The Application class is a good place to declare all globals in an application although it's not mandatory. We will update this file as and when we add components to our application. We need to edit this file to declare various components, features, permissions, etc. The AndroidManifest.xml describes the Android application. You may want to wrap the data manipulation calls in a transaction to improve performance or preserve data integrity. In db.query() passing the second argument as null fetches all the columns. Here is some relevant piece of code from void onCreate(SQLiteDatabase db) void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) ) Additionally, create DbHelper class which extends SQLiteOpenHelper. ![]() It's an abstract class which we need to subclass and implement the onCreate() and onUpgrade() methods.Ĭreate a package to hold the data model classes. Here is a class diagram which depicts the data model.Īndroid provides SQLite database for data persistence and SQLiteOpenHelper class for managing the database. The app needs to support persistance of a simple note, a checklist, and a snapshot as well as allow user to categorize his notes. It's a good approach to define the data model first before diving into UI implementation so that's what we discuss next. The project gets created in your workspace. In New Android Project dialog enter the project details as follows.Ĭlick Finish. In Eclipse, go to File > New > Project and in the New Project dialog, expand Android folder to select Android Project. We will give all the details as we implement each feature so let's start coding! Additionally, there is a settings screen (not shown above) implemented using PreferenceActivity which allows user to save his preferences. We will be using various Android widgets to implement the screens. So we will create separate Activity for each of these use cases. This app allows user to create a simple note, a checklist, or a snapshot. The Browse tab is implemented using a ListView whereas the Manage tab is implemented using ExpandableListView. Here is the final result we want to achieve and which you might have sketched before getting into coding.Īs you can see the main screen of the app consists of a TabHost which allows the user to browse and manage the notes. However, we will make a pretty decent application with most of the basic features a notepad application should have and may be a little more in some other respect. Since this is our first app in the series so we will focus more on Android UI layouts and widgets and hence the design of the application and keep things simple functionality wise. Then sketch the design and flow of the application before you jump into actual development. ![]() The first thing to do after you have your (million dollar?!!) app idea is to list down all the features you want in your app. In this article, we show you how to create a notepad application in Android.
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