Develop Reference

Android Apptitude practice app

I want to develop an aptitude app..
for that in my text view i have to display first question .. On clicking next button i have to display second question.. on again clicking same next button third question have to be displayed.. liked that i want to display some 30 questions ..all questions should be displayed in single java file.I Tried to display two questions . but for multiple questions i could not find the code..
package com.example.asl;
import java.util.Arrays;
import java.util.Random;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;
public class Aptitude extends Activity {
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.aptitude);
Button b=(Button) findViewById(R.id.button1);
final TextView tv=(TextView) findViewById(R.id.textView1);
final String Question[]={"what is UR Name","What is ur Age","Whats ur Qualification"};
Button btnNext = (Button) findViewById(R.id.button1);
final TextView cumulos = (TextView) findViewById(R.id.textView1);
//TextView respostas = (TextView)findViewById(R.id.respostas);
Random randPhrase = new Random();
final String[] cum = {"what is UR Name","What is ur Age","Whats ur Qualification"};
//String[] resp = getResources().getStringArray(R.array.resp_cumulos);
String textout = "";
String textresp = "";
//Button btnPrevious = (Button) findViewById(R.id.yourPreviousbutton);
btnNext.setOnClickListener(new OnClickListener(){
public void onClick(View arg0) {
int i = 0;
if(i<cum.length-1){
i+=1;
cumulos.setText(cum[i]);
// respostas.setText(resp[i]);
}
}
});
//btnPrevious.setOnClickListener(new OnClickListener(){
//public void onClick(View arg0) {
//if(i>0){
// i-=1;
// cumulos.setText(cum[i]);
// respostas.setText(resp[i]);
// }
// }
//});
}
}
enter code here

Initializing your counter in your onClick() is always going to reset it
Initialize it outside of onClick() and increment it in onClick() as you are.
public class Aptitude extends Activity {
int i = 0;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.aptitude);
Button b=(Button) findViewById(R.id.button1);
...
}
public void onClick(View arg0) { // rename arg0 to something meaningful
// like v or view for readibility
// int i = 0; remove this guy
if(i<cum.length-1){
i+=1;
cumulos.setText(cum[i]);
If this doesn't fix your problem then please explain what the problem is but I'm sure this part was causing you trouble.

How to implement the prev and next button

I want to implement 2 activities , one is a listview with image and text which works well now. The other one is a onClicklistener when I click any ListItem it will start another activity to show more information, with 1 previous button and next button to see the Prev information or next. However there is something wrong with the button. It can only see the previous one and next one once. Which means you can't click the next button twice. Any suggestions will be appreciated .
Here is my main activity code
package com.example.manchesterunited;
import com.example.manchesterunited.R;
import android.os.Bundle;
import android.app.AlertDialog;
import android.app.ListActivity;
import android.content.Intent;
import android.view.View;
import android.widget.ListView;
import android.widget.Toast;
public class MainActivity extends ListActivity {
static PlayerData data = new PlayerData();
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
CustomAdapter adapter = new CustomAdapter(this);
setListAdapter(adapter);
}
public void onListItemClick(ListView l,View v, int pos, long id){
int playerId = (int)id;
Toast.makeText(getApplicationContext(),"Selected "+data.getName(pos),Toast.LENGTH_SHORT).show();
Intent intent = new Intent(this, InfoActivity.class);
intent.putExtra("playerId", playerId);
startActivity(intent);
}
}
And here is the second activity
package com.example.manchesterunited;
import android.os.Bundle;
import android.app.Activity;
import android.content.Intent;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;
public class InfoActivity extends Activity {
TextView dobText;
TextView pobText;
TextView internationalText;
Button prevButton;
Button nextButton;
PlayerData data = new PlayerData();
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_info);
dobText = (TextView)findViewById(R.id.textView1);
pobText = (TextView)findViewById(R.id.textView2);
internationalText = (TextView)findViewById(R.id.textView3);
prevButton = (Button)findViewById(R.id.prev);
nextButton = (Button)findViewById(R.id.next);
Intent intent = getIntent();
final int playerId = intent.getExtras().getInt("playerId");
dobText.setText("Birthdate:"+String.valueOf(data.getPlayer(playerId).getDob()));
pobText.setText("Birthplace:"+String.valueOf(data.getPlayer(playerId).getPob()));
internationalText.setText("International:"+data.getPlayer(playerId).getInternational());
prevButton.setOnClickListener(new OnClickListener(){
#Override
public void onClick(View v) {
// TODO Auto-generated method stub
int newId = playerId-1;
dobText.setText("Birthdate:"+String.valueOf(data.getPlayer(newId).getDob()));
pobText.setText("Birthplace:"+String.valueOf(data.getPlayer(newId).getPob()));
internationalText.setText("International:"+data.getPlayer(newId).getInternational());
}
});
nextButton.setOnClickListener(new OnClickListener(){
#Override
public void onClick(View v) {
// TODO Auto-generated method stub
int newId = playerId+1;
dobText.setText("Birthdate:"+String.valueOf(data.getPlayer(newId).getDob()));
pobText.setText("Birthplace:"+String.valueOf(data.getPlayer(newId).getPob()));
internationalText.setText("International:"+data.getPlayer(newId).getInternational());
}
});}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.activity_info, menu);
return true;
}
}

