I am a newbie in android dev.
I want to develop a very small and simple discount rate calculator.
in which there will be drop down menu with options like:
calculate 10%
calculate 20%
calculate 30%
Based on the selection of option from the drop down menu the discount rate should change.
After selection, there will be a textbox which should ask user to enter price.
and on the click even of "Calculate" button, the resultant amount (discounted rate) should be displayed.
I guess it is very simple for you guys. If anyone can help me with the code, i will deeply appreciate.
thank you
ok this is what I have done till now:
I created an Android Project names as :MyDC
MyDC.java
Code:
package com.super.mydc;
import android.app.Activity;
import android.os.Bundle;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Button;
import android.view.View;
public class MyDC extends Activity {
private EditText amount1;
private double x=0;
private double y=2.0;
private double z=0;
private TextView tt;
private Button calculate;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle icicle) {
super.onCreate(icicle);
// We want to view some very simple text, so we need a TextView
TextView tv = new TextView(this);
// Put some text to the newly created TextVIew
tv.setText("Test");
// Tell our Application to display the textView
this.setContentView(tv);
super.onCreate(icicle);
setContentView(R.layout.main);
initControls();
}
private void initControls()
{
amount1=(EditText)findViewById(R.id.amount1);
tt=(TextView)findViewById(R.id.tt);
calculate=(Button)findViewById(R.id.calculate);
calculate.setOnClickListener(new Button.OnClickListener()
{public void onClick
(View v) { calculate();}});
}
private void calculate()
{
x=Double.parseDouble(amount1.getText().toString());
z=x-(x*y/100);
tt.setText(Double.toString(z));
}
}
This is main.xml
Code:
<?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"
>
<Spinner android:layout_width="match_parent" android:layout_height="wrap_content" android:id="@+id/spinner1"></Spinner>
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Enter the price"
/>
<EditText android:layout_height="wrap_content" android:id="@+id/amount1" android:text="" android:layout_width="match_parent"></EditText>
<Button android:text="Calculate Result" android:id="@+id/calculate" android:layout_width="wrap_content" android:layout_height="wrap_content"></Button>
<EditText android:layout_height="wrap_content" android:id="@+id/tt" android:text="" android:layout_width="match_parent"></EditText>
</LinearLayout>
This is string.xml
Code:
<?xml version="1.0" encoding="utf-8"?>
<resources>
<string name="hello">Hi, MyDC!</string>
<string name="app_name">My, DC</string>
<string name="spinner1">Choose discount type</string>
</resources>
This is what I am able to get:
{
"lightbox_close": "Close",
"lightbox_next": "Next",
"lightbox_previous": "Previous",
"lightbox_error": "The requested content cannot be loaded. Please try again later.",
"lightbox_start_slideshow": "Start slideshow",
"lightbox_stop_slideshow": "Stop slideshow",
"lightbox_full_screen": "Full screen",
"lightbox_thumbnails": "Thumbnails",
"lightbox_download": "Download",
"lightbox_share": "Share",
"lightbox_zoom": "Zoom",
"lightbox_new_window": "New window",
"lightbox_toggle_sidebar": "Toggle sidebar"
}
I am able to calculate discount on the button click, BUT i have hardcoded the discount rate.
I want to select discount rate based on the dropdown menu (I don't know how to set dropdown values with different discount rate in this problem)
In the dropdown menu I would like to have values like this:
Type 1 discount
Type 2 discount
Type 3 discount
Here is the respective discount rate for the above drop-down values:
Type 1 discount - 10%
Type 2 discount - 15%
Type 3 discount - 18%
PLZ HELP ME
Ok somehow I was able to add spinner tool on my application.
Now the question is how to select discount rate based on selected value from spinner.
