Android application tutorials

This example shows how create ImageGallery in android.

Algorithm:
1.) Create a new project by File-> New -> Android Project name it ImageGalleryExample.
2.) Add some sample .png image files to res/drawables folder.

3.) Write following into main.xml file:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
   android:layout_width="match_parent"
   android:layout_height="match_parent">
   
    <ImageSwitcher android:id="@+id/switcher"
       android:layout_width="match_parent"
       android:layout_height="match_parent"
       android:layout_alignParentTop="true"
       android:layout_alignParentLeft="true"
   />
   
    <Gallery android:id="@+id/gallery"
       android:background="#55000000"
       android:layout_width="match_parent"
       android:layout_height="60dp"
       android:layout_alignParentBottom="true"
       android:layout_alignParentLeft="true"
       
       android:gravity="center_vertical"
       android:spacing="16dp"
   />
</RelativeLayout>

4.) Run for output.

Steps:
1.) Create a project named ImageGalleryExample and set the information as stated in the image.
Build Target: Android 4.0
Application Name: ImageGalleryExample
Package Name: com. example. ImageGalleryExample
Activity Name: ImageGalleryExample
Min SDK Version: 14

2.) Open ImageGalleryExample.java file and write following code there:

package com.example.ImageGalleryExample;
import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.view.Window;
import android.view.animation.AnimationUtils;
import android.widget.AdapterView;
import android.widget.BaseAdapter;
import android.widget.Gallery;
import android.widget.Gallery.LayoutParams;
import android.widget.ImageSwitcher;
import android.widget.ImageView;
import android.widget.ViewSwitcher;
public class ImageGalleryExample extends Activity implements
        AdapterView.OnItemSelectedListener, ViewSwitcher.ViewFactory {
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        requestWindowFeature(Window.FEATURE_NO_TITLE);
        setContentView(R.layout.main);
        mSwitcher = (ImageSwitcher) findViewById(R.id.switcher);
        mSwitcher.setFactory(this);
        mSwitcher.setInAnimation(AnimationUtils.loadAnimation(this,
                android.R.anim.fade_in));
        mSwitcher.setOutAnimation(AnimationUtils.loadAnimation(this,
                android.R.anim.fade_out));
        Gallery g = (Gallery) findViewById(R.id.gallery);
        g.setAdapter(new ImageAdapter(this));
        g.setOnItemSelectedListener(this);
    }
    public void onItemSelected(AdapterView<?> parent, View v, int position, long id) {
        mSwitcher.setImageResource(mImageIds[position]);
    }
    public void onNothingSelected(AdapterView<?> parent) {
    }
    public View makeView() {
        ImageView i = new ImageView(this);
        i.setBackgroundColor(0xFF000000);
        i.setScaleType(ImageView.ScaleType.FIT_CENTER);
        i.setLayoutParams(new ImageSwitcher.LayoutParams(LayoutParams.MATCH_PARENT,
                LayoutParams.MATCH_PARENT));
        return i;
    }
    private ImageSwitcher mSwitcher;
    public class ImageAdapter extends BaseAdapter {
        public ImageAdapter(Context c) {
            mContext = c;
        }
        public int getCount() {
            return mThumbIds.length;
        }
        public Object getItem(int position) {
            return position;
        }
        public long getItemId(int position) {
            return position;
        }
        public View getView(int position, View convertView, ViewGroup parent) {
            ImageView i = new ImageView(mContext);
            i.setImageResource(mThumbIds[position]);
            i.setAdjustViewBounds(true);
            i.setLayoutParams(new Gallery.LayoutParams(
                    LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
            i.setBackgroundResource(R.drawable.picture_frame);
            return i;
        }
        private Context mContext;
    }
    private Integer[] mThumbIds = {
            R.drawable.sample_thumb_0, R.drawable.sample_thumb_1,
            R.drawable.sample_thumb_2, R.drawable.sample_thumb_3};
    private Integer[] mImageIds = {
            R.drawable.sample_0, R.drawable.sample_1, R.drawable.sample_2,
            R.drawable.sample_3};
}

3.) Compile and build the project.
Output

Posted in Android Development, Android programming, Free Android Tutorials | Tagged Android Image Gallery Example, Android Tutorials, Image Gallery Example, Image Gallery Example in Android | Leave a comment

Live Wallpaper in Android

This example explains how to create and set live wallpaper in android.

