Nothing is showing

Nothing is showing - android

I'm working on an app where I have the option of "posting", when you press the post button you go to another activity where we have an EditText and a Button, once the Button is pressed the text should be taken and "posted" in the feed page in a ListView.
Now when I press the Button everything is working fine but nothing appears in the listview.
Here's the code:
Post:
package com.example.ali.test1;
import android.app.Activity;
import android.content.Intent;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.text.Editable;
import android.view.View;
import android.widget.EditText;
public class Post extends ActionBarActivity {
EditText input;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_post);
// android:id="#+id/input"
input = (EditText) findViewById(R.id.input);
}
public void addToList(View v) {
Editable text = input.getText();
Intent intent = new Intent();
intent.putExtra("result", text);
setResult(Activity.RESULT_OK, intent);
finish();
}
}
The class where the message should be seen:
package com.example.ali.test1;
import android.app.Activity;
import android.content.Intent;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import java.util.ArrayList;
public class MainActivity extends ActionBarActivity {
ListView list;
ArrayAdapter<String> adapter;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
list= (ListView) findViewById(R.id.list);
adapter = new ArrayAdapter<>(this, android.R.layout.simple_list_item_1, new ArrayList<String>());
list.setAdapter(adapter);
}
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
if (requestCode == 1) {
if (resultCode == Activity.RESULT_OK) {
String result = data.getStringExtra("result");
adapter.add(result);
adapter.notifyDataSetChanged();
}
}
}
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();
int id2 = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
else if (id2 == R.id.action_cart) {
startActivityForResult(new Intent(MainActivity.this , Post.class), 1);
}
return super.onOptionsItemSelected(item);
}
}
The xml files:
Post:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
android:layout_height="match_parent" android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
android:paddingBottom="#dimen/activity_vertical_margin"
tools:context="com.example.ali.test1.Post">
<EditText
android:id="#+id/input"
android:layout_width="match_parent"
android:layout_height="wrap_content"
/>
<Button
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Add to list"
android:onClick="addToList"
android:layout_below="#id/input"/>
</RelativeLayout>
Main:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
android:layout_height="match_parent" android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
android:paddingBottom="#dimen/activity_vertical_margin"
tools:context="com.example.ali.test1.MainActivity">
<ListView
android:id="#+id/list"
android:layout_width="match_parent"
android:layout_height="200dp"
android:layout_weight="1" />
</RelativeLayout>
The problem is that nothing is showing in the listview
any help?

Your not sending your intent.
startActivity(intent);
Then you are not receiving your intent on the other end properly.
You are using the startActivityForResult(); strategy.
In your second activity call the getIntent() method to retrieve your intent and data.

Related

link adapter to a list view in another activity

I'm working on a posting system in an app.
What I want to do is when I press on the post icon I'll go to another Activity where I have an EditText and a Button.
When I press the button I want to get the text from the EditText and post it in the ListView of the main page or the "feed" page.
I don't seem to know how to link the array adapter to the feed so that the text appears on the ListView.
This is the code:
Main where I need to know what to do:
package com.example.ali.test1;
import android.content.Intent;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.EditText;
import android.widget.ListView;
import java.util.ArrayList;
public class MainActivity extends ActionBarActivity {
EditText input;
ListView list1;
ArrayAdapter<String> adapter;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
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();
int id2 = item.getItemId();
if (id == R.id.action_settings) {
return true;
} else if (id2 == R.id.action_cart) {
startActivity(new Intent(MainActivity.this, Post.class));
}
return super.onOptionsItemSelected(item);
}
}
This is the post activity :
package com.example.ali.test1;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.EditText;
import android.widget.ListView;
import java.util.ArrayList;
public class Post extends ActionBarActivity {
ArrayAdapter<String> adapter1;
EditText input;
ListView list;
ArrayAdapter<String> adapter;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_post);
// android:id="#+id/input"
input = (EditText) findViewById(R.id.input);
// android:id="#+id/list"
adapter = new ArrayAdapter<>(this, android.R.layout.simple_list_item_1, new ArrayList<String>());
}
// android:onClick="addToList"
public void addToList(View view) {
adapter.add(input.getText().toString());
adapter.notifyDataSetChanged();
// Clear the input
input.setText("");
}
#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_post, 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);
}
}
These are xml:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
android:layout_height="match_parent" android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
android:paddingBottom="#dimen/activity_vertical_margin"
tools:context="com.example.ali.test1.MainActivity">
<ListView
android:id="#+id/list1"
android:layout_width="match_parent"
android:layout_height="200dp"
android:layout_weight="1" />
</RelativeLayout>
post:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
android:layout_height="match_parent" android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
android:paddingBottom="#dimen/activity_vertical_margin"
tools:context="com.example.ali.test1.Post">
<EditText
android:id="#+id/input"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_below="#id/list" />
<Button
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Add to list"
android:onClick="addToList"
android:layout_below="#id/input"/>
</RelativeLayout>
Thank you!

