June 2018

The Media lesson teaches how to integrate video content into your app using the Android multimedia framework. You can play these video files from your app resources (raw resources) or from the device filesystem, or you can stream the files over the network. The practical tutorial guides you through building an app that lets the user play and control video.

Faculty Spotlight: Satyanandaram N

Satyanandaram N, Lecturer in the Department of Computer Science at IIIT-RK Valley

Initially, when this course was introduced in their college, students had some issues with the 4 GB RAM systems in their Mobile Application Development Lab. Satyanandaram asked his Head of Department and the IT team to upgrade the RAM in those systems and also to equip them with a good internet connection. Thanks to his efforts and cooperation from the management, students now have 8GB RAM systems with high-speed internet.

Satyanandaram also published two papers in the International Journal of Engineering Research in Computer Science and Engineering:

• Low cost Integrated Communication Technologies for Controlling Home Appliances from Anywhere — An Outcome of IoT
• Impact of Social Networking Sites on Educational Institutes — A Case Study on RGUKT

Prashanth Teja, one of the students who Satyanandaram trained, got a job placement in DataHome—GrupoDG Inc. in Mexico. Although from a rural background, he worked his way up to become an entrepreneur, and he co-funded a career planning startup, CEDURA​, and a logistics based startup in South India. He also leads India’s top coding boot camp, THE HACKING SCHOOL​, in Hyderabad.

Ask Jhansi

Hello, I am Jhansi, a passionate mobile developer. Many of you may already know me as Faculty Support in the Google Developers Training team. After working with Symbian, Windows Mobile, and a few other mobile operating systems, I landed in Android. Well, it seems like I've finally arrived where I belong :)

Today’s question is from Professor Ravindra Jagannath Mandale from Rajarambapu Institute of Technology, Rajaramnagar. Thank you Ravindra for asking this question!

Q: What is the difference between minSdkVersion, maxSdkVersion, targetSdkVersion, and compileSdkVersion ?

We all might have seen these properties in the Gradle file in the android->defaultConfig block. Now, let's see what they mean.

minSdkVersion: This is the minimum API level you are willing to support with your app. Also, the Google Play Store uses this property to prevent a user from installing your app if the user’s phone’s API level is lower than the minSdkVersion. You should always declare this property.

maxSdkVersion: Using this property is no longer recommended. If you do specify the property, the Google Play Store uses it to filter your app. If the API level of the user's phone is higher than maxSdkVersion (starting from API level 6), the app is not visible to the user.

targetSdkVersion:This property should be the latest Android version available. If not set, the default value will be the same as minSdkVersion. This property indicates that you have tested your app using this target version. (So, please make sure that you test it. Your users will thank you!)

Starting in Aug 2018, all new apps that are published in the Google Play Store must target at least Android 8.0 (API level 26).

compileSdkVersion: This is used only by the Gradle build system to compile your app with this version of the Android SDK. Changing this value does not change runtime behavior. It is strongly recommended that you always compile with the latest SDK.

Putting it all together, the relationship would look like this:

minSdkVersion (lowest SDK possible) <= targetSdkVersion == compileSdkVersion (latest SDK)

Let's build an app: Spring animation

Today we will build an app using spring animation in Android, which is explained in the Animations lesson in the Advanced Android Development course.

Why do we need animations? Well, to put it simply, animation gives our app the WOW factor! This in turn helps our app stand out in the crowd (considering the fact that there are a ton of apps already in the Google Play Store), which may also eventually help increase the user base. I personally feel that animations not only change the look and feel of an app, but also help the user to navigate the app with ease.

Android includes different types of animations depending on what type of animation you want. Let’s discuss a few of them today.

3. Change the “Hello World” Textview to the ImageView below, which we will be animating today. For simplicity, I am re-using the launcher icon, but feel free to add your own images or icons.

activity_main.xml

<ImageView

  android:id="@+id/android_image"

  android:layout_width="wrap_content"

  android:layout_height="wrap_content"

  android:src="@mipmap/ic_launcher_round"

  app:layout_constraintBottom_toBottomOf="parent"

  app:layout_constraintLeft_toLeftOf="parent"

  app:layout_constraintRight_toRightOf="parent"

  app:layout_constraintTop_toTopOf="parent" />

In MainActivity.java, inside the onCreate() method:

1. Initialize the ImageView.

MainActivity.java

ImageView androidImage = findViewById(R.id.android_image);

2. Create a SpringAnimation object providing the view to be animated (androidImage) and the property to be animated. The property we are animating today is TRANSLATION_X, because we will bounce our ImageView along the x-axis (from right to left).

MainActivity.java

final SpringAnimation springAnimationX = new SpringAnimation(androidImage,DynamicAnimation.TRANSLATION_X, 0);

3. Create a SpringForce object with 0 as the final resting position of the spring so that the view will bounce back to the starting point. Also set the stiffness and damping ratio of the spring.

MainActivity.java

SpringForce springForceX = new SpringForce(0);

springForceX.setStiffness(SpringForce.STIFFNESS_MEDIUM);

springForceX.setDampingRatio(SpringForce.DAMPING_RATIO_HIGH_BOUNCY);

Stiffness, is the strength of the spring, for example if we use STIFFNESS_HIGH the view comes back to the initial position very quickly.

Damping ratio, indicates how rapidly you want the oscillations (the bouncing) to decrease. If you set damping ratio to 0, the view will bounce forever.

4. Set the SpringForce and some initial velocity of the SpringAnimation.

MainActivity.java

springAnimationX.setSpring(springForceX);

springAnimationX.setStartVelocity(1000);

5. Create a click listener for the ImageView. Set the starting value and start the animation.

MainActivity.java

androidImage.setOnClickListener(new View.OnClickListener() {

          @Override

          public void onClick(View view) {

              springAnimationX.setStartValue(300);

              springAnimationX.start();

          }

      });