PLZ HELP ME WITH THE CODE
Here is my current code:
MyDC.java
Code:
package com.super.mydc;
import android.app.Activity;
import android.os.Bundle;
import android.widget.ArrayAdapter;
import android.widget.EditText;
import android.widget.Spinner;
import android.widget.TextView;
import android.widget.Button;
import android.view.View;
public class MyDC extends Activity {
private EditText amount1;
private double x=0;
private double y=2.0;
private double z=0;
private TextView tt;
private Button calculate;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle icicle) {
super.onCreate(icicle);
// We want to view some very simple text, so we need a TextView
TextView tv = new TextView(this);
// Put some text to the newly created TextVIew
tv.setText("Test");
// Tell our Application to display the textView
this.setContentView(tv);
super.onCreate(icicle);
setContentView(R.layout.main);
Spinner spinner = (Spinner) findViewById(R.id.spinner);
ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(
this, R.array.planets_array, android.R.layout.simple_spinner_item);
adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
spinner.setAdapter(adapter);
initControls();
}
private void initControls()
{
amount1=(EditText)findViewById(R.id.amount1);
tt=(TextView)findViewById(R.id.tt);
calculate=(Button)findViewById(R.id.calculate);
calculate.setOnClickListener(new Button.OnClickListener()
{public void onClick
(View v) { calculate();}});
}
private void calculate()
{
x=Double.parseDouble(amount1.getText().toString());
z=x-(x*y/100);
tt.setText(Double.toString(z));
}
}
main.xml
Code:
<?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"
>
<Spinner android:layout_width="match_parent" android:layout_height="wrap_content" android:id="@+id/spinner1"></Spinner>
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_marginTop="10dip"
android:text="@string/planet_prompt"
/>
<Spinner
android:id="@+id/spinner"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:prompt="@string/planet_prompt"
/>
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Enter the price"
/>
<EditText android:layout_height="wrap_content" android:id="@+id/amount1" android:text="" android:layout_width="match_parent"></EditText>
<Button android:text="Calculate Result" android:id="@+id/calculate" android:layout_width="wrap_content" android:layout_height="wrap_content"></Button>
<EditText android:layout_height="wrap_content" android:id="@+id/tt" android:text="" android:layout_width="match_parent"></EditText>
</LinearLayout>
strings.xml
Code:
<?xml version="1.0" encoding="utf-8"?>
<resources>
<string name="hello">Hi, MyDC!</string>
<string name="app_name">My, DC</string>
<string name="spinner1">Choose a planet</string>
<string name="planet_prompt">Choose a planet</string>
<string-array name="planets_array">
<item>10% discount A</item>
<item>15% discount B</item>
<item>18% discount C</item>
</string-array>
</resources>
Anyone ? Please Help ?
Im sorry to not be of very much help I studied java as a highschool unfortunately it was senior year and I am good at slacking. I would like to add suggestions though. first off i would try to find someway of implementing a way to get closer increments such as 5 or 1 %. such as a text box. let me sift through your code and see what i can see. are you having specific errors or what. we need some info.
Ok i looked at your code and im having a hard time reading it just because it isnt the norm that I look at. first off ya need to name your variables more recognizable things then x and y. that will make coding immensely more easy. also I am not seeing where you gathered the information from the drop down or spinner. at some point in the code you have to collect the information from the drop down or spinner and use it for the percent. also i didn't see any point where you gave the drop down any values. if you have any questions or anything feel free to pm I have xda app on my phone so even if not im not online ill get a notification on my phone.
{SBR}_L3GION said:
Ok i looked at your code and im having a hard time reading it just because it isnt the norm that I look at. first off ya need to name your variables more recognizable things then x and y. that will make coding immensely more easy. also I am not seeing where you gathered the information from the drop down or spinner. at some point in the code you have to collect the information from the drop down or spinner and use it for the percent. also i didn't see any point where you gave the drop down any values. if you have any questions or anything feel free to pm I have xda app on my phone so even if not im not online ill get a notification on my phone.
Click to expand...
Click to collapse
Hi,
Yes, I know I haven't defined values to drop down because that is the thing I need help with.
I also posted above this:
"Now the question is how to select discount rate based on selected value from spinner.
PLZ HELP ME WITH THE CODE"
I need help - How to define discount rate based on selection of drop down values.