Algorithm:
1.) Create a new project by File-> New -> Android Project name it LiveWallpaper.
2.) Write following into manifest file:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"  
   package="com.example.LiveWallpaper" android:versionCode="1"  
   android:versionName="1.0">
    <application android:icon="@drawable/ic_launcher" android:label="@string/app_name">
 
 
        <service android:name="MyWallpaperService" android:enabled="true"  
           android:permission="android.permission.BIND_WALLPAPER" android:label="Wallpaper Example ">
            <intent-filter>
                <action android:name="android.service.wallpaper.WallpaperService"></action>
            </intent-filter>
            <meta-data android:name="android.service.wallpaper"  
               android:resource="@xml/mywallpaper"></meta-data>
        </service>
        <activity android:label="@string/app_name" android:name=".LiveWallpaperActivity"  
           android:theme="@android:style/Theme.Light.WallpaperSettings"  
           android:exported="true">
        </activity>
    </application>
    <uses-sdk android:minSdkVersion="10" />
    <uses-feature android:name="android.software.live_wallpaper"  
       android:required="true"></uses-feature>
 
</manifest>

3.) Create “xml” folder into res directory and create and write following into mywallpaper.xml:

<?xml version="1.0" encoding="UTF-8"?>
<wallpaper  
   android:settingsActivity="de.vogella.android.wallpaper.MyPreferencesActivity"  
   xmlns:android="http://schemas.android.com/apk/res/android"  
   android:description="@string/wallpaper_description"  
   android:thumbnail="@drawable/ic_launcher" />

4.) Create and write following into prefs.xml:

<?xml version="1.0" encoding="utf-8"?>
<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android">
    <CheckBoxPreference android:key="touch"  
       android:title="Enable Touch"></CheckBoxPreference>
    <EditTextPreference android:key="numberOfCircles"  
       android:title="Number of Circles"></EditTextPreference>
</PreferenceScreen>

5.) Create and write following code into src/MyPoints.java:

package com.example.LiveWallpaper;
public class MyPoint {
    public String text;
    public float x;
    public float y;
 
    public MyPoint(String text, float x, float y) {
        this.text = text;
        this.x = x;
        this.y = y;
    }
 
}

6.) Create a service class to make the wallpaper application run from background. Write following into MyWallpaperService.java:

package com.example.LiveWallpaper;
import java.util.ArrayList;
import java.util.List;
 
import android.content.SharedPreferences;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.os.Handler;
import android.preference.PreferenceManager;
import android.service.wallpaper.WallpaperService;
import android.view.MotionEvent;
import android.view.SurfaceHolder;
 
public class MyWallpaperService extends WallpaperService {
 
    @Override
    public Engine onCreateEngine() {
        return new MyWallpaperEngine();
    }
 
    private class MyWallpaperEngine extends Engine {
        private final Handler handler = new Handler();
        private final Runnable drawRunner = new Runnable() {
            @Override
            public void run() {
                draw();
            }
 
        };
        private List<MyPoint> circles;
        private Paint paint = new Paint();
        private int width;
        int height;
        private boolean visible = true;
        private int maxNumber;
        private boolean touchEnabled;
 
        public MyWallpaperEngine() {
            SharedPreferences prefs = PreferenceManager
                    .getDefaultSharedPreferences(MyWallpaperService.this);
            maxNumber = Integer
                    .valueOf(prefs.getString("numberOfCircles", "10"));
            touchEnabled = prefs.getBoolean("touch", false);
            circles = new ArrayList<MyPoint>();
            paint.setAntiAlias(true);
            paint.setColor(Color.GREEN);
            paint.setStyle(Paint.Style.STROKE);
            paint.setStrokeJoin(Paint.Join.ROUND);
            paint.setStrokeWidth(10f);
            handler.post(drawRunner);
        }
 
