I have a simple app that updates a TextView from a values generated in a loop when i click on a button.
But when i run the app, it only shows the last number in the TextView. I added a Thread.sleep() to slow down the loop but it did not work, Still the same result. What am i doing wrong here? Thanks in advace
public class MainThread extends ActionBarActivity {
Button btnShow;
TextView txtSee;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main_thread);
btnShow = (Button) findViewById(R.id.btnShow);
txtSee = (TextView) findViewById(R.id.txtSee);
btnShow.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
try {
for (int i = 0; i <= 5; i++) {
String text1 = "Iteration No " + i + " occured";
txtSee.setText(text1);
Thread.sleep(2000);
}
} catch (InterruptedException e) {
}
}
});
}
....
}
use
txtSee.append(text1);
instead of
txtSee.setText(text1);
your loop is executing too fast to let you observe the changes
Call another function inside loop and use
txtSee.setText(text1); inside that function.
or (int i = 0; i <= 5; i++) {
String text1 = "Iteration No " + i + " occured";
call_function(text1,txtSee);
}
call_function:-
call_function(String text1,TextView txtSee;){
txtSee.setText(text1);
Thread.sleep(2000);
}
Related
"goClicked" function is a onClick function to the button "Go" but it is not executing when I click on the button "Go"( I am able to say this because the toast is not appearing ) until I comment the while loop in "goClicked" function. I am pasting the code for only 2 functions "goClicked" and "countdown" because they are the only functions that alter the variable "counterRunning".
public void goClicked(View view) {
afterGoPressed();
countDown();
correctCount = 0;
totalCount = 0;
TextView time = (TextView) findViewById(R.id.time);
while (counterRunning) {
int sum = generateQuestion();
pickOption = generateOptions(sum);
}
}
public void countDown() {
counterRunning = true;
final TextView time = (TextView) findViewById(R.id.time);
final Button tryAgain = (Button) findViewById(R.id.tryAgain);
final TextView result = (TextView) findViewById(R.id.result);
final TextView score = (TextView) findViewById(R.id.score);
int secondsLeft = 30;
time.setText(secondsLeft+"");
CountDownTimer countDownTimer = new CountDownTimer(30000,1000) {
#Override
public void onTick(long millisUntilFinished) {
time.setText(millisUntilFinished/1000 + "");
}
#Override
public void onFinish() {
tryAgain.setVisibility(View.VISIBLE);
result.setText("Your score: " + score.getText());
result.setVisibility(View.VISIBLE);
counterRunning = false;
}
}.start();
}
It is because you're using an infinite loop with the following code:
while (counterRunning) {
int sum = generateQuestion();
pickOption = generateOptions(sum);
}
the code will blocking all other instruction until it found the counterRunning is changed to false inside the while block. But it never happened. Hence the infinite loop.
I have an autogenerated list of edittexts gotten from the user input. What i want to do is shuffle the edittexts when the shuffle button is clicked or get the texts and set them to different edittexts. What i tried doing is to get the texts of each edittext adding it to an arraylist and shuffling it and then recreating the layout with the shuffled list. But that in itself is giving me errors. When the shuffle button is clicked it gives me this error
java.lang.NullPointerException: Attempt to invoke virtual method 'android.text.Editable android.widget.EditText.getText()' on a null object reference
Thanks For the help
`
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
btnForCreate = (Button) findViewById(R.id.btnCreateTxt);
editTextForInputToCreate = (EditText) findViewById(R.id.textForInputToCreate);
listLayout = (LinearLayout) findViewById(R.id.listLayout);
btnDisplay = (Button) findViewById(R.id.btnDisplay);
btnShuffleTxt = (Button) findViewById(R.id.btnShuffleTxt);
editTextForInputToCreate.animate().translationX(-1000f);
btnForCreate.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
bringTextInputBackOnScreen();
}
});
btnDisplay.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
if (editTextForInputToCreate.getText().toString().length() >= 0) {
try {
listLayout.removeAllViews();
} catch (Throwable throwable) {
throwable.printStackTrace();
}
}
length = Integer.parseInt(editTextForInputToCreate.getText().toString());
for (i = 0; i < length; i++) {
editTextCollection = new EditText[length];
editText = new EditText(MainActivity.this);
editText.setId(i + 1);
editText.setLayoutParams(new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT));
editText.setHint("Input" + " " + (i + 1));
listLayout.addView(editText);
editTextCollection[i] = editText;
}
}
});
btnShuffleTxt.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
listLayout.removeAllViews();
for (EditText gottenEditText:editTextCollection)
{
String gottenTexts = gottenEditText.getText().toString();
list.add(gottenTexts);
}
Collections.shuffle(list);
}
});
}
private void bringTextInputBackOnScreen()
{
editTextForInputToCreate.animate().translationXBy(1000f).setDuration(2000);
}
`
Please make some corrections in your EditTextCollection.
