disappear button itself

disappear button itself - java

I do this code to disappear a button itself. but it doesn't work at all:
againbtn.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
againbtn.setVisibility(View.GONE);
}
});
UPDATE:
my againbtn is invisible at activity load, and in my code, inside another buttun click, i make it visible with this code:
//answer button off animation
Animation anim2 = AnimationUtils.loadAnimation(MainActivity.this, R.anim.askbtnoffanim);
anim2.setFillAfter(true);
askbtn.startAnimation(anim2);
as you can see im not using againbtn.setVisibility(View.VISIBLE); or other things. animation itself appear the button. do you think my problem related to this? i try to do another animation to disappear the button itselft, it works but still clicklistener works for this button at his position area!!
why?

try this
againbtn.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
runOnUiThread(new Runnable()
{
#Override
public void run()
{
againbtn.setVisibility(View.GONE);
}
});
}
});

check with the class which you imported, import the following class:
import android.view.View.OnClickListener;
instead of:
import android.content.DialogInterface.OnClickListener;
I am giving the complete code here, you can use it:
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
public class MainActivity extends Activity {
Button b;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
b = (Button) findViewById(R.id.button1);
b.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
// TODO Auto-generated method stub
b.setVisibility(View.GONE);
}
});
}
}
And here is the activity_main.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" >
<Button
android:id="#+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:text="Button" />
</RelativeLayout>

Related

How to get Hint and Text of a button In android studio

I am using this code to get the id of the button which is clicked and then use the id to get the text and hint of the same button
I don't know why but maybe this code this crashing the app after I use getID() method.
I am using Relative Layout.
The Java code
package com.example.firstapp;
import androidx.appcompat.app.AlertDialog;
import androidx.appcompat.app.AppCompatActivity;
import androidx.constraintlayout.widget.ConstraintLayout;
import android.annotation.SuppressLint;
import android.os.Bundle;
import android.provider.ContactsContract;
import android.text.TextUtils;
import android.util.Log;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.LinearLayout;
import android.widget.ListView;
import android.widget.RelativeLayout;
import android.widget.TextView;
import android.widget.Toast;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.util.ArrayList;
public class MainActivity extends AppCompatActivity{
public AlertDialog.Builder dialogBuilder;
public AlertDialog dialog;
public EditText Name,Password;
public Button Save,Cancel,temp,ok,x;
public String file_location = "Passwords.txt";
public String name_x,pass_y;
public LinearLayout mylayout = null;
public RelativeLayout rl = null;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
public void View_Password(Button x){
ok = (Button) findViewById(R.id.button6);
ok.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
dialog.dismiss();
}
});
};
public void NewPassword(){
dialogBuilder = new AlertDialog.Builder(this);
final View NewPassSaveView = getLayoutInflater().inflate(R.layout.newpasspopup, null);
Name = (EditText) NewPassSaveView.findViewById(R.id.editTextTextPersonName);
Password = (EditText) NewPassSaveView.findViewById(R.id.editTextTextPersonName2);
Save = (Button) NewPassSaveView.findViewById(R.id.button4);
Cancel = (Button) NewPassSaveView.findViewById(R.id.button);
dialogBuilder.setView(NewPassSaveView);
dialog = dialogBuilder.create();
dialog.show();
Save.setOnClickListener(new View.OnClickListener() {
#SuppressLint("ResourceType")
#Override
public void onClick(View view) {
if (TextUtils.isEmpty(Name.getText().toString())) {
Name.setError("This Field is compulsory");
return;
} else if (TextUtils.isEmpty(Password.getText().toString())) {
Password.setError("This Field is compulsory");
return;
}
rl = (RelativeLayout) findViewById(R.id.layout2);
Toast.makeText(getApplicationContext(), "Password Saving...", Toast.LENGTH_SHORT).show();
Toast.makeText(getApplicationContext(), "Password Saved", Toast.LENGTH_SHORT).show();
Button temp = new Button(MainActivity.this);
temp.setLayoutParams(new RelativeLayout.LayoutParams(
RelativeLayout.LayoutParams.MATCH_PARENT,
RelativeLayout.LayoutParams.WRAP_CONTENT
));
rl.addView(temp);
temp.setText(Name.getText().toString());
temp.setHint(Password.getText().toString());
temp.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
int btn_id = v.getId();
btn2string(btn_id);
}
});
dialog.dismiss();
}
});
Cancel.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
dialog.dismiss();
}
});
}
public void AddNew(View view) {
NewPassword();
}
public void btn2string(int x){
Button btn = findViewById(x);
name_x = btn.getText().toString();
pass_y = btn.getHint().toString();
See_Password(name_x,pass_y);
}
public void See_Password(String name,String pass){
Toast.makeText(getApplicationContext(), "Name: "+name+"\n"+"Password: "+pass, Toast.LENGTH_SHORT).show();
}
}
//The XML
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/heading"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<TextView
android:id="#+id/textView4"
android:layout_width="319dp"
android:layout_height="50dp"
android:text="Password Manager"
android:textSize="34sp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.051" />
<Button
android:id="#+id/button2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginEnd="28dp"
android:layout_marginRight="28dp"
android:onClick="AddNew"
android:text="Add new"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toBottomOf="#+id/textView4"
app:layout_constraintVertical_bias="0.973" />
<RelativeLayout
android:id="#+id/layout2"
android:layout_width="366dp"
android:layout_height="541dp"
android:layout_marginTop="28dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.488"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/textView4"
app:layout_constraintVertical_bias="0.0"/>
</androidx.constraintlayout.widget.ConstraintLayout>
Please tell if there is any other way to do this or tell the mistakes in the above code so that I can get the hint and text of that button which is clicked...
Thank You.

