Develop Reference

Having a button return the string value of a second spinner

I have a fragment that loads 3 spinners and a button. The list array of the second and third spinner is determined by the value of spinner 1 so when you change spinner 1, the arrays of spinners 2 and 3 change on select.
This works but I'm now struggling to retrieve the string value (and ultimately the relative numerical value) of spinner 2 on the click of the button.
In order to test my code I'm just using Toast to display the string.
The ultimate goal is to have a calculation in the background (e.g. spinner 2 multiplied by spinner 3) but when I use OnClick, the string of spinner 2 at time of onCreate is displayed.
I have tried to put a switch in OnItemSelectedListener to attribute this to both spinners but it's not worked.
Really, I want to click the button and the string of spinner 2 is displayed in toast.
Here's my code:
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.Spinner;
import android.widget.Toast;
public class Convertor extends Fragment {
public Convertor() {
// Required empty public constructor
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
final View view=inflater.inflate(R.layout.convertor_1, container, false);
String [] values_conversion = {"Convert1","Convert2",};
final Spinner spinner1 = view.findViewById(R.id.spinner1);
final Spinner spinner2 = view.findViewById(R.id.spinner2);
final Spinner spinner3 = view.findViewById(R.id.spinner3);
final ArrayAdapter adapter1 = ArrayAdapter.createFromResource(getActivity(), R.array.array1_array, android.R.layout.simple_spinner_item);
adapter1.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
final ArrayAdapter adapter2 = ArrayAdapter.createFromResource(getActivity(), R.array.array2_array, android.R.layout.simple_spinner_item);
adapter2.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
final ArrayAdapter adapter3 = ArrayAdapter.createFromResource(getActivity(), R.array.array3_array, android.R.layout.simple_spinner_item);
adapter1.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
final ArrayAdapter adapter4 = ArrayAdapter.createFromResource(getActivity(), R.array.array4_array, android.R.layout.simple_spinner_item);
adapter1.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
spinner2.setAdapter(adapter1);
spinner3.setAdapter(adapter3);
ArrayAdapter<String> adapter = new ArrayAdapter<String>(this.getActivity(), android.R.layout.simple_spinner_item, values_conversion);
adapter.setDropDownViewResource(android.R.layout.simple_dropdown_item_1line);
spinner1.setAdapter(adapter);
spinner1.setSelection(0);
spinner1.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
public void onItemSelected(AdapterView<?> arg0, final View view, int position,
long id) {
switch (position) {
case 0:
spinner2.setAdapter(adapter1);
spinner3.setAdapter(adapter3);
break;
case 1:
spinner2.setAdapter(adapter2);
spinner3.setAdapter(adapter4);
break;
}
}
#Override
public void onNothingSelected(AdapterView<?> parent) {
}
});
final String from_unit1 = spinner2.getSelectedItem().toString(); // This gives the from string
final Button convert_btn = (Button) view.findViewById(R.id.convert_btn);
convert_btn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Toast toast = Toast.makeText(getContext(), from_unit1, Toast.LENGTH_SHORT);
toast.show();
}
});
return view;
}
}

try this
final Button convert_btn = (Button) view.findViewById(R.id.convert_btn);
convert_btn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
String from_unit1 = spinner2.getSelectedItem().toString();
Toast toast = Toast.makeText(getContext(), from_unit1, Toast.LENGTH_SHORT);
toast.show();
}
});

Array Adapter is not functioning Correctly

I am using an array adapter to populate a listview from user input. The array adpter will not work however and crashes the app. I don't no why it does this and I would appreciate if anyone could explain why. Below is my class and the error I get.
My Class
import android.content.Intent;
import android.os.Bundle;
import android.app.Activity;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.Toast;
public class AddScore extends AppCompatActivity {
private ListView lv;
private EditText player;
private EditText description;
private EditText winner;
private EditText game;
private Button btn3;
private String TAG = "Hannah";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_add_score);
// MySQLiteHelper db = new MySQLiteHelper(this);
lv = (ListView) findViewById(R.id.lv);
player = (EditText) findViewById(R.id.player);
description = (EditText) findViewById(R.id.description);
winner = (EditText) findViewById(R.id.winner);
game = (EditText) findViewById(R.id.game);
btn3 = (Button) findViewById(R.id.button3);
btn3.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
List<String> sLog = new ArrayList<>();
MySQLiteHelper Helper = new MySQLiteHelper(view.getContext());
List sLogs = Helper.getAllScores();
sLog.add(player.getText().toString().trim());
sLog.add(description.getText().toString().trim());
sLog.add(winner.getText().toString().trim());
sLog.add(game.getText().toString().trim());
for (int i = 0; i < sLog.size(); i++) {
Score score = new Score();
sLog.add(score.toString());
}
//ListView listView = (ListView) findViewById(R.id.lv);
ArrayAdapter<String> arrayAdapter = new ArrayAdapter<>(this, android.R.layout.simple_list_item_1, sLog);
Log.d(TAG, "**************************");
lv.setAdapter(arrayAdapter);
Score score = new Score();
arrayAdapter.add(String.valueOf(score));
Toast.makeText(AddScore.this, "Button Clicked", Toast.LENGTH_SHORT).show();
}
});
}
}
Error
Error:(62, 53) error: cannot infer type arguments for ArrayAdapter<>

