Develop Reference

Why is Android closing the application without showing the "<application> has stopped unexpectedly" message?

I am in the process of learning Android development and was trying to crash my application at runtime. I made a button that calls a method when clicked and then made sure that the method does not exist.
The application starts up fine. As soon as i click the button, the application closes just as intended. The only unexpected thing was that my device did not show any error message like application has closed unexpectedly or that the application force closed.
Did I accidentally turn off some setting in the Developer Options or is it just my device that doesn't like showing error messages ? Any more information needed ?
activity_main.xml :
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/activity_main"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
android:orientation="vertical"
tools:context="com.example.android.justjava.MainActivity">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Quantity"
android:textAllCaps="true" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/quantity_text_view"
android:layout_marginBottom="16dp"
android:layout_marginTop="16dp"
android:textColor="#000000"
android:text="0"
android:textSize="16sp" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Price"
android:textAllCaps="true" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/price_text_view"
android:layout_marginBottom="16dp"
android:layout_marginTop="16dp"
android:textColor="#000000"
android:text="$0"
android:textSize="16sp" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAllCaps="true"
android:text="ORDER"
android:onClick="submitOrder"/>
</LinearLayout>
MainActivity.java:
package com.example.android.justjava;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.TextView;
import java.text.NumberFormat;
/**
* This app displays an order form to order coffee.
*/
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
/**
* This method is called when the order button is clicked.
*/
public void submitOrders(View view) {
int quantity = 5 ;
display(quantity) ;
displayPrice(quantity * 50) ;
}
/**
* This method displays the given quantity value on the screen.
*/
private void display(int number) {
TextView quantityTextView = (TextView) findViewById(R.id.quantity_text_view);
quantityTextView.setText("" + number);
}
private void displayPrice(int number) {
TextView priceTextView = (TextView) findViewById(R.id.price_text_view);
priceTextView.setText(NumberFormat.getCurrencyInstance().format(number));
}
}
Logcat:
01-20 16:08:54.087 28870-28893/? I/OpenGLRenderer: Initialized EGL,
version 1.4 01-20 16:08:54.087 28870-28893/? D/OpenGLRenderer: Swap
behavior 1 01-20 16:08:58.044 28870-28870/com.example.android.justjava
V/BoostFramework: BoostFramework() : mPerf =
com.qualcomm.qti.Performance#b82000f 01-20 16:08:58.119
28870-28870/com.example.android.justjava D/AndroidRuntime: Shutting
down VM 01-20 16:08:58.120 28870-28870/com.example.android.justjava
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.android.justjava, PID: 28870
java.lang.IllegalStateException: Could not find method
submitOrder(View) in a parent or ancestor Context for android:onClick
attribute defined on view class
android.support.v7.widget.AppCompatButton
at
android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.resolveMethod(AppCompatViewInflater.java:327)
at
android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:284)
at android.view.View.performClick(View.java:5642)
at android.view.View$PerformClick.run(View.java:22338)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6209)
at java.lang.reflect.Method.invoke(Native Method)
at
com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:865)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:755) 01-20
16:08:58.120 28870-28870/com.example.android.justjava D/AppTracker:
App Event: crash 01-20 16:08:58.132 28870-28870/? I/Process: Sending
signal. PID: 28870 SIG: 9
It's based on this Udacity course.

In your XML button, its submitOrder not submitOrders. See the extra S :
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAllCaps="true"
android:text="ORDER"
android:onClick="submitOrder"/>
So, change this:
public void submitOrders(View view) {
With this:
public void submitOrder(View view) {

Remove s from method name submitOrders
public void submitOrder(View view) {
int quantity = 5 ;
display(quantity) ;
displayPrice(quantity * 50) ;
}
Or You can remove android:onClick="submitOrder"
<Button
android:id="#+id/order"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAllCaps="true"
android:text="ORDER"/>
than in your java file
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button order = (Button)findViewById(R.id.order);
order.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
int quantity = 5 ;
display(quantity) ;
displayPrice(quantity * 50) ;
}
});
}