Please help me with the code....
I also tried doing this quite awhile with an app I was writing and then discovered I had not enough experience to with the android system to write the program I should look it up and fix both of our programs but I've had a migraine for days and I'm just getting close to sleeping but when I get a chance I will look up giving values to the drop down and collecting them unless you want to google it first.
Sent from my Synergized xda Premium Evo
I have tried to find the solution on google but didn't get anything but somehow from google I was able to do (whatever I did above)
thanks, I think that would be great, if you can test my program on your side by that we both will be on the same page.
That's fine, you can test it whenever you get some time.
I appreciate your help!
I would setup radio buttons for the discount percentages
0 10% 0 20% etc.
Name each radio button and use a case statement to set a float to it's value:
switch(radioGroupName) {
case 10Percent:
int discountValue = .10
break;
...
Then do something like:
int discountedAmount = usersAmount - (usersAmount * discountValue);
Try this code.
myDC.java
Code:
package com.mydc;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Spinner;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.TextView;
import android.widget.Toast;
public class myDC extends Activity {
double initial_price;
double discount;
double final_price;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Spinner spinner = (Spinner) findViewById(R.id.spinner1);
ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(
this, R.array.discount, android.R.layout.simple_spinner_item);
adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
spinner.setAdapter(adapter);
spinner.setOnItemSelectedListener(new OnItemSelectedListener(){
@Override
public void onItemSelected(AdapterView<?> parent, View view, int pos, long id) {
if (pos==0){
discount=10;
}
else if (pos==1){
discount=15;
}
else if (pos==2){
discount=18;
}
}
@Override
public void onNothingSelected(AdapterView<?> arg0) {
// TODO Auto-generated method stub
}
});
Button calculate = (Button) findViewById(R.id.calculate);
calculate.setOnClickListener(new OnClickListener(){
@Override
public void onClick(View v) {
EditText amount1 = (EditText) findViewById(R.id.amount1);
if (amount1.length()>0 ) {
initial_price=Double.parseDouble(amount1.getText().toString());
TextView final_price_text = (TextView) findViewById(R.id.final_price);
final_price=initial_price-(initial_price*discount/100);
final_price_text.setText("Final Price : "+final_price);
}
else {
Toast.makeText(getBaseContext(), "Please enter price", Toast.LENGTH_SHORT).show();
}
}
});
}
}
main.xml
Code:
<?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">
<Spinner
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/spinner1"></Spinner>
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Enter the price" />
<EditText
android:layout_height="wrap_content"
android:id="@+id/amount1"
android:text=""
android:layout_width="match_parent"
android:numeric="decimal"></EditText>
<Button
android:text="Calculate Result"
android:id="@+id/calculate"
android:layout_width="wrap_content"
android:layout_height="wrap_content"></Button>
<TextView
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceLarge"
android:layout_width="fill_parent"
android:id="@+id/final_price"></TextView>
</LinearLayout>
strings.xml
Code:
<?xml version="1.0" encoding="utf-8"?>
<resources>
<string name="hello">Hello World, main!</string>
<string name="app_name">myDC</string>
<string-array name="discount">
<item>10% discount A</item>
<item>15% discount B</item>
<item>18% discount C</item>
</string-array>
</resources>
Re: Need Help
Hello nemoc 23 ,
Firstly thank you very much for replying back with a solution.
It did work and solved my problem upto some extend.
Now what I only want 2 things to be done:
1) Right now, if we enter price in decimal or anything, if the final result is in decimal, it is being displayed as EXACT something like 99.9999999
How to limit the RESULT upto 2 decimal points only ?
2) What I am trying to do is to have this calculator on 3 different pages (in each page I will just modify the discounted rate). So I want a homepage (which will work as MENU) with 3 or 4 buttons and each button should be connected with specific page that will have ITS OWN above discount calculator.
Could you please show me how to create a homepage screen (which will work as MENU) and 3 or 4 buttons on it which are linked with different pages (in each page you can copy the same above calculator and I will modify the rate by myself)
thank you
Why 3 pages? Just do this:
Enter discount amount: ___________
Enter discount rate:______
Discounted Amount: ___________
Easy peasy.
