Splas Screen - Doing it right way

Step 1: First create an XML Drwable in res/drwable folder.

<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">

    <item
        android:drawable="@color/gray"/>

    <item>
        <bitmap
            android:gravity="center"
            android:src="@mipmap/ic_launcher"/>
    </item>

</layer-list>

Step 2: Next, you will set this as your splash activity’s background in the theme. Navigate to your styles.xml file and add a new theme for your splash activity:

<resources>

    <!-- Base application theme. -->
    <style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">
        <!-- Customize your theme here. -->
    </style>

    <style name="SplashTheme" parent="Theme.AppCompat.NoActionBar">
        <item name="android:windowBackground">@drawable/background_splash</item>
    </style>

</resources>

Step 3: In your new SplashTheme, set the window background attribute to your XML drawable. Configure this as your splash activity’s theme in your AndroidManifest.xml:

<activity
    android:name=".SplashActivity"
    android:theme="@style/SplashTheme">
    <intent-filter>
        <action android:name="android.intent.action.MAIN" />

        <category android:name="android.intent.category.LAUNCHER" />
    </intent-filter>
</activity>

Step 4: Finally, your SplashActivity class should just forward you along to your main activity:

public class SplashActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        Intent intent = new Intent(this, MainActivity.class);
        startActivity(intent);
        finish();
    }
}

Doing it Right

With these steps completed, you will have a splash screen implemented the right way:

Ref : splash-screens-the-right-way

Read file from SD card in Android

Use this function to read files from SD card. Pass the path of the file with file name 
  -  ("/TestFolder/TestFile.text")

public static BufferedReader readFileFromSdCard(String fileName){
        File sdcard = Environment.getExternalStorageDirectory();
        File file=new File(sdcard,fileName);
              BufferedReader myReader = null;
        try {
            if (file.exists()){
            FileInputStream iStream =  new FileInputStream(file);
             myReader = new BufferedReader(
                    new InputStreamReader(iStream));
             Log.i("File", fileName+" Exists ");
            }
        } catch (FileNotFoundException e) {
            // TODO Auto-generated catch block
            Log.e("File", fileName+" Not found");
            e.printStackTrace();
        }
        return myReader;

    }

Android Connectivity test

import android.content.Context;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.telephony.TelephonyManager;
import android.widget.Toast;

public class Connectivity {
/*
 * HACKISH: These constants aren't yet available in my API level (7), but I need to handle these cases if they come up, on newer versions
 */
public static final int NETWORK_TYPE_EHRPD=14; // Level 11
public static final int NETWORK_TYPE_EVDO_B=12; // Level 9
public static final int NETWORK_TYPE_HSPAP=15; // Level 13
public static final int NETWORK_TYPE_IDEN=11; // Level 8
public static final int NETWORK_TYPE_LTE=13; // Level 11

/**
 * Check if there is any connectivity
 * @param context
 * @return
 */
public static boolean isConnected(Context context){
    ConnectivityManager cm = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
    NetworkInfo info = cm.getActiveNetworkInfo();
    return (info != null && info.isConnected());
}

public static boolean isRoming(Context context){
TelephonyManager telephony = (TelephonyManager) context.getSystemService(Context.TELEPHONY_SERVICE);
if(telephony.isNetworkRoaming()){
     

    Toast.makeText(context, "Is Roaming", Toast.LENGTH_LONG).show();
}
return true;

}


/**
 * Check if there is fast connectivity
 * @param context
 * @return
 */
public static boolean isConnectedFast(Context context){
    ConnectivityManager cm = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
    NetworkInfo info = cm.getActiveNetworkInfo();
    return (info != null && info.isConnected() && Connectivity.isConnectionFast(info.getType(),info.getSubtype()));
}