        @Override
        public void onVisibilityChanged(boolean visible) {
            this.visible = visible;
            if (visible) {
                handler.post(drawRunner);
            } else {
                handler.removeCallbacks(drawRunner);
            }
        }
 
        @Override
        public void onSurfaceDestroyed(SurfaceHolder holder) {
            super.onSurfaceDestroyed(holder);
            this.visible = false;
            handler.removeCallbacks(drawRunner);
        }
 
        @Override
        public void onSurfaceChanged(SurfaceHolder holder, int format,
                int width, int height) {
            this.width = width;
            this.height = height;
            super.onSurfaceChanged(holder, format, width, height);
        }
 
        @Override
        public void onTouchEvent(MotionEvent event) {
            if (touchEnabled) {
 
                float x = event.getX();
                float y = event.getY();
                SurfaceHolder holder = getSurfaceHolder();
                Canvas canvas = null;
                try {
                    canvas = holder.lockCanvas();
                    if (canvas != null) {
                        canvas.drawColor(Color.BLACK);
                        circles.clear();
                        circles.add(new MyPoint(
                                String.valueOf(circles.size() + 1), x, y));
                        drawCircles(canvas, circles);
 
                    }
                } finally {
                    if (canvas != null)
                        holder.unlockCanvasAndPost(canvas);
                }
                super.onTouchEvent(event);
            }
        }
 
        private void draw() {
            SurfaceHolder holder = getSurfaceHolder();
            Canvas canvas = null;
            try {
                canvas = holder.lockCanvas();
                if (canvas != null) {
                    if (circles.size() >= maxNumber) {
                        circles.clear();
                    }
                    int x = (int) (width * Math.random());
                    int y = (int) (height * Math.random());
                    circles.add(new MyPoint(String.valueOf(circles.size() + 1),
                            x, y));
                    drawCircles(canvas, circles);
                }
            } finally {
                if (canvas != null)
                    holder.unlockCanvasAndPost(canvas);
            }
            handler.removeCallbacks(drawRunner);
            if (visible) {
                handler.postDelayed(drawRunner, 5000);
            }
        }
 
        // Surface view requires that all elements are drawn completely  
        private void drawCircles(Canvas canvas, List<MyPoint> circles) {
            canvas.drawColor(Color.BLACK);
            for (MyPoint point : circles) {
                canvas.drawCircle(point.x, point.y, 20.0f, paint);
            }
        }
    }
 
}

7.) Run for output.
Steps:
1.) Create a project named LiveWallpaper and set the information as stated in the image.
Build Target: Android 4.0
Application Name: LiveWallpaper
Package Name: com. example. LiveWallpaper
Activity Name: LiveWallpaperActivity
Min SDK Version: 14

2.) Open LiveWallpaperActivity.java file and write following code there:

package com.example.LiveWallpaper;
import android.os.Bundle;
import android.preference.Preference;
import android.preference.Preference.OnPreferenceChangeListener;
import android.preference.PreferenceActivity;
import android.widget.Toast;
 
public class LiveWallpaperActivity extends PreferenceActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        addPreferencesFromResource(R.xml.prefs);
 
        // We want to add a validator to the number of circles so that it only  
        // accepts numbers  
        Preference circlePreference = getPreferenceScreen().findPreference(
                "numberOfCircles");
 
        // Add the validator  
        circlePreference.setOnPreferenceChangeListener(numberCheckListener);
    }
 
        Preference.OnPreferenceChangeListener numberCheckListener = new OnPreferenceChangeListener() {
 
