android Clear Button in a simple counter

android Clear Button in a simple counter - java

I have a counter program for number. I define 3 buttons for Plus, Minus and Clear.
When I use clear button for clear TextView it's good. But after using Plus and Minus it it is Continuation last counter. that is my code.
please Help me.
public class CounterActivity extends Activity {
private Button btnPlus;
private Button btnMinus;
private Button btnClear;
private TextView txtCounter;
int counter = 0;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.counter_menu);
btnPlus = (Button) findViewById(R.id.btnPlus);
btnMinus = (Button) findViewById(R.id.btnMinus);
btnClear = (Button) findViewById(R.id.btnClear);
txtCounter = (TextView) findViewById(R.id.txtCounter);
btnPlus.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View view) {
counter++;
txtCounter.setText(counter + "");
}
});
btnMinus.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View view) {
counter--;
txtCounter.setText(counter + "");
}
});
btnClear.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
txtCounter.setText(0 + "");
}
});
}
}

Change your clear button onClick method as follows:
btnClear.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
counter = 0;
txtCounter.setText(0 + "");
}
});

Related

How do I pass the string from a textview to another texview on the same activity?

I am working with this bingo callboard project in Android Studio. The principle is when I click a number button, it will show on the first textview. When I click the second number button, the first textview will show the current number pressed and the previous string will be passed to the second textview. How would I do this? Screenshot of app included. A sample of the MainActivity.java code is here:
import android.app.Activity;
import android.graphics.drawable.Drawable;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
public class MainActivity extends AppCompatActivity {
private Activity mainActivity;
#Override
protected void onCreate(final Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mainActivity = MainActivity.this;
final Button button1 = findViewById(R.id.b1);
final Button button2 = findViewById(R.id.b2);
final Button button3 = findViewById(R.id.b3);
final Button button4 = findViewById(R.id.b4);
final Button button5 = findViewById(R.id.b5);
final TextView txt = (TextView) findViewById(R.id.presentcall);
final TextView lst = (TextView) findViewById(R.id.lastcall);
button1.setOnClickListener(new View.OnClickListener() {
Drawable background = button1.getBackground();
#Override
public void onClick(View v) {
txt.setText("B1");
if (button1.getText().equals("1"))
{
button1.setText(" 1 ");
button1.setBackgroundResource(R.drawable.onclick_border);
}
else if (button1.getText().equals(" 1 "))
{
button1.setText("1");
button1.setBackground(background);
}
}
});
button2.setOnClickListener(new View.OnClickListener() {
Drawable background = button2.getBackground();
#Override
public void onClick(View v) {
txt.setText("B2");
if (button2.getText().equals("2"))
{
button2.setText(" 2 ");
button2.setBackgroundResource(R.drawable.onclick_border);
}
else if (button2.getText().equals(" 2 "))
{
button2.setText("2");
button2.setBackground(background);
}
}
});
button3.setOnClickListener(new View.OnClickListener() {
Drawable background = button3.getBackground();
#Override
public void onClick(View v) {
txt.setText("B3");
if (button3.getText().equals("3"))
{
button3.setText(" 3 ");
button3.setBackgroundResource(R.drawable.onclick_border);
}
else if (button3.getText().equals(" 3 "))
{
button3.setText("3");
button3.setBackground(background);
}
}
});
button4.setOnClickListener(new View.OnClickListener() {
Drawable background = button4.getBackground();
#Override
public void onClick(View v) {
txt.setText("B4");
if (button4.getText().equals("4"))
{
button4.setText(" 4 ");
button4.setBackgroundResource(R.drawable.onclick_border);
}
else if (button4.getText().equals(" 4 "))
{
button4.setText("4");
button4.setBackground(background);
}
}
});
button5.setOnClickListener(new View.OnClickListener() {
Drawable background = button5.getBackground();
#Override
public void onClick(View v) {
txt.setText("B5");
if (button5.getText().equals("5"))
{
button5.setText(" 5 ");
button5.setBackgroundResource(R.drawable.onclick_border);
}
else if (button5.getText().equals(" 5 "))
{
button5.setText("5");
button5.setBackground(background);
}
}
});
Screenshot