You need to use the method startActivityForResult(new Intent(MainActivity.this, Post.class),1);
in the post activity
public void finish (View v){
String text = input.getText();
Intent intent = new Intent();
intent.putExtra("result",text);
setResult(Activity.RESULT_OK,intent);
finish();
}
and in the main activity you need to define a list for arrayAdapter and add the result to the arrayList
#Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
if (requestCode == 1) {
if(resultCode == Activity.RESULT_OK){
String result=data.getStringExtra("result");
list.add(result);
adapter.notifyDataSetChanged();
}
}
}

If the post activity is opened from the main activity - then the sensible way to do this here is to use "startActivityForResult". Your main activity should start your post activity and receive the result in
it's all here in the documentation : http://developer.android.com/training/basics/intents/result.html
You can pass the text value from the post activity back to the main activity in the extras bundle passed to onActivityResult.

editText.getText() returns null

I have tried searching for answers but i haven't found the fix for my problem yet. I have 2 activities -apple and Bacon. I am trying to learn intents and data passing between activities. The apple activity is supposed to pass the value entered in the EditText field on a button click to the bacon activity which just displays the value.
I am getting the following exception on the stack
Caused by: java.lang.NullPointerException: Attempt to invoke
virtual method 'android.text.Editable android.widget.EditText.getText()'
on a null object reference
The code snippets are as follows:-
apples.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
android:layout_height="match_parent" android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
android:paddingBottom="#dimen/activity_vertical_margin" tools:context=".Apple"
android:background="#009900">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceLarge"
android:text="Apples"
android:id="#+id/applesText"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Go to Bacon"
android:id="#+id/applesButton"
android:layout_below="#+id/applesText"
android:layout_centerHorizontal="true"
android:layout_marginTop="104dp"
android:onClick="onClickApples"/>
<EditText
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:inputType="textPersonName"
android:ems="10"
android:id="#+id/personName"
android:layout_below="#+id/applesText"
android:layout_centerHorizontal="true" />
Apples.java
package com.example.karan.intentexample;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.content.Intent;
import android.widget.EditText;
public class Apple extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_apple);
}
#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_apple, 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);
}
public void onClickApples(View view){
final EditText applesInput = (EditText)view.findViewById(R.id.personName);
String userMessage = applesInput.getText().toString();
Intent i = new Intent(this, Bacon.class);
//putExtra takes data in the form of a key-value pair
i.putExtra("appleMessage", userMessage);
startActivity(i);
}
}
Bacon.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
android:layout_height="match_parent" android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
android:paddingBottom="#dimen/activity_vertical_margin"
tools:context="com.example.karan.intentexample.Bacon"
android:background="#72231F">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceLarge"
android:text="Bacon"
android:id="#+id/baconText"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:layout_marginTop="39dp" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="New Button"
android:id="#+id/baconButton"
android:layout_below="#+id/baconText"
android:layout_centerHorizontal="true"
android:layout_marginTop="99dp" />
Bacon.java
package com.example.karan.intentexample;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.TextView;
public class Bacon extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_bacon);
Bundle applesData;
applesData = getIntent().getExtras();
//if there is no data in the intent
if(applesData==null)
return;
//get value by using the key in the getString method
String appleMessage = applesData.getString("appleMessage");
final TextView baconText = (TextView)findViewById(R.id.baconText);
baconText.setText(appleMessage);
}
#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_bacon, 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);
}
}