AndroidRuntime shutting down Fatal Exception: main Android Studio 2.2

working on an app and ran into a problem only when I run it on a phone.
Here is the Run info:
09/24 21:02:00: Launching app
Cold swapped changes.
$ adb shell am start -n "com.example.crow.page3/com.example.crow.page3.Page3main" -a android.intent.action.MAIN -c android.intent.category.LAUNCHER
Client not ready yet..Connected to process 1154 on device oneplus-a0001-793b4d36
I/art: Late-enabling -Xcheck:jni
W/System: ClassLoader referenced unknown path: /data/app/com.example.crow.page3-2/lib/arm
I/InstantRun: Instant Run Runtime started. Android package is com.example.crow.page3, real application class is null.
W/System: ClassLoader referenced unknown path: /data/app/com.example.crow.page3-2/lib/arm
I/LoadedApk: No resource references to update in package common
I/LoadedApk: No resource references to update in package com.blinq.theme.CleanUI.blue
I/LoadedApk: No resource references to update in package com.blinq.theme.CleanUI.blue
W/art: Before Android 4.1, method android.graphics.PorterDuffColorFilter android.support.graphics.drawable.VectorDrawableCompat.updateTintFilter(android.graphics.PorterDuffColorFilter, android.content.res.ColorStateList, android.graphics.PorterDuff$Mode) would have incorrectly overridden the package-private method in android.graphics.drawable.Drawable
D/AndroidRuntime: Shutting down VM
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.crow.page3, PID: 1154
Theme: themes:{default=overlay:com.blinq.theme.CleanUI.blue, iconPack:com.blinq.theme.CleanUI.blue, fontPkg:com.blinq.theme.CleanUI.blue, com.android.systemui=overlay:com.blinq.theme.CleanUI.blue, com.android.systemui.navbar=overlay:com.blinq.theme.CleanUI.blue}
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.crow.page3/com.example.crow.page3.Page3main}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.TabHost.setup()' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2450)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2510)
at android.app.ActivityThread.-wrap11(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1363)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5461)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.TabHost.setup()' on a null object reference
at com.example.crow.page3.Page3main.onCreate(Page3main.java:54)
at android.app.Activity.performCreate(Activity.java:6251)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1108)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2403)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2510) 
at android.app.ActivityThread.-wrap11(ActivityThread.java) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1363) 
at android.os.Handler.dispatchMessage(Handler.java:102) 
at android.os.Looper.loop(Looper.java:148) 
at android.app.ActivityThread.main(ActivityThread.java:5461) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616) 
I/Process: Sending signal. PID: 1154 SIG: 9
Application terminated.
I have tried several things and been over the code multiple times. below is the code for com.example.crow.page3.Page3main:
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.EditText;
import android.widget.Button;
import android.widget.TabHost;
import android.app.Activity;
import com.google.android.gms.appindexing.Action;
import com.google.android.gms.appindexing.AppIndex;
import com.google.android.gms.appindexing.Thing;
import com.google.android.gms.common.api.GoogleApiClient;
public class Page3main extends AppCompatActivity implements NavigationView.OnNavigationItemSelectedListener {
EditText nameTxt, phoneTxt, emailTxt, addressTxt;
/**
* ATTENTION: This was auto-generated to implement the App Indexing API.
* See https://g.co/AppIndexing/AndroidStudio for more information.
*/
private GoogleApiClient client;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//add new contact:--------------------------------------------------
setContentView(R.layout.activity_page3main);
nameTxt = (EditText) findViewById(R.id.txtName);
phoneTxt = (EditText) findViewById(R.id.txtPhone);
emailTxt = (EditText) findViewById(R.id.txtEmail);
addressTxt = (EditText) findViewById(R.id.txtAddress);
//define tabs for from add contact tabs
TabHost tabHost = (TabHost) findViewById(R.id.tabHost);
tabHost.setup();
TabHost.TabSpec tabSpec = tabHost.newTabSpec("creator");
tabSpec.setContent(R.id.tabAddContact);
tabSpec.setIndicator("Creator");
tabHost.addTab(tabSpec);
tabSpec = tabHost.newTabSpec("list");
tabSpec.setContent(R.id.tabContactList);
tabSpec.setIndicator("List");
tabHost.addTab(tabSpec);
final Button addBtn = (Button) findViewById(R.id.btnAdd);
//What happens on :
nameTxt.addTextChangedListener(new TextWatcher() {
#Override
public void beforeTextChanged(CharSequence s, int i, int i2, int i3) {
}
#Override
public void onTextChanged(CharSequence s, int i, int i2, int i3) {
//check if there was input in the text
addBtn.setEnabled(!nameTxt.getText().toString().trim().isEmpty());
}
#Override
public void afterTextChanged(Editable editable) {
}
});
//-------------------------------------------------------------------
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
.setAction("Action", null).show();
}
});
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
drawer.setDrawerListener(toggle);
toggle.syncState();
NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
navigationView.setNavigationItemSelectedListener(this);
// ATTENTION: This was auto-generated to implement the App Indexing API.
// See https://g.co/AppIndexing/AndroidStudio for more information.
client = new GoogleApiClient.Builder(this).addApi(AppIndex.API).build();
}
#Override
public void onBackPressed() {
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
if (drawer.isDrawerOpen(GravityCompat.START)) {
drawer.closeDrawer(GravityCompat.START);
} else {
super.onBackPressed();
}
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.page3main, 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);
}
#SuppressWarnings("StatementWithEmptyBody")
#Override
public boolean onNavigationItemSelected(MenuItem item) {
// Handle navigation view item clicks here.
int id = item.getItemId();
FragmentManager fragmentManager = getFragmentManager();
if (id == R.id.nav_logbook) {
fragmentManager.beginTransaction()
.replace(R.id.content_frame, new FirstFragmentLogbook()).commit();
} else if (id == R.id.nav_contacts) {
fragmentManager.beginTransaction()
.replace(R.id.content_frame, new SecondFragmentContacts()).commit();
} else if (id == R.id.nav_map) {
fragmentManager.beginTransaction()
.replace(R.id.content_frame, new ThirdFragmentMap()).commit();
} else if (id == R.id.nav_site_info) {
} else if (id == R.id.nav_share) {
} else if (id == R.id.nav_send) {
}
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
drawer.closeDrawer(GravityCompat.START);
return true;
}
/**
* ATTENTION: This was auto-generated to implement the App Indexing API.
* See https://g.co/AppIndexing/AndroidStudio for more information.
*/
public Action getIndexApiAction() {
Thing object = new Thing.Builder()
.setName("Page3main Page") // TODO: Define a title for the content shown.
// TODO: Make sure this auto-generated URL is correct.
.setUrl(Uri.parse("http://[ENTER-YOUR-URL-HERE]"))
.build();
return new Action.Builder(Action.TYPE_VIEW)
.setObject(object)
.setActionStatus(Action.STATUS_TYPE_COMPLETED)
.build();
}
#Override
public void onStart() {
super.onStart();
// ATTENTION: This was auto-generated to implement the App Indexing API.
// See https://g.co/AppIndexing/AndroidStudio for more information.
client.connect();
AppIndex.AppIndexApi.start(client, getIndexApiAction());
}
#Override
public void onStop() {
super.onStop();
// ATTENTION: This was auto-generated to implement the App Indexing API.
// See https://g.co/AppIndexing/AndroidStudio for more information.
AppIndex.AppIndexApi.end(client, getIndexApiAction());
client.disconnect();
}
}
Any ideas would be greatly appreciated. Thanks
Layout code:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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"
tools:context=".Page3main"
android:orientation="vertical"
android:baselineAligned="false"
android:weightSum="1">
<TabHost
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:id="#+id/tabHost"
android:layout_gravity="left|center_vertical">
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical">
<TabWidget
android:id="#android:id/tabs"
android:layout_width="fill_parent"
android:layout_height="wrap_content">
</TabWidget>
<FrameLayout
android:id="#android:id/tabcontent"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<LinearLayout
android:id="#+id/tabContactList"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<TextView
android:text="TextView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="#+id/textView3"
android:textAppearance="#android:style/TextAppearance.Material.Large"
android:layout_margin="10dp"
android:layout_gravity="center"
android:textAlignment="center" />
<ListView
android:layout_width="match_parent"
android:layout_height="match_parent" />
</LinearLayout>
<LinearLayout
android:id="#+id/tabAddContact"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/lblCreatorTitle"
android:layout_gravity="center"
android:textAppearance="?android:attr/textAppearanceLarge"
android:text="New Contact"
android:layout_margin="10dp" />
<EditText
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:ems="10"
android:id="#+id/txtName"
android:hint="Name"
android:inputType="textPersonName"
android:layout_gravity="center"
android:layout_weight="0.10"
android:drawableStart="#drawable/ic_contacts_black_24dp" />
<EditText
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:inputType="phone"
android:ems="10"
android:id="#+id/txtPhone"
android:hint="Phone"
android:layout_gravity="center"
android:layout_weight="0.10"
android:drawableStart="#drawable/ic_call_black_24dp" />
<EditText
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:inputType="textEmailAddress"
android:ems="10"
android:id="#+id/txtEmail"
android:hint="Email"
android:layout_gravity="center"
android:layout_weight="0.10"
android:drawableStart="#drawable/ic_email_black_24dp" />
<EditText
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:inputType="textPostalAddress"
android:ems="10"
android:id="#+id/txtAddress"
android:hint="Address"
android:layout_gravity="center"
android:layout_weight="0.10"
android:drawableStart="#drawable/ic_place_black_24dp" />
<Button
android:text="Add"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="#+id/btnAdd"
android:textAlignment="center"
android:layout_gravity="center" />
</LinearLayout>
</FrameLayout>
</LinearLayout>
</TabHost>
</LinearLayout>