Hey so from what I understand you need to update the lst textview with the data of txt textView. Well you can write a common method which can be called from any button click with the new data. something like this:
public class MainActivity extends AppCompatActivity {
private Activity mainActivity;
#Override
protected void onCreate(final Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mainActivity = MainActivity.this;
final Button button1 = findViewById(R.id.b1);
final Button button2 = findViewById(R.id.b2);
final Button button3 = findViewById(R.id.b3);
final Button button4 = findViewById(R.id.b4);
final Button button5 = findViewById(R.id.b5);
final TextView txt = (TextView) findViewById(R.id.presentcall);
final TextView lst = (TextView) findViewById(R.id.lastcall);
button1.setOnClickListener(new View.OnClickListener() {
Drawable background = button1.getBackground();
#Override
public void onClick(View v) {
txt.setText("B1");
updateTextView("B1");
if (button1.getText().equals("1"))
{
button1.setText(" 1 ");
button1.setBackgroundResource(R.drawable.onclick_border);
}
else if (button1.getText().equals(" 1 "))
{
button1.setText("1");
button1.setBackground(background);
}
}
});
button2.setOnClickListener(new View.OnClickListener() {
Drawable background = button2.getBackground();
#Override
public void onClick(View v) {
txt.setText("B2");
updateTextView("B2");
if (button2.getText().equals("2"))
{
button2.setText(" 2 ");
button2.setBackgroundResource(R.drawable.onclick_border);
}
else if (button2.getText().equals(" 2 "))
{
button2.setText("2");
button2.setBackground(background);
}
}
});
button3.setOnClickListener(new View.OnClickListener() {
Drawable background = button3.getBackground();
#Override
public void onClick(View v) {
txt.setText("B3");
updateTextView("B3");
if (button3.getText().equals("3"))
{
button3.setText(" 3 ");
button3.setBackgroundResource(R.drawable.onclick_border);
}
else if (button3.getText().equals(" 3 "))
{
button3.setText("3");
button3.setBackground(background);
}
}
});
button4.setOnClickListener(new View.OnClickListener() {
Drawable background = button4.getBackground();
#Override
public void onClick(View v) {
txt.setText("B4");
updateTextView("B4");
if (button4.getText().equals("4"))
{
button4.setText(" 4 ");
button4.setBackgroundResource(R.drawable.onclick_border);
}
else if (button4.getText().equals(" 4 "))
{
button4.setText("4");
button4.setBackground(background);
}
}
});
button5.setOnClickListener(new View.OnClickListener() {
Drawable background = button5.getBackground();
#Override
public void onClick(View v) {
txt.setText("B5");
updateTextView("B5");
if (button5.getText().equals("5"))
{
button5.setText(" 5 ");
button5.setBackgroundResource(R.drawable.onclick_border);
}
else if (button5.getText().equals(" 5 "))
{
button5.setText("5");
button5.setBackground(background);
}
}
});
}
private void updateTextView(String newData){
String oldData = txt.getText().toString();
lst.setText(oldData);
txt.setText(newData);
}
}
This will update your last textview with your txt textview data. YOu can call this method from your button clicks with the new data as a parameter . Hope this helps you

There is nothing wrong with p.matthew13's code. The problem is with the code sequence. I may also have to delete a line on my code because it's already redundant.
The redundant code is txt.setText(""); which contradicts txt.setText(newData);
I have to delete my setText code and replace it with the updateTextView("");
Also, I did place p.matthew13's code before my public void.
And that fixes my problem, after trying to shuffle up the code execution sequence.
Thanks very much!