Here:
final EditText applesInput = (EditText)view.findViewById(R.id.personName);
view.findViewById causing issue.change it to:
final EditText applesInput = (EditText)Apple.this.findViewById(R.id.personName);
Because EditText with personName id is in Activity layout instead of inside Button layout(view parameter of onClickApples)

public class Apple extends AppCompatActivity {
private EditText applesInput;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_apple);
applesInput = (EditText)findViewByID(R.id.personName);
}
public void onClickApples(View view){
String userMessage = applesInput.getText().toString();
Intent i = new Intent(this, Bacon.class);
//putExtra takes data in the form of a key-value pair
i.putExtra("appleMessage", userMessage);
startActivity(i);
}
}

Android Spinner: Application cannot compile when using setVisibility on spinner

I've been having issues when trying to setVisibility to a spinner. Basically there are two spinners. The first spinner has the options yes and no. When the program starts the default option will be yes and the second spinner should be invisible. When the user selects no on the first spinner then the second spinner becomes visible. When I comment out the code for visibility the program compiles on the emulator.
I don't know why the app keeps crashing as soon as i try to make the spinner visible or invisible. Any help would be much appreciated. I thank you in advance for your time and effort.
This is my 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" android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
android:paddingBottom="#dimen/activity_vertical_margin" tools:context=".MainActivity">
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="horizontal" >
<TextView android:text="#string/CO" android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/co" />
<Spinner
android:id="#+id/attendance"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:entries="#array/Attendance"
android:prompt="#string/present" />
<Spinner
android:id="#+id/status"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:entries="#array/Status"
android:prompt="#string/status" />
</LinearLayout>
This is strings.xml
<resources>
<string name="app_name">Parade State Gen</string>
<string name="CO">CO</string>
<string name="present">Present?</string>
<string name="status">Status</string>
<string name="action_settings">Settings</string>
<string-array name="Attendance">
<item>Yes</item>
<item>No</item>
</string-array>
<string-array name="Status">
<item>LL</item>
<item>OL</item>
<item>PCL</item>
<item>CCL</item>
<item>O/S</item>
<item>CNB</item>
<item>TNB</item>
<item>MC</item>
<item>RSO</item>
<item>RS</item>
<item>OC</item>
<item>AS</item>
<item>AO</item>
</string-array>
This is the main class
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import java.util.ArrayList;
import java.util.List;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.Spinner;
import android.widget.Toast;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemSelectedListener;
public class MainActivity extends ActionBarActivity {
Spinner attendance, status;
private Button btnSubmit;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
addItemsOnAttendance();
//addListenerOnButton();
}
public void addItemsOnAttendance() {
attendance = (Spinner) findViewById(R.id.attendance);
final ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(
this, R.array.Attendance, android.R.layout.simple_spinner_item);
adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
attendance.setAdapter(adapter);
attendance.setOnItemSelectedListener(new OnItemSelectedListener() {
#Override
public void onItemSelected(AdapterView<?> parentView, View selectedItemView, int position, long id) {
String myData = attendance.getSelectedItem().toString();
int pos = adapter.getPosition(myData);
if (pos == 1) {
status.setVisibility(View.INVISIBLE);
//Toast.makeText(getBaseContext(), myData + " already in Spinner", Toast.LENGTH_LONG).show();
// addListenerOnSpinnerItemSelection();
} else {
}
}
#Override
public void onNothingSelected(AdapterView<?> parentView) {
// your code here
}
});
}
public void addListenerOnSpinnerItemSelection () {
status = (Spinner) findViewById(R.id.status);
ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(
this, R.array.Status, android.R.layout.simple_spinner_item);
adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
status.setAdapter(adapter);
}
#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);
}
}

You initialize spinner variable after call setVisiblity, that's why you receiving NullPointerException. It should be something like that:
addListenerOnSpinnerItemSelection();
status.setVisibility(View.INVISIBLE);
Btw, read something about logcat - it impossible to do android apps without it.

