Gestion des images Bitmaps

Pour afficher un Bitmap :

Par exemple pour une icône de 64×64 pixels :

a) Créer un Layout avec une image view :

   <ImageView  
     android:id="@+id/imgView"  
     android:layout_width="64dp"  
     android:layout_height="64dp">  
   </ImageView>  

b) Remplissage de l’image view avec le Bitmap :

     setContentView(R.layout.activity_main);  
     ImageView profile = (ImageView) findViewById(R.id.imgView);  
     profile.setImageBitmap(ficbitmap);  

Pour convertir un Drawable en Bitmap :

Utilisez la fonction DecodeBitmap :

BitmapFactory.decodeResource(getResources(), R.drawable.<nom_du_drawable>);

exemple :

profile.setImageBitmap(BitmapFactory.decodeResource(
        getResources(), R.drawable.horse));

Pour redimensionner une image Bitmap :

      Bitmap ImageFromGal = BitmapFactory   
        .decodeFile(imgDecodableString);   
      ImageFromGal = Bitmap.createScaledBitmap(   
        ImageFromGal, 64, 64, false);   

Pour obtenir des images à partir de la gallerie du smartphone :

attention inclure dans le manifest la permissions :

   <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />  
  
   public void loadImagefromGallery(View view) {  
     // Create intent to Open Image applications like Gallery, Google Photos  
     Intent galleryIntent = new Intent(Intent.ACTION_PICK,  
         android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);  
     // Start the Intent  
     startActivityForResult(galleryIntent, RESULT_LOAD_IMG);  
   }  
      @Override  
   protected void onActivityResult(int requestCode, int resultCode, Intent data) {  
     super.onActivityResult(requestCode, resultCode, data);  
     try {  
       // When an Image is picked  
       if (requestCode == RESULT_LOAD_IMG && resultCode == RESULT_OK  
           && null != data)   
                     {  
         // Get the Image from data  
         Uri selectedImage = data.getData();  
         String[] filePathColumn = {MediaStore.Images.Media.DATA};  
         // Get the cursor  
         Cursor cursor = getContentResolver().query(selectedImage,  
             filePathColumn, null, null, null);  
         // Move to first row  
         cursor.moveToFirst();  
         int columnIndex = cursor.getColumnIndex(filePathColumn[0]);  
         imgDecodableString = cursor.getString(columnIndex);  
         cursor.close();  
         ImageView imgView = (ImageView) findViewById(R.id.imgView);  
         //-- Resize Image to 64x64  
         Bitmap ImageFromGal = BitmapFactory  
             .decodeFile(imgDecodableString);  
         ImageFromGal = Bitmap.createScaledBitmap(  
             ImageFromGal, 64, 64, false);  
         bFic = UtilityImg.getBytes(ImageFromGal);  
         DbHelper.updateContact(dbContact, bFic);  
         //-- Set Image in Image View  
         imgView.setImageBitmap(ImageFromGal);  
                  } finally {  
               if (cursor != null) {  
               cursor.close();  
             }  
           }  
             } else  
         {  
         Toast.makeText(this, "You haven't picked Image",  
             Toast.LENGTH_LONG).show();  
         }  
     } catch (Exception e) {  
       Toast.makeText(this, "Can't load picture...", Toast.LENGTH_LONG)  
           .show();  
     }  
           }  

Pour obtenir des images à partir des contacts du répertoire :

Inclure dans le manifest la permission :

   
   <uses-permission android:name="android.permission.READ_CONTACTS" />  
 public void loadImagefromContact(View view) {  
 //-- On recherche le contact  
 Intent intent = new Intent(Intent.ACTION_GET_CONTENT);  
 intent.setType(ContactsContract.CommonDataKinds.Phone.CONTENT_ITEM_TYPE);  
 startActivityForResult(intent, RESULT_LOAD_CONTACT);  
 }  
 if (requestCode == RESULT_LOAD_CONTACT && resultCode == RESULT_OK  
 && null != data) { ///  
 Uri uri = data.getData();  
 if (uri != null) {  
 Cursor cursor = null;  
 try {       
 cursor = getContentResolver().query(uri, new String[]{  
 ContactsContract.CommonDataKinds.Phone.NUMBER,  
 ContactsContract.CommonDataKinds.Phone.CONTACT_ID,  
 ContactsContract.CommonDataKinds.Phone.NORMALIZED_NUMBER},  
 null, null, null);  
 String phoneNumber = null, contactId = null;  
 if (cursor != null && cursor.moveToFirst()) {  
 contactId = cursor.getString(cursor.getColumnIndex(ContactsContract.CommonDataKinds.Phone.CONTACT_ID));  
 phoneNumber = cursor.getString(cursor.getColumnIndex(ContactsContract.CommonDataKinds.Phone.NUMBER));  
 //phoneNorm = cursor.getString(cursor.getColumnIndex(ContactsContract.CommonDataKinds.Phone.NORMALIZED_NUMBER));  
 ///  
 ImageView profile = (ImageView) findViewById(R.id.imgView);  
 Uri my_contact_Uri = Uri.withAppendedPath(ContactsContract.Contacts.CONTENT_URI, String.valueOf(contactId));  
 InputStream photo_stream = ContactsContract.Contacts.openContactPhotoInputStream(getContentResolver(), my_contact_Uri);  
 BufferedInputStream buf = new BufferedInputStream(photo_stream);  
 if (photo_stream!=null){  
 Bitmap my_btmp = BitmapFactory.decodeStream(buf);  
 bFic=UtilityImg.getBytes(my_btmp);  
 DbHelper.updateContact(dbContact, bFic);  
 profile.setImageBitmap(my_btmp);  
 try {  
 buf.close();  
 } catch (IOException e) {  
 e.printStackTrace();  
 }}}}}}  

