wrap_content"
android:layout_marginTop="160dp"
android:layout_marginRight="50dp"
android:text="1"
android:textSize="18sp"
android:textStyle="bold" />
</RelativeLayout>
strings.xml
<string-array name="chapters">
<item>this is tes1</item>
<item>this is test2</item>
</string-array>
Main Class
public class Lipok extends AppCompatActivity implements View.OnClickListener {
Toolbar mActionBarToolbar;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_lipok);
mActionBarToolbar=(Toolbar)findViewById(R.id.CHAPTERS);
setSupportActionBar(mActionBarToolbar);
getSupportActionBar().setTitle("CHAPTERS");
}
#Override
public void onClick(View v) {
String text="";
switch(v.getId()){
case R.id.OKILA : {
text = getResources().getStringArray(R.array.testArray)[0];
break;
}
case R.id.button1 : {
text = getResources().getStringArray(R.array.testArray)[1];
break;
}
}
Toast.makeText(this, text, Toast.LENGTH_LONG).show();
Intent intent = new Intent(this, YOUR_ACTIVITY_NAME.class);
intent.putExtra("DATA", text);
startActivity(intent);
// Or else you can do whatever you want to do here with that text
}
}
Then in your other activity
String data = getIntent().getStringExtra("DATA");
YOUR_TEXTVIEW_NAME.setText(data);

This is basics of Android so before answering I suggest you to go
through basic tutorials before posting on Stackoberflow.
Now,
Here is how you can access the items from your string_array.
String[] chapters= getResources().getStringArray(R.array.chapters);
Now,here is pseudo code that might help you.
btn1.setOnClickListener(
your_text_view.setText(chapters[0])
)
//Here 0 means your first item, likewise you can access items by their index in
array