As per your log you are getting a null pointer exception at android.widget.TabHost.setup()
The problem is probably in the following lines of code
//define tabs for from add contact tabs
TabHost tabHost = (TabHost) findViewById(R.id.tabHost);
tabHost.setup();
In the above code the R.id.tabHost is returning a null pointer. Please check that you have this id defined in your layout. Also if you post the code where this ID is placed I could assist you further.
EDIT
Ok so the problem is you are calling setup method after you have loaded the tabs using findViewById. You must call setup method before loading tabs by findViewByid.
See the screenshot below of the developer documentation.
Here is the link to the documentation page. I hope this helps.

getSelectedItemPosition android

I have been racking my brain trying to figure out why this won't work. I need to return the index of a selected item in a spinner (4 spinners actually but can't even get one to work).
Here is the XML file
<?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="match_parent"
android:layout_height="match_parent"
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
tools:context="com.agcinstruments.lab41.MainActivity"
android:background="#color/Navy">
<ImageView
android:id="#+id/resistor2"
android:layout_width="fill_parent"
android:layout_height="200dp"
android:src="#drawable/resistor2"/>
<TextView
android:background="#color/Navy"
android:layout_marginTop="36dp"
android:layout_marginLeft="120dp"
android:layout_width="25dp"
android:layout_height="73dp"
/>
<TextView
android:background="#color/Navy"
android:layout_marginTop="36dp"
android:layout_centerHorizontal="true"
android:layout_width="25dp"
android:layout_height="73dp"
/>
<TextView
android:id="#+id/q"
android:background="#color/Navy"
android:layout_marginTop="36dp"
android:layout_marginLeft="208dp"
android:layout_width="25dp"
android:layout_height="73dp"
/>
<TextView
android:background="#color/Navy"
android:layout_marginTop="26dp"
android:layout_marginLeft="257dp"
android:layout_width="25dp"
android:layout_height="94dp"
/>
<Spinner
android:id="#+id/Spinner1"
android:layout_below="#+id/resistor2"
android:layout_width="85dp"
android:entries="#array/color_array1"
android:layout_height="wrap_content"
android:background="#color/White"/>
<Spinner
android:id="#+id/Spinner2"
android:layout_below="#id/resistor2"
android:layout_toRightOf="#+id/Spinner1"
android:layout_width="85dp"
android:entries="#array/color_array2"
android:layout_height="wrap_content"
android:background="#color/White"/>
<Spinner
android:id="#+id/Spinner3"
android:layout_below="#id/resistor2"
android:layout_toRightOf="#+id/Spinner2"
android:layout_width="85dp"
android:entries="#array/color_array3"
android:layout_height="wrap_content"
android:background="#color/White"/>
<Spinner
android:id="#+id/Spinner4"
android:layout_below="#id/resistor2"
android:layout_toRightOf="#+id/Spinner3"
android:layout_width="85dp"
android:entries="#array/color_array4"
android:layout_height="wrap_content"
android:background="#color/White"/>
<Button
android:id="#+id/calculate"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="#id/Spinner4"
android:layout_centerHorizontal="true"
android:text="#string/calculate"
android:onClick="onClickCalculate"/>
<TextView
android:id="#+id/resultText"
android:layout_width="50dp"
android:layout_height="50dp"
android:textColor="#color/Red"
android:layout_below="#+id/calculate"
android:layout_centerHorizontal="true"
android:background="#color/White" />
<EditText
android:id="#+id/tolerance"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textColor="#color/Red"/>
<EditText
android:id="#+id/ohm"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textColor="#color/Red"/>
</RelativeLayout>
And here is the java code
package com.agcinstruments.lab41;
import android.net.Uri;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.app.ListActivity;
import android.widget.ArrayAdapter;
import android.widget.Spinner;
import android.widget.TextView;
import com.google.android.gms.appindexing.Action;
import com.google.android.gms.appindexing.AppIndex;