Android EditText not editable

I have a 2 activities with edittexts on them the first activity work fine but the second activity's EditText is focused but I can't edit it nor can I click the button on it.
Also everything works in the emulator but not when I install it on the device. (The keyboard popup also does not come up in the second activity where as it does in the first activity)
Below is the code for the1st and second activity
First Activity Class
package com.rohan.rohan_pc.sportappnew;
import android.content.Intent;
import android.os.AsyncTask;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
public class LoginActivity extends ActionBarActivity {
EditText edtEmail, edtPassword;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
//Initialize components
edtEmail = (EditText) findViewById(R.id.edtEmail);
edtPassword = (EditText) findViewById(R.id.edtPassword);
Button btnLogin = (Button) findViewById(R.id.btnLogin);
btnLogin.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
if (edtEmail.getText().toString().length() > 0 && edtPassword.getText().toString().length() > 0) {
new GetAllCustomerTask().execute(new ConnecterClass());
}
}
});
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.login, 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);
}
// Connect to the DB
private class GetAllCustomerTask extends AsyncTask<ConnecterClass, Long, JSONArray>
{
#Override
protected JSONArray doInBackground(ConnecterClass... params) {
// Execute in background
return params[0].usrLogin(edtEmail.getText().toString(), edtPassword.getText().toString());
}
#Override
protected void onPostExecute(JSONArray jsonArray) {
if (jsonArray != null) {
JSONObject json = null;
try {
json = jsonArray.getJSONObject(0);
if (edtEmail.getText().toString().equals(json.getString("email"))) {
if (edtPassword.getText().toString().equals(json.getString("pass"))) {
Toast toast = Toast.makeText(getApplicationContext(), "login successful", Toast.LENGTH_SHORT);
toast.show();
Intent intent = new Intent(LoginActivity.this, SearchActivity.class);
//Pass the school_id
intent.putExtra("SCHOOL_ID", json.getInt("school_id"));
startActivity(intent);
} else {
Toast toast = Toast.makeText(getApplicationContext(), "password incorrect", Toast.LENGTH_SHORT);
toast.show();
}
} else {
Toast toast = Toast.makeText(getApplicationContext(), "failed to login ...", Toast.LENGTH_SHORT);
toast.show();
}
} catch (JSONException e) {
e.printStackTrace();
}
//login(edtEmail.getText().toString(),""
/*
//Got to second screen if login is successful
Intent intent = new Intent(LoginActivity.this, AfterLogin.class);
//Pass the table name through
intent.putExtra("CLIENT_DB", clientDB);
startActivity(intent);
*/
}
}
}
}
Second Activity Class
> package com.rohan.rohan_pc.sportappnew;
import android.content.Intent;
import android.os.AsyncTask;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.WindowManager;
import android.widget.AdapterView;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.Toast;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
public class SearchActivity extends ActionBarActivity {
EditText edtFName, edtLName, edtIDNum;
ListView listViewSearch;
String sFName, sLName, sIDNum;
int school_id;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_search);
edtFName = (EditText) findViewById(R.id.edtFirstName);
edtLName = (EditText) findViewById(R.id.edtLastName);
edtIDNum = (EditText) findViewById(R.id.edtIDNum);
Button btnSearch = (Button) findViewById(R.id.btnSearch);
listViewSearch = (ListView) this.findViewById(R.id.listViewSearch);
//Initialize the default values for the search criteria variables
sFName = "";
sLName = "";
sIDNum = "";
//Load school_id
school_id = getIntent().getExtras().getInt("SCHOOL_ID");
if(edtFName.requestFocus()) { getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_STATE_ALWAYS_VISIBLE); }
btnSearch.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
if(edtFName.getText().toString().length() > 0)
{
sFName = edtFName.getText().toString().trim();
}
if(edtLName.getText().toString().length() > 0)
{
sLName = edtLName.getText().toString().trim();
}
if(edtIDNum.getText().toString().length() > 0)
{
sIDNum = edtIDNum.getText().toString().trim();