Inside,
NewPassword()
method just change the following code.
public void NewPassword(){
......
save.setOnClickListener(...){
........
temp.setOnClickListener(new View.OnClickListener(){
#Override
public void onClick(View v){
int btn_id = v.getId(); // remove this line.
btn2String(temp); //directly pass temp i.e. Button you created.
}
});
dialog.dismiss();
}
});
..........
}
And, pass Button type as a parameter in btn2String() method. as below:
public void btn2String(Button x){
Button btn = findViewById(x); // remove this line of code.
name_x = x.getText().toString();
pass_y = x.getHint().toString();
See_Password(name_x, pass_y);
}

Android w/ Java: Using Seekbar to adjust volume

I'm new to Android App development (on android studio) and to start off I'm creating a simple 'bonk' soundboard app, and testing it using the Pixel 2 android emulator. The goal of the app is to play the bonk noise whenever someone presses the BONK button on my main screen. I also wanted to implement a seekbar that adjusts the volume when you slide it. To do this I followed a simple implementation I found here on StackOverflow (shown below).
Even though the rest of my app works fine, for some reason my volume won't adjust whenever I slide the seekbar. Here is my code:
MainActivity.java
package com.example.bonk;
import androidx.appcompat.app.AppCompatActivity;
import android.media.AudioManager;
import android.media.MediaPlayer;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.SeekBar;
public class MainActivity extends AppCompatActivity {
Button bonkButton;
SeekBar volumeSeekBar;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
bonkButton = (Button)findViewById(R.id.bonkButton);
volumeSeekBar = (SeekBar)findViewById(R.id.volumeSeekBar);
final MediaPlayer mp = MediaPlayer.create(this, R.raw.bonksound);
bonkButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
mp.start();
}
});
}
}
Volumizer.java
package com.example.bonk;
import android.app.Activity;
import android.content.Context;
import android.media.AudioManager;
import android.os.Bundle;
import android.widget.SeekBar;
import android.widget.SeekBar.OnSeekBarChangeListener;
public class Volumizer extends Activity {
//Called when the activity is first created.
private SeekBar volumeSeekbar = null;
private AudioManager audioManager = null;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setVolumeControlStream(AudioManager.STREAM_MUSIC);
setContentView(R.layout.activity_main);
initControls();
}
private void initControls() {
try {
volumeSeekbar = findViewById(R.id.volumeSeekBar);
audioManager = (AudioManager) getSystemService(Context.AUDIO_SERVICE);
volumeSeekbar.setMax(audioManager
.getStreamMaxVolume(AudioManager.STREAM_MUSIC));
volumeSeekbar.setProgress(audioManager
.getStreamVolume(AudioManager.STREAM_MUSIC));
volumeSeekbar.setOnSeekBarChangeListener(new OnSeekBarChangeListener() {
#Override
public void onStopTrackingTouch(SeekBar arg0) {
}
#Override
public void onStartTrackingTouch(SeekBar arg0) {
}
#Override
public void onProgressChanged(SeekBar arg0, int progress, boolean arg2) {
audioManager.setStreamVolume(AudioManager.STREAM_MUSIC,
progress, 0);
}
});
} catch (Exception e) {
e.printStackTrace();
}
}
}
Activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<Button
android:id="#+id/bonkButton"
android:layout_width="296dp"
android:layout_height="232dp"
android:text="#string/bonk"
android:textSize="30sp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<SeekBar
android:id="#+id/volumeSeekBar"
android:layout_width="276dp"
android:layout_height="26dp"
android:layout_marginBottom="116dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.496"
app:layout_constraintStart_toStartOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>
Please let me know if you have any ideas as of what I may be doing wrong. Thank you!