editTextCollection = new EditText[length];// initialization outside the loop
for (i = 0; i < length; i++) {
editText = new EditText(MainActivity.this);
editText.setId(i + 1);
editText.setLayoutParams(new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT));
editText.setHint("Input" + " " + (i + 1));
listLayout.addView(editText);
editTextCollection[i] = editText;
}
btnShuffleTxt.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
listLayout.removeAllViews();
for (EditText gottenEditText:editTextCollection)
{
String gottenTexts = gottenEditText.getText().toString();
list.add(gottenTexts);
}
Collections.shuffle(list);
for (EditText gottenEditText:editTextCollection)
{
gottenEditText.setText(list.get(editTextCollection.indexOf(gottenEditText)));
}
}
});
I have created a simple program to try to figure out how to do this. it has two edit text fields (input type number decimal), a text view and a button. I want the sum of the two input fields to be displayed in the text view when the user hits the button. can someone tell me how to set the value of one edit text field to zero if the user left it blank? I have tried many ways but nothing worked.
Edit: i want to achieve this while keeping the hint of edit text as before (without changing the value to zero like " setText("0"); ".
here's my java code (tell me what to add)
package com.example.android.testedittexttozero;
import...
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
public void calculate(View v) { //the button
final EditText number1 = (EditText) findViewById(R.id.numberFirst);
EditText number2 = (EditText) findViewById(R.id.numberSecond);
TextView total = (TextView) findViewById(R.id.totalTV);
try {
int a = Integer.parseInt(number1.getText().toString());
int b = Integer.parseInt(number2.getText().toString());
int sum = a + b;
total.setText("" + sum);
} catch (Exception e) {
Toast.makeText(getApplicationContext(), "One or more field is empty", Toast.LENGTH_LONG).show();
}
}
}
Do you know that in java if you dont initialize a variable with a default value, it's default value be 0?
in short:
try {
int a;//by default, it will be 0;
int b = Integer.parseInt(number2.getText().toString());//let it be 2
int sum = a + b;
total.setText("" + sum);//Ans will be 2 only
} catch (Exception e) {
Toast.makeText(getApplicationContext(), "One or more field is empty", Toast.LENGTH_LONG).show();
}
If you don't enter any value in a, it will be set to as 0. Like if you leave a blank, and enter 2 in second edittext, the ans will be two nevertheless..
public void ZeroingEmpytEditText() {
int f= 0; // Zeroing Factor
if (number1.getText().toString().length() > 0) {
a = Integer.parseInt(number1.getText().toString());
} else {
a=f;
}
if (number2.getText().toString().length() > 0) {
b = Integer.parseInt(number2.getText().toString());
} else {
b=f;
}
int sum = a + b ;
total.setText(sum + "");
}
you can set value 0 of edit text in oncreate method.
like,
public class MainActivity extends AppCompatActivity {
EditText number1,number2;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
number1 = (EditText) findViewById(R.id.numberFirst);
number2 = (EditText) findViewById(R.id.numberSecond);
number1.settext("0");
number2.settext("0");
}
public void calculate(View v) { //the button
TextView total = (TextView) findViewById(R.id.totalTV);
try {
int a = Integer.parseInt(number1.getText().toString());
int b = Integer.parseInt(number2.getText().toString());
int sum = a + b;
total.setText("" + sum);
} catch (Exception e) {
Toast.makeText(getApplicationContext(), "One or more field is empty", Toast.LENGTH_LONG).show();
}
}
}
its helpfull for you.
i'm new to android programming. I have the following code happening on a button click
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
final Button button = (Button) findViewById(R.id.morse_btn);
button.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
loopCode();
}
});
}
which calls this:
public void loopCode()
{
String code = "Hello There";
TextView view = (TextView) findViewById(R.id.code_txt);
String s = "";
for(int i = 0; i < code.length(); i++)
{
s+=code.charAt(i);
view.setText(s);
try {
TimeUnit.SECONDS.sleep(1);
} catch(InterruptedException ex) {
Thread.currentThread().interrupt();
}
}
}
but when i run it on my phone, the text does not get appended until after the for loop has gone through, i.e i press the button, and after a few seconds, the whole string "Hello There" appears.
