Android Seekbar Scrubber

Description:

In this article I'm gonna show you scrubber seek bar demo with drawable in android.
It include a layer-list with background and progress properties of seek bar.Thats it!!!

Scrubber Seek bar

Lets get started!!!

Step 1:Create a drawable scrubber_layer_list.xml

 <?xml version="1.0" encoding="utf-8"?>  
 <layer-list xmlns:android="http://schemas.android.com/apk/res/android">  
   <item android:id="@android:id/background">  
     <shape android:shape="rectangle">  
       <size android:height="5dp"/>  
       <solid android:color="#ffc6c8cc"/>  
       <stroke android:color="#000000" android:width="1dp"/>  
     </shape>  
     </item>  
   <item android:id="@android:id/progress">  
     <clip>  
       <shape android:shape="rectangle">  
         <size android:height="5dp"/>  
         <solid android:color="#ff7092cc"/>  
         <stroke android:color="#000000" android:width="1dp"/>  
       </shape>  
     </clip>  
   </item>  
 </layer-list>  

The above drawable is used to create the background and progress of seek bar using layer-list..



Step 2: Create a simple layout(activity_main) containing seekbar and textView.

 <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"  
   android:paddingLeft="@dimen/activity_horizontal_margin"  
   android:paddingRight="@dimen/activity_horizontal_margin"  
   android:paddingTop="@dimen/activity_vertical_margin"  
   android:paddingBottom="@dimen/activity_vertical_margin"  
   tools:context=".MainActivity">  
   <SeekBar  
     android:max="100"  
     android:progress="0"  
     android:thumb="@null"  
     android:progressDrawable="@drawable/scrubber_layer_list"  
     android:layout_centerInParent="true"  
     android:layout_width="match_parent"  
     android:layout_height="wrap_content"  
     android:id="@+id/seekBar"/>  
   <TextView  
     android:id="@+id/scrubber_update_tv"  
     android:layout_below="@id/seekBar"  
     android:layout_centerInParent="true"  
     android:layout_marginTop="10dp"  
     android:textStyle="bold"  
     android:textSize="16sp"  
     android:text="0%"  
     android:layout_width="wrap_content"  
     android:layout_height="wrap_content" />  
 </RelativeLayout>  

Step 3: Finally add listener to witness the seek percentage.

 public class MainActivity extends ActionBarActivity {  
   private TextView scrubberTv;  
   private SeekBar seekBar;  
   @Override  
   protected void onCreate(Bundle savedInstanceState) {  
     super.onCreate(savedInstanceState);  
     setContentView(R.layout.activity_main);  
     scrubberTv = (TextView) findViewById(R.id.scrubber_update_tv);  
     seekBar = (SeekBar) findViewById(R.id.seekBar);  
     seekBar.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {  
       @Override  
       public void onProgr --Cha!-- (SeekBar seekBar, int i, boolean b) {  
         scrubberTv.setText("" + i +  --);  
       }  
       @Override  
       public void onStartTrackingTouch(SeekBar seekBar) {  
       }  
       @Override  
       public void onStopTrackingTouch(!-- Bar seekBar) {  
       }  
     });  
   }  
 }  

Output:

                                     

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Android Sqlite Trigger Demo

Description:

Triggers are some structured code that are executed  automatically when certain events occurred in our database. Events can be like INSERT, DELETE, UPDATE.

Example: Consider a database of any University. So if any Student record is added in student table , new row(tuple) is added automatically in  library section or canteen section etc.

So by writting a simple trigger we can automatically insert new records in other sections avoiding boiler plate code.

Schema:

 CREATE TABLE student (sid INTEGER PRIMARY KEY, sname TEXT)  
 CREATE TABLE canteen (cid , sid )  
 CREATE TABLE library (lid INTEGER PRIMARY KEY, sid TEXT)  

Trigger to automatically add records in library and canteen table:

 CREATE TRIGGER if not exists add_student   
   AFTER INSERT  
 ON[student]  
   for each row  
     BEGIN  
        insert into library values (2 , new.sid );  
        insert into canteen values (3 , new.sid);  
     END;  

Explanation:The concept here is to create a trigger ,which insert the values in canteen and library based on new student id.

Trigger to delete records from library and canteen table:

 CREATE TRIGGER if not exists delete_student   
   AFTER DELETE   
 ON[student]  
  for each row  
    BEGIN  
        delete from library where sid = old.sid;  
        delete from library where sid = old.sid;  
    END;  

Explanation:The concept here is to  delete a record from student which thereby delete the values from library and canteen with old id of student.