Android SQLite : Take and Save Photo to DB as Base64 string... Then retrieve

I would like to develop a full-proof solution to a common problem for new android developers. I want to create a tutorial and example (for myself and others to follow) to taking a photo witin an app and then saving it to base64 string within a SQLite android database. Then I will be able to upload this string to an online database at a later stage, rather than the JPG image I originally took.
So to re-iterate it must...
Open Camera,
Take Image
Save as Base64 String to SQLite DB
(the reason that I need it to be stored in the DB as a string, is due to the fact that this will be uploaded to a central document system at some point in the future, and large JPG images will be slow and not ideal, hence why a Base64 string in the DB would be better. I also want to limit the possibility that users can delete the images they take which would be referenced in the DB should be just refrence the path to the file (which is the alternative - although I believe a less suitable one))
Thanks, I really look forward to working on this and developing a great solution that others will be able to follow.
MY EFFORTS SO FAR...
I have spent a number of days looking into this, and at the moment I am more confused than at the start. There seems to be so much outthere about this, but nothing with step by step sections to follow, about what line does what, where it comes from, what its doing etc. So to start with, I think I may need to break this down into two tasks now...
Taking an image using the camera and giving the file as an output somehow...then saving this as a base64 string to the DB or something like this.
I appreciate that usually storing binary data to the DB can cause slow and painful queries, however due to the face that only a few images will ever be displayed at once, we shouldn't have too much of an issue here, and the SQLite queries are small.
So to start with I was following Android: how to take picture with camera and convert bitmap to byte array and save to sqlite db? however the instructions to save images locally and reference the file path, really don't work. and so I was back to square one almost...
I have been reading through http://developer.android.com/guide/topics/media/camera.html to learn about the camera... confused.com !!!
To be fair, I have read so much, and now understand so little, I need a dummies guide to this now. Wish I could unlearn all the useless crap which I have read about this and start from scratch... Where is Format /F for your brain?
OK so i started again...
Things are going a lot better for me now, I have even added audio, but I won't get into that. My app at the moment, takes a photo, previews it (using the standard camera intent) and then on clicking save, displays it locally on the app. Instead of it displaying the image, on clicking save, I need it to save to a database as a blob/bit64
Here is my code so you can see where I am at...
trying to use this as the call to take the image...
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical"
>
<ScrollView
android:layout_height="fill_parent"
android:layout_width="fill_parent"
>
<LinearLayout
android:layout_height="fill_parent"
android:layout_width="fill_parent"
android:orientation="vertical">
>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Inspection ID" />
<EditText
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:id="#+id/txtName"
android:inputType="number"
android:maxLength="5"
android:digits="0123456789"
android:singleLine="true"
/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Text1" />
<EditText
android:id="#+id/txt1"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:autoText="false"
android:gravity="top|left"
android:lines="4"
android:maxLines="4"
android:minLines="4"
android:scrollbars="vertical"
android:singleLine="false"
android:width="0dip" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Project Ref"
/>
<EditText
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:id="#+id/txtAge"
android:inputType="number"
android:maxLength="5"
android:digits="0123456789"
android:singleLine="true"
/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Drop Down"
/>
<Spinner
android:id="#+id/spinDept"
android:layout_width="fill_parent"
android:layout_height="wrap_content" />
<Button
android:id="#+id/btnPhotoCamera"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="10dp"
android:text="camera" />
<Button
android:id="#+id/btnPhotoGallery"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="10dp"
android:text="gallery" />
<TextView
android:id="#+id/lblDisplayImage"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="#+id/btnCancel"
android:layout_centerHorizontal="true"
android:layout_marginTop="10dp"
android:text="below_this_text_image_will_be_displayed"
android:textSize="13dp" />
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_below="#+id/lblDisplayImage"
android:layout_centerInParent="true"
android:layout_marginTop="10dp"
android:gravity="bottom" >
<!--
<ScrollView
android:layout_width="match_parent"
android:layout_height="wrap_content" >
-->
<ImageView
android:id="#+id/imgDisplayImage"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_centerInParent="true"
android:contentDescription="area_where_image_is_to_be_displayed" />
<!-- </ScrollView> -->
</RelativeLayout>
<Button
android:id="#+id/btnAudio"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:onClick="btnAudio"
android:text="Audio" />
<Button
android:id="#+id/btnAdd"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:onClick="btnAddEmp_Click"
android:text="Save Inspection" />
<Button
android:id="#+id/btnCancel"
android:layout_width="120dp"
android:layout_height="wrap_content"
android:layout_below="#+id/btnPhotoGallery"
android:layout_centerHorizontal="true"
android:layout_marginTop="19dp"
android:text="Reset/Clear Form Data" />
<TextView
android:id="#+id/txtEmps"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Number of Inspections on Device " />
</LinearLayout>
</ScrollView>
</LinearLayout>
with the following .java
package mina.android.DatabaseDemo;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.InputStream;
