Develop Reference

New layout doesn't pop up

I am making an app in android Studio and if you open the app on your phone you see the Launcer activity. I have a button that sends you to a new activity where te game is located. Once i click the Start button, The app closes and doesn't goes to the other activity. Why is that?
This is my code of the Launcher activity:
package joenio.sirname;
import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
public class SirName_launcher extends AppCompatActivity {
public static Button button_start;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_sir_name_launcher);
StartButton();
}
public void StartButton(){
button_start = (Button) findViewById(R.id.button_start);
button_start.setOnClickListener(
new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent intent1 = new Intent("joenio.sirname.Game");
startActivity(intent1);
}
}
);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.menu_sir_name_launcher, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}
And this is the code of the second activity:
package joenio.sirname;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import java.util.ArrayList;
import android.widget.Toast;
public class Game extends AppCompatActivity {
public static EditText editText_surname;
public static TextView textView_name;
public static Button button_check;
int x =0; //to keep track of qustions
//Context editText_this = this;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_game);
Displayquestions();
}
public void Displayquestions(){
final ArrayList<String> mQuestionList = new ArrayList<>();
mQuestionList.add("1+2");
mQuestionList.add("6+8");
mQuestionList.add("5 * 6");
mQuestionList.add("8*5");
mQuestionList.add("6+16");
mQuestionList.add("18-5");
textView_displayquestion.setText((mQuestionList.get(x)));//displayquestion is textview
final ArrayList<String> mAnswerList=new ArrayList<>();
mAnswerList.add("3");
mAnswerList.add("14");
mAnswerList.add("30");
mAnswerList.add("40");
mAnswerList.add("22");
mAnswerList.add("13");
//button_check is the button when user click it will first check answer and than move to next question if answer is correct
button_check.setOnClickListener(new View.OnClickListener(){
#Override
public void onClick(View v) {
//editText_this;
String answer = editText_ans.getText().toString();
if (answer.equals(mAnswerList.get(x))) {
x = x + 1;
textView_displayquestion.setText(mQuestionList.get(x)); //answer is correct display next quesion
Toast.makeText(getApplication().getBaseContext(),
(R.string.Nice), Toast.LENGTH_SHORT).show();
} else {
Toast.makeText(getApplication().getBaseContext(),
(R.string.tryagain), Toast.LENGTH_SHORT).show();
}
}
});
}
}

You are no where initializing your TextView and Button which must be causing NullPointerException.
Change your Game activity like this
TextView textView_displayquestion;
Button button_check;
EditText editText_ans;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_game);
textView_displayquestion = (TextView)findViewById(R.id.displayquestion); //change as per your id
button_check = (Button)findViewById(R.id.buttoncheck); //change as per your id
editText_ans = (EditText)findViewById(R.id.answer); //change as per your id
Displayquestions();
}

In your button click , change the code as below.
Intent intent1 = new Intent(SirName_launcher.this, Game.class);
startActivity(intent1);
And also add the new Game Activity in your Manifest file too.

Passing an drawable image from 1st activity to 2nd does not work (only from 2nd to 1ast does) Android