import com.google.android.gms.common.api.GoogleApiClient;
import com.google.android.gms.common.server.converter.StringToIntConverter;
import java.util.List;
public class MainActivity extends AppCompatActivity {
public Spinner Spinner1;
public Spinner Spinner2;
public Spinner Spinner3;
public Spinner Spinner4;
int value = 0 ;
int position = 0 ;
TextView resultText;
/**
* ATTENTION: This was auto-generated to implement the App Indexing API.
* See https://g.co/AppIndexing/AndroidStudio for more information.
*/
private GoogleApiClient client;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
resultText = (TextView) findViewById(R.id.resultText);
// ATTENTION: This was auto-generated to implement the App Indexing API.
// See https://g.co/AppIndexing/AndroidStudio for more information.
client = new GoogleApiClient.Builder(this).addApi(AppIndex.API).build();
}
public void onClickCalculate(View view) {
position = Spinner2.getSelectedItemPosition(); // This is the problem.I suspect the adaptor is not working.
value = position * 10;
resultText.setText(Integer.toString(value));
//resultText.setBackgroundColor()
}
public void resistorValue2(View view) {
value = value + (1);
}
public void resistorMultiplier(View view) {
value = value + (1);
}
public void resistorTolerance(View view) {
value = value + (1);
}
#Override
public void onStart() {
super.onStart();
// ATTENTION: This was auto-generated to implement the App Indexing API.
// See https://g.co/AppIndexing/AndroidStudio for more information.
client.connect();
Action viewAction = Action.newAction(
Action.TYPE_VIEW, // TODO: choose an action type.
"Main Page", // TODO: Define a title for the content shown.
// TODO: If you have web page content that matches this app activity's content,
// make sure this auto-generated web page URL is correct.
// Otherwise, set the URL to null.
Uri.parse("http://host/path"),
// TODO: Make sure this auto-generated app deep link URI is correct.
Uri.parse("android-app://com.agcinstruments.lab41/http/host/path")
);
AppIndex.AppIndexApi.start(client, viewAction);
}
#Override
public void onStop() {
super.onStop();
// ATTENTION: This was auto-generated to implement the App Indexing API.
// See https://g.co/AppIndexing/AndroidStudio for more information.
Action viewAction = Action.newAction(
Action.TYPE_VIEW, // TODO: choose an action type.
"Main Page", // TODO: Define a title for the content shown.
// TODO: If you have web page content that matches this app activity's content,
// make sure this auto-generated web page URL is correct.
// Otherwise, set the URL to null.
Uri.parse("http://host/path"),
// TODO: Make sure this auto-generated app deep link URI is correct.
Uri.parse("android-app://com.agcinstruments.lab41/http/host/path")
);
AppIndex.AppIndexApi.end(client, viewAction);
client.disconnect();
}
}
This is the strings.xml file i use to populate the array.
<resources>
<string name="app_name">lab4.1</string>
<string name="calculate">CALCULATE</string>
<string-array name="color_array1">
<item>BLACK</item>
<item>BROWN</item>
<item>RED</item>
<item>ORANGE</item>
<item>YELLOW</item>
<item>GREEN</item>
<item>BLUE</item>
<item>PURPLE</item>
<item>GREY</item>
<item>WHITE</item>
</string-array>
<string-array name="color_array2">
<item>BLACK</item>
<item>BROWN</item>
<item>RED</item>
<item>ORANGE</item>
<item>YELLOW</item>
<item>GREEN</item>
<item>BLUE</item>
<item>PURPLE</item>
<item>GREY</item>
<item>WHITE</item>
</string-array>
<string-array name="color_array3">
<item>BLACK</item>
<item>BROWN</item>
<item>RED</item>
<item>ORANGE</item>
<item>YELLOW</item>
<item>GREEN</item>
<item>BLUE</item>
<item>PURPLE</item>
<item>GREY</item>
<item>WHITE</item>
</string-array>
<string-array name="color_array4">
<item>BLACK</item>
<item>BROWN</item>
<item>RED</item>
<item>ORANGE</item>
<item>YELLOW</item>
<item>GREEN</item>
<item>BLUE</item>
<item>PURPLE</item>
<item>GREY</item>
<item>WHITE</item>
</string-array>
I am do not know a lot of JAVA this is a stumbling block on my road to enlightnment hopefully. Any help would be greatly appreciated. I have spent hours trying to figure out a solution.

