Develop Reference

Android Studio: "My First App" does not work

I'm definitely new to Android development.
I'm following along this tutorial: https://developer.android.com/training/basics/firstapp/running-app.html, and it seems I can't run the app on the AVD because I don't see the application launcher icon nor the "Hello world" text. It does not show in the Apps Menu nor in the "Manage my apps" window.
I'm running an emulator for a 3.2 QVGA phone with API Level 22 (Android 5.1.1) using the armeabi-v7a ABI.
Here's the code I got:
AndroidManifest.xml:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.gregory.myfirstapp" >
<application
android:allowBackup="true"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<activity
android:name=".MyActivity"
android:label="#string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
MyActivity.java:
package com.example.gregory.myfirstapp;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
public class MyActivity extends ActionBarActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_my);
}
#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_my, 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);
}
}
activity_my.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=".MyActivity">
<TextView android:text="#string/hello_world"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</RelativeLayout>
menu_my.xml:
<menu xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
tools:context=".MyActivity">
<item android:id="#+id/action_settings"
android:title="#string/action_settings"
android:orderInCategory="100" app:showAsAction="never" />
</menu>
Please help me out here!

I had the same problem with my Android Studio. I've started the application in the Debug-Mode (The green bug next to the play button). Sometimes the emulator is very slow, so you have to wait 5 to 50 seconds after unlocking the virtual phone. Normally the app should open up itself on the screen, and after the first run the app should appear in your App Menu.

"Unfortunately application has stopped." in Android - trying to send SMSmessage

I'm beginner in Android development and I'm trying to make Android app which will send SMS to another phone when button is clicked. I don't have Android phone so I'm trying to do that via emulators. I start one emulator which will be my "phone" which send SMS and another emulator which receives SMS.
Everything is compiled well and app starts, but when I click on button, I got message that "Unfortunately, app has stopped".
Here is the code which I have made.
acitivity_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: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.example.email.MainActivity" >
<Button
android:id="#+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="23dp"
android:layout_marginTop="44dp"
android:text="Button" />
and here is MainActivity.java
package com.example.email;
import com.example.email.R;
import android.app.Activity;
import android.os.Bundle;
import android.telephony.SmsManager;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
public class MainActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//adding listener to the button
final Button button = (Button) findViewById(R.id.button1);
button.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
// Perform action on click
String phoneNumber = "5556";
String message = "Proba";
//sends SMS to emulator with number 5556
SmsManager sms = SmsManager.getDefault();
sms.sendTextMessage(phoneNumber, null, message, null, null);
}
});
}
//this is default function, I haven't changed anything
#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);
}
}
manifest file
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.email"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="14"
android:targetSdkVersion="17" />
<application
android:allowBackup="true"
android:icon="#drawable/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>
</application>
</manifest>

add
<uses-permission android:name="android.permission.SEND_SMS" />
in your manifest.xml

Can not see add from admob hello world android program

This is my main class -
package com.example.trial;
import com.google.android.gms.ads.AdRequest;
import com.google.android.gms.ads.AdView;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
public class MainActivity extends ActionBarActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
AdView adview = (AdView) this.findViewById(R.id.adView);
AdRequest adrequest = new AdRequest.Builder().build();
adview.loadAd(adrequest);
}
#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);
}
}
This is activity_main.xml
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:ads="http://schemas.android.com/apk/res-auto"
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.example.trial.MainActivity" >
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/hello_world" />
<com.google.android.gms.ads.AdView android:id="#+id/adView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
ads:adSize="BANNER"
ads:adUnitId="ca-app-pub-00000000000000000/1111111111"/>
</RelativeLayout>
ANother file I modified is AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.trial"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="21" />
<uses-permission android:name="android.permission.INTERNET"/>
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
<application
android:allowBackup="true"
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<meta-data android:name="com.google.android.gms.version"
android:value="#integer/google_play_services_version"/>
<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="com.google.android.gms.ads.AdActivity"
android:configChanges="keyboard|keyboardHidden|orientation|screenLayout|uiMode|screenSize|smallestScreenSize"/>
</application>
</manifest>
I have added google-play-services_lib properly in my project buildpath.
Project in eclipse shows no error as such. But It is not showing ad after running app.
Internet connection is proper (Checked by running browser on android emulator)
Can someone suggest what might have gone wrong ?
I am new to admob. I have created ad unit default setting and using its id. Is there anything else to be done ??
update - when I removed these two lines
<uses-permission android:name="android.permission.INTERNET"/>
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
It showed error in box where ad is supposed to be placed. That means view has been created ??

