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Android java code to add + and - button beside edittext

for(int i=0;i<j.size();i++)
{
TableLayout.LayoutParams tableRowParams=
new TableLayout.LayoutParams
(TableLayout.LayoutParams.FILL_PARENT,TableLayout.LayoutParams.WRAP_CONTENT);
JsonObject jb = (JsonObject) j.get(i);
String item = jb.get("item").getAsString();
String unit = jb.get("unit").getAsString();;
String price = jb.get("price").getAsString();;
TableRow tbrow1 = new TableRow(this);
TextView tv01 = new TextView(this);
tv01.setText(item);
tv01.setTextColor(Color.BLACK);
tbrow1.addView(tv01);
TextView tv11 = new TextView(this);
tv11.setText(unit);
tv11.setTextColor(Color.BLACK);
tbrow1.addView(tv11);
TextView tv21 = new TextView(this);
tv21.setText(price);
tv21.setTextColor(Color.BLACK);
tbrow1.addView(tv21);
Button button = new Button(this);
button.setText("+");
button.setTag(item);
tbrow1.addView(button);
final String id_ = (String) button.getTag();
EditText edText = new EditText(this);
edText.setInputType(InputType.TYPE_CLASS_NUMBER);
//edText.setText(0);
tbrow1.addView(edText);
Button button1 = new Button(this);
button1.setText("-");
button.setTag(item);
tbrow1.addView(button1);
final String id1_ = (String) button.getTag();
button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Toast.makeText(getBaseContext(), "button clicked for "+id_, Toast.LENGTH_LONG).show();
}
});
button1.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Toast.makeText(getBaseContext(), "button clicked for "+id1_, Toast.LENGTH_LONG).show();
}
})
}
I'm developing Android app for grocery shop . I'm getting itms details in json
Depending on items number I'm creating dynamic rows.
Now I want to add + and - button in each row .
I want it programmatically
How to to do it.
Example: + - button in zomato while adding food to cart .
As i click + or - button that corresponding item number should increment/decrement

You can use this library. It is a simple Android library to implement a number counter with increment and decrement buttons.
https://github.com/ashik94vc/ElegantNumberButton

try this,
MainActivity.java
public class MainActivity extends AppCompatActivity {
TextView textViewCount;
int count=1;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
textViewCount=findViewById(R.id.textViewCount);
textViewCount.setText(""+count);
}
public void itemSubtractClick(View view) {
if (count>0)
textViewCount.setText(""+count--);
else
Toast.makeText(this, "not allowed", Toast.LENGTH_SHORT).show();
}
public void itemAddClick(View view) {
textViewCount.setText(""+count++);
}
}
activity_main.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center">
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="#drawable/shape"
android:gravity="center"
android:orientation="horizontal">
<ImageView
android:onClick="itemSubtractClick"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="#drawable/icon_subtract" />
<TextView
android:id="#+id/textViewCount"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="#17F44336"
android:padding="10dp"
android:text="2"
android:textSize="18sp" />
<ImageView
android:onClick="itemAddClick"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="#drawable/icon_add" />
</LinearLayout>

How can i make a button change the text on a screen? [closed]

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I am new to Android and Java programming and I am trying to make an app where it starts out with "Goodbye World" and a button underneath. i am trying to make it so that when you press the button "Goodbye World" changes to "Hello World". Does anyone know how you can do this?

Basic idea to do this would be like this
TextView text = (TextView) findViewById(R.id.textview); // change with your TextView id
text.setText("Goodbye World");
Button btn = (Button) findViewById(R.id.button); // change with your button id
btn.setOnClickListener( new View.OnClickListener() {
#Override
public void onClick(View v) {
text.setText("Hello World");
}
});

if you want to change the text of Button
public void on Create(Bundle saved Instance State) {
super.onCreate(savedInstanceState);
set Content View(R.layout.main);
btn=(Button) findViewById(R.id.button);
btn.setOnClickListener(new OnclickListener(){
#override
public void onClick(view view){
btn.setText("Hello World");
}
});

Your Java file will look like this:
`package com.example.button;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
public class MainActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
final TextView textView = (TextView)findViewById(R.id.textView);
Button button = (Button)findViewById(R.id.button1);
button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
textView.setText("Hello World");
}
});
}
}
Your XML file will look like this:
<TextView
android:id="#+id/textView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:text="#string/hello_world" />
<Button
android:id="#+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="#+id/textView"
android:layout_centerHorizontal="true"
android:text="#string/a" />
`

The answer for your question is here.
activity_main.xml:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<TextView
android:id="#+id/tv1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Goodbye World" />
<TextView
android:id="#+id/tv2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Hello World"
android:visibility="gone" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:onClick="click"
android:text="click" />
</LinearLayout>
on click of button:
public void click(View v){
text1.setVisibility(TextView.GONE);
text2.setVisibility(TextView.VISIBLE);
}