import android.app.Activity;
import android.app.Dialog;
import android.content.Intent;
import android.database.Cursor;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.net.Uri;
import android.os.Bundle;
import android.os.Environment;
import android.provider.MediaStore;
import android.text.Spannable;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.AdapterView;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.SimpleCursorAdapter;
import android.widget.Spinner;
import android.widget.TextView;
import android.widget.AdapterView.OnItemSelectedListener;
import com.AssentApp.V100.R;
public class AddEmployee extends Activity {
EditText txtName;
EditText txtAge;
TextView txtEmps;
DatabaseHelper dbHelper;
Spinner spinDept;
/** The Constant PICK_IMAGE. */
private static final int PICK_IMAGE = 0;
/** The Constant PICK_IMAGE_FROM_GALLERY. */
private static final int PICK_IMAGE_FROM_GALLERY = 1;
/** The btn cancel. */
private Button btnPhotoCamera,btnPhotoGallery,btnCancel;
/** The img view. */
private ImageView imgView;
/** The u. */
private Uri u;
/* (non-Javadoc)
* #see android.app.Activity#onCreate(android.os.Bundle)
*/
#Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.addemployee);
txtName=(EditText)findViewById(R.id.txtName);
txtAge=(EditText)findViewById(R.id.txtAge);
txtEmps=(TextView)findViewById(R.id.txtEmps);
spinDept=(Spinner)findViewById(R.id.spinDept);
imgView=(ImageView)findViewById(R.id.imgDisplayImage);
btnPhotoCamera=(Button)findViewById(R.id.btnPhotoCamera);
btnPhotoGallery=(Button)findViewById(R.id.btnPhotoGallery);
btnCancel=(Button)findViewById(R.id.btnCancel);
btnPhotoCamera.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
Intent camera=new Intent();
camera.setAction(MediaStore.ACTION_IMAGE_CAPTURE);
camera.putExtra("crop", "false");
File f=Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES);
u = Uri.fromFile(new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES),"myFile.jpg"));
camera.putExtra(MediaStore.EXTRA_OUTPUT, u);
startActivityForResult(camera, PICK_IMAGE);
}
});
btnPhotoGallery.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
Intent intent = new Intent(Intent.ACTION_PICK);
intent.setType("image/*");
startActivityForResult(intent, PICK_IMAGE_FROM_GALLERY);
}
});
btnCancel.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
Intent goStartUp=new Intent(AddEmployee.this, AddEmployee.class);
goStartUp.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(goStartUp);
finish();
}
});
}
/* (non-Javadoc)
* #see android.app.Activity#onActivityResult(int, int, android.content.Intent)
*/
#Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
// TODO Auto-generated method stub
if (resultCode==RESULT_OK )
{
if(requestCode == PICK_IMAGE) {
InputStream is=null;
try {
is = this.getContentResolver().openInputStream(u);
} catch (FileNotFoundException e) {
e.printStackTrace();
}
Bitmap bmp=BitmapFactory.decodeStream(is);
imgView.setImageBitmap(bmp);
Log.i("Inside", "PICK_IMAGE");
}
if (requestCode == PICK_IMAGE_FROM_GALLERY) {
Uri selectedImage = data.getData();
String[] filePathColumn = { MediaStore.Images.Media.DATA };
Log.d("data",filePathColumn[0]);
Cursor cursor = getContentResolver().query(selectedImage,filePathColumn, null, null, null);
cursor.moveToFirst();
int columnIndex = cursor.getColumnIndex(filePathColumn[0]);
String picturePath = cursor.getString(columnIndex);
cursor.close();
imgView.setImageBitmap(BitmapFactory.decodeFile(picturePath));
Log.i("Inside", "PICK_IMAGE_FROM_GALLERY");
}
}
}
public void onStart()
{
try
{
super.onStart();
dbHelper=new DatabaseHelper(this);
txtEmps.setText(txtEmps.getText()+String.valueOf(dbHelper.getEmployeeCount()));
Cursor c=dbHelper.getAllDepts();
startManagingCursor(c);
//SimpleCursorAdapter ca=new SimpleCursorAdapter(this,android.R.layout.simple_spinner_item, c, new String [] {DatabaseHelper.colDeptName}, new int []{android.R.id.text1});
SimpleCursorAdapter ca=new SimpleCursorAdapter(this,R.layout.deptspinnerrow, c, new String [] {DatabaseHelper.colDeptName,"_id"}, new int []{R.id.txtDeptName});
//ca.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
spinDept.setAdapter(ca);
spinDept.setOnItemSelectedListener(new OnItemSelectedListener() {
#Override
public void onItemSelected(AdapterView<?> parent, View selectedView,
int position, long id) {
// TODO Auto-generated method stub
}
#Override
public void onNothingSelected(AdapterView<?> arg0) {
// TODO Auto-generated method stub
}
});
//never close cursor
}
catch(Exception ex)
{
CatchError(ex.toString());
}
}
public void btnAddEmp_Click(View view)
{
boolean ok=true;
try
{
Spannable spn=txtAge.getText();
String name=txtName.getText().toString();
int age=Integer.valueOf(spn.toString());
int deptID=Integer.valueOf((int)spinDept.getSelectedItemId());
Employee emp=new Employee(name,age,deptID);
dbHelper.AddEmployee(emp);
}
catch(Exception ex)
{
ok=false;
CatchError(ex.toString());
}
finally
{
if(ok)
{
//NotifyEmpAdded();
Alerts.ShowEmpAddedAlert(this);
txtEmps.setText("Number of Inspections on Device "+String.valueOf(dbHelper.getEmployeeCount()));
}
}
}
void CatchError(String Exception)
{
Dialog diag=new Dialog(this);
diag.setTitle("Adding new Inspection");
TextView txt=new TextView(this);
txt.setText(Exception);
diag.setContentView(txt);
diag.show();
}
void NotifyEmpAdded()
{
Dialog diag=new Dialog(this);
diag.setTitle("Success");
TextView txt=new TextView(this);
txt.setText("Inspection Added Successfully");
diag.setContentView(txt);
diag.show();
try {
diag.wait(1000);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
CatchError(e.toString());
}
diag.notify();
diag.dismiss();
}
public void btnAudio(View view)
{
Intent intent = new Intent(AddEmployee.this, AudioRecordTest.class);
startActivity(intent);
}
}
seems to do the trick, but now I need to edit it for the DB section. I need to save it "by converting image into Byte[] then save as Blob in sqlite" - or so I believe ... Whats my first step in doing this? Note, I don't want it to display the image view anymore, but instead save to DB with unique ID/Integer.
any pointers would be great !!