/**
 * Check if the connection is fast
 * @param type
 * @param subType
 * @return
 */
public static boolean isConnectionFast(int type, int subType){
    if(type==ConnectivityManager.TYPE_WIFI){
        System.out.println("CONNECTED VIA WIFI");
        return true;
    }else if(type==ConnectivityManager.TYPE_MOBILE){
        switch(subType){
        case TelephonyManager.NETWORK_TYPE_1xRTT:
            return false; // ~ 50-100 kbps
        case TelephonyManager.NETWORK_TYPE_CDMA:
            return false; // ~ 14-64 kbps
        case TelephonyManager.NETWORK_TYPE_EDGE:
            return false; // ~ 50-100 kbps
        case TelephonyManager.NETWORK_TYPE_EVDO_0:
            return true; // ~ 400-1000 kbps
        case TelephonyManager.NETWORK_TYPE_EVDO_A:
            return true; // ~ 600-1400 kbps
        case TelephonyManager.NETWORK_TYPE_GPRS:
            return false; // ~ 100 kbps
        case TelephonyManager.NETWORK_TYPE_HSDPA:
            return true; // ~ 2-14 Mbps
        case TelephonyManager.NETWORK_TYPE_HSPA:
            return true; // ~ 700-1700 kbps
        case TelephonyManager.NETWORK_TYPE_HSUPA:
            return true; // ~ 1-23 Mbps
        case TelephonyManager.NETWORK_TYPE_UMTS:
            return true; // ~ 400-7000 kbps
        // NOT AVAILABLE YET IN API LEVEL 7
        case Connectivity.NETWORK_TYPE_EHRPD:
            return true; // ~ 1-2 Mbps
        case Connectivity.NETWORK_TYPE_EVDO_B:
            return true; // ~ 5 Mbps
        case Connectivity.NETWORK_TYPE_HSPAP:
            return true; // ~ 10-20 Mbps
        case Connectivity.NETWORK_TYPE_IDEN:
            return false; // ~25 kbps
        case Connectivity.NETWORK_TYPE_LTE:
            return true; // ~ 10+ Mbps
        // Unknown
        case TelephonyManager.NETWORK_TYPE_UNKNOWN:
            return false;
        default:
            return false;
        }
    }else{
        return false;
    }
}

}

Creating Custom Dialog in Android

In this tutorial, we show you how to create a custom dialog in Android. See following steps :

1. Create a custom dialog layout (XML file).
2. Attach the layout to Dialog.
3. Display the Dialog.
4. Done.

dialog.xml

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    android:orientation="vertical" >

    <ImageView

        android:id="@+id/imageView1"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:src="@drawable/ic_launcher" />

    <TextView

        android:id="@+id/textView1"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:text="Medium Text"

        android:textAppearance="?android:attr/textAppearanceMedium" />

    <LinearLayout

        android:layout_width="match_parent"

        android:layout_height="wrap_content" >

        <Button

            android:id="@+id/button1"

            android:layout_width="wrap_content"

            android:layout_height="wrap_content"

            android:text="Button" />

        <Button

            android:id="@+id/button2"

            android:layout_width="wrap_content"

            android:layout_height="wrap_content"

            android:text="Button" />

        <Button

            android:id="@+id/button3"

            android:layout_width="wrap_content"

            android:layout_height="wrap_content"

            android:text="Button" />

    </LinearLayout>

</LinearLayout>

activity_caustom_dialog_main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"

    xmlns:tools="http://schemas.android.com/tools"

    android:layout_width="match_parent"

    android:layout_height="match_parent" >

    <TextView

        android:id="@+id/textView1"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_centerHorizontal="true"

        android:layout_centerVertical="true"

        android:padding="@dimen/padding_medium"

        android:text="@string/hello_world"

        tools:context=".CaustomDialogMainActivity" />

    <Button

        android:id="@+id/btn_show_dialog"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignLeft="@+id/textView1"

        android:layout_below="@+id/textView1"

        android:text="Button" />

</RelativeLayout>

CaustomDialogMainActivity.java

package com.savtech.android.caustomdialog;

import android.os.Bundle;

import android.app.Activity;

import android.app.Dialog;

import android.view.Menu;

import android.view.MenuItem;

import android.view.View;

import android.view.View.OnClickListener;

import android.webkit.WebChromeClient.CustomViewCallback;

import android.widget.Button;

import android.widget.ImageView;

import android.widget.TextView;

import android.widget.Toast;

import android.support.v4.app.NavUtils;

public class CaustomDialogMainActivity extends Activity {

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_caustom_dialog_main);