Enabled logcat from here -
How to enable LogCat/Console in Eclipse for Android?
Solved problem using this -
Not enough space to show ad (AdMob)
Thanks #William !!!

Android app icon doesn't show on actionbar

I am creating an android app using eclipse and I have a problem. the app icon doesn't show on actionbar. can anybody tell me what's wrong? here is the manifest:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.gowemto.gnoulashe"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="16"
android:targetSdkVersion="21" />
<application
android:allowBackup="true"
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:theme="#style/Theme.AppCompat.Light" >
<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=".CalcResultActivity"
android:label="#string/title_activity_calc_result"
android:parentActivityName=".MainActivity" >
<meta-data
android:name="android.support.PARENT_ACTIVITY"
android:value="com.gowemto.gnoulashe.MainActivity" />
</activity>
</application>
</manifest>
and here's the main activity code:
package com.gowemto.gnoulashe;
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;
public class MainActivity extends ActionBarActivity {
String result;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
#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);
}
public void intent1(View view) {
Intent intent = new Intent(this, CalcResultActivity.class);
startActivity(intent);
}
}
and here's the xml file of main activity:
<?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"
android:orientation="vertical">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="16sp"
android:text="#string/welcome_message" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/add_the_dates"
android:onClick="intent1" />
</LinearLayout>
and this is what the actionbar look like when I run the app: http://i.imgur.com/jADDz7b.png
The app doesn't show any errors, and the icon is put in the right way in the directories. so can anyone tell me what's the problem and how can I fix it?

The problem with #ZsoltBoldizsár's answer is that you are using ActionBarActivity. Change getActionBar() to getSupportActionBar()
Add the following code in onCreate(Bundle) after you call super.onCreate(Bundle):
getSupportActionBar().setDisplayShowHomeEnabled(true);
getSupportActionBar().setIcon(R.drawable.ic_launcher);
Appcompat-v7 automatically disables setDisplayShowHomeEnabled so you must set it to true to show an icon.

You need to configure the actionbar. Read the documentation, but the line below might help you.
getActionBar().setHomeButtonEnabled(true);
getActionBar().setIcon(here comes your drawable id) (eg. R.drawable.ic_launcher)

Try with this:
ActionBar ab = getActionBar();
ab.setHomeButtonEnabled(true);
ab.setDisplayHomeAsUpEnabled(true);
ab.setDisplayShowTitleEnabled(false);
ab.setDisplayShowCustomEnabled(true);
ab.setTitle(Html.fromHtml("your text"));
ColorDrawable colorDrawable = new ColorDrawable(Color.parseColor(your_colorCode));
ab.show();

Helloworld Doesn't run on Emulator

Okay, this is really ticking me off. I ran it on both my emulator and on an android device. The code does NOT display "Helloworld, Android -mykong.com". I start the app, find it on the emulator, click on it, and it goes to interface of the app. However, it is just a blank screen! This error is not an issue of me finding the app, its not with the emulator or the android phone, the issue has to lie either in the code or in the way the code is structured/built. I know the the helloworld code is 100% correct because its from a reputable tutorial site. These are my three pairs of code. Please help, I am in desperate need!
AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.test123"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="17" />
<application
android:allowBackup="true"
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<activity
android:name="com.example.test123.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>
</application>
</manifest>
MainActivity.java
package com.example.test123;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
public class MainActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
public void activity()
{
Intent helloWorld = new Intent(getApplicationContext(), HelloWorldjavaactivity.class );
startActivity( helloWorld );
}
#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;
}
}
HelloWorldjavaactivity.java
package com.example.test123;
import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;
public class HelloWorldjavaactivity extends Activity {
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
TextView text = new TextView(this);
text.setText("Hello World, Android - mkyong.com");
setContentView(text);
}
}
Activity_main.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
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=".MainActivity" >
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:layout_marginLeft="35dp"
android:layout_marginTop="57dp"
android:text=""
/>
</RelativeLayout>

You're not starting the HelloWorldjavaactivity.java activity. You need something like the following in your MainActivity:
Intent helloWorld = new Intent(getApplicationContext(), HelloWorldjavaactivity.class );
startActivity( helloWorld );
Of course, you need that code to be triggered by some even, a button press for example.
It would be easier to just eliminate the second activity (since your MainActivity isn't doing anything anyway) and put the code in your MainActivity instead. You'll also need to edit the layout for your MainActivity so that it includes the appropriate views.