TextView isn't updating in Android

I'm making a simple "novelty" app that counts how many sneezes are done, it's more of a fun app that builds up experience until I do my huge project during the summer. I have two buttons, one adds a sneeze and the other clears how many sneezes there currently are. It holds the highest number of sneezes that there were previously. The problem is, the TextViews never update, they only initialize to zero. I used a Toast.makeText() to make sure that the buttons are working (they are). Any help is appreciated. Thanks
Java code:
public class MainActivity extends ActionBarActivity {
private int record_number = 0;
private int current_number = 0;
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.fragment_main);
Button add_one = (Button) findViewById(R.id.addone);
Button clear_1 = (Button) findViewById(R.id.clear);
add_one.setOnClickListener(new OnClickListener()
{
public void onClick(View v)
{
current_number += 1;
Toast.makeText(MainActivity.this, "Button Clicked " + current_number, Toast.LENGTH_SHORT).show();
}
});
clear_1.setOnClickListener(new OnClickListener() {
public void onClick(View v)
{
current_number = 0;
Toast.makeText(MainActivity.this, "Button Clicked", Toast.LENGTH_SHORT).show();
}
});
TextView rec_text = (TextView) findViewById(R.id.record_num);
TextView cur_text = (TextView) findViewById(R.id.current_num);
if (current_number >= record_number)
{
record_number = current_number;
}
rec_text.setText(String.valueOf(record_number));
cur_text.setText(String.valueOf(current_number));
}
}
XML:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
android:paddingBottom="#dimen/activity_vertical_margin"
tools:context="com.michail.sneezecounter.MainActivity">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceLarge"
android:text="Sneeze Counter"
android:id="#+id/title"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceLarge"
android:text="Record Number of Sneezes:"
android:id="#+id/textView"
android:layout_below="#+id/title"
android:layout_centerHorizontal="true"
android:layout_marginTop="72dp" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Add one Sneeze"
android:id="#+id/addone"
android:layout_alignParentBottom="true"
android:layout_centerHorizontal="true"
android:layout_marginBottom="76dp"/>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Clear Current Number of Sneezes"
android:id="#+id/clear"
android:layout_marginBottom="13dp"
android:layout_alignParentBottom="true"
android:layout_centerHorizontal="true" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceMedium"
android:id="#+id/record_num"
android:layout_below="#+id/textView"
android:layout_centerHorizontal="true"
android:singleLine="false" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceLarge"
android:text="Current Number of Sneezes:"
android:id="#+id/currentLabel"
android:layout_centerVertical="true"
android:layout_alignRight="#+id/textView"
android:layout_alignEnd="#+id/textView" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceMedium"
android:layout_below="#+id/currentLabel"
android:layout_alignLeft="#+id/record_num"
android:layout_alignStart="#+id/record_num"
android:layout_marginTop="21dp"
android:id="#+id/current_num" />
</RelativeLayout>

You need to update the text of the TextViews inside the onClickListeners. In fact, all your logic for counting, clearing, and recording the record needs to be done in your onClickListeners (or methods called by them). Right now you only do it once in onCreate, then never again. You can do this in onCreate:
final TextView cur_text = (TextView) findViewById(R.id.current_num);
add_one.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
current_number += 1;
cur_text.setText(Integer.toString(current_number);
}
});
And similar for the other TextView & onClickListener.

You only set the contents of your TextViews once. You should update them every time you get a click event. Specifically:
add_one.setOnClickListener(new OnClickListener()
{
public void onClick(View v)
{
current_number += 1;
if (current_number >= record_number)
{
record_number = current_number;
rec_text.setText(String.valueOf(record_number));
}
cur_text.setText(String.valueOf(current_number));
}
});
clear_1.setOnClickListener(new OnClickListener() {
public void onClick(View v)
{
current_number = 0;
cur_text.setText(String.valueOf(current_number));
}
});
NOTE: if your variables current_number, record_number, cur_text, and rec_text aren't already declared as class member variables, you'll want to do that do that so that they're accessible once you leave the scope of the method you're doing all this in (I assume it's onCreate(...).

What you are going to need to do here is update the labels during the on click events of the button. You currently only update them on activity create. This doesn't execute every time there is a click. Can I answer any questions about the fixed up version below?
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.fragment_main);
final TextView rec_text = (TextView) findViewById(R.id.record_num);
final TextView cur_text = (TextView) findViewById(R.id.current_num);
Button add_one = (Button) findViewById(R.id.addone);
Button clear_1 = (Button) findViewById(R.id.clear);
add_one.setOnClickListener(new OnClickListener()
{
public void onClick(View v)
{
current_number += 1;
if (current_number >= record_number)
record_number = current_number;
cur_text.setText(String.valueOf(current_number));
rec_text.setText(String.valueOf(record_number));
}
});
clear_1.setOnClickListener(new OnClickListener() {
public void onClick(View v)
{
current_number = 0;
cur_text.setText(String.valueOf(current_number));
rec_text.setText(String.valueOf(record_number));
}
});
cur_text.setText(String.valueOf(current_number));
rec_text.setText(String.valueOf(record_number));
}

Android app - Multiply and divide the user entered values values in the two forms