Button btn_ShowDialog = (Button) findViewById(R.id.btn_show_dialog);

btn_ShowDialog.setOnClickListener(new OnClickListener() {

@Override

public void onClick(View v) {

// TODO Auto-generated method stub

final Dialog dialog = new Dialog(CaustomDialogMainActivity.this);

// to set dialog a custom layout.......

dialog.setContentView(R.layout.dialog);

// to set dialog title .......

dialog.setTitle("This is Dialog Title ...");

TextView text = (TextView) dialog.findViewById(R.id.textView1);

text.setText("Android custom dialog example!");

ImageView image = (ImageView) dialog

.findViewById(R.id.imageView1);

image.setImageResource(R.drawable.ic_launcher);

Button dialogButton1 = (Button) dialog

.findViewById(R.id.button1);

Button dialogButton2 = (Button) dialog

.findViewById(R.id.button2);

Button dialogButton3 = (Button) dialog

.findViewById(R.id.button3);

dialogButton1.setOnClickListener(new OnClickListener() {

@Override

public void onClick(View v) {

// TODO Auto-generated method stub

Toast.makeText(getApplicationContext(), "Button 1",

Toast.LENGTH_SHORT).show();

}

});

dialogButton2.setOnClickListener(new OnClickListener() {

@Override

public void onClick(View v) {

// TODO Auto-generated method stub

Toast.makeText(getApplicationContext(), "Button 2",

Toast.LENGTH_SHORT).show();

}

});

dialogButton3.setOnClickListener(new OnClickListener() {

@Override

public void onClick(View v) {

// TODO Auto-generated method stub

Toast.makeText(getApplicationContext(), "Button 3",

Toast.LENGTH_SHORT).show();

}

});

dialog.show();

}

});

}

}

Now run this application ......

Now click on the Button and you will see this Dialog...with Image View ,Text View and 3 Buttons.

Now click on Button 2 ......see the Toast Message .....

Enjoy...........

To change Airplane mode on android programmatically

 public static boolean isAirplaneModeOn(Context context) 
                { 
                        return Settings.System.getInt(context.getContentResolver 
(),Settings.System.AIRPLANE_MODE_ON, 0) != 0; 
                } 
                /** 
                 * 
                 * @param status 
                 */ 
                public static void setAirplaneMode(Context context,boolean status) 
                { 
                        boolean isAirplaneModeOn = isAirplaneModeOn(context); 

                        if(isAirplaneModeOn && status) 
                        { 
                                return; 
                        } 
                        if(!isAirplaneModeOn && !status) 
                        { 
                                return; 
                        } 
                        if(isAirplaneModeOn && !status) 
                        { 
                                Settings.System.putInt(AppContext.getInstance().getContext 
().getContentResolver(), 
                                Settings.System.AIRPLANE_MODE_ON, 0); 

                        Intent intent = new Intent
(Intent.ACTION_AIRPLANE_MODE_CHANGED); 

                        intent.putExtra("state", 0); 
                        AppContext.getInstance().getContext().sendBroadcast 
(intent); 
                        return; 
                        } 
                        if(!isAirplaneModeOn && status) 
                        { 
                                Settings.System.putInt(AppContext.getInstance().getContext 
().getContentResolver(), 
                                Settings.System.AIRPLANE_MODE_ON, 1); 

                        Intent intent = new Intent
(Intent.ACTION_AIRPLANE_MODE_CHANGED); 

                        intent.putExtra("state", 1); 
                        AppContext.getInstance().getContext().sendBroadcast 
(intent); 
                        return; 
                        } 
                }

Set wallpaper image from Gallery programmatically in Android

Follow the stapes and intregrate the pice of codes in your application :

1.  final int RESULT_LOAD_IMAGE=1;

2.call this intent to open gallery and select an Image:

Intent i = new Intent(Intent.ACTION_PICK,

                        android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI); startActivityForResult(i, lodImage);

3. Now on Activity result you can get the selected image path and you can set the Wallpaper :

 protected void onActivityResult(int requestCode, int resultCode, Intent data) {

        super.onActivityResult(requestCode, resultCode, data);

         

        /*

         * if request made to select a image from gallery

         */

        if (requestCode == RESULT_LOAD_IMAGE && resultCode == RESULT_OK && null != data) {

           String wallpaper= selectedWallpaperImage(getApplicationContext(),data);

           WallpaperManager wallpaperManager = WallpaperManager.getInstance(this);

           

           try {

wallpaperManager.setBitmap(BitmapFactory.decodeFile(wallpaper));

                         //this line of code will set the selected image as your wallpaper...........