Application Unfortunately stopped when going from 2nd activity to 3rd activity

I'm new to Android developing. This is an assignment which was given to me. I have to convert the value and the converted value must be shown in the next activity. But when I press the submit button its crashes.I don;t know what is the problem. Is there a problem with my RadioButtons. Please help me...
This is the second activity(ConvertActivity)
package com.gihan.temperatureconverter;
import android.content.Intent;
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.EditText;
import android.widget.RadioButton;
public class ConvertActivity extends ActionBarActivity {
//RadioButton cel=(RadioButton) findViewById(R.id.rCel);
//RadioButton fah=(RadioButton) findViewById(R.id.rFah);
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_convert);
}
#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_convert, 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 calculation(View view) {
EditText val=(EditText) findViewById(R.id.editText);
int value = Integer.valueOf(val.getText().toString()).intValue();
int ans=0;
int fahval=0;
int celval=0;
boolean checked = ((RadioButton) view).isChecked();
switch(view.getId()) {
case R.id.rCel:
if (checked){
ans=((value-32)*5/9);
fahval=value;
celval=ans;}
break;
case R.id.rFah:
if (checked){
ans=((value*9)/5)+32;
celval=value;
fahval=ans;}
break;
}
/*if (cel.isChecked()){
ans=((value-32)*5/9);
fahval=value;
celval=ans;
}
if (fah.isChecked()){
ans=((value*9)/5)+32;
celval=value;
fahval=ans;
}*/
Intent intent = new Intent(ConvertActivity.this, LastActivity.class);
intent.putExtra("celval", getText(celval));
intent.putExtra("fahval", getText(fahval));
ConvertActivity.this.startActivity(intent);
}
}
This is the 2nd XML(activity_convert)
<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.gihan.temperatureconverter.ConvertActivity"
android:background="#drawable/ic_background">
<EditText
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:inputType="numberDecimal"
android:ems="10"
android:id="#+id/editText"
android:layout_alignParentTop="true"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_marginTop="50dp"
android:hint="Enter Value"
android:textSize="20dp"/>
<RadioGroup
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/radioGroup"
android:layout_below="#+id/editText"
android:layout_centerHorizontal="true">
<RadioButton
android:layout_width="200dp"
android:layout_height="wrap_content"
android:text="To Celsius"
android:id="#+id/rCel"
android:layout_below="#+id/editText"
android:layout_centerHorizontal="true"
android:layout_marginTop="50dp"
android:checked="false"
android:gravity="fill_horizontal"
android:textColor="#ffc80301"
android:textSize="25sp"/>
<RadioButton
android:layout_width="200dp"
android:layout_height="wrap_content"
android:text="To Fahrenheit"
android:id="#+id/rFah"
android:checked="false"
android:gravity="fill_horizontal"
android:textColor="#ffc80301"
android:textSize="25sp"
android:layout_below="#+id/rCel"
android:layout_alignLeft="#+id/rCel"
android:layout_alignStart="#+id/rCel" />
</RadioGroup>
<Button
android:layout_width="200dp"
android:layout_height="wrap_content"
android:text="Submit"
android:id="#+id/sub"
android:onClick="calculation"
android:layout_below="#+id/radioGroup"
android:layout_centerHorizontal="true"
android:layout_marginTop="80dp" />
</RelativeLayout>
This is the 3rd activity(LastActivity)
package com.gihan.temperatureconverter;
import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.TextView;
public class LastActivity extends ActionBarActivity {
TextView vFah=(TextView)findViewById(R.id.vFah);
TextView vCel=(TextView)findViewById(R.id.vCel);
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_last);//use whatever layout you want.
Bundle extras = getIntent().getExtras();
int celval=extras.getInt("celval");
int fahval=extras.getInt("fahval");
//String cel=String.valueOf(celval);
//String fah=String.valueOf(fahval);
vCel.setText(Integer.toString(celval));
vFah.setText(Integer.toString(fahval));
}
#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_convert, 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 again(View view) {
Intent intent = new Intent(LastActivity.this, ConvertActivity.class);
LastActivity.this.startActivity(intent);
}
public void home(View view) {
Intent intent = new Intent(LastActivity.this, MainActivity.class);
LastActivity.this.startActivity(intent);
}
}
This is the 3rd XML(activity_last)
<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:background="#drawable/ic_background"
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.gihan.temperatureconverter.LastActivity">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceLarge"
android:text="Successfully Converted"
android:id="#+id/textView2"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:layout_marginTop="30dp"
android:textColor="#ffff0004"
android:textSize="30sp"/>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Home"
android:id="#+id/button2"
android:layout_alignParentBottom="true"
android:layout_centerHorizontal="true"
android:layout_marginBottom="70dp"
android:gravity="center_horizontal"
android:textSize="25sp"
android:onClick="home"/>
<Button
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Calculate again"
android:id="#+id/button3"
android:layout_marginBottom="45dp"
android:gravity="center_horizontal"
android:layout_above="#+id/button2"
android:layout_centerHorizontal="true"
android:textSize="25sp"
android:onClick="again"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceLarge"
android:text="Fahrenheit"
android:id="#+id/textView3"
android:layout_below="#+id/textView2"
android:layout_centerHorizontal="true"
android:layout_marginTop="30dp"
android:textColor="#ff0010ff" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceLarge"
android:text="Celsius"
android:id="#+id/textView4"
android:layout_below="#+id/textView3"
android:layout_centerHorizontal="true"
android:layout_marginTop="52dp"
android:textColor="#ff0010ff" />
<TextView
android:layout_width="wrap_content"
android:layout_height="20sp"
android:id="#+id/vFah"
android:layout_below="#+id/textView3"
android:layout_centerHorizontal="true"
android:textColor="#ff9300ff"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="20sp"
android:id="#+id/vCel"
android:layout_below="#+id/textView4"
android:layout_centerHorizontal="true"
android:textColor="#ff9300ff"/>
</RelativeLayout>
AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.gihan.temperatureconverter" >
<application
android:allowBackup="true"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<activity
android:name=".MainActivity"
android:label="#string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name=".ConvertActivity"
android:label="#string/app_name">
</activity>
<activity
android:name=".LastActivity"
android:label="#string/app_name">
</activity>
</application>
</manifest>
Logcat
--------- beginning of crash
06-09 21:05:58.413 2381-2381/? E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.gihan.temperatureconverter, PID: 2381
java.lang.IllegalStateException: Could not execute method of the activity
at android.view.View$1.onClick(View.java:4020)
at android.view.View.performClick(View.java:4780)
at android.view.View$PerformClick.run(View.java:19866)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5257)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
Caused by: java.lang.reflect.InvocationTargetException
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at android.view.View$1.onClick(View.java:4015)
at android.view.View.performClick(View.java:4780)
at android.view.View$PerformClick.run(View.java:19866)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5257)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
Caused by: java.lang.ClassCastException: android.support.v7.widget.AppCompatButton cannot be cast to android.widget.RadioButton
at com.gihan.temperatureconverter.ConvertActivity.calculation(ConvertActivity.java:56)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at android.view.View$1.onClick(View.java:4015)
at android.view.View.performClick(View.java:4780)
at android.view.View$PerformClick.run(View.java:19866)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5257)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
Some Comments were some ways I tried. It's also failed.
And also this is Android Studio Project.