I was able to solve the problem by moving my initControls() function definition into my MainActivity.java class and calling it onCreate.

Passing data between activities for a voting app

I am new to android programming and have ran into a problem. I am trying to create a voting app where when a user opens up the application and the MainActivity is shown, from here they press a button to go into the second Screen (Screen2) which shows images of people and their names as buttons. When a persons name (in a button on Screen2) is pressed , a text field shows the number of times the button is pressed in an another activity (Screen4) . The problem here is that when i try to show this (Screen4), the app crashes. I am quite new to this so if you didn't understand my issue or need more information please let me know. Any help is appreciated. Thank you.
EDIT : After some help I used Intent to try send the data across but now when when the button in screen2 is pressed the app refreshes and then takes me back to the mainActivity and when this process is tried again the app crashes.
This is the new Screen2 :
package com.example.myapplication1;
import androidx.appcompat.app.AppCompatActivity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.TextView;
public class Screen2 extends AppCompatActivity {
TextView showValue;
int counter = 0;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_screen2);
showValue = findViewById(R.id.VoteCountAnnie);//VoteCountAnnie is the On click for the Textview in a different activity.
}
public void AnCount(View v) {
//increase the count
counter++;
showValue.setText(Integer.toString(counter));
}
public void ButtonToGoToTheOtherActivity(View v) {
Intent intent = new Intent(this, Screen4.class);
intent.putExtra("valueOfCounter", counter); //the code for sending data to the other activity.
startActivity(intent);
}
}
This is the XML for screen 2 :
<?xml version="1.0" encoding="utf-8"?>
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent">
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
tools:context=".Screen2">
<Button
android:id="#+id/AnnieBtn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="32dp"
android:layout_marginLeft="32dp"
android:text="#string/annie_liou"
android:onClick="AnCount"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/imageView5"
/>
This is my Screen4:
package com.example.myapplication1;
import androidx.appcompat.app.AppCompatActivity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
public class Screen4 extends AppCompatActivity {
private Button Button3;
int counter;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_screen4);
Button3 = (Button) findViewById(R.id.Button3);
Button3.setOnClickListener(new View.OnClickListener() {
public void onClick(View view) { openActivity4();
}
}
);
counter = getIntent().getIntExtra("valueOfCounter", 0); // 0 is default value
}
public void openActivity4() {
Intent intent = new Intent(Screen4.this, MainActivity.class);
startActivity(intent);
}
}
Here is the XML for screen4:
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/MainScreen"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".Screen4">
<TextView
android:id="#+id/textView5"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="193dp"
android:layout_marginLeft="193dp"
android:layout_marginEnd="109dp"
android:layout_marginRight="109dp"
android:layout_marginBottom="660dp"
android:text="This is 4th screen"
android:textSize="32sp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.664"
app:layout_constraintStart_toStartOf="parent" />
<Button
android:id="#+id/Button3" // return to main screen
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="532dp"
android:text="Return"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.498"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/textView5" />
<TextView
android:id="#+id/VoteCountAnnie" // textview where i want the increment to show
android:layout_width="121dp"
android:gravity="center"
android:layout_height="52dp"
android:layout_marginStart="116dp"
android:layout_marginLeft="116dp"
android:layout_marginTop="82dp"
android:layout_marginEnd="174dp"
android:layout_marginRight="174dp"
android:text="0"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/textView5" />
</androidx.constraintlayout.widget.ConstraintLayout>
This is my main Activity Screen (not used for the clicking but if there is something wrong in this that could affect the other Screens please let me know) :
package com.example.myapplication1;
import androidx.appcompat.app.AppCompatActivity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
public class MainActivity extends AppCompatActivity {
private Button button;
private Button button2;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
button = (Button) findViewById(R.id.button);
button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
openActivity2();
}
});
button2 = (Button) findViewById(R.id.button2);
button2.setOnClickListener(new View.OnClickListener() {
public void onClick(View view) {
openActivity3();
}
}
);
}
public void openActivity2() {
Intent intent = new Intent(this, Screen2.class);
startActivity(intent);
}
public void openActivity3() {
Intent intent = new Intent(this, Screen3.class);
startActivity(intent);
}
}
Here is the XML for screen 4:

This works same using intent .
Main Class :
package com.example.cameraone;
import android.content.Intent;
import android.support.annotation.Nullable;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
public class MainActivity extends AppCompatActivity {
public static String EXTRA_VOTE_KEY = "com.example.cameraone.EXTRA_VOTE_KEY";
private Button counter,show;
private int count = 0;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
if(savedInstanceState != null){
count = savedInstanceState.getInt(EXTRA_VOTE_KEY);
}
counter = findViewById(R.id.bt_counter);
show = findViewById(R.id.bt_show);
counter.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
count++;
}
});
show.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
go();
}
});
/* Intent intent = new Intent(this,DisplayCount.class);
//intent.putExtras(intent);
startActivity(intent,bundle);*/
}
#Override
protected void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
outState.putInt(EXTRA_VOTE_KEY,count);
}
public void go(){
Intent intent = new Intent(this,DisplayCount.class);
intent.putExtra(EXTRA_VOTE_KEY,count);
startActivity(intent);
}
}
Activity of Main Class :
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
tools:context=".MainActivity">
<Button
android:id="#+id/bt_counter"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="16dp"
android:text="PressMe"
/>
<Button
android:id="#+id/bt_show"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="#+id/bt_counter"
android:text="Done"
/>
</RelativeLayout
Display Class :
package com.example.cameraone;
import android.content.Intent;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v7.app.AppCompatActivity;
import android.widget.Button;
import android.widget.TextView;
import org.w3c.dom.Text;
public class DisplayCount extends AppCompatActivity{
private TextView textView;
private int count;
#Override
protected void onCreate(#Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.display_count_activity);
textView = findViewById(R.id.tv_vote_count);
Intent intent = getIntent();
count = intent.getIntExtra(MainActivity.EXTRA_VOTE_KEY,0);
textView.setText(Integer.toString(count));
}
}
Activity of display class :
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content" android:layout_height="wrap_content"
android:layout_gravity="center">
<TextView
android:id="#+id/tv_vote_count"
android:layout_width="wrap_content"
android:inputType="number"
android:layout_height="wrap_content"
android:textStyle="bold"
android:maxLength="10"/>
</RelativeLayout>
Manifest :
include following in your manifest file :
<activity android: name =".DisplayCount"></activity>

