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CPET 565 Mobile Computing SystemsCPET/ITC 499 Mobile Computing
Tutorial 2
Tap Button Counter AppReference
Android Programming Concepts, by Trish Cornez and Richard Cornez, pubslihed by Jones & Barlett Learning, pp. 68-81.
Android Developer API Guides, http://developer.android.com/guide/index.html
Paul I-Hai Lin, ProfessorSpring 2017
A Specialty Course Purdue University M.S. Technology Graduate Program
Dept. of Computer, Electrical and Information Technology
Purdue University Fort Wayne CampusProf. Paul Lin
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Tap Button Counter App
Objectives1. Add an orientation to the Manifest file2. Construct a new user interface file3. Use the “onClick” property for a button in the layout
file4. Employ the Model-View-Controller architecture
Counter.java - Java source file will serve as the Model blue print of the application
A Counter object will present the data related to the count of taps on the application
View object – in main_layout.xml file as visual display object
MainActivity.java – the Controller acting as the conduit between the Counter object and the visual display objects of the user interface
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Model-View-Controller Architecture
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Model-View-Controller Architecture
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Model-View-Controller Architecture
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Tap Button Counter App
Procedure – Creating the Android Project1) Launch Android Studio2) Start a new Android Studio Project 3) Configure the project with the following settings* Application Name: Tap Button Counter* Company Domain:* Package Name:* Form: Phone Tablet* Minimum SDK:* Empty Activity* File Name options:** Activity Name: MainActivity** Layout Name: activity_main
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AndroidManifest.xml<?xml version="1.0" encoding="utf-8"?><manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.cornez.tapbuttoncounter" ><application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"android:label=""Tap Button Counter"android:theme="@style/AppTheme" >
<activityandroid:screenOrientation="landscape"
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>
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app/res/values/string.xml
<resources>
<string name="app_name">Tap Button Counter</string>
<string name="hello_world">Hello world!</string>
<string name="action_settings">Settings</string>
<string name="tap_btn">TAP</string>
<string name="zero">0</string>
</resources>
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Create a new main_layout.xml Res/layout, right click => New > XML => Layout.xml
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Create a new main_layout.xml Res/layout, right click => New > XML => Layout.xml
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Create a new main_layout.xml Res/layout, right click => New > XML => Layout.xml
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Create a new main_layout.xml RelativeLayout
• TextView• button
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Create a new main_layout.xml Res/layout, right click => New > XML => Layout.xml<?xml version="1.0" encoding="utf-8"?>
<RelativeLayoutxmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent" android:layout_height="match_parent">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceLarge"
android:text="@string/zero"
android:id="@+id/textView"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:textSize="60sp" />
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Create a new main_layout.xml Res/layout, right click => New > XML => Layout.xml
<Buttonandroid:layout_width="wrap_content"android:layout_height="wrap_content"android:text="@string/tap_btn"android:id="@+id/button"android:layout_centerVertical="true"android:layout_centerHorizontal="true"android:textSize="60sp"android:onClick="countTap" />
</RelativeLayout>
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Create a new menu_main.xml Res/ right click => New > Directory => menu_main.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=".MainActivity">
<item android:id="@+id/action_settings" android:title="@string/action_settings"
android:orderInCategory="100" app:showAsAction="never" />
</menu>
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Counter.java Class
package com.lin.tapbuttoncounter;class Counter {
private int mCount;
public Counter(){ mCount = 0;
} public void addCount(){
mCount++; } public Integer getCount() { return mCount; }
}
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MainActivity.java package com.lin.tapbuttoncounter;
//import android.support.v7.app.AppCpmatActivity;
import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.TextView;
public class MainActivity extends Activity {
//MODEL
private Counter count;
//VIEW
private TextView display;Prof. Paul Lin
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MainActivity.java @Override
protected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.main_layout);
count = new Counter();display = (TextView) findViewById(R.id.textView);
}public void countTap(View view){
count.addCount();display.setText(count.getCount().toString());
}
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MainActivity.java @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_main,
menu);return true;
}
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MainActivity.java @Overridepublic 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);
}}
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Summary
Q/A?
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