i don't think u can do it using base64 , but yes you can do that thing by converting image into Byte[] then save as Blob in sqlite.

debug error : confirm perspective switch

when i click on button add debug error
and opens confirm perspective switch dialog box
shows error in dis line " EditText add = (EditText) d1.findViewById(R.id.add); "
what is the mistake in my code??
xml page
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<TextView
android:id="#+id/TextView01"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Question1" >
</TextView>
<EditText
android:id="#+id/question"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="" >
</EditText>
<EditText
android:id="#+id/answer"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="" >
</EditText>
<Button
android:id="#+id/registerques"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="registerques" >
</Button>
</LinearLayout>
java class
showing error in editext line
package quesansw.the1;
import android.app.Activity;
import android.app.Dialog;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.Window;
import android.view.WindowManager;
import android.widget.Button;
import android.widget.EditText;
public class Memo extends Activity {
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
final Dialog d1 = new Dialog(this);
Window window = d1.getWindow();
window.setFlags(WindowManager.LayoutParams.FLAG_BLUR_BEHIND,
WindowManager.LayoutParams.FLAG_BLUR_BEHIND);
d1.setTitle("Register Questions");
d1.setContentView(R.layout.memo);
d1.show();
Button view1 = (Button) d1.findViewById(R.id.view);
Button add = (Button) d1.findViewById(R.id.add);
add.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
EditText add = (EditText) d1.findViewById(R.id.add);
EditText view = (EditText) d1.findViewById(R.id.view);
System.out.println(add.toString());
System.out.println(view.toString());
}
});
view1.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
Intent intent = new Intent(getBaseContext(), View.class);
startActivity(intent);
}
});
}
}

Probably da error in the code is that you never defined an id "add" - you have #+id/TextView01 in the xml "page" (you mean file - and you must tell us which file) but no #+id/add

Android: duplicate items in ListVew. Maybe getView() called too many times?