add following to manifest :
// Main Activity //
- List item
package com.example.cameraone;
import android.content.Intent;
import android.support.annotation.Nullable;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
public class MainActivity extends AppCompatActivity {
public static String EXTRA_VOTE_KEY = "com.example.cameraone.EXTRA_VOTE_KEY";
private Button counter,show;
private int count = 0;
#Override
protected void onCreate(#Nullable final Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
counter = findViewById(R.id.bt_counter);
show = findViewById(R.id.bt_show);
counter.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
count++;
}
});
show.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
go();
}
});
}
public void go(){
DisplayCount.setVoteCount(count);
Intent intent = new Intent(this, DisplayCount.class);
startActivity(intent);
}
#Override
protected void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
outState.putInt(EXTRA_VOTE_KEY,count);
}
}
/** Class to display: **/
- List item
package com.example.cameraone;
import android.content.Intent;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v7.app.AppCompatActivity;
import android.widget.Button;
import android.widget.TextView;
import org.w3c.dom.Text;
public class DisplayCount extends AppCompatActivity{
private TextView textView ;
private static int count ;
#Override
protected void onCreate(#Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.display_count_activity);
textView = findViewById(R.id.tv_vote_count);
textView.setText(Integer.toString(count));`enter code here`
}
public static void setVoteCount(int c){
count = c;
}
}
/***** Activity files *****/
- List item
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content" android:layout_height="wrap_content"
android:layout_gravity="center">
<TextView
android:id="#+id/tv_vote_count"
android:layout_width="wrap_content"
android:inputType="number"
android:layout_height="wrap_content"
android:textStyle="bold"
android:maxLength="10"/>
</RelativeLayout>
/**** Activity That display's ****/
-List item
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
tools:context=".MainActivity">
<Button
android:id="#+id/bt_counter"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="16dp"
android:text="PressMe"
/>
<Button
android:id="#+id/bt_show"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="#+id/bt_counter"
android:text="Done"
/>
</RelativeLayout>

As Mike M. said you are using id of a textview which is in a different activity. In android we cannot access ids of views in a different activity. We can only access ids of view in the same activity in which we are.
So that is for the error you are getting.
For accessing Data from another activity you can pass the data like this:
public class Screen2 extends AppCompatActivity {
int counter;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_screen1);
showValue = (TextView) findViewById(R.id.VoteCountAnnie);//VoteCountAnnie is the Id for the Textview in a different activity.
}
public void AnnieCountInc (View view) {
//increase the count
counter++;
showValue.setText(Integer.toString(counter));
}
//make another button with a method like
public void ButtonToGoToTheOtherActivity(View view){
Intent intent =new Intent(this,Screen4.class);
intent.putExtra("valueOfCounter",counter); //the code for sending data to the other activity.
startActivity(intent);
}
Then in your Screen4 activity you can get the value of "counter" in the onCreate method by:
counter = getIntent().getIntExtra("valueOfCounter",0); // 0 is default value
This is one method.
You can also use a static variable to pass on data easily by defining your counter varaible as
public static int counter;
Then you can access it directly and it will show you the value.

Android Button findViewByID returns null

I had three button on my main form. I added a third. When I try to assign the button using findViewById a null is returned.
This is my main.xml
<?xml version="1.0" encoding="utf-8"?>
<TableLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent" android:weightSum="1" android:clickable="false">
<TextView android:layout_width="wrap_content"
style="#style/TitleText"
android:text="#string/app_name"
android:background="#drawable/black_gradient">
</TextView>
<Button android:id="#+id/btnvalidatemark"
android:background="#drawable/grad_btn_green"
style="#style/ButtonText" android:text="#string/validate_mark_button">
</Button>
<Button android:id="#+id/btncheckregistry"
android:background="#drawable/grad_btn_yellow"
style="#style/ButtonText" android:text="#string/check_registry_button">
</Button>
<Button android:id="#+id/btnregcreds"
android:background="#drawable/grad_btn_red"
style="#style/ButtonText" android:text="#string/registry_config_button">
</Button>
</TableLayout>
This is my Activity code:
package uid.android.uidchecker;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.Window;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.util.Log;
public class UIDCheckerActivity
extends Activity
{
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.main);
Button validatebutton = (Button) findViewById(R.id.btnvalidatemark);
Button checkbutton = (Button) findViewById(R.id.btncheckregistry);
Button setcredbutton = (Button) findViewById(R.id.btnregcreds);
validatebutton.setOnClickListener(new OnClickListener()
{
public void onClick(View v)
{
Intent i = new Intent(UIDCheckerActivity.this, SelectFileActivity.class);
i.putExtra("func", "validatemark");
startActivity(i);
}
});
checkbutton.setOnClickListener(new OnClickListener()
{
public void onClick(View v)
{
//Intent i = new Intent(UIDCheckerActivity.this, validatemark.class);
Intent i = new Intent(UIDCheckerActivity.this, SelectFileActivity.class);
i.putExtra("func", "checkregisrty");
startActivity(i);
}
});
setcredbutton.setOnClickListener(new OnClickListener()
{
public void onClick(View v)
{
Intent i = new Intent(UIDCheckerActivity.this, RegistryCredsActivity.class);
startActivity(i);
}
});
}
}