enter code hereThis is my First Activity::> I need:
1) select an option
2) click send an image (from drawable) should go to the second activity but it does not only from 2nd to 1st works fine all my xml and manifest files are correct (I double checked)
package com.example.damianlopez.myassignment;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.ActionBar;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import android.widget.Toast;
public class MainActivity extends AppCompatActivity {
Button toBob;
private ImageView burgerImage;
private RadioGroup radioGroupChoice;
private RadioButton radBurger;
private RadioButton radScare;
private RadioButton radSick;
private final int MY_SELECTION = 111;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
try {
setContentView(R.layout.activity_main);
//get radio Buttons
//radioGroupChoice = (RadioGroup) findViewById(R.id.radGroupChoice);
radBurger = (RadioButton)findViewById(R.id.radBurger);
radScare = (RadioButton)findViewById(R.id.radScare);
radSick = (RadioButton)findViewById(R.id.radSick);
//display app icon
ActionBar ab = getSupportActionBar();
ab.setDisplayShowHomeEnabled(true);
ab.setIcon(R.mipmap.ic_launcher);
//getting Intent
Intent getIntent = getIntent();
Bundle myBundle2 = getIntent.getExtras();
setResult(Activity.RESULT_OK, getIntent);
//
}catch(Exception e ){
}
}//End onCreate()
public void onClickButton(View v){
try {
//get radio gruop id's
radioGroupChoice = (RadioGroup) findViewById(R.id.radGroupChoice);
int mySelection = radioGroupChoice.getCheckedRadioButtonId();
if(radioGroupChoice.getCheckedRadioButtonId() == -1){
Toast.makeText(getApplicationContext(), "Please make a selection", Toast.LENGTH_LONG).show();
}else {
//creating new Intent
Intent msgToBob = new Intent(MainActivity.this, Main22Activity.class);
Bundle myBundle = new Bundle();
myBundle.putInt("imageChoice", mySelection);
msgToBob.putExtras(myBundle);
startActivityForResult(msgToBob, MY_SELECTION);
}
}catch(Exception e ){
}
}//End of onClick()
#Override
protected void onActivityResult(int requestCode, int resultCode, Intent myData) {
super.onActivityResult(requestCode, resultCode, myData);
Log.i("OnActivityResult() call", "***********");
radioGroupChoice = (RadioGroup) findViewById(R.id.radGroupChoice);
int selected = radioGroupChoice.getCheckedRadioButtonId();
//get Images
burgerImage = (ImageView) findViewById(R.id.pumpkin_burger);
if(radioGroupChoice.getCheckedRadioButtonId() == -1){
Toast.makeText(getApplicationContext(), "Please make a selection", Toast.LENGTH_LONG).show();
}
else {
switch (requestCode) {
case MY_SELECTION: {
if (resultCode == Activity.RESULT_OK) {
if (radBurger.isChecked()) {
burgerImage.setImageResource(R.drawable.pumpkin_burger);
} else if (radScare.isChecked()) {
burgerImage.setImageResource(R.drawable.pumpkin_scared);
} else if (radSick.isChecked()) {
burgerImage.setImageResource(R.drawable.pumpkin_sick);
};
}
break;
}//end case
}//end switch
}//end else if
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();``
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}
This is my Second Activity===>
package com.example.damianlopez.myassignment;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.ActionBar;
import android.support.v7.app.AppCompatActivity;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import android.widget.Toast;
public class Main22Activity extends AppCompatActivity {
private RadioGroup radioGroupChoice2;
private RadioButton radBurger;
private RadioButton radScare;
private RadioButton radSick;
private Button toAlice;
private ImageView currentImage;
private ImageView scareImage;
private ImageView sickImage;
private final int MY_SELECTION2 = 222;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main22);
//display app icon
ActionBar ab = getSupportActionBar();
ab.setDisplayShowHomeEnabled(true);
ab.setIcon(R.mipmap.ic_launcher);
//Buttons
radioGroupChoice2 = (RadioGroup)findViewById(R.id.radGroupChoice);
//toAlice = (Button) findViewById(R.id.sndToAlice);
//get the intent called
Intent myLocalIntent = getIntent();
Bundle myBundle = myLocalIntent.getExtras();
myLocalIntent.putExtras(myBundle);
setResult(Activity.RESULT_OK, myLocalIntent);
}
public void onClickButton2(View v){
try {
radioGroupChoice2 = (RadioGroup) findViewById(R.id.radGroupChoice);
if (radioGroupChoice2.getCheckedRadioButtonId() == -1) {
Toast.makeText(getApplicationContext(), "Please make a selection", Toast.LENGTH_LONG).show();
} else {
Intent myIntent2 = new Intent();
Bundle myBundle2 = new Bundle();
int myImage = radioGroupChoice2.getCheckedRadioButtonId();
myBundle2.putInt("selectedImage", myImage);
myIntent2.putExtras(myBundle2);
setResult(Activity.RESULT_OK, myIntent2);
}
}catch(Exception e) {
}
finish();
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main22, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}

how to direct to another activity after successful login, Android Developer Studio