CODE:

 public class MainActivity extends ActionBarActivity {  
   @Override  
   protected void onCreate(Bundle savedInstanceState) {  
     super.onCreate(savedInstanceState);  
     setContentView(R.layout.activity_main);  
     DatabaseHelper databaseHelper = new DatabaseHelper(this , DatabaseHelper.DB_NAME , null , DatabaseHelper.version);  
     databaseHelper.insertIntoStudent("100" , "Lionel Messi");  
     //Similarly if we delete any record the trigger get fired:e.g  
     //databaseHelper.deleteFromStudent("100");  
   }  
   public class DatabaseHelper extends SQLiteOpenHelper {  
     static final public String DB_NAME = "trigger_demo";  
     static final public int version =1;  
     public DatabaseHelper(Context context, String name, SQLiteDatabase.CursorFactory factory, int version) {  
       super(context, name, null, version);  
     }  
     @Override  
     public void onCreate(SQLiteDatabase sqLiteDatabase) {  
       sqLiteDatabase.execSQL("CREATE TABLE student (sid INTEGER PRIMARY KEY, sname TEXT)");  
       sqLiteDatabase.execSQL("CREATE TABLE canteen (cid INTEGER PRIMARY KEY, sid TEXT)");  
       sqLiteDatabase.execSQL("CREATE TABLE library (lid INTEGER PRIMARY KEY, sid TEXT)");  
       sqLiteDatabase.execSQL(insertRecordTrigger()); // create trigger  
       sqLiteDatabase.execSQL(deleteRecordTrigger()); // delete trigger  
     }  
     @Override  
     public void onUpgrade(SQLiteDatabase sqLiteDatabase, int i, int i2) {  
       sqLiteDatabase.execSQL("DROP table student");  
       sqLiteDatabase.execSQL("DROP table student");  
       sqLiteDatabase.execSQL("DROP table student");  
       sqLiteDatabase.execSQL("DROP trigger add_student"); // Drop trigger  
       sqLiteDatabase.execSQL("DROP trigger delete_student"); // Drop trigger  
       onCreate(sqLiteDatabase);  
     }  
     public String deleteRecordTrigger(){  
       String deleteRecord = "CREATE TRIGGER if not exists delete_student " +  
           " AFTER DELETE " +  
           " ON[student] " +  
           " for each row " +  
           " BEGIN " +  
           "  delete from library where sid = old.sid; " +  
           "  delete from library where sid = old.sid; " +  
           " END; ";  
       return deleteRecord;  
     }  
     public String insertRecordTrigger(){  
       String insertRecord = "CREATE TRIGGER if not exists add_student "  
           + " AFTER INSERT "  
           + " ON[student] "  
           + " for each row "  
           + " BEGIN "  
           + " insert into library values (2 , new.sid );"  
           + " insert into canteen values (3 , new.sid);"  
           + " END;";  
       return insertRecord;  
     }  
     /**  
      * Insert new student record into student table which eventually fire trigger and insert record into canteen and library  
      */  
     public void insertIntoStudent(String sid , String sname){  
       ContentValues insertValues = new ContentValues();  
       insertValues.put("sid", sid);  
       insertValues.put("sname", sname);  
       SQLiteDatabase db = getWritableDatabase();  
       db.insert("student", null, insertValues);  
     }  
     /**  
      * Delete student record from student table which eventually fire trigger and delete record from canteen and library  
      */  
     public void deleteFromStudent(String sid){  
       SQLiteDatabase db = getWritableDatabase();  
       db.execSQL("delete from student where sid = '"+sid+"'");  
     }  
   }  
 }  

Output:

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Android:How to find on which thread code is exceuting?

Description:
As we normally say it code is running in “background thread or UI thread”.

Question: How to find on which thread the code is executing?
This article helps to find on which thread the code is executing in Android.

Example:

public static boolean isFromMainThread(){
        return Looper.getMainLooper().getThread().getId() == Thread.currentThread().getId();
  }

Example with thread:
As we say that thread exceute in seperate thread here is the proof:

Thread thread = new Thread(new Runnable() {
                @Override
                public void run() {
                    if (isFromMainThread()) {
                        Log.d("Fetch", " Runnable Executing From Main Thread");
                    } else {
                        Log.d("Fetch", " Runnable Executing From Background Thread");
                    }
                }
            });

thread.start();

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Blur behind Alert Dialog

Update:

We can also use renderscript apis to blur the background for api level >= 17. Please find below github project

Github Blur Behind Dialog

Description:

As we know from API 14 the below technique to Blur the screen has been deprecated.

dialog.getWindow().addFlags(WindowManager.LayoutParams.FLAG_BLUR_BEHIND);

Below is the technique to help to blur background of the alert Dialog. 