I'm trying to make an android app, and as I am a total beginner, I am wondering if anyone could help me out with the code.
There will be three boxes to enter different numbers, and I want the app to divide the second value by the first, and then multiply it by the third. And then display the answer on screen.
And the app does have a purpose aha.
So like (b/a)*c

For taking inputs take 3 EditText and take one Button for get Result by Clicking on it.
Follow this
public class result extends Activity
{
private EditText edit1;
private EditText edit2;
private EditText edit3;
public void onCreate(Bundle savedInstanceState)
{
try
{
super.onCreate(savedInstanceState);
setContentView(R.layout.result);
edit1 = (EditText)findViewById(R.id.edit1);
edit2 = (EditText)findViewById(R.id.edit2);
edit3 = (EditText)findViewById(R.id.edit3);
Button click = (Button)findViewById(R.id.btn);
click.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
int a = Integer.parseInt(edit1.getText().toString());
int b = Integer.parseInt(edit2.getText().toString());
int c = Integer.parseInt(edit3.getText().toString());
double result = ((double) a/b)*c;
Toast.makeText(result.this, Double.toString(result),Toast.LENGTH_LONG).show();
}
});
}catch (Exception e) {
e.printStackTrace();
}
}
}
Result.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"
android:background="#fff"
>
<EditText
android:id="#+id/edit1"
android:layout_width="fill_parent"
android:layout_height="40dp"
android:inputType="text"/>
<EditText
android:id="#+id/edit2"
android:layout_width="fill_parent"
android:layout_height="40dp"
android:inputType="text"/>
<EditText
android:id="#+id/edit3"
android:layout_width="fill_parent"
android:layout_height="40dp"
android:inputType="text"/>
<Button
android:id="#+id/btn"
android:layout_width="fill_parent"
android:layout_height="40dp"
android:text="Click"/>
</LinearLayout>

Declare 3 EditTexts in your applications layout, as well as a button, and a TextView. Give them unique id's.
The following code will do what you want. It's very simple, so make sure you don't just copy and paste,and that you understand it. I always find it easier to learn from examples, which is why I'm giving one. I hope it helps.
public class MainActivity extends Activity {
//Declare textviews as fields, so they can be accessed throughout the activity.
EditText mEditText1;
EditText mEditText2;
EditText mEditText3;
TextView mTextView;
Button mButton;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//Bind the EditText views
mEditText1 = (EditText)findViewById(R.id.editText1);
mEditText2 = (EditText)findViewById(R.id.editText2);
mEditText3 = (EditText)findViewById(R.id.editText3);
mTextView = (TextView)findViewById(R.id.textView1);
mButton = (Button)findViewById(R.id.calculateButton);
mButton.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
//When the button is clicked, call the calucate method.
calculate();
}
});
}
public void calculate(){
//get entered texts from the edittexts,and convert to integers.
Double value1 = Double.parseDouble(mEditText1.getText().toString());
Double value2 = Double.parseDouble(mEditText2.getText().toString());
Double value3 = Double.parseDouble(mEditText3.getText().toString());
//do the calculation
Double calculatedValue = (value2/value1)*value3;
//set the value to the textview, to display on screen.
mTextView.setText(calculatedValue.toString());
}
}

int answer=(Integer.parse(editTextB.getText()) /Integer.parse(editTextA.getText())*Integer.parse(editTextC.getText()

Android TextView

Hi I'm new to Android Programming and I'm trying to make a simple program that changes the text by clicking a button. Here's my code:
public class HelloAndroidActivity extends Activity {
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
final Button button_scan = (Button) findViewById(R.id.button_scan);
button_scan.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
buttonBeenPressed();
}
});
}
public void buttonBeenPressed(){
final Button button_scan = (Button) findViewById(R.id.button_scan);
TextView tv_barcode = (TextView)findViewById(R.id.textview_barcode);
if (tv_barcode != null){
tv_barcode.setText("been pressed.");
} else {
button_scan.setText("it's null dawg.");
}
}
}
And my 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"
>
<Button android:text="Scan" android:layout_height="wrap_content" android:layout_width="match_parent" android:id="#+id/button_scan"></Button>
<TextView android:layout_height="wrap_content" android:layout_width="wrap_content" android:text="TextView" android:textAppearance="?android:attr/textAppearanceLarge" android:id="#+id/textview_barcode"></TextView>
</LinearLayout>
However the TextView is returning NULL and i don't know why. Any suggestions? Thanks.

Hmmm i got no problems with your code, runs without any error! Are you working with eclipse? Then try to clean your project.

Looks all correct to me....
Your best bet to debug this may be to run your app on the emulator or a phone and run hierarchyviewer, find your TextView and check the id.

You can use textview or a button. Here is an example with a textview I've found from http://www.ahotbrew.com/android-textview-example/
<TextView
android:text="#string/textview_onclick"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/textview_onclick"
android:layout_below="#+id/textview_center"
android:textSize="25dp"
android:onClick="changeTextColor"
android:clickable="true"/>
In your MainActivity do this
public void changeTextColor (View view)
{
TextView textView = (TextView) view.findViewById(R.id.textview_onclick);
textView.setText("newWord");
}