}
new SearchAllCustomers().execute(new ConnecterClass());
}
});
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.search, 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);
}
//Search in the background
public void setListViewArray(final JSONArray jsonArray)
{
this.listViewSearch.setAdapter(new Search_ListView_Adapter(jsonArray, this));
//Setup what happens when a user clicks on a searched item
this.listViewSearch.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
try{
JSONObject clickedItem = jsonArray.getJSONObject(position);
Intent askActivity = new Intent(getApplicationContext(), AskActivity.class);
askActivity.putExtra("IDNUM", clickedItem.getString("idnum"));
askActivity.putExtra("SCHOOL_ID", clickedItem.getInt("school_id"));
startActivity(askActivity);
} catch (JSONException e) {
e.printStackTrace();
}
}
});
}
// Connect to the DB
private class SearchAllCustomers extends AsyncTask<ConnecterClass, Long, JSONArray>
{
#Override
protected JSONArray doInBackground(ConnecterClass... params) {
// Execute in background
return params[0].searchPlayers(school_id, sFName, sLName, sIDNum);
}
#Override
protected void onPostExecute(JSONArray jsonArray) {
if (jsonArray != null) {
setListViewArray(jsonArray);
//login(edtEmail.getText().toString(),""
/*
//Got to second screen if login is successful
Intent intent = new Intent(LoginActivity.this, AfterLogin.class);
//Pass the table name through
intent.putExtra("CLIENT_DB", clientDB);
startActivity(intent);
*/
}
}
}
}
The XML - First Activity
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
android:paddingBottom="#dimen/activity_vertical_margin"
tools:context=".LoginAcivity">
<EditText
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:inputType="textEmailAddress"
android:ems="10"
android:id="#+id/edtEmail"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:layout_marginTop="52dp"
android:hint="email ..."
/>
<EditText
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:inputType="textPassword"
android:ems="10"
android:id="#+id/edtPassword"
android:layout_below="#+id/edtEmail"
android:layout_centerHorizontal="true"
android:layout_marginTop="44dp"
android:hint="password ..."
/>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="New Button"
android:id="#+id/btnLogin"
android:layout_below="#+id/edtPassword"
android:layout_centerHorizontal="true"
android:layout_marginTop="49dp" />
</RelativeLayout>
The XML - Second Activity
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
android:paddingBottom="#dimen/activity_vertical_margin"
tools:context="com.rohan.rohan_pc.sportsappv001.SearchActivity">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceLarge"
android:text="Search"
android:id="#+id/textView"
android:layout_alignParentTop="true"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true" />
<EditText
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:inputType="textPersonName"
android:hint="Name"
android:ems="10"
android:id="#+id/edtFirstName"
android:layout_below="#+id/textView"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true" />
<EditText
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:inputType="textPersonName"
android:hint="Surname"
android:ems="10"
android:id="#+id/edtLastName"
android:layout_below="#+id/edtFirstName"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true" />
<EditText
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/edtIDNum"
android:hint="ID Number"
android:layout_below="#+id/edtLastName"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_alignRight="#+id/edtLastName"
android:layout_alignEnd="#+id/edtLastName" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Search"
android:id="#+id/btnSearch"
android:layout_below="#+id/edtIDNum"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_marginLeft="64dp"
android:layout_marginTop="42dp" />
<ListView
android:layout_width="wrap_content"
android:layout_height="200dp"
android:id="#+id/listViewSearch"
android:layout_alignParentBottom="true"
android:layout_toEndOf="#+id/edtIDNum"
android:layout_alignTop="#+id/edtFirstName"
android:clickable="true"
/>

I just figured to re-create the app. I dont think it is a wise decision to copy the raw files to another directory and use that.