So Let's get started

Step1: Take the Snapshot of Your Background using Below Code 

    public static Bitmap takeScreenShot(Activity activity) {
        View view = activity.getWindow().getDecorView();
        view.setDrawingCacheEnabled(true);
        view.buildDrawingCache();


        Bitmap b1 = view.getDrawingCache();
        Rect frame = new Rect();
        activity.getWindow().getDecorView().getWindowVisibleDisplayFrame(frame);
        int statusBarHeight = frame.top;

        Display display = activity.getWindowManager().getDefaultDisplay();
        Point size = new Point();
        display.getSize(size);
        int width = size.x;
        int height = size.y;

        Bitmap b = Bitmap.createBitmap(b1, 0, statusBarHeight, width, height - statusBarHeight);
        view.destroyDrawingCache();
        return b;
    }  

Step2: Call the method  Bitmap fast = fastblur(map, 10); Got it From Here

   public Bitmap fastblur(Bitmap sentBitmap, int radius) {  
     Bitmap bitmap = sentBitmap.copy(sentBitmap.getConfig(), true);  
     if (radius < 1) {  
       return (null);  
     }  
     int w = bitmap.getWidth();  
     int h = bitmap.getHeight();  
     int[] pix = new int[w * h];  
     Log.e("pix", w + " " + h + " " + pix.length);  
     bitmap.getPixels(pix, 0, w, 0, 0, w, h);  
     int wm = w - 1;  
     int hm = h - 1;  
     int wh = w * h;  
     int div = radius + radius + 1;  
     int r[] = new int[wh];  
     int g[] = new int[wh];  
     int b[] = new int[wh];  
     int rsum, gsum, bsum, x, y, i, p, yp, yi, yw;  
     int vmin[] = new int[Math.max(w, h)];  
     int divsum = (div + 1) >> 1;  
     divsum *= divsum;  
     int dv[] = new int[256 * divsum];  
     for (i = 0; i < 256 * divsum; i++) {  
       dv[i] = (i / divsum);  
     }  
     yw = yi = 0;  
     int[][] stack = new int[div][3];  
     int stackpointer;  
     int stackstart;  
     int[] sir;  
     int rbs;  
     int r1 = radius + 1;  
     int routsum, goutsum, boutsum;  
     int rinsum, ginsum, binsum;  
     for (y = 0; y < h; y++) {  
       rinsum = ginsum = binsum = routsum = goutsum = boutsum = rsum = gsum = bsum = 0;  
       for (i = -radius; i <= radius; i++) {  
         p = pix[yi + Math.min(wm, Math.max(i, 0))];  
         sir = stack[i + radius];  
         sir[0] = (p & 0xff0000) >> 16;  
       sir[1] = (p & 0x00ff00) >> 8;  
     sir[2] = (p & 0x0000ff);  
     rbs = r1 - Math.abs(i);  
     rsum += sir[0] * rbs;  
     gsum += sir[1] * rbs;  
     bsum += sir[2] * rbs;  
     if (i > 0) {  
       rinsum += sir[0];  
       ginsum += sir[1];  
       binsum += sir[2];  
     } else {  
       routsum += sir[0];  
       goutsum += sir[1];  
       boutsum += sir[2];  
     }  
       }  
       stackpointer = radius;  
       for (x = 0; x < w; x++) {  
         r[yi] = dv[rsum];  
         g[yi] = dv[gsum];  
         b[yi] = dv[bsum];  
         rsum -= routsum;  
         gsum -= goutsum;  
         bsum -= boutsum;  
         stackstart = stackpointer - radius + div;  
         sir = stack[stackstart % div];  
         routsum -= sir[0];  
         goutsum -= sir[1];  
         boutsum -= sir[2];  
         if (y == 0) {  
           vmin[x] = Math.min(x + radius + 1, wm);  
         }  
         p = pix[yw + vmin[x]];  
         sir[0] = (p & 0xff0000) >> 16;  
       sir[1] = (p & 0x00ff00) >> 8;  
       sir[2] = (p & 0x0000ff);  
       rinsum += sir[0];  
       ginsum += sir[1];  
       binsum += sir[2];  
       rsum += rinsum;  
       gsum += ginsum;  
       bsum += binsum;  
       stackpointer = (stackpointer + 1) % div;  
       sir = stack[(stackpointer) % div];  
       routsum += sir[0];  
       goutsum += sir[1];  
       boutsum += sir[2];  
       rinsum -= sir[0];  
       ginsum -= sir[1];  
       binsum -= sir[2];  
       yi++;  
       }  
       yw += w;  
     }  
     for (x = 0; x < w; x++) {  
       rinsum = ginsum = binsum = routsum = goutsum = boutsum = rsum = gsum = bsum = 0;  
       yp = -radius * w;  
       for (i = -radius; i <= radius; i++) {  
         yi = Math.max(0, yp) + x;  
         sir = stack[i + radius];  
         sir[0] = r[yi];  
         sir[1] = g[yi];  
         sir[2] = b[yi];  
         rbs = r1 - Math.abs(i);  
         rsum += r[yi] * rbs;  
         gsum += g[yi] * rbs;  
         bsum += b[yi] * rbs;  
         if (i > 0) {  
           rinsum += sir[0];  
           ginsum += sir[1];  
           binsum += sir[2];  
         } else {  
           routsum += sir[0];  
           goutsum += sir[1];  
           boutsum += sir[2];  
         }  
         if (i < hm) {  
           yp += w;  
         }  
       }  
       yi = x;  
       stackpointer = radius;  
       for (y = 0; y < h; y++) {  
         // Preserve alpha channel: ( 0xff000000 & pix[yi] )  
         pix[yi] = ( 0xff000000 & pix[yi] ) | ( dv[rsum] << 16 ) | ( dv[gsum] << 8 ) | dv[bsum];  
         rsum -= routsum;  
         gsum -= goutsum;  
         bsum -= boutsum;  
         stackstart = stackpointer - radius + div;  
         sir = stack[stackstart % div];  
         routsum -= sir[0];  
         goutsum -= sir[1];  
         boutsum -= sir[2];  
         if (x == 0) {  
           vmin[y] = Math.min(y + r1, hm) * w;  
         }  
         p = x + vmin[y];  
         sir[0] = r[p];  
         sir[1] = g[p];  
         sir[2] = b[p];  
         rinsum += sir[0];  
         ginsum += sir[1];  
         binsum += sir[2];  
         rsum += rinsum;  
         gsum += ginsum;  
         bsum += binsum;  
         stackpointer = (stackpointer + 1) % div;  
         sir = stack[stackpointer];  
         routsum += sir[0];  
         goutsum += sir[1];  
         boutsum += sir[2];  
         rinsum -= sir[0];  
         ginsum -= sir[1];  
         binsum -= sir[2];  
         yi += w;  
       }  
     }  
     Log.e("pix", w + " " + h + " " + pix.length);  
     bitmap.setPixels(pix, 0, w, 0, 0, w, h);  
     return (bitmap);  
   }  