as i said, how do i direct to the next activity after successfully login? im kinda stuck for a while now, and it is necessary for this to run. im practicing my android skills awhile back. so i am using android developer studio for my practices of developing android. this is my code. hope you guys can help.
`package com.mikesaclolo.pinasarap;
import android.app.Activity;
import android.graphics.Color;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
import java.io.FileInputStream;
import java.io.FileOutputStream;
public class MainActivity extends Activity {
Button b1,b2;
EditText ed1,ed2;
TextView tx1;
int counter = 3;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
b1=(Button)findViewById(R.id.button);
ed1=(EditText)findViewById(R.id.editText);
ed2=(EditText)findViewById(R.id.editText2);
b2=(Button)findViewById(R.id.button2);
tx1=(TextView)findViewById(R.id.textView3);
tx1.setVisibility(View.GONE);
b1.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if(ed1.getText().toString().equals("admin") &&
ed2.getText().toString().equals("admin")) {
Toast.makeText(getApplicationContext(), "Redirecting...",Toast.LENGTH_SHORT).show();
}
else{
Toast.makeText(getApplicationContext(), "Wrong Credentials",Toast.LENGTH_SHORT).show();
tx1.setVisibility(View.VISIBLE);
tx1.setBackgroundColor(Color.RED);
counter--;
tx1.setText(Integer.toString(counter));
if (counter == 0) {
b1.setEnabled(false);
}
}
}
});
b2.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
finish();
}
});
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}`

start activity using Intent :
if(ed1.getText().toString().equals("admin") &&
ed2.getText().toString().equals("admin")) {
Toast.makeText(getApplicationContext(), "Redirecting...",Toast.LENGTH_SHORT).show();
Intent intent=new Intent(MainActivity.this,LoginActivity.class); // redirecting to LoginActivity.
startActivity(intent);
}

MP3 songs do not play in media player

I am trying out below code
here is the MainActivity.java
import java.io.File;
import java.util.ArrayList;
import javax.crypto.spec.PSource;
import android.R.string;
import android.support.v7.app.ActionBarActivity;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.os.Environment;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.AdapterViewFlipper;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.Toast;
public class MainActivity extends ActionBarActivity {
ListView lv;
String[] items;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
lv = (ListView) findViewById(R.id.lvPlaylist);
final ArrayList<File> mySongs = findSongs(Environment.getExternalStorageDirectory());
items = new String[mySongs.size () ];
for (int i = 0; i < mySongs.size(); i++) {
//toast(mySongs.get(i).getName().toString());
items[i] = mySongs.get(i).getName().toString();
}
ArrayAdapter<String> adp = new ArrayAdapter<String>(getApplicationContext(),R.layout.list_item,R.id.textView1,items);
lv.setAdapter(adp);
lv.setOnItemClickListener(new OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
// TODO Auto-generated method stub
startActivity(new Intent(getApplicationContext(), player.class).putExtra("pos", position).putExtra("songlist",mySongs));
}
});
}
public ArrayList<File> findSongs(File root){
ArrayList al = new ArrayList<File>();
File[] files = root.listFiles();
for(File singleFile : files){
if (singleFile.isDirectory()&& !singleFile.isHidden()) {
al.addAll(findSongs(singleFile));
}
else {
if (singleFile.getName().endsWith(".mp3") || singleFile.getName().endsWith(".wav")) {
al.add(singleFile);
}
}
}
return al;
}
public void toast(String text) {
Toast.makeText(getApplicationContext(), text, Toast.LENGTH_SHORT).show();
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}
above code gives me a list of mp3 files when we click on one of the songs it takes to player.ja and songs are played
and
player.java
import java.io.File;
import java.util.ArrayList;
import android.content.Intent;
import android.media.MediaPlayer;
import android.net.Uri;
import android.os.Bundle;
import android.support.v4.widget.SimpleCursorAdapter.ViewBinder;
import android.support.v7.app.ActionBarActivity;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.Button;
import android.widget.SeekBar;
public class player extends ActionBarActivity implements View.OnClickListener{
static MediaPlayer mp;
ArrayList<File> mySongs;
int position;
Uri u;
SeekBar sb;
Button btPv, btFB,btplay,btFF, btNxt;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_player);
btFB = (Button) findViewById(R.id.btFB);
btPv = (Button) findViewById(R.id.btPv);
btplay = (Button) findViewById(R.id.btplay);
btFF = (Button) findViewById(R.id.btFF);
btNxt = (Button) findViewById(R.id.btNxt);
btFB.setOnClickListener(this) ;
btPv.setOnClickListener(this);
btplay.setOnClickListener(this);
btFF.setOnClickListener(this);
btNxt.setOnClickListener(this);
//
if(mp != null)
{
mp.stop();
mp.release();
}
Intent i = getIntent();
Bundle b = i.getExtras();
mySongs = (ArrayList) b.getParcelableArrayList("songlist");
position = b.getInt("pos", 0);
u = Uri.parse(mySongs.get(position).toString());
mp = MediaPlayer.create(getApplicationContext(), u).start();
mp.start();
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
#Override
public void onClick(View v)
{
int id = v.getId();
switch (id) {
case R.id.btplay:
if(mp.isPlaying())
{btplay.setText("play");
mp.pause();
}
else
{ btplay.setText("play");
mp.start();
}
break;
case R.id.btFF:
mp.seekTo(mp.getCurrentPosition()+ 5000);
break;
case R.id.btFB:
mp.seekTo(mp.getCurrentPosition()- 5000);
break;
case R.id.btNxt:
mp.stop();
mp.release();
position = (position+1)%mySongs.size();
u = Uri.parse(mySongs.get(position).toString());
mp = MediaPlayer.create(getApplicationContext(), u);
mp.start();
break;
case R.id.btPv :
mp.stop();
mp.release();
// Important
position = (position-1<0) ? mySongs.size()-1: position-1;
/*if(position-1 < 0)
{
position = mySongs.size()-1;
}
else
{
position= position-1;
}*/
u = Uri.parse(mySongs.get(position).toString());
mp = MediaPlayer.create(getApplicationContext(), u);
mp.start();
default:
break;
}
}
}
While the above code works perfectly fine for few songs which are mp3 but it does not work for other songs which are also mp3 . I have tried this on an actual device the app would just crash if the song has some problem
the mp3 files which give me problems work perfectly on other media players and even the default android media player
What exactly could be the issue?