Two Views, one Animation but there's a problem

This is my code:
AlphaAnimation anim_fadeIn;
Button button, button2;
TextView t, e;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_splash);
t = findViewById(R.id.text_Splash_t);
e = findViewById(R.id.text_Splash_e);
button = findViewById(R.id.button);
button2 = findViewById(R.id.button2);
button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
mAnimate();
}
});
button2.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
mAnimate2();
}
});
anim_fadeIn = new AlphaAnimation(0.0f, 1.0f);
anim_fadeIn.setDuration(1000);
anim_fadeIn.setFillAfter(true);
private void mAnimate() {
t.startAnimation(anim_fadeIn);
}
private void mAnimate2() {
e.startAnimation(anim_fadeIn);
}
Scenario:
press button1 and text1 will animate (even if you do it some times). Then pressing button2 will add the view somewhere so no matter if you press the button1 or 2, both Texts will animate
Scenario 2:
press button2 and text2 will animate (even if you do it some times). Then pressing button1 will add the view somewhere so no matter if you press the button1 or 2, both Texts will animate.
How can I avoid this problem

Remove new Thread wrap, just call mAnimate() or mAnimate2() in main thread like this:
...
button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
mAnimate();
}
});
button2.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
mAnimate2();
}
});
...
Also mAnimate, mAnimate2 can be optimized like this:
private void mAnimate() {
t.startAnimation(anim_fadeIn);
}
private void mAnimate2() {
e.startAnimation(anim_fadeIn);
}

What you actually do is you register the same animation to two Views. If you want to only animate one view at the same time you have to clear the Animation for the other View at first otherwise both will start. E.g.
private void mAnimate() {
e.clearAnimation();
t.startAnimation(anim_fadeIn);
}
private void mAnimate2() {
t.clearAnimation();
e.startAnimation(anim_fadeIn);
}

whenever i perform any operations like add sub equals etc in andriod studio EditText box , my app crashes

I have been trying to make a simple calculator on Android studio. It shows the calculations perfectly fine. but whenever I try to press equals or plus sub or minus operation when the EditText box is empty, my app always crashes.
I tried different ways but it didn't help.
Is there any way that I can do it and stop my app from crashing?
Here's my java code
package com.example.mathcalculator;
import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
public class MainActivity extends AppCompatActivity {
Button button0,button1,button2,button3,button4,button5,button6,button7,button8,button9,buttonClear,buttonMul,buttonSub,buttonAdd,buttonDec,buttonEqual,buttonDiv;
float val1,val2;
EditText result;
boolean mAdditon,msubtraction,mMultiplication, mDivision;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
button0 = (Button) findViewById(R.id.button0);
button1 = (Button) findViewById(R.id.button1);
button2 = (Button) findViewById(R.id.button2);
button3 = (Button) findViewById(R.id.button3);
button4 = (Button) findViewById(R.id.button4);
button5 = (Button) findViewById(R.id.button5);
button6 = (Button) findViewById(R.id.button6);
button7 = (Button) findViewById(R.id.button7);
button8 = (Button) findViewById(R.id.button8);
button9 = (Button) findViewById(R.id.button9);
buttonAdd = (Button) findViewById(R.id.buttonAdd);
buttonMul = (Button) findViewById(R.id.buttonMul);
buttonDiv = (Button) findViewById(R.id.buttonDiv);
buttonClear = (Button) findViewById(R.id.buttonClear);
buttonEqual = (Button) findViewById(R.id.buttonEqual);
buttonDec = (Button) findViewById(R.id.buttonDec);
buttonSub = (Button) findViewById(R.id.buttonSub);
result = (EditText) findViewById(R.id.result);
button0.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
result.setText(result.getText()+"0");
}
});
button1.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
result.setText(result.getText()+"1");
}
});
button2.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
result.setText(result.getText()+"2");
}
});
button3.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
result.setText(result.getText()+"3");
}
});
button4.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
result.setText(result.getText()+"4");
}
});
button5.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
result.setText(result.getText()+"5");
}
});
button6.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
result.setText(result.getText()+"6");
}
});
button7.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
result.setText(result.getText()+"7");
}
});
button8.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
result.setText(result.getText()+"8");
}
});
button9.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
result.setText(result.getText()+"9");
}
});
buttonDec.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
result.setText(result.getText()+".");
}
});
buttonAdd.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if (result == null)
{
result.setText("");
}
else
{
val1 =Float.parseFloat(result.getText()+"");
mAdditon=true;
result.setText(null);
}
}
});
buttonSub.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
{
val1=Float.parseFloat(result.getText()+"");
msubtraction=true;
result.setText(null);
}
}
});
buttonDiv.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
{
val1=Float.parseFloat(result.getText()+"");
mDivision=true;
result.setText(null);
}
}
});
buttonMul.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
{
val1=Float.parseFloat(result.getText()+"");
mMultiplication = true;
result.setText(null);
}
}
});
buttonClear.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
result.setText("");
}
});
buttonEqual.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
val2 = Float.parseFloat(result.getText() + "");
if (mAdditon == true) {
result.setText(val1 + val2 + "");
mAdditon = false;
}
if (msubtraction == true) {
result.setText(val1 - val2 + "");
msubtraction = false;
}
if (mMultiplication == true) {
result.setText(val1 * val2 + "");
msubtraction = false;
}
if (mDivision == true) {
if (val2 == 0) {
result.setText("Can't Divide by Zero");
return;
} else {
result.setText(val1 / val2 + "");
msubtraction = false;
}
}
}
});
}
}