Step 3: Finally just Add click listener on button.

   btnblur.setOnClickListener(new OnClickListener() {  
       @Override  
       public void onClick(View view) {  
         AlertDialog.Builder builder=new AlertDialog.Builder(BlurImageView.this,R.style.Theme_D1NoTitleDim);  
         builder.setTitle("Content");  
         builder.setMessage("CLICK OK to Exit");  
         builder.setPositiveButton("ON", new DialogInterface.OnClickListener() {  
           @Override  
           public void onClick(DialogInterface dialog, int which) {  
             dialog.cancel();  
           }  
         });  
         alert=builder.create();  
         Bitmap map=takeScreenShot(BlurImageView.this);  
         Bitmap fast=fastblur(map, 10);  
         final Drawable draw=new BitmapDrawable(getResources(),fast);  
         alert.getWindow().setBackgroundDrawable(draw);  
         alert.show();  
       }  
     });  

Output:

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AsyncTask Android Example

Introduction

Asynctask(Asynchronous task) in android enable us to perform the task in Background thread giving us the way to separate our tedious work from UI Thread and publish our work back to UI thread after our work get completed.

It has following method(listed in sequence of execution):

• onPreExceute
• doInBackGround
• publishProgress
• onProgressUpdate
• onPostExceute

Note:  We can't access any android widgets (button, progressDialog etc.) elements in       doInBackground. So for updating our work status we publish the progress from doInBackground.

Android Example: Asynctask<Params,Progress,Result>

class AsyncTaskExample extends AsyncTask<Void, Integer, String> {
    
    private  final String TAG = AsyncTaskExample.class.getName();
    
    protected void onPreExecute(){
        Log.d(TAG, "On preExceute...");
    }
    
    protected String doInBackground(Void...arg0) {
        
        Log.d(TAG, "On doInBackground...");
        
        for(int i = 0; i<5; i++){
            Integer in = new Integer(i);
            publishProgress(i);
        }
        
        return "You are at PostExecute";}
    
    protected void onProgressUpdate(Integer...a){
        Log.d(TAG,"You are in progress update ... " + a[0]);
    }
    
    protected void onPostExecute(String result) {
        Log.d(TAG,result); 
    }
}

Call in your activity(Any):

 new AsyncTaskExample().execute() - In Our example

 new AsyncTaskExample().executeOnExecutor(AsyncTask.SERIAL_EXECUTOR); - for serial task execute.  
 new AsyncTaskExample().executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR)- For Parallel task.  

Output:

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