Your Error Solved Check this code
mainactivity.java
public class MainActivity extends ActionBarActivity {
EditText val;
public static int ans;
public static String fahval="";
public static String celval="";
RadioButton Box1,Box2;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
val =(EditText) findViewById(R.id.editText);
}
public void calculation(View v)
{
//get value from edit text box and convert into double
double a=Double.parseDouble(String.valueOf(val.getText()));
Box1 = (RadioButton) findViewById(R.id.rCel);
Box2 = (RadioButton) findViewById(R.id.rFah);
//check which radio button is checked
if(Box1.isChecked())
{
//display conversion
celval = String.valueOf(f2c(a));
// Toast.makeText(getApplicationContext(), celval,Toast.LENGTH_LONG).show();
Box1.setChecked(true);
}
else
{
fahval = String.valueOf(c2f(a));
// Toast.makeText(getApplicationContext(), fahval,Toast.LENGTH_LONG).show();
Box2.setChecked(true);
}
Intent intent = new Intent(this, LastActivity.class);
intent.putExtra("celval", celval);
intent.putExtra("fahval", fahval);
startActivity(intent);
}
//Celcius to Fahrenhiet method
private double c2f(double c)
{
return (c*9)/5+32;
}
//Fahrenhiet to Celcius method
private double f2c(double f)
{
return (f-32)*5/9;
}
}
LastActivity.java
public class LastActivity extends ActionBarActivity {
TextView vFah;
TextView vCel;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.last);//use whatever layout you want.
vFah=(TextView)findViewById(R.id.vFah);
vCel=(TextView)findViewById(R.id.vCel);
Bundle extras = getIntent().getExtras();
String celval=extras.getString("celval");
String fahval=extras.getString("fahval");
//String cel=String.valueOf(celval);
//String fah=String.valueOf(fahval);
vCel.setText(celval);
vFah.setText(fahval);
}
public void again(View view) {
Intent intent = new Intent(LastActivity.this, MainActivity.class);
LastActivity.this.startActivity(intent);
}
public void home(View view) {
Intent intent = new Intent(LastActivity.this, MainActivity.class);
LastActivity.this.startActivity(intent);
}
}