You say it crashes when the EditText box is empty, so most likely, what is happening is that when you do
Float.parseFloat(result.getText() + "");
result.getText() returns "", or you end up doing
Float.parseFloat("");
which result in java.lang.NumberFormatException: empty String
Try replacing
val1=Float.parseFloat(result.getText()+"");
with
val1 = 0;
if(!result.getText().isEmpty())
val1 = Float.parseFloat(result.getText());
NOTE:
Also, as you use it several times, you can make a method for it
private float getResult() {
int result = 0;
if(!result.getText().isEmpty())
val1=Float.parseFloat(result.getText());
return result;
}
and then replace everywhere with val1 = getResult();

as above code when get data from EditText use edit.getText().toString()
and for Parsing it always wrap it with try/catch block as EditText it is initially empty
some hints about the code
- here if (result == null) result.setText(""); result is always not null.
so for better solution always use try/catch when parsing EditText.

How to access array of drawables from a method

I have researched similar problems but none is a fit for this problem. Am trying to access the arrays of drawables from the method name called nextQuestion(), but i keep getting the error cannot resolve symbol 'ballArray' any help please. I just feel that this should work but don't know why. Here is my code.
public class MainActivity extends AppCompatActivity {
ImageView mBallDisplay;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
int quote;
mBallDisplay = (ImageView) findViewById(R.id.image_eightBall);
Button nextbutton = (Button) findViewById(R.id.nextbutton);
Button prevbutton = (Button) findViewById(R.id.prevbutton);
final int[] ballArray = {
R.drawable.ball1,
R.drawable.ball2,
R.drawable.ball3,
R.drawable.ball4,
R.drawable.ball5
};
//next button
nextbutton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
nextQuestion();
}
});
//previous button
prevbutton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
prevQuestion();
}
});
}
private void nextQuestion(){
mBallDisplay.setImageResource(ballArray[4]);
}
private void prevQuestion(){
}
}

The reason you can't access ballArray from within nextQuestion() is because it's declared in a separate method. If you want it accessible from within nextQuestion(), you would need to make it visible at that level:
ImageView mBallDisplay;
final int[] ballArray = {
R.drawable.ball1,
R.drawable.ball2,
R.drawable.ball3,
R.drawable.ball4,
R.drawable.ball5
};
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
int quote;
mBallDisplay = (ImageView) findViewById(R.id.image_eightBall);
Button nextbutton = (Button) findViewById(R.id.nextbutton);
Button prevbutton = (Button) findViewById(R.id.prevbutton);
//next button
nextbutton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
nextQuestion();
}
});
//previous button
prevbutton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
prevQuestion();
}
});
}
private void nextQuestion(){
mBallDisplay.setImageResource(ballArray[4]);
}
private void prevQuestion(){
}
}