        @Override
        public boolean onPreferenceChange(Preference preference, Object newValue) {
            // Check that the string is an integer  
            if (newValue != null && newValue.toString().length() > 0
                    && newValue.toString().matches("\\d*")) {
                return true;
            }
            // If now create a message to the user  
            Toast.makeText(LiveWallpaperActivity.this, "Invalid Input",
                    Toast.LENGTH_SHORT).show();
            return false;
        }
    };
}

3.) Compile and build the project.
Output

Layout Animation in Android

This example explains about the default layout animation in android.
Algorithm:

1.)  Create a new project by File-> New -> Android Project name it LayoutAnimation.
2.)  Write following into main.xml file:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
   android:orientation="vertical"
   android:layout_width="match_parent"
   android:layout_height="match_parent"
   >
    <Button
       android:layout_width="wrap_content"
       android:layout_height="wrap_content"

       android:id="@+id/gridContainer"
       android:animateLayoutChanges="true"
       />
</LinearLayout>

3.)  Run for output.
Steps:
1.) Create a project named LayoutAnimation and set the information as stated in the image.
Build Target: Android 4.0
Application Name: LayoutAnimation
Package Name: com. example. LayoutAnimation
Activity Name: LayoutAnimationActivity
Min SDK Version: 14

2.) Open LayoutAnimationActivity.java file and write following code there:

package com.example.layoutanimation;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.GridLayout;
public class LayoutAnimationActivity extends Activity {
        private int numButtons = 1;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        final GridLayout gridContainer = (GridLayout) findViewById(R.id.gridContainer);
        Button addButton = (Button) findViewById(R.id.addNewButton);
        addButton.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                Button newButton = new Button(LayoutAnimationActivity.this);
                newButton.setText(String.valueOf(numButtons++));
                newButton.setOnClickListener(new View.OnClickListener() {
                    public void onClick(View v) {
                        gridContainer.removeView(v);
                    }
                });
                gridContainer.addView(newButton, Math.min(1, gridContainer.getChildCount()));
            }
        });
    }
}

3.) Compile and build the project.

Output

Calendar Application

 
This example explains how to call and use system calendar into your application.
Algorithm:

1.)   Create a new project by File-> New -> Android Project name it CalendarApplication.
2.)   Write following into main.xml file:

&lt;?xml version=<em>"1.0"</em> encoding=<em>"utf-8"</em>?&gt;
&lt;LinearLayout xmlns:android=<em>"http://schemas.android.com/apk/res/android"</em>
android:layout_width=<em>"fill_parent"</em>
android:layout_height=<em>"fill_parent"</em>
android:orientation=<em>"vertical"</em> &gt;
&lt;Button
android:id=<em>"@+id/button1"</em>
android:layout_width=<em>"wrap_content"</em>
android:layout_height=<em>"wrap_content"</em>
android:onClick=<em>"onClick"</em>
android:text=<em>"Create Event"</em> /&gt;
&lt;Button
android:id=<em>"@+id/button2"</em>
android:layout_width=<em>"wrap_content"</em>
android:layout_height=<em>"wrap_content"</em>
android:onClick=<em>"queryCalendar"</em>
android:text=<em>"Query Calendar"</em> /&gt;
&lt;/LinearLayout&gt;

3.)   Put INTERNET permission to manifest file:
<uses-permission
android:name=“android.permission.READ_CALENDAR”>
</uses-permission>
<uses-permission
android:name=“android.permission.WRITE_CALENDAR”>
</uses-permission>
4.)   Run for output.
Steps:

1.) Create a project named CalendarApplication and set the information as stated in the image.
Build Target: Android 4.0
Application Name: CalendarApplication
Package Name: com. example. CalendarApplication
Activity Name: CalendarApplicationActivity
Min SDK Version: 14


2.) Open CalendarApplicationActivity.java file and write following code there:

<strong>package</strong> com.example.CalendarApplication;
<strong>import</strong> java.util.GregorianCalendar;
<strong>import</strong> android.app.Activity;
<strong>import</strong> android.content.ContentResolver;
<strong>import</strong> android.content.Intent;
<strong>import</strong> android.database.Cursor;
<strong>import</strong> android.net.Uri;
<strong>import</strong> android.os.Bundle;
<strong>import</strong> android.provider.CalendarContract;
<strong>import</strong> android.provider.CalendarContract.Calendars;
<strong>import</strong> android.provider.CalendarContract.Events;
<strong>import</strong> android.view.View;
<strong>import</strong> android.widget.Toast;
<strong>public</strong> <strong>class</strong> CalendarApplicationActivity  <strong>extends</strong> Activity {
<strong>public</strong> <strong>static</strong> <strong>final</strong> String[] <em>EVENT_PROJECTION</em> = <strong>new</strong> String[] {
Calendars.<em>_ID</em>, // 0
Calendars.<em>ACCOUNT_NAME</em>, // 1
Calendars.<em>CALENDAR_DISPLAY_NAME</em> // 2
};
<strong>private</strong> <strong>static</strong> <strong>final</strong> <strong>int</strong> <em>PROJECTION_DISPLAY_NAME_INDEX</em> = 2;
@Override
<strong>public</strong> <strong>void</strong> onCreate(Bundle savedInstanceState) {
<strong>super</strong>.onCreate(savedInstanceState);
setContentView(R.layout.<em>main</em>);
}
<strong>public</strong> <strong>void</strong> onClick(View view) {
Intent intent = <strong>new</strong> Intent(Intent.<em>ACTION_INSERT</em>);
intent.setType("vnd.android.cursor.item/event");
intent.putExtra(Events.<em>TITLE</em>, "Learn Android");
intent.putExtra(Events.<em>EVENT_LOCATION</em>, "Home suit home");
intent.putExtra(Events.<em>DESCRIPTION</em>, "Download Examples");
GregorianCalendar calDate = <strong>new</strong> GregorianCalendar(2012, 10, 02);
intent.putExtra(CalendarContract.<em>EXTRA_EVENT_BEGIN_TIME</em>,
calDate.getTimeInMillis());
intent.putExtra(CalendarContract.<em>EXTRA_EVENT_END_TIME</em>,
calDate.getTimeInMillis());
intent.putExtra(CalendarContract.<em>EXTRA_EVENT_ALL_DAY</em>, <strong>true</strong>);
intent.putExtra(Events.<em>RRULE</em>,
"FREQ=WEEKLY;COUNT=11;WKST=SU;BYDAY=TU,TH");
intent.putExtra(Events.<em>ACCESS_LEVEL</em>, Events.<em>ACCESS_PRIVATE</em>);
intent.putExtra(Events.<em>AVAILABILITY</em>, Events.<em>AVAILABILITY_BUSY</em>);
startActivity(intent);
}
<strong>public</strong> <strong>void</strong> queryCalendar(View view) {
Cursor cur = <strong>null</strong>;
ContentResolver cr = getContentResolver();
Uri uri = Calendars.<em>CONTENT_URI</em>;
String selection = "((" + Calendars.<em>ACCOUNT_NAME</em> + " = ?) AND ("
+ Calendars.<em>ACCOUNT_TYPE</em> + " = ?))";
String[] selectionArgs = <strong>new</strong> String[] { "Lars.Vogel@gmail.com",
"com.google" };
cur = cr.query(uri, <em>EVENT_PROJECTION</em>, selection, selectionArgs, <strong>null</strong>);
<strong>while</strong> (cur.moveToNext()) {
String displayName = <strong>null</strong>;
displayName = cur.getString(<em>PROJECTION_DISPLAY_NAME_INDEX</em>);
Toast.<em>makeText</em>(<strong>this</strong>, "Calendar " + displayName, Toast.<em>LENGTH_SHORT</em>)
.show();
}
}
}

3.) Compile and build the project.

Output


4.) If your phone doesn’t have any default calendar installed you will see the screen as below. Follow the instructions and see your calendar.