} catch (IOException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

        }

    }

4.You need this method to get the Gallery image path

public static String selectedWallpaperImage(Context context,Intent data){

Uri selectedImage = data.getData();

     String[] filePathColumn = { MediaStore.Images.Media.DATA };

     Cursor cursor = context.getContentResolver().query(selectedImage,

             filePathColumn, null, null, null);

     cursor.moveToFirst();

     int columnIndex = cursor.getColumnIndex(filePathColumn[0]);

     String picturePath = cursor.getString(columnIndex);

     cursor.close();

return picturePath;

}

Enable/disable data and WiFi connection in android programmatically

For accessing the WIFI state :

WifiManager wifiManager ;
wifiManager  = (WifiManager)this.getSystemService(this.WIFI_SERVICE);
wifiManager.setWifiEnabled(true);        //True - to enable WIFI connectivity .



For accessing the DATA/3G state :


ConnectivityManager dataManager;
dataManager  = (ConnectivityManager)getSystemService(Context.CONNECTIVITY_SERVICE);
Method dataMtd = ConnectivityManager.class.getDeclaredMethod("setMobileDataEnabled", boolean.class);
dataMtd.setAccessible(true);
dataMtd.invoke(dataManager, true);        //True - to enable data connectivity .

Now you need to add this permissions in Manifest file :


    <uses-permission android:name="android.permission.CHANGE_WIFI_STATE"/>
    <uses-permission android:name="android.permission.ACCESS_WIFI_STATE"/>
    <uses-permission android:name="android.permission.INTERNET"/>
    <uses-permission android:name="android.permission.CHANGE_NETWORK_STATE"/>

Android Activity Lifecycle :Understanding it completely with a small example.

An Activity is an application component that provides a screen with which users can interact in order to do something, such as dial the phone, take a photo, send an email, or view a map. Each activity is given a window in which to draw its user interface. The window typically fills the screen, but may be smaller than the screen and float on top of other windows.

Managing the lifecycle of your activities by implementing callback methods is crucial to developing a strong and flexible application. The lifecycle of an activity is directly affected by its association with other activities, its task and back stack.

• Activity contains the following states in its entire life-cycle.

1. onCreate();
2. onStrart();
3. onResume();
4. onPause();
5. onStop();
6. onDestroy();
7. onRestrat();

An activity can exist in essentially three states:

Resumed

The activity is in the foreground of the screen and has user focus. (This state is also sometimes referred to as "running".)

Paused

Another activity is in the foreground and has focus, but this one is still visible. That is, another activity is visible on top of this one and that activity is partially transparent or doesn't cover the entire screen. A paused activity is completely alive (theActivity object is retained in memory, it maintains all state and member information, and remains attached to the window manager), but can be killed by the system in extremely low memory situations.

Stopped

The activity is completely obscured by another activity (the activity is now in the "background"). A stopped activity is also still alive (the Activity object is retained in memory, it maintains all state and member information, but is not attached to the window manager). However, it is no longer visible to the user and it can be killed by the system when memory is needed elsewhere.

If an activity is paused or stopped, the system can drop it from memory either by asking it to finish (calling its finish()method), or simply killing its process. When the activity is opened again (after being finished or killed), it must be created all over.

To make an effective and stable application you should have a clear idea about the Activity Life-cycle.As many of the developers doesn't consider all the states of an activity .To get an idea i have created a simple application that contains three Activity, we can navigate from one activity to another .

• Download the source code and try to run it in your Eclipse .
• You can download the code from this link.
• After starting the application you will see this screens Image :1,Image :2. with Buttons to navigate between Activities. 

    

Image:1



Image :2

• Take a look at the LogCat file it will give you a clear vision and proper understanding of an Activity Life-cycle .
• The logcat will show you something like the Image :3

After navigating from one activity to other try something different , press the Home key button,then again come back to the application.See the changes in the log . I think it will clear all the confusion in your mind about Activity Life-cycle .