You're not updating the playerID.
You're just getting a new ID.
you should put
int newId = playerId+1;
playerID = newId; //insert this line
so that when you click again,
playerID gets updated.

You are always adding just 1 to player ID which will now point to next item. But as soon as you re-click the button it will have the same player ID that was passed through intent. So again it will add in the same value. Make a new variable which will store the current player ID that is visible and keep on incrementing it then you will be able to browse next and vice versa in the previous case.
You can't increment player ID as it has been declared as final, so you can either make a global variable or put a variable in intent and increment it on button clicks.
nextButton.setOnClickListener(new OnClickListener(){
#Override
public void onClick(View v)
{
// TODO Auto-generated method stub
//make newId global then it will work. And keep on updating it when the button is clicked accordingly.
newId = playerId+1;
dobText.setText("Birthdate:"+String.valueOf(data.getPlayer(newId).getDob()));
pobText.setText("Birthplace:"+String.valueOf(data.getPlayer(newId).getPob()));
internationalText.setText("International:"+data.getPlayer(newId).getInternational());
}
});}

Try this on InfoActivity,
private int playerId;
...
...onCreate(...){
...
playerId = intent.getExtras().getInt("playerId");
prevButton.setOnClickListener(new OnClickListener(){
#Override
public void onClick(View v) {
...
playerId--;
dobText.setText("Birthdate:"+String.valueOf(data.getPlayer(playerId).getDob()));
pobText.setText("Birthplace:"+String.valueOf(data.getPlayer(playerId).getPob()));
internationalText.setText("International:"+data.getPlayer(playerId).getInternational());
}
}
nextButton.setOnClickListener(new OnClickListener(){
#Override
public void onClick(View v) {
...
playerId++;
dobText.setText("Birthdate:"+String.valueOf(data.getPlayer(playerId).getDob()));
pobText.setText("Birthplace:"+String.valueOf(data.getPlayer(playerId).getPob()));
internationalText.setText("International:"+data.getPlayer(playerId).getInternational());
}
}
}