Rootstonian said:
Why 3 pages? Just do this:
Enter discount amount: ___________
Enter discount rate:______
Discounted Amount: ___________
Easy peasy.
Click to expand...
Click to collapse
I know it is easy but it is not what I am looking for. My requirement is what I posted above. Thanks
Help
Hello nemoc 23 ,
Just giving you an update. I did try the tutorial you asked me to try. I am having some problem in it which you can see here: http://forum.xda-developers.com/showthread.php?p=15612542
Coming back my question (this calculator topic) - I created a screen layout to give you an idea what I want to do and need your help with.
This is what I want to do:
In this each button click will open separate page (or I guess it is called activity). I have mentioned on button what each button will open.
Please help me. thanks
Intent i = new Intent(this, calculator1.class);
startActivity(i);
You are still better off creating just ONE new Activity and passing to it which calculator you want to run. It is poor programming to code 3 activities when one will suffice. You'll need "extras" to do this.
Need Help
Ok somehow I was able to code for this problem but I am not getting desired output.
I have 3 buttons on my welcome screen "calculator", "calculator2", "exit" - My buttons are not working, I don't know why.
**Below is my complete code / programs:**
**welcome.java**
Code:
package com.testcalculator;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
public class welcome extends Activity implements OnClickListener
{
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.welcome1);
//////// MENU //////////
Button playBtn = (Button) findViewById(R.id.playBtn);
playBtn.setOnClickListener(this);
Button playBtn2 = (Button) findViewById(R.id.playBtn);
playBtn2.setOnClickListener(this);
Button exitBtn = (Button) findViewById(R.id.exitBtn);
exitBtn.setOnClickListener(this);
}
/**
* Listener for game menu
*/
public void onClick(View v) {
Intent i;
switch (v.getId()){
case R.id.playBtn :
i = new Intent(this, testcalculator.class);
startActivity(i);
break;
case R.id.playBtn2 :
i = new Intent(this, testcalculator2.class);
startActivity(i);
break;
case R.id.exitBtn :
finish();
break;
}
}
}
**welcome1.xml**
Code:
<?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"
>
<Button
android:id ="@+id/playBtn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Calculator"
/>
<Button
android:id ="@+id/playBtn2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Calculator2"
/>
<Button
android:id ="@+id/exitBtn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Exit"
/>
</LinearLayout>
**testcalculator.java**
Code:
package com.testcalculator;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Spinner;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.TextView;
import android.widget.Toast;
public class testcalculator extends Activity {
double initial_price;
double discount;
double final_price;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Spinner spinner = (Spinner) findViewById(R.id.spinner1);
ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(
this, R.array.discount, android.R.layout.simple_spinner_item);
adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
spinner.setAdapter(adapter);
spinner.setOnItemSelectedListener(new OnItemSelectedListener(){
@Override
public void onItemSelected(AdapterView<?> parent, View view, int pos, long id) {
if (pos==0){
discount=10;
}
else if (pos==1){
discount=15;
}
else if (pos==2){
discount=18;
}
}
@Override
public void onNothingSelected(AdapterView<?> arg0) {
// TODO Auto-generated method stub
}
});
Button calculate = (Button) findViewById(R.id.calculate);
calculate.setOnClickListener(new OnClickListener(){
@Override
public void onClick(View v) {
EditText amount1 = (EditText) findViewById(R.id.amount1);
if (amount1.length()>0 ) {
initial_price=Double.parseDouble(amount1.getText().toString());
TextView final_price_text = (TextView) findViewById(R.id.final_price);
final_price=initial_price-(initial_price*discount/100);
final_price_text.setText("Final Price : "+final_price);
}
else {
Toast.makeText(getBaseContext(), "Please enter price", Toast.LENGTH_SHORT).show();
}
}
});
}
}
**testcalculator.xml**
Code:
<?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"
>
<Spinner
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/spinner1"></Spinner>
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Enter the price" />
