Android

There are times when you need to display a dialog window to get a confirmation from the user. In this case , you can override the onCreateDialog() protected method defined in the Activity base class to display a dialog window. The following Try It Out shows you how. 1. Using Android Studio , create a new Android project and name it Dialog. When presented with the option , name the main activity DialogActivity. 2.Add the following theme in bold to the AndroidMainfest.xml file. Be sure to change all instances of "com.android" to whatever package name your project is using. <?xml version="1.0" encoding="utd-8"?> <manifest xmlns:android"http://schemas.android.com/apk/res/android" package="com.android.dialog">      <application           android:allowBackup="true"           android:icon:="@mipmap/ic_launcher"         ...

You can also hide the title of an activity if desired ( Such as when you just want to display a status update to the user). To do so , use the requestWindowFeature() method and pass it the window .FEATURE_NO_TITLE constant, like This : import android.support.v7.app.AppCompatActivity; import android.os.Bundle; import android.view.Window; public class MainActivity extends AppCompatActivity{            @Override            protected void onCreate ( Bundle savedInstanceState )            {                         super.onCreate (savedInstanceState );                         setContentView (R.layout.activit...

By default , an activity is themed to the default Android theme. However , there been a push in recent year to adopt a new theme known as Material . The Material theme has a much more modern and clean look to it. There are two versions of the Material theme available to Android developers : Material Light and Material Dark , Either of these themes can be applied from the AndroidManifest.xml To apply one of the Material themes to an activity , simply modify the <Application> element in the AndroidManifest.xml file by changing the default android:theme attribute. (Please be sure to change all instances of "com.android" to whatever package name your project is using.) <?xml version="1.0" encoding="utf-8"?> <manifest xmls:android="http://schemas.android.com/apk/res/android"        xmlns:tools="http://schemas.android.com/tools"        package="com.android.activity101">        <application ...

1. Using Android Studio , create a new Android project and name is Activity101. 2. In the Activity101Activity.java file , add the following highlighted statements. Package com.example.activity101; import androidx.appcompat.app.AppCompatActivity; import android.os.Bundle; import android.util.Log; public class MainActivity extends AppCompatActivity {        String tag="LifeCycle Step";       @Override        protected void onCreate(Bundle savedInstanceState)        {                super.onCreate(savedInstanceState);                setContentView(R.layout.activity_main);                Log.d(tag,msg:"In the onCreate () event");        }        public void onStart()        {           ...

This blog begins by showing you to create an activity. To create an activity , you create a Java class that extends the Activity base class : public class MainActivity extends AppcompatActivity {           @Override           protected void onCreate(Bundle savedInstanceState)           {                     super.onCreate(savedInstanceState);                     setContentView(R.laout.activity_main);           } } Your activity class loads its user interface ( UI ) component using the XML file defined in your res/layout folder . In this example , you would load the UI from the main.xml file :   ...

After you have created , and fully debugged , you application , you might want to deploy it to the Google.Store for others to enjoy. The following sections outline the steps for publishing your applications. Generating a Signed APK To Publish Your finished application on the Google Play Store , you must generate a signed APK ( the Android application package ) . The APK is the compiled , executable version of your application. Signing it is much like signing your name to a document. The signature identifies the app's developer to Google and the users who install your application. More importantly , unless your Android Studio is in developer mode , unsigned application will not run . Use the following steps to generate a signed APK :   1. Generate a signed APK from your code by selecting Build -> Generate Signed APK from the Menu bar to bring up the Generate Signed APK window as show in figure   2. Assuming you have never published an application from Andr...

While in debug mode , Android Studio pauses at any breakpoint that you have set . This is , as long as a breakpoint has been set on a reachable line of code (  a line of code that would be executed by system ) , Android Studio halts execution at that line until you tell it to continue. When Android Studio hits , and pauses at , a breakpoint , the circle in the margin next to the corresponding line of code changes to circle with a check mark. Once a breakpoint has been hit , the debug window opens at the bottom Android Studio , as show in Figure . The debug window contains many of the tools you use to navigate around your code. Notice the navigation buttons located in the menu bar of the debug window . The most commonly used are Step Over and Step Into . Step Over advances you to the line of code that immediately follows the one at which you are currently paused . This means that if you are paused at a method call , and you press Step Over , Android Studio executes the met...