Do like this:-
public class MainActivity extends AppCompatActivity {
ImageView mBallDisplay;
int[] ballArray = {
R.drawable.ball1,
R.drawable.ball2,
R.drawable.ball3,
R.drawable.ball4,
R.drawable.ball5
};
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
int quote;
mBallDisplay = (ImageView) findViewById(R.id.image_eightBall);
Button nextbutton = (Button) findViewById(R.id.nextbutton);
Button prevbutton = (Button) findViewById(R.id.prevbutton);
//next button
nextbutton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
nextQuestion();
}
});
//previous button
prevbutton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
prevQuestion();
}
});
}
private void nextQuestion(){
mBallDisplay.setImageResource(ballArray[4]);
}
private void prevQuestion(){
}
}

how do you add two or more numbers selected randomly by the user in a single EditText using android studio?

I am making a mobile calculator and I am aware there are many that have been created. I tried using others as an example to build mine but I have been stuck for days. I was able to display numbers on the EditText when user selects random numbers, but I cannot figure how to add, sub, multi, divide, the numbers that were selected by the user. Please show an example of how I can solve it. This is my first mobile application.
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
final TextView editText = (EditText) findViewById(R.id.edit_text);
final Button Button0 = (Button) findViewById(R.id.Button_0);
final Button Button1 = (Button) findViewById(R.id.Button_1);
Button Button2 = (Button) findViewById(R.id.Button_2);
Button Button3 = (Button) findViewById(R.id.Button_3);
Button Button4 = (Button) findViewById(R.id.Button_4);
Button Button5 = (Button) findViewById(R.id.Button_5);
Button Button6 = (Button) findViewById(R.id.Button_6);
Button Button7 = (Button) findViewById(R.id.Button_7);
Button Button8 = (Button) findViewById(R.id.Button_8);
Button Button9 = (Button) findViewById(R.id.Button_9);
Button clear_Btn = (Button) findViewById(R.id.C_Button);
Button decimal_Btn = (Button) findViewById(R.id.Decimal_Button);
Button equal_Btn = (Button) findViewById(R.id.equal_Button);
final Button add_Btn = (Button) findViewById(R.id.Addition_Button);
/////////////////// NUMBER BUTTONS ///////////////////////
Button0.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
editText.setText(editText.getText().toString() + 0);
}
});
Button1.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
editText.setText(editText.getText().toString() + 1);
}
});
Button2.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
editText.setText(editText.getText().toString() + 2);
}
});
Button3.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
editText.setText(editText.getText().toString() + 3);
}
});
Button4.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
editText.setText(editText.getText().toString() + 4);
}
});
Button5.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
editText.setText(editText.getText().toString() + 5);
}
});
Button6.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
editText.setText(editText.getText().toString() + 6);
}
});
Button7.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
editText.setText(editText.getText().toString() + 7);
}
});
Button8.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
editText.setText(editText.getText().toString() + 8);
}
});
Button9.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
editText.setText(editText.getText().toString() + 9);
}
});
///////////////////// Sign Buttons /////////////////////
// Clear Button
clear_Btn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
editText.setText("");
}
});
// Decimal Button
decimal_Btn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
editText.setText(editText.getText().toString() + ".");
}
});
// Equal button
equal_Btn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
}
});
// Add button
add_Btn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
editText.setText(editText.getText().toString() + "+");
}
});
}
}

A couple ways to achieve this, you just need a way to retrieve the current number in the calculator and perform an operation against the new selected number
So store the main number in its own variable, and then perform the desired operation against a new number, before you set the new edittext value

Develop Reference

Java is a programming language and computing platform first released by Sun Microsystems in 1995.

android Clear Button in a simple counter - java

Change your clear button onClick method as follows: btnClear.setOnClickListener(new OnClickListener() { #Override public void onClick(View v) { counter = 0; txtCounter.setText(0 + ""); } });

Related

How do I pass the string from a textview to another texview on the same activity?

Two Views, one Animation but there's a problem

whenever i perform any operations like add sub equals etc in andriod studio EditText box , my app crashes

How to access array of drawables from a method

how do you add two or more numbers selected randomly by the user in a single EditText using android studio?

Categories

Resources