you need to call mediaPlayer.prepare() or mediaPlayer.prepareAsync() before you call , mediaPlayer.start(), also if the application crash, post your log so we can know the problem.

Why doesn't my "SharedPreferences" work?

The Problem is, that the Text field which is in "Wizard2Activity" just shows "nothing" and not what the user has typed in the "EditText" in "Wizard1".
Wizard1.java:
package com.CENSORED.CENSORED;
import android.app.Activity;
import android.content.Intent;
import android.content.SharedPreferences;
import android.content.SharedPreferences.Editor;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
public class Wizard1 extends Activity {
public static final String PREFS ="examplePrefs";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_wizard1);
final EditText et = (EditText)findViewById(R.id.editText1);
Button nextAct = (Button)findViewById(R.id.button1);
nextAct.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v){
String message = et.getText().toString();
SharedPreferences examplePrefs = getSharedPreferences(PREFS, 0);
Editor editor = examplePrefs.edit();
editor.putString("usermessage", message);
editor.commit();
Intent i = new Intent(getApplicationContext(),
Wizard2Activity.class);
startActivity(i);
}
});
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is
present.
getMenuInflater().inflate(R.menu.wizard1, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}
And Wizard 2 Activity:
package com.CENSORED.CENSORED;
import android.app.Activity;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.TextView;
public class Wizard2Activity extends Activity {
public static final String PREFS ="examplePrefs";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.wizard2);
TextView tv = (TextView)findViewById(R.id.textView1);
SharedPreferences example = getSharedPreferences(PREFS, 0);
String userString = example.getString("userMessage", "nothing");
tv.setText(userString);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is
present.
getMenuInflater().inflate(R.menu.wizard2, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}
Thank you for your help! :)

You should change
String userString = example.getString("userMessage", "nothing");
to
String userString = example.getString("usermessage", "nothing");
key is usermessage. It's just typo.

Because the method
editor.putString("usermessage", message);
and
example.getString("userMessage", "nothing");
have different key.