<EditText
android:layout_height="wrap_content"
android:id="@+id/amount1"
android:text=""
android:layout_width="match_parent"
android:numeric="decimal"></EditText>
<Button
android:text="Calculate Result"
android:id="@+id/calculate"
android:layout_width="wrap_content"
android:layout_height="wrap_content"></Button>
<TextView
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceLarge"
android:layout_width="fill_parent"
android:id="@+id/final_price"></TextView>
</LinearLayout>
**testcalculator2.java**
Code:
package com.testcalculator;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Spinner;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.TextView;
import android.widget.Toast;
public class testcalculator2 extends Activity {
double initial_price;
double discount2;
double final_price2;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Spinner spinner = (Spinner) findViewById(R.id.spinner2);
ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(
this, R.array.discount2, android.R.layout.simple_spinner_item);
adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
spinner.setAdapter(adapter);
spinner.setOnItemSelectedListener(new OnItemSelectedListener(){
@Override
public void onItemSelected(AdapterView<?> parent, View view, int pos, long id) {
if (pos==0){
discount2=20;
}
else if (pos==1){
discount2=25;
}
else if (pos==2){
discount2=28;
}
}
@Override
public void onNothingSelected(AdapterView<?> arg0) {
// TODO Auto-generated method stub
}
});
Button calculate2 = (Button) findViewById(R.id.calculate2);
calculate2.setOnClickListener(new OnClickListener(){
@Override
public void onClick(View v) {
EditText amount2 = (EditText) findViewById(R.id.amount2);
if (amount2.length()>0 ) {
initial_price=Double.parseDouble(amount2.getText().toString());
TextView final_price_text = (TextView) findViewById(R.id.final_price2);
final_price2=initial_price-(initial_price*discount2/100);
final_price_text.setText("Final Price : "+final_price2);
}
else {
Toast.makeText(getBaseContext(), "Please enter price", Toast.LENGTH_SHORT).show();
}
}
});
}
}
**testcalculator2.xml**
Code:
<?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"
>
<Spinner
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/spinner2"></Spinner>
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Enter the price" />
<EditText
android:layout_height="wrap_content"
android:id="@+id/amount2"
android:text=""
android:layout_width="match_parent"
android:numeric="decimal"></EditText>
<Button
android:text="Calculate Result"
android:id="@+id/calculate2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"></Button>
<TextView
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceLarge"
android:layout_width="fill_parent"
android:id="@+id/final_price2"></TextView>
</LinearLayout>
**AndroidManifest.xml**
Code:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.testcalculator"
android:versionCode="1"
android:versionName="1.0">
<application android:icon="@drawable/icon" android:label="@string/app_name">
<activity android:name=".welcome"
android:label="@string/app_name">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name=".testcalculator" />
<activity android:name=".testcalculator2" />
</application>
</manifest>
**strings.xml**
Code:
<?xml version="1.0" encoding="utf-8"?>
<resources>
<string name="hello">Hello World, testcalculator!</string>
<string name="app_name">testcalculator</string>
<string-array name="discount">
<item>10% discount A</item>
<item>15% discount B</item>
<item>18% discount C</item>
</string-array>
<string-array name="discount2">
<item>20% discount A</item>
<item>25% discount B</item>
<item>28% discount C</item>
</string-array>
</resources>
**main.xml**
Code:
<?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="fill_parent"
android:layout_height="wrap_content"
android:text="@string/hello"
/>
</LinearLayout>
When I click Button1 "Calculator" - I get error saying ""The application testcalculator (process com.testcalculator) has stopped unexpectedly. Please try again.""
Button2 "Calculator2" doesn't do anything and same with 3rd button "exit:
**Please help me!!!**
You got a couple options. First instead of the startActivity() throw in a Toast so you can see if your onClick() is ok. You can also throw some inline clicklisteners (anonymous inner class) inside the setOnClickListener() instead of using 'this'. I find that way is a bit easier to organize.