Change
ArrayAdapter<String> arrayAdapter = new ArrayAdapter<>(this, android.R.layout.simple_list_item_1, sLog);
to
ArrayAdapter<String> arrayAdapter = new ArrayAdapter<>(getActivity(), android.R.layout.simple_list_item_1, sLog);
You need to pass the context. As this is inside a closure, you need to explicitly getActivity() as this will be not get you the context.

Because using only this refers to View.OnClickListener class not activity class. And ArrayAdapter<> requires context as first argument which can be provided here by activity and not View.OnClickListener.
So try like this:
ArrayAdapter<String> arrayAdapter = new ArrayAdapter<>(AddScore.this, android.R.layout.simple_list_item_1, sLog);
Log.d(TAG, "**************************");
lv.setAdapter(arrayAdapter);

Why is my program crashing when i click on the button?

I am doing my coursework for computing and every time i try and run my app and go onto this activity it crashes and says unfortunately activity has stopped. If i delete the last part of the code from the line (-----) down, the activity appears and works. But with it, it doesn't work. Does anyone know why this is the case and how i could fix it.
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.LinearLayout;
import android.widget.Spinner;
import android.widget.TextView;
public class BedroomDoorSigns extends AppCompatActivity {
private String[] wood;
private Spinner spinner;
private String[] colour;
private String[] size;
private Button mButton;
private LinearLayout mLayout;
private EditText mEditText;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.content_bedroom_door_signs);
wood = getResources().getStringArray(R.array.wood_list);
spinner = (Spinner) findViewById(R.id.wood_spinner);
colour = getResources().getStringArray(R.array.colour_list);
spinner = (Spinner) findViewById(R.id.colour_spinner);
size = getResources().getStringArray(R.array.size_list);
spinner = (Spinner) findViewById(R.id.size_spinner);
Button Buttons = (Button) findViewById(R.id.Cart);
mLayout = (LinearLayout) findViewById(R.id.linearLayout);
mEditText = (EditText) findViewById(R.id.editText);
mButton = (Button) findViewById(R.id.button);
mButton.setOnClickListener(onClick());
TextView textView = new TextView(this);
textView.setText("New text");
ArrayAdapter<String> dataAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item, wood);
dataAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
spinner.setAdapter(dataAdapter);
ArrayAdapter<String> dataAdapter2 = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item, colour);
dataAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
spinner.setAdapter(dataAdapter2);
ArrayAdapter<String> dataAdapter3 = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item, size);
dataAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
spinner.setAdapter(dataAdapter3);
}
public View.OnClickListener onClick() {
return new View.OnClickListener() {
public void onClick(View v) {
mLayout.addView(createNewTextView(mEditText.getText().toString()));
}
};
}
public TextView createNewTextView(String text) {
final ViewGroup.LayoutParams lparams = new ViewGroup.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT);
final TextView textView = new TextView(this);
textView.setLayoutParams(lparams);
textView.setText("BASKET: " + text);
return textView;
}
}
Thank you

try like this
mButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
mLayout.addView(createNewTextView(mEditText.getText().toString()));
}
});

java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.Button.setOnClickListener(android.view.View$OnClickListener)' on a null object reference at com.example.emily.activity414timber.BedroomDoorSigns.onCreate(BedroomDoorSigns.java:41) at
your button object (mButton) is null and so it is throwing 'nullpointerexception' when you call 'setOnclickListner' method on that object