I am trying to create a simple program which displays a "shopping
cart" list of items, along with a few buttons below it to manage the
cart.
The biggest problem is that items are getting duplicate entries in the
list view. That is, for every item I want to enter I see it appear
two times in the list view. What's the problem? Also, the scrollable
area of my cart is not big enough. How do I set it so that it is
bigger but I can still see my buttons? Perhaps I should put the
buttons above the cart?
Here is my shopping cart's layout XML:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Shopping Cart" />
<ScrollView android:id="#+id/ScrollView01"
android:layout_width="fill_parent"
android:layout_height="110px">
<ListView
android:id="#+id/BookList"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
</ListView>
</ScrollView>
<Button android:text="Add Another Book"
android:id="#+id/AddAnother"
android:layout_width="250px"
android:textSize="18px"
android:layout_height="55px">
</Button>
<Button android:text="Checkout"
android:id="#+id/Checkout"
android:layout_width="250px"
android:textSize="18px"
android:layout_height="55px">
</Button>
</LinearLayout>
Here is the layout for individual row items:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="horizontal"
android:layout_width="fill_parent"
android:layout_height="?android:attr/listPreferredItemHeight"
android:padding="8dip">
<LinearLayout
android:orientation="vertical"
android:layout_width="0dip"
android:layout_weight="1"
android:layout_height="fill_parent">
<TextView
android:id="#+id/BookTitle"
android:layout_width="fill_parent"
android:layout_height="0dip"
android:layout_weight="1"
android:singleLine="true"
android:gravity="center_vertical"
/>
<TextView
android:id="#+id/BookPrice"
android:layout_width="fill_parent"
android:layout_height="0dip"
android:layout_weight="1"
android:singleLine="true"
android:ellipsize="marquee"
/>
</LinearLayout>
<Button
android:id="#+id/buttonLine"
android:gravity="center"
android:layout_height="wrap_content"
android:layout_width="wrap_content"
android:layout_alignParentRight="true"
android:text="Delete"
/>
</LinearLayout>
here is the java code for the shopping cart activity:
package com.sellbackyourbook.sellback;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Iterator;
import android.app.Activity;
//import android.app.ListActivity;
import android.content.Context;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ListView;
import android.widget.TextView;
public class cart extends Activity
{
private ListView m_bookListView;
private BookAdapter m_adapter;
//private static String[] data = new String[] = { ""
/** Called when the activity is first created. */
public void onCreate(Bundle savedInstanceState)
{
ShoppingCartSingleton shoppingCart = ShoppingCartSingleton.getInstance();
super.onCreate(savedInstanceState);
setContentView(R.layout.shoppingcart);
this.m_adapter = new BookAdapter(this, R.layout.cartitem,
shoppingCart.m_books);
m_bookListView = (ListView) findViewById(R.id.BookList);
m_bookListView.setAdapter(this.m_adapter);
//setListAdapter(this.m_adapter);
if (shoppingCart.m_books != null && shoppingCart.m_books.size() > 0)
{
//m_adapter.notifyDataSetChanged();
try
{
//m_adapter.clear();
//for(int i=0;i<1;i++)
Log.i("ARRAY", "m_books.size() before loop" + shoppingCart.m_books.size());
int size = shoppingCart.m_books.size();
for(int i=0;i<size;i++)
{
Log.i("ARRAY", "size in loop" + size);
Log.i("ARRAY", "adding item to adapter" + i);
m_adapter.add(shoppingCart.m_books.get(i));
}
} catch (RuntimeException e) {
e.printStackTrace();
}
//m_adapter.notifyDataSetChanged();
}
Button buttonAddAnother = (Button) findViewById(R.id.AddAnother);
buttonAddAnother.setOnClickListener(new View.OnClickListener()
{
public void onClick(View view)
{
Intent intent = new Intent();
setResult(RESULT_OK, intent);
finish();
}
});
// TODO: only show this button if the shopping cart is not empty
Button buttonCheckout = (Button) findViewById(R.id.Checkout);
buttonCheckout.setOnClickListener(new View.OnClickListener()
{
public void onClick(View view)
{
// TODO: open sellbackyourbook website using book ISBNs
ShoppingCartSingleton shoppingCart = ShoppingCartSingleton.getInstance();
String isbnList = "";
String checkoutURL = "http://www.sellbackyourbook.com/androidcart.php?isbn=";
for (Iterator<Book> i = shoppingCart.m_books.iterator(); i.hasNext(); )
{
Book currentBook = (Book) i.next();
isbnList = isbnList + currentBook.getBookISBN() + ",";
}
checkoutURL = checkoutURL + isbnList;
Log.i("CHECKOUT URL", "checkout URL to submit: " + checkoutURL);
Intent myIntent = new Intent(Intent.ACTION_VIEW);
myIntent.setData(Uri.parse(checkoutURL));
startActivity(myIntent);
}
});
}
private class BookAdapter extends ArrayAdapter<Book> {
private ArrayList<Book> books;
public BookAdapter(Context _context, int _textViewResourceId, ArrayList<Book> _books)
{
super(_context, _textViewResourceId, _books);
this.books = _books;
}
#Override
public View getView(int position, View convertView, ViewGroup parent)
{
System.out.println("getView " + position + " " + convertView);
View v = convertView;
if (v == null) {
LayoutInflater vi = (LayoutInflater)getSystemService(Context.LAYOUT_INFLATER_SERVICE);
v = vi.inflate(R.layout.cartitem, null);
}
Book b = books.get(position);
if (b != null)
{
TextView bTitle = (TextView) v.findViewById(R.id.BookTitle);
TextView bPrice = (TextView) v.findViewById(R.id.BookPrice);
if (bTitle != null)
{
bTitle.setText(b.getBookTitle());
}
if (bPrice != null)
{
bPrice.setText(b.getBookPrice());
}
}
return v;
}
}
}
Here is the Java code for my shopping cart. Am I using the singleton correctly? I really just wanted a quick and dirty way to allow multiple activities access to the shopping cart, as a different activity actually grabs the books from the user and this activity displays them in the cart.
I had an issue iterating through the books in onCreate() as well. the size() function kept increasing in the loop for some reason, so I changed the code and added a "size" variable to avoid making the size() call in the loop itself. I'm not really sure what that was all about.

I'm doing exactly the same thing and my getView is not called at all.
here is the script I was inspired by maybe it would help :
http://mfarhan133.wordpress.com/2010/10/14/list-view-tutorial-for-android/

Yes you are right at the point of BookAdapter's constructor. But the getView() method of BookAdapter is wrong. Please have a look at http://www.youtube.com/watch?v=wDBM6wVEO70 (from Google) to get the right way on how to work with ListView.

Removing the loop where I had this fixed the problem:
m_adapter.add(shoppingCart.m_books.get(i));
It seems like the BookAdapter constructor already took care of populating it, so I was duplicating the items by using the add() method.