How can I make it write the text one character at a time, like a typewriter style.
Thanks
You need to use view.append("") which will append new text to the existing one.
Try this code:
int i = 0; //declare this globally
final Handler handler = new Handler();
handler.postDelayed(new Runnable() {
#Override
public void run() {
if(i != 10) {
text.append(" " + i);
i++;
handler.postDelayed(this, 1000);
}
}
}, 1000);
}
This code will append a new number to the TextView every one second until it has reached the count 10. You can apply the same logic.
I had provided this solution to a question here -
[EDIT]
Try this:
String code = "Hello There"; //declare variable globally
int i = 0; //declare globally
TextView view; //declare globally
public void loopCode()
{
view = (TextView) findViewById(R.id.code_txt);
//String s = "";
final Handler handler = new Handler();
handler.postDelayed(new Runnable() {
#Override
public void run() {
if(i != code.length()) {
view.append(" " + code.charAt(i));
i++;
handler.postDelayed(this, 1000);
}
}
}, 1000);
}
}
Don't forget to declare int i = 0 and String code = "Hello There" globally.
Exist 2 different method setText in TextView.
public final void setText (int resid)
public final void setText (CharSequence text)
when you put variable int in setText, the android try find String in classe R variable in same code.
To resolve this you then cast int to string using String.valueOF(...)
see more in;
http://developer.android.com/reference/android/widget/TextView.html#setText(java.lang.CharSequence)
http://docs.oracle.com/javase/6/docs/api/java/lang/String.html#valueOf(int)
try
public void loopCode()
{
String code = "Hello There";
TextView view = (TextView) findViewById(R.id.code_txt);
String s = "";
for(int i = 0; i < code.length(); i++)
{
view.setText(String.valueOf(i));
try {
TimeUnit.SECONDS.sleep(1);
} catch(InterruptedException ex) {
Thread.currentThread().interrupt();
}
}
}
I have created a dynamic array of buttons that come from sqllite database. For the life of me I cannot get a click listener set up to address each button individually. I have been searching for 3 hours with no success at all.
Any help would be appreciated. Don't worry about the database crap, it's just the listener.
imports...
public class CreatePlayList extends Activity {
ScrollView scrollleft, scrollright;
LinearLayout songsright, songsleft;
TextView testtext;
String[][] allsongs;
int numofsongs, i;
Button b1[];
#Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.createplaylist);
scrollleft = (ScrollView) findViewById(R.id.scrollleft);
scrollright = (ScrollView) findViewById(R.id.scrollright);
songsright = (LinearLayout) findViewById(R.id.layRight);
songsleft = (LinearLayout) findViewById(R.id.layLeft);
LyricDb connect = new LyricDb(CreatePlayList.this);
connect.open();
numofsongs = connect.getNumSongs();
b1 = new Button[(numofsongs)];
allsongs = new String[numofsongs][2];
allsongs = connect.getSongArray();
connect.close();
testtext = new TextView(this);
testtext.setText("Test");
songsleft.addView(testtext);
for (i = 0; i < allsongs.length; i++) {
b1[i] = new Button(this);
b1[i].setText(allsongs[i][1]);
songsright.addView(b1[i]);
}
b1[19].setText("test 123");
createClic();
}
public void createClic(){
for (i = 0; i < (allsongs.length - 1); i++) {
b1[i].setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
// TODO Auto-generated method stub
testtext.setText(b1[i].getText());
}
});
}
}
}
Dump the 'i' declared at class level. Replace method with this (the "Button theButton" needs to stay 'final').
public void createClic()
{
for (int i = 0; i < (allsongs.length - 1); i++)
{
final Button theButton = b1[i];
theButton.setOnClickListener(new View.OnClickListener()
{
public void onClick(View v)
{
// TODO Auto-generated method stub
testtext.setText(theButton.getText());
}
});
}
}
First implement OnClickListener in your Activity and call setOnClickListener() method to all of your buttons when you are creating it.
b[i].setOnClickListener(this);
and also set id with each button
b[i].setId(i);
//and override this method
#Override
public void onClick(View v)
{
//here check which button called
if(v.getId==1)
{
//its Button 1 do what ever u want
}
if(v.getId==2)
{
//its Button 2 do what ever u want its Button 2
}
......
}
Try it once...
b1[i] = new Button[allsongs.length];
for (i = 0; i < allsongs.length; i++) {
b1[i].setText(allsongs[i][1]);
songsright.addView(b1[i]);
}