Toast giving incorrect answer from Radio box references

I am pretty new to this and are not entirely sure why I am having this problem. From my code:
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.RadioButton;
import android.widget.Toast;
public class MainActivity extends Activity {
RadioButton wavelength1;
RadioButton wavelength2;
double ray;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
wavelength1 = (RadioButton) findViewById(R.id.lowave);
wavelength2 = (RadioButton) findViewById(R.id.hiwave);
Button button = (Button) findViewById(R.id.button);
button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
// TODO Auto-generated method stub
If (wavelength1.isChecked());{
ray = 0.7125;
}
If (wavelength2.isChecked());{
ray = 0.4436;
}
Toast.makeText(MainActivity.this, String.valueOf(ray), Toast.LENGTH_LONG).show();
}
private void If(boolean checked) {
// TODO Auto-generated method stub
}
});
}
}
When I click on either radio boxes, the same output is given in the toast (as 0.4436) when they should be different. I am really at a loss to know what is going on. The app is aimed at API 10 and I am using Eclipse. (I am sure I am missing something).

Remove semicolor(;) at the end of if statement
If (wavelength1.isChecked()); < -- remove this
And also
use small (i) if it is method If();
remove this method
private void If(boolean checked) {
}

How to restore values of a activity when i move to next activity and come back again?

I want the values of edit text restored when user comes back to my first activity?
Please help me out.
Thanks in advance
this is my first activity code for getting user values in edit text
public class IntentActivity extends Activity {
EditText ed1, ed2;
float ed1_val, ed2_val;
#Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
ed1 = (EditText) findViewById(R.id.editText1);
ed2 = (EditText) findViewById(R.id.editText2);
Button next = (Button) findViewById(R.id.button1);
next.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
Intent intent = new Intent(getApplicationContext(),
Second_activity.class);
startActivity(intent);
}
});
}
/** Called when the activity is first created. */
#Override
public void onSaveInstanceState(Bundle savedInstanceState) {
super.onSaveInstanceState(savedInstanceState);
ed1_val = Float.parseFloat(ed1.getText().toString());
ed2_val = Float.parseFloat(ed2.getText().toString());
Log.v("TAG", "inside saved instance");
savedInstanceState.putFloat("ed1", +ed1_val);
savedInstanceState.putFloat("ed2", +ed2_val);
}
#Override
public void onRestoreInstanceState(Bundle savedInstanceState) {
super.onRestoreInstanceState(savedInstanceState);
Log.v("TAG", "inside on restore");
float ed_val = savedInstanceState.getFloat("ed1");
float ed2_val = savedInstanceState.getFloat("ed2");
ed1.setText("" + ed_val);
ed2.setText("" + ed2_val);
}
}
this is my second activity code
public class Second_activity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.second_xml);
Button back = (Button) findViewById(R.id.button1);
back.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
Intent intent = new Intent(getApplicationContext(),
IntentActivity.class);
startActivity(intent);
}
});
}
}

It is not a good idea to start the first activity again on back pressed. Call finish() in the second activity. This will lead to the resume of the first activity which is what you need.
back.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
finish(); }
});
}