Changing the position of the thumb of the SeekBar using a different Button

I'm trying to move the position of the seekbar using a button. Basically I have a seekbar from 0 to 100. and I have button presents set up at arbitrary values (40,50,60 etc). When I try to set the progress on the seekbar via button, I get a fault.. I've already initialized the seekBar in the onCreate() method.
SeekBar seekBar = (SeekBar) findViewById(R.id.seekBar1);
currentProgress = 40;
seekBar.setMax(100);
seekBar.setProgress(currentProgress);
button40.setOnClickListener(button40Listener);
But when use the below, it crashes.
private OnClickListener button40Listener = new OnClickListener() {
public void onClick(View v) {
currentProgress = 40;
seekBar.setProgress(currentProgress);
}
}
This seems straight-forward. Any ideas?

You shouldn't need to put up another Seekbar. The initial one should be fine. Without the exception message and stack trace I'm not sure what is causing the crash. However, I just coded an example and works as you would expect. Perhaps by looking at my example you can identify your issue.
SeekbarTest.java:
package com.example.seekbartest;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.SeekBar;
public class SeekbarTest extends Activity {
/** Called when the activity is first created. */
private SeekBar seekBar;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
seekBar = (SeekBar)findViewById(R.id.seekBar1);
Button fortyPctButton = (Button)findViewById(R.id.buttonFortyPct);
fortyPctButton.setOnClickListener(new OnClickListener()
{
#Override
public void onClick(View v)
{
seekBar.setProgress(40);
}
});
Button sixtyPctButton = (Button)findViewById(R.id.buttonSixtyPct);
sixtyPctButton.setOnClickListener(new OnClickListener()
{
#Override
public void onClick(View v)
{
seekBar.setProgress(60);
}
});
Button eightyPctButton = (Button)findViewById(R.id.buttonEightyPct);
eightyPctButton.setOnClickListener(new OnClickListener()
{
#Override
public void onClick(View v)
{
seekBar.setProgress(80);
}
});
}
}
And here is the main.xml it is referencing for the layout:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<TextView
android:layout_width="fill_parent"
android:text="#string/hello"
android:id="#+id/textView1"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"/>
<SeekBar
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="#+id/seekBar1"
android:layout_below="#+id/textView1"
android:layout_alignLeft="#+id/textView1"
android:layout_alignRight="#+id/textView1"/>
<Button
android:layout_width="wrap_content"
android:text="40%"
android:id="#+id/buttonFortyPct"
android:layout_height="wrap_content"
android:layout_below="#+id/seekBar1"
android:layout_alignLeft="#+id/seekBar1"/>
<Button
android:layout_width="wrap_content"
android:text="60%"
android:id="#+id/buttonSixtyPct"
android:layout_height="wrap_content"
android:layout_toRightOf="#+id/buttonFortyPct"
android:layout_alignTop="#+id/buttonFortyPct"
android:layout_alignBottom="#+id/buttonFortyPct"/>
<Button
android:layout_width="wrap_content"
android:text="80%"
android:id="#+id/buttonEightyPct"
android:layout_height="wrap_content"
android:layout_toRightOf="#+id/buttonSixtyPct"
android:layout_alignTop="#+id/buttonSixtyPct"
android:layout_alignBottom="#+id/buttonSixtyPct"/>
</RelativeLayout>
Just create a new android app and replace the generated code + layout with the example above. It should work for you.
Good luck,
Craig

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disappear button itself - java

try this againbtn.setOnClickListener(new OnClickListener() { #Override public void onClick(View v) { runOnUiThread(new Runnable() { #Override public void run() { againbtn.setVisibility(View.GONE); } }); } });

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