I was building some apps this week, and couldn't figure out why I couldn't navigate from the Main Activity to a second activity and from there to a 3rd level activity (that would pop to 2nd activity), and app kept crashing when I added the 3rd. Finally looked in the Logcat to figure out what's wrong, and then read "Cannot Navigate from 'second activity'.... This View will not accept Navigation". Searched through code to find errors, but Never thought to look there before.

Android - IllegalStateException - Could not find a method startRhythmandAnimation in the activity class

I can't understand why I'm getting this error message. My method IS in the activity class and the spelling is correct.
02-09 18:23:57.211: E/AndroidRuntime(19939): FATAL EXCEPTION: main
02-09 18:23:57.211: E/AndroidRuntime(19939): Process: stacy.example.assignment3_stacy_v1, PID: 19939
02-09 18:23:57.211: E/AndroidRuntime(19939): java.lang.IllegalStateException: Could not find a method startRhythmandAnimation(View) in the activity class stacy.example.assignment3_stacy_v1.Assignment3MainActivity for onClick handler on view class android.widget.Button with id 'startbutton'
MainActivity.java
package stacy.example.assignment3_stacy_v1;
import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.view.View;
import android.view.animation.Animation;
import android.view.animation.AnimationUtils;
import android.widget.EditText;
public class Assignment3MainActivity extends Activity {
private View mMileTimeGoal;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_assignment3_main);
mMileTimeGoal = findViewById(R.id.miletimegoal);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.assignment3_main, menu);
return true;
}
public void startRhythmandAnimation () {
String MileTime = mMileTimeGoal.getContext().toString();
String[] time_array = MileTime.split(":");
int hours = Integer.parseInt(time_array[0]);
int minutes = Integer.parseInt(time_array[1]);
int seconds = Integer.parseInt(time_array[2]);
int duration = 3600 * hours + 60 * minutes + seconds;
int steps_per_second = 3;
int running_rate = duration * steps_per_second;
View rightfoot = findViewById(R.id.rightfoot);
View leftfoot = findViewById(R.id.leftfoot);
rightfoot.setVisibility(View.VISIBLE);
Animation anim = AnimationUtils.makeInChildBottomAnimation(this);
rightfoot.startAnimation(anim);
leftfoot.setVisibility(View.VISIBLE);
leftfoot.startAnimation(anim);
}
public void resetTimetoZeroes () {
String MileTime = mMileTimeGoal.getContext().toString();
//Int MileTime = 0;
}
}
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:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
tools:context=".Assignment3MainActivity" >
<ImageView
android:id="#+id/leftfoot"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBottom="#+id/rightfoot"
android:layout_toLeftOf="#+id/rightfoot"
android:src="#drawable/leftfoot" />
<EditText
android:id="#+id/miletimegoal"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:layout_marginTop="18dp"
android:ems="10"
android:inputType="time"
android:hint="Mile Time Goal?" />
<ImageView
android:id="#+id/rightfoot"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentRight="true"
android:layout_marginBottom="74dp"
android:layout_marginRight="36dp"
android:src="#drawable/rightfoot" />
<Button
android:id="#+id/startbutton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_above="#+id/leftfoot"
android:layout_alignRight="#+id/leftfoot"
android:onClick="startRhythmandAnimation"
android:text="#string/start_button" />
<Button
android:id="#+id/resetbutton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="#+id/startbutton"
android:layout_alignBottom="#+id/startbutton"
android:layout_alignLeft="#+id/rightfoot"
android:text="#string/reset_button"
android:onClick="resetTimetoZeroes" />

You need to include a single View parameter for the system to find your method:
public void startRhythmandAnimation (View view)