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android_learning:headfirst_android_development_notes:chapter_12

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android_learning:headfirst_android_development_notes:chapter_12 [2016/04/24 03:01] – mithatandroid_learning:headfirst_android_development_notes:chapter_12 [2016/04/24 04:08] (current) – [p. 513-514: Code block] mithat
Line 1: Line 1:
 ====== Chapter 12 ====== ====== Chapter 12 ======
  
-<WRAP center round info 60%> +This is just some text to get the section below to clear the Table of Contents. Otherwise the whole code block would appear very narrow. 
-Under development. + 
-</WRAP>+Kludgey for sure, but it gets the job done.  \\ 
 + \\  
 + \\  
 + \\  
 + \\ 
  
 ===== p. 493: Code block ===== ===== p. 493: Code block =====
Line 34: Line 38:
         try {         try {
             // Gain access to our app's database:             // Gain access to our app's database:
-            SQLiteOpenHelper starbuzzDatabaseHelper = new StarbuzzDatabaseHelper(this);+            SQLiteOpenHelper starbuzzDatabaseHelper = 
 +                new StarbuzzDatabaseHelper(this);
             SQLiteDatabase db = starbuzzDatabaseHelper.getReadableDatabase();             SQLiteDatabase db = starbuzzDatabaseHelper.getReadableDatabase();
  
Line 69: Line 74:
             db.close();             db.close();
         } catch (SQLiteException e) {         } catch (SQLiteException e) {
-            Toast toast = Toast.makeText(this, "Database unavailable", Toast.LENGTH_SHORT);+            Toast toast = Toast.makeText(this, "Database unavailable",  
 +                Toast.LENGTH_SHORT);
             toast.show();             toast.show();
         }         }
Line 106: Line 112:
     protected void onCreate(Bundle savedInstanceState) {     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);         super.onCreate(savedInstanceState);
-        ListView listDrinks = getListView(); // i.e., this.getListView(); get the ListView used by this ListActivity+        ListView listDrinks = getListView(); // i.e., this.getListView();  
 +                                             // get the ListView used by  
 +                                             // this ListActivity
  
         // Use a cursor via an adapter to populate listDrinks         // Use a cursor via an adapter to populate listDrinks
         try {         try {
             // Gain access to our app's database:             // Gain access to our app's database:
-            SQLiteOpenHelper starbuzzDatabaseHelper = new StarbuzzDatabaseHelper(this);+            SQLiteOpenHelper starbuzzDatabaseHelper =  
 +                new StarbuzzDatabaseHelper(this);
             db = starbuzzDatabaseHelper.getReadableDatabase();             db = starbuzzDatabaseHelper.getReadableDatabase();
  
Line 130: Line 139:
             listDrinks.setAdapter(listAdapter);             listDrinks.setAdapter(listAdapter);
         } catch (SQLiteException e) {         } catch (SQLiteException e) {
-            Toast.makeText(this, "Database unavailable", Toast.LENGTH_SHORT).show();+            Toast.makeText(this, "Database unavailable",  
 +                Toast.LENGTH_SHORT).show();
         }         }
     }     }
Line 145: Line 155:
     protected void onListItemClick(ListView l, View v, int position, long id) {     protected void onListItemClick(ListView l, View v, int position, long id) {
         super.onListItemClick(l, v, position, id);         super.onListItemClick(l, v, position, id);
-        Intent intent = new Intent(DrinkCategoryActivity.this, DrinkActivity.class);+        Intent intent = new Intent(DrinkCategoryActivity.this,  
 +            DrinkActivity.class);
         intent.putExtra(DrinkActivity.EXTRA_DRINKNO, (int) id);         intent.putExtra(DrinkActivity.EXTRA_DRINKNO, (int) id);
         startActivity(intent);         startActivity(intent);
Line 185: Line 196:
         try {         try {
             // Gain access to our app's database:             // Gain access to our app's database:
-            SQLiteOpenHelper starbuzzDatabaseHelper = new StarbuzzDatabaseHelper(this);+            SQLiteOpenHelper starbuzzDatabaseHelper =  
 +                new StarbuzzDatabaseHelper(this);
             SQLiteDatabase db = starbuzzDatabaseHelper.getWritableDatabase();             SQLiteDatabase db = starbuzzDatabaseHelper.getWritableDatabase();
  
             // Get the name, description, and image for drinkNo:             // Get the name, description, and image for drinkNo:
             Cursor cursor = db.query ("DRINK",             Cursor cursor = db.query ("DRINK",
-                    new String[] {"NAME", "DESCRIPTION", "IMAGE_RESOURCE_ID", "FAVORITE"},+                    new String[] 
 +                        {"NAME", "DESCRIPTION", "IMAGE_RESOURCE_ID", "FAVORITE"},
                     "_id = ?",                     "_id = ?",
                     new String[] {Integer.toString(drinkNo)},                     new String[] {Integer.toString(drinkNo)},
Line 225: Line 238:
             db.close();             db.close();
         } catch (SQLiteException e) {         } catch (SQLiteException e) {
-            Toast toast = Toast.makeText(this, "Database unavailable", Toast.LENGTH_SHORT);+            Toast toast = Toast.makeText(this, "Database unavailable", 
 +                Toast.LENGTH_SHORT);
             toast.show();             toast.show();
         }         }
Line 239: Line 253:
         drinkValues.put("FAVORITE", favorite.isChecked());         drinkValues.put("FAVORITE", favorite.isChecked());
  