Pour stocker des images dans une base de données :

Pour gérer la base de données, créez une classe « DbHelper » :

  import android.content.ContentValues;  
 import android.content.Context;  
 import android.database.Cursor;  
 import android.database.DatabaseUtils;  
 import android.database.sqlite.SQLiteDatabase;  
 import android.database.sqlite.SQLiteOpenHelper;  
 import android.util.Log;  
 public class DbHelper extends SQLiteOpenHelper {  
   private static final String DATABASE_NAME = "dbimg.db";  
   private static final int DATABASE_VERSION = 1;  
   public DbHelper(Context context) {  
     super(context, DATABASE_NAME, null, DATABASE_VERSION);  
   }  
   @Override  
   public void onCreate(SQLiteDatabase db) {  
     //-- Table contact contient les raccourcis  
     db.execSQL(  
         "CREATE TABLE IF NOT EXISTS contact ( " +  
             "ficico blob," +  
             "idico integer)");  
   }  
   public static long CompteContact(SQLiteDatabase db) {  
     Log.d("Base", "Nb enr=" + String.valueOf(DatabaseUtils.queryNumEntries(db, "contact")));  
     return DatabaseUtils.queryNumEntries(db, "contact");  
   }  
   public static int updateContact(SQLiteDatabase db, byte[] FicIco) {  
     ContentValues values = new ContentValues();  
     values.put("ficico", FicIco);  
     return db.update("contact", values, "idico = 1" , null);  
   }  
   public static byte[] litImageContact(SQLiteDatabase db) {  
     byte[] byteImage=null;  
     Cursor cursor = db.query("contact", null,  
         "idico = 1", null, null, null, null);  
     if (cursor.moveToFirst()) {  
       do {  
         byteImage = cursor.getBlob(0);  
       } while (cursor.moveToNext());  
     }  
     return byteImage;  
   }  
   public static long insertContact(SQLiteDatabase db, byte[] FicIco) {  
     ContentValues values = new ContentValues();  
     values.put("idico", 1);  
     values.put("ficico", FicIco);  
     return db.insert("contact", null, values);  
   }  
   //////////////////////  
   @Override  
   public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {  
     if (oldVersion >= newVersion)  
       return;  
     if (oldVersion == 1) {  
       Log.d("New Version", "Datas can be upgraded");  
     }  
     Log.d("Sample Data", "onUpgrade   : " + newVersion);  
   }  
 }  

L’utilisation étant :

On défini un tableau de bytes qui va stocker l’image : private byte[] bFic=null;

Stockage :

bFic=UtilityImg.getBytes(BitmapFactory.decodeResource(getResources(), R.drawable.horse));
DbHelper.insertContact(dbContact,bFic);

Restitution :

bFic=DbHelper.litImageContact(dbContact);

Pour convertir le tableau de bytes on utilise la fonction getPhoto (décrite en bas de page) :

profile.setImageBitmap(UtilityImg.getPhoto(bFic));

Les trois dernières fonctionnalités énoncées ont besoin des fonctions :

   // convert from bitmap to byte array  
   public static byte[] getBytes(Bitmap bitmap) {  
     ByteArrayOutputStream stream = new ByteArrayOutputStream();  
     bitmap.compress(CompressFormat.PNG, 0, stream);  
     return stream.toByteArray();  
   }  
   // convert from byte array to bitmap  
   public static Bitmap getPhoto(byte[] image) {  
     return BitmapFactory.decodeByteArray(image, 0, image.length);  
   }  
 }  

Références :

Un exemple de mise en oeuvre est ici

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