App is crashing before opening

I'm working on an app and I've been working on a "post" service where you can write a post and display it on a feed screen made of listview.
Now everything seem to be fine but I don't know why it's crashing before even starting.
Here is the code:
Post class:
package com.example.ali.test1;
import android.app.Activity;
import android.content.Intent;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.text.Editable;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.EditText;
import android.widget.ListView;
import java.util.ArrayList;
public class Post extends ActionBarActivity {
EditText input;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_post);
// android:id="#+id/input"
input = (EditText) findViewById(R.id.input);
// android:id="#+id/list"
startActivityForResult(new Intent(Post.this , MainActivity.class), 1);
}
public void addToList(View v) {
Editable text = input.getText();
Intent intent = new Intent();
intent.putExtra("result", text);
setResult(Activity.RESULT_OK, intent);
finish();
}
}
in this class I have an edit text and abutton once the button is pressed I'm supposed to get the text in edit text and post in the listView of the other class
Main:
package com.example.ali.test1;
import android.app.Activity;
import android.content.Intent;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import java.util.ArrayList;
public class MainActivity extends ActionBarActivity {
ListView list;
ArrayAdapter<String> adapter;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
adapter = new ArrayAdapter<>(this, android.R.layout.simple_list_item_1, new ArrayList<String>());
list.setAdapter(adapter);
}
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
if (requestCode == 1) if (resultCode == Activity.RESULT_OK) {
String result = data.getStringExtra("result");
adapter.add(result);
adapter.notifyDataSetChanged();
}
}
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();
int id2 = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
else if (id2 == R.id.action_cart) {
startActivity(new Intent(MainActivity.this, Post.class));
}
return super.onOptionsItemSelected(item);
}
}
And the xml files are:
Post:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
android:layout_height="match_parent" android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
android:paddingBottom="#dimen/activity_vertical_margin"
tools:context="com.example.ali.test1.Post">
<EditText
android:id="#+id/input"
android:layout_width="match_parent"
android:layout_height="wrap_content"
/>
<Button
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Add to list"
android:onClick="addToList"
android:layout_below="#id/input"/>
</RelativeLayout>
Main:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
android:layout_height="match_parent" android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
android:paddingBottom="#dimen/activity_vertical_margin"
tools:context="com.example.ali.test1.MainActivity">
<ListView
android:id="#+id/list1"
android:layout_width="match_parent"
android:layout_height="200dp"
android:layout_weight="1" />
</RelativeLayout>
any help would be appreciated I've been stuck here for too long.
Thank You.

You are trying to add adapter to a listview which is null, that's why you must be getting NullPointerException. You need to initialize it before you can use it.
You need to add
list= (ListView) findViewById(R.id.mylistview); // replace R.id.mylistview with the id of your listview in layout activity_main
after
setContentView(R.layout.activity_main);
in onCreate method of MainActivity

Change your MainActivity .Because you not initialize Listview properly.
ListView list;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
list= (ListView) findViewById(R.id.list1);
adapter = new ArrayAdapter<>(this, android.R.layout.simple_list_item_1, new ArrayList<String>());
list.setAdapter(adapter);
}

First, sorry for my english.
There is problem with android app going to background, where OS release memory for other functions on OS or other application, when it need's memory. There release your object and you have NullPointerException on resume.
How fix this? OnResume event check object value and if it is null, create object.
How test this? Kill process in Android Device Monitor

Develop Reference

The Android operating system is a mobile operating system that was developed by Google (GOOGL?) to be primarily used for touchscreen devices, cell phones, and tablets.

Nothing is showing - android

Your not sending your intent. startActivity(intent); Then you are not receiving your intent on the other end properly. You are using the startActivityForResult(); strategy. In your second activity call the getIntent() method to retrieve your intent and data.

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