Item from listview saved state of previously item

I am a new android developer and I need your help.
I created a simple listview. I add items in this listview through the keyboard.
Moreover I add action on item. When user click "OK" the app will be strike out text and set background green.
But when I add the next item,I see that it applies that strike out and background option from previously item.
Can you advise me what I need to do in this situation? How to improve it?
My Code:
package com.example.boytsov.foodbasketapp;
import android.app.Activity;
import android.graphics.Color;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
import java.util.ArrayList;
/**
* Created by Boytsov on 23.07.2015.
*/
public class ProductList extends Activity implements View.OnClickListener,AdapterView.OnItemClickListener,AdapterView.OnItemLongClickListener {
EditText myText;
ListView lvMain;
ArrayList<String> catnames;
ArrayAdapter<String> adapter;
Button button;
final String LOG_TAG = "myLogs";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.productlist);
lvMain = (ListView) findViewById(R.id.lvMain);
myText = (EditText) findViewById(R.id.editText);
button=(Button)findViewById(R.id.button);
catnames= new ArrayList<String>();
// создаем адаптер
adapter = new ArrayAdapter<String>(this,
android.R.layout.simple_list_item_1, catnames);
// присваиваем адаптер списку
lvMain.setAdapter(adapter);
lvMain.setOnItemClickListener(this);
lvMain.setOnItemLongClickListener(this);
// Прослушиваем нажатия клавиш
button.setOnClickListener(this);
}
#Override
public void onClick(View view) {
switch (view.getId()){
case R.id.button :
catnames.add(0, myText.getText().toString());
adapter.notifyDataSetChanged();
myText.setText("");
myText.setBackgroundColor(Color.TRANSPARENT);
myText.setPaintFlags(0);
break;
}
}
#Override
public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
Log.d(LOG_TAG, "itemClick: position = " + i + ", id = "
+ l);
TextView textview= (TextView) view;
if (textview.getPaintFlags() != 16){
textview.setPaintFlags(16);
textview.setBackgroundColor(Color.parseColor("#77dd77"));
Toast.makeText(this, "Куплено", Toast.LENGTH_SHORT).show();
} else {
textview.setPaintFlags(0);
textview.setBackgroundColor(Color.TRANSPARENT);
}
}
#Override
public boolean onItemLongClick(AdapterView<?> parent, View view, int position, long id) {
catnames.remove(position);
adapter.notifyDataSetChanged();
Toast.makeText(this, "Удалено", Toast.LENGTH_SHORT).show();
Log.d(LOG_TAG, "onItemClick: position = " + position + ", id = "
+ id);
return true;
}
}

every listview item has its own R.id.editText so having one global myText = (EditText) findViewById(R.id.editText); does not work.
Instead you have to find the edit in the onClick handler
#Override
public void onClick(View view) {
switch (view.getId()){
case R.id.button : {
// EditText myText = (EditText) view.findViewById(R.id.editText);
TextView myText = (TextView) view;
catnames.add(0, myText.getText().toString());
adapter.notifyDataSetChanged();
myText.setText("");
myText.setBackgroundColor(Color.TRANSPARENT);
myText.setPaintFlags(0);
}
break;
}
}
[Update 28.7.2015]
Your adapter is using android.R.layout.simple_list_item_1 :
adapter = new ArrayAdapter<String>(this,
android.R.layout.simple_list_item_1, catnames);
wich does not have an EditText with id R.id.editText. therefore you get an exception.
simple_list_item_1 is a textview. using
TextView myText = (TextView) view;
might work

ArrayAdapter constructer undefined

The following code gives me this error: The constructor ArrayAdapter(TrainingDetails, int, String[]) is undefined. How to rectify it? Please help. Here I am trying to retrieve the value of the selected spinner and store it in another string.
package com.example.fragments;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.EditText;
import android.widget.Spinner;
import android.widget.Toast;
import android.widget.AdapterView.OnItemSelectedListener;
import com.example.R;
public class TrainingDetails extends BaseFragment
{
View view;
private EditText nameEdt;
private Spinner trainingTypes;
private Spinner trainerProfile;
String data1[] = {"1", "2", "3"};
String data2[] = {"a", "b", "c"};
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
view=inflater.inflate(R.layout.training_details, container,false);
nameEdt = (EditText) view.findViewById(R.id.name_edt);
trainingTypes = (Spinner) view.findViewById(R.id.trainingtypes_spn);
ArrayAdapter<String> adapter_state = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item, data1);
adapter_state.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
trainingTypes.setAdapter(adapter_state);
trainingTypes.setOnItemSelectedListener(new OnItemSelectedListener()
{
#Override
public void onItemSelected(AdapterView<?> arg0, View arg1, int arg2, long arg3)
{
int index = arg0.getSelectedItemPosition();
String selectedItem = data1[index];
}
#Override
public void onNothingSelected(AdapterView<?> arg0)
{
}
});
trainerProfile = (Spinner) view.findViewById(R.id.trainerprofile_spn);
return view;
}
}

change
ArrayAdapter<String> adapter_state = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item, data1);
to
ArrayAdapter<String> adapter_state = new ArrayAdapter<String>(getActivity(), android.R.layout.simple_spinner_item, data1);
in Fragment you'll get Context by using getActivity()

For ArrayAdapter you need to pass Context
change this
ArrayAdapter<String> adapter_state = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item, data1);
into
ArrayAdapter<String> adapter_state = new ArrayAdapter<String>(getActivity(), android.R.layout.simple_spinner_item, data1);

The first parameter of ArrayAdapter is a Context object not an instance of a Fragment. Change
new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item, data1);
with
new ArrayAdapter<String>(getActivity(), android.R.layout.simple_spinner_item, data1);