Annd might I suggest you follow the Java guidelines for capitalisation of class names. Its confusing when reading your code and seeing testcalculator.class when usually instances of objects are lower case while the class name is capitalized. Like TestCalculator.class
From something awesome
I'm creating an app to keep track of all the messier objects in the sky. I have made a list view in the main activity that holds all the objects, when clicked it should open my other activity and display the objects info.
The program now goes to my second activity no matter what item i choose but doesn't change any of the TextView text without foreclosing.
also how can I recognize what object was clicked and change the information displayed for each object
The main Activity Java looks like this:
Code:
package com.kabluey.messier;
import android.app.ListActivity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.TextView;
public class MessierCatalog extends ListActivity
{
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
// Set string array
setListAdapter(new ArrayAdapter<String>(this, R.layout.main, objects));
ListView lv = getListView();
lv.setTextFilterEnabled(true);
lv.setOnItemClickListener(new OnItemClickListener()
{
public void onItemClick(AdapterView<?> parent, View view,
int position, long id)
{
// When clicked, change text in object info to clicked object name
TextView objText = (TextView) findViewById(R.id.txtObjName);
objText.setText(((TextView) view).getText());
Intent i = new Intent(MessierCatalog.this,Objectinfo.class);
startActivity(i);
}
});
}
static final String[] objects = new String[]
{
"m1", "m2","m3","m4","m5", "m6","m7","m8","m9","m10","m11","m12","m13","m14"
,"m15","m16","m17","m18","m19","m19","m20","m21","m22","m23","m24","m25","m26","m27","m28","m29","m30","m31","m32","m33"
,"m34","m35","m36","m37","m38","m39","m40","m41","m42","m43","m44","m45","m46","m47","m48","m49","m50","m51","m52","m53"
,"m54","m55","m56","m57","m58","m59","m60","m61","m62","m63","m64","m65","m66","m67","m68","m69","m70","m71","m72","m73"
,"m74","m75","m76","m77","m78","m79","m80","m81","m82","m83","m84","m85","m86","m87","m88","m89","m90","m91","m92","m93"
,"m94","m95","m96","m97","m98","m99","m100","m101","m102","m103","m104","m105","m106","m107","m108","m109","m110"
};
}
The second activity has no code in it now and is just an xml layout:
Code:
<?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"
>
<ImageView
android:layout_height="wrap_content"
android:layout_width="fill_parent"
android:src="@drawable/crab"
/>
<TableLayout
android:layout_width="fill_parent"
android:id="@+id/tableLayout1"
android:layout_height="wrap_content"
android:stretchColumns="1">
<TableRow>
<TextView
android:text="Name of Object:"
android:padding="3dip"/>
<TextView
android:id="@+id/txtObjName"
android:text="Object name here"
android:padding="3dip"
android:paddingLeft="5dip" />
android:id="@+id/tableRow1"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</TableRow>
<TableRow>
<TextView
android:text="Apparent Magnitude:"
android:padding="3dip"/>
<TextView
android:id="@+id/txtMagnitude"
android:paddingLeft="5dip"
android:text="9.0"/>
android:id="@+id/tableRow1"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</TableRow>
</TableLayout>
</LinearLayout>
I think it may have to do with your casting of "view" to type "TextView" in you onItemClick override. I don't think the "View" passed to this override is a "TextView" is it? I would think it is the ListView to which you added the OnItemClickListener event handler.