You don't need neither onSaveInstanceState nor onRestoreInstanceState.
Just call finish in the onClick listener for the button in the second Activity:
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
public class IntentActivity extends Activity {
EditText ed1, ed2;
float ed1_val, ed2_val;
#Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
ed1 = (EditText) findViewById(R.id.editText1);
ed2 = (EditText) findViewById(R.id.editText2);
Button next = (Button) findViewById(R.id.button1);
next.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
Intent intent = new Intent(getApplicationContext(),
Second_activity.class);
startActivity(intent);
}
});
}
}
This is the second one:
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
public class Second_activity extends Activity {
// TODO Auto-generated method stub
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.second_xml);
Button back = (Button) findViewById(R.id.button1);
back.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
finish();
}
});
}
}
That way you are resuming the previous Activity instead of starting new one.
If you need to pass data between them you could use startActivityForResult / onActivityResult and setResult methods:
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;
import android.widget.EditText;
public class IntentActivity extends Activity {
private static final int GET_VALUES_REQUEST_ID = 1;
public static final String FIRST_VALUE_ID = "first_value_id";
public static final String SECOND_VALUE_ID = "second_value_id";
private static final float DEFAULT_VALUE = 0;
EditText ed1, ed2;
float ed1_val, ed2_val;
#Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
ed1 = (EditText) findViewById(R.id.editText1);
ed2 = (EditText) findViewById(R.id.editText2);
Button next = (Button) findViewById(R.id.button1);
next.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
Intent intent = new Intent(getApplicationContext(),
Second_activity.class);
startActivityForResult(intent, GET_VALUES_REQUEST_ID);
}
});
}
#Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
switch (requestCode) {
case GET_VALUES_REQUEST_ID: {
if (Activity.RESULT_OK == resultCode) {
ed1_val = data.getFloatExtra(FIRST_VALUE_ID, DEFAULT_VALUE);
ed2_val = data.getFloatExtra(SECOND_VALUE_ID, DEFAULT_VALUE);
setValues();
}
break;
}
}
super.onActivityResult(requestCode, resultCode, data);
}
protected void setValues() {
ed1.setText(Float.toString(ed1_val));
ed2.setText(Float.toString(ed2_val));
}
}
The second activity could be something like that:
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 Second_activity extends Activity {
// TODO Auto-generated method stub
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.second_xml);
Button back = (Button) findViewById(R.id.button1);
back.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
Intent data = new Intent();
data.putExtra(IntentActivity.FIRST_VALUE_ID, 324f);
data.putExtra(IntentActivity.SECOND_VALUE_ID, 32234f);
setResult(Activity.RESULT_OK, data);
finish();
}
});
}
}
This is a very basic example so I just hardcoded some return values - please implement something more meaningful.
Beside that you could avoid using underscores as word separator in class names - camel case is much more accepted as name convention.

just finish the second activity don't start it via intent.
When you finish the second activity first activity will be automatically resumed,

you can go for overriding protected void onSaveInstanceState(Bundle outState) and protected void onRestoreInstanceState(Bundle savedInstanceState)
Here is an example
Remember it will work when you will not finish your previous activity.Do this in your first activity.

You are starting a new activity by pressing back button on Second Activity. The new activity instance is not the previous one that has started the Second Activity hence onRestoreInstanceState callback is not getting called.

Its easy if you do not need to send data back to the first activity. How do send back data without using an intent.

How to set numeric value in EditText?

I want to make a simple calculator My code is below:
package som.dev.android.calc;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
public class CalcApp extends Activity {
/** Called when the activity is first created. */
Button addValues, subValues, equalsValue;
EditText inputValue;
int inputNum = 0;
public int value1;
public int value2;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
// initializing Views
inputValue = (EditText) findViewById(R.id.editText1);
addValues = (Button) findViewById(R.id.addBtn);
subValues = (Button) findViewById(R.id.subBtn);
equalsValue = (Button) findViewById(R.id.equalsBtn);
// adding onClick Listeners
addValues.setOnClickListener(new View.OnClickListener() {
public void onClick(View arg0) {
// TODO Auto-generated method stub
pressed = true;
value1 = Integer.parseInt(inputValue.getText().toString());
inputValue.setText("");
}
});
equalsValue.setOnClickListener(new View.OnClickListener() {
public void onClick(View arg0) {
// TODO Auto-generated method stub
value2 = Integer.parseInt(inputValue.getText().toString());
int result = value1+value2;
inputValue.setText(result);// There an exception occurs....
}
});
}
}
But it does not sets result to Edittext in my app and an exception occurs and message comes Unfortunately app is colsed some thing like that so please any one tell me the solution of this problem

use this inputValue.setText(""+result);instead of inputValue.setText(result);// There an exception occurs....
just conversion integer into string

The reason you get an exception is that the EditText thinks you are setting a resource id. You need to convert the integer to a string yourself Integer.toString(result) before using it in the EditText Object. http://developer.android.com/reference/android/widget/TextView.html

change Following Line:-
inputValue.setText(result);
to
inputValue.setText(String.Valueof(result));
then your error is solved.