Have some suggestion / tips:
1. This is more organized, also initializes first the Strings
Code:
package com.kabluey.messier;
import android.app.ListActivity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.TextView;
public class MessierCatalog extends ListActivity
{
/** Called when the activity is first created. */
private static final String[] objects = {
"m1", "m2","m3","m4","m5", "m6","m7","m8","m9","m10","m11","m12","m13","m14"
,"m15","m16","m17","m18","m19","m19","m20","m21","m22","m23","m24","m25","m26","m27","m28","m29","m30","m31","m32","m33"
,"m34","m35","m36","m37","m38","m39","m40","m41","m42","m43","m44","m45","m46","m47","m48","m49","m50","m51","m52","m53"
,"m54","m55","m56","m57","m58","m59","m60","m61","m62","m63","m64","m65","m66","m67","m68","m69","m70","m71","m72","m73"
,"m74","m75","m76","m77","m78","m79","m80","m81","m82","m83","m84","m85","m86","m87","m88","m89","m90","m91","m92","m93"
,"m94","m95","m96","m97","m98","m99","m100","m101","m102","m103","m104","m105","m106","m107","m108","m109","m110"
};
}
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
// Set string array
setListAdapter(new ArrayAdapter<String>(this, R.layout.main, objects));
ListView lv = getListView();
lv.setTextFilterEnabled(true);
lv.setOnItemClickListener(new OnItemClickListener()
{
public void onItemClick(AdapterView<?> parent, View view,
int position, long id)
{
// When clicked, change text in object info to clicked object name
TextView objText = (TextView) findViewById(R.id.txtObjName);
objText.setText(((TextView) view).getText());
//Log here!, but im almost sure this is bad
Intent i = new Intent(MessierCatalog.this,Objectinfo.class);
startActivity(i);
}
});
}
2. Could you make a Log.i("APP", ((TextView) view).getText()) and upload output?. That appears like you're setting to your textview, the same text you got from it ( that's actually null / empty )
3. If output it's empty or not output, then this is the answer
Code:
package com.kabluey.messier;
import android.app.ListActivity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.TextView;
public class MessierCatalog extends ListActivity
{
/** Called when the activity is first created. */
private static final String[] objects = {
"m1", "m2","m3","m4","m5", "m6","m7","m8","m9","m10","m11","m12","m13","m14"
,"m15","m16","m17","m18","m19","m19","m20","m21","m22","m23","m24","m25","m26","m27","m28","m29","m30","m31","m32","m33"
,"m34","m35","m36","m37","m38","m39","m40","m41","m42","m43","m44","m45","m46","m47","m48","m49","m50","m51","m52","m53"
,"m54","m55","m56","m57","m58","m59","m60","m61","m62","m63","m64","m65","m66","m67","m68","m69","m70","m71","m72","m73"
,"m74","m75","m76","m77","m78","m79","m80","m81","m82","m83","m84","m85","m86","m87","m88","m89","m90","m91","m92","m93"
,"m94","m95","m96","m97","m98","m99","m100","m101","m102","m103","m104","m105","m106","m107","m108","m109","m110"
};
}
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
// Set string array
setListAdapter(new ArrayAdapter<String>(this, R.layout.main, objects));
ListView lv = getListView();
lv.setTextFilterEnabled(true);
lv.setOnItemClickListener(new OnItemClickListener()
{
public void onItemClick(AdapterView<?> parent, View view,
int position, long id)
{
// When clicked, change text in object info to clicked object name
TextView objText = (TextView) findViewById(R.id.txtObjName);
objText.setText(objects[position]);
Intent i = new Intent(MessierCatalog.this,Objectinfo.class);
startActivity(i);
}
});
}
Also for this cases it's not really needed TableRow, With a Relative layout it's enough, but I don't think that's a prob.
If you have some problem, feel free to contact me through PM.
Good luck, and cheers from colombia.
D4.
solved!
I searched the nets and found a solution, it seems to be working quite well.
thanks for all the help
My click listener now stores the value so both activities can access it
Code:
public void onItemClick(AdapterView<?> parent, View view,int position,long id)
{
Intent i = new Intent(MessierCatalog.this,Objectinfo.class);
//Get ListViews text and store it to "myText"
i.putExtra("myText", (((TextView) view).getText()));
startActivity(i);
}
The ObjectInfo activity now has code to store the ListViews text in String Variable and then set the text..
Code:
public class Objectinfo extends Activity
{
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.objectinfo);
TextView objName = (TextView) findViewById(R.id.txtObjName);
//store ListViews Text to String
String str = getIntent().getStringExtra("myText");
//Set text to stored ListView string
objName.setText(str);
}
}