-        SQLiteOpenHelper starbuzzDatabaseHelper = new StarbuzzDatabaseHelper(DrinkActivity.this);+        SQLiteOpenHelper starbuzzDatabaseHelper =  
 +            new StarbuzzDatabaseHelper(DrinkActivity.this);
  
         try {         try {
             SQLiteDatabase db = starbuzzDatabaseHelper.getWritableDatabase();             SQLiteDatabase db = starbuzzDatabaseHelper.getWritableDatabase();
-            db.update("DRINK", drinkValues, "_id = ?", new String[] {Integer.toString(drinkNo)});+            db.update("DRINK", drinkValues, "_id = ?", 
 +                new String[] {Integer.toString(drinkNo)});
             db.close();             db.close();
         } catch(SQLiteException e) {         } catch(SQLiteException e) {
-            Toast.makeText(DrinkActivity.this, "Database unavailable", Toast.LENGTH_SHORT).show();+            Toast.makeText(DrinkActivity.this, "Database unavailable", 
 +                Toast.LENGTH_SHORT).show();
         }         }
     }     }
Line 281: Line 298:
         setContentView(R.layout.activity_top_level);         setContentView(R.layout.activity_top_level);
  
-        AdapterView.OnItemClickListener itemClickListener = new AdapterView.OnItemClickListener() {+        AdapterView.OnItemClickListener itemClickListener = 
 +            new AdapterView.OnItemClickListener() { 
             @Override             @Override
-            public void onItemClick(AdapterView<?> parent, View view, int position, long id) { +            public void onItemClick (AdapterView<?> parent, View view, 
-                if (position == 0) { +                int position, long id) { 
-                    Intent intent = new Intent(TopLevelActivity.this, DrinkCategoryActivity.class); +                    if (position == 0) { 
-                    startActivity(intent); +                        Intent intent = new Intent(TopLevelActivity.this,  
-                }+                            DrinkCategoryActivity.class); 
 +                        startActivity(intent); 
 +                    }
             }             }
         };         };
Line 298: Line 319:
         ListView listFavrotites = (ListView)findViewById(R.id.list_favorites);         ListView listFavrotites = (ListView)findViewById(R.id.list_favorites);
         try {         try {
-            SQLiteOpenHelper starbuzzDatabaseHelper = new StarbuzzDatabaseHelper(this);+            SQLiteOpenHelper starbuzzDatabaseHelper =  
 +                new StarbuzzDatabaseHelper(this);
             db = starbuzzDatabaseHelper.getReadableDatabase();             db = starbuzzDatabaseHelper.getReadableDatabase();
  
Line 308: Line 330:
  
             // Map data to list via adapter             // Map data to list via adapter
-            CursorAdapter favoriteAdapter = new SimpleCursorAdapter(TopLevelActivity.this,+            CursorAdapter favoriteAdapter = new SimpleCursorAdapter( 
 +                    TopLevelActivity.this,
                     android.R.layout.simple_list_item_1,                     android.R.layout.simple_list_item_1,
                     favoritesCursor,                     favoritesCursor,
Line 317: Line 340:
  
             // Handle click events on list items - show favorite item's activity             // Handle click events on list items - show favorite item's activity
-            listFavrotites.setOnItemClickListener(new AdapterView.OnItemClickListener() {+            listFavrotites.setOnItemClickListener( 
 +                new AdapterView.OnItemClickListener() {
                 @Override                 @Override
-                public void onItemClick(AdapterView<?> parent, View view, int position, long id) { +                public void onItemClick( 
-                    Intent intent = new Intent(TopLevelActivity.this, DrinkActivity.class); +                    AdapterView<?> parent, View view, int position, long id) { 
-                    intent.putExtra(DrinkActivity.EXTRA_DRINKNO, (int)id); +                        Intent intent =  
-                    startActivity(intent);+                            new Intent(TopLevelActivity.this, DrinkActivity.class); 
 +                        intent.putExtra(DrinkActivity.EXTRA_DRINKNO, (int)id); 
 +                        startActivity(intent); 
 +                    }
                 }                 }
-            });+            );
  
  
         } catch(SQLiteException e) {         } catch(SQLiteException e) {
-            Toast.makeText(TopLevelActivity.this, "Database unavailable", Toast.LENGTH_SHORT).show();+            Toast.makeText(TopLevelActivity.this, "Database unavailable", 
 +                Toast.LENGTH_SHORT).show();
         }         }
     }     }
Line 347: Line 375:
         super.onRestart();         super.onRestart();
         try{         try{
-            StarbuzzDatabaseHelper starbuzzDatabaseHelper = new StarbuzzDatabaseHelper(this);+            StarbuzzDatabaseHelper starbuzzDatabaseHelper = 
 +                new StarbuzzDatabaseHelper(this);
             db = starbuzzDatabaseHelper.getReadableDatabase();             db = starbuzzDatabaseHelper.getReadableDatabase();
  
Line 363: Line 392:
             favoritesCursor = newCursor;             favoritesCursor = newCursor;
         } catch(SQLiteException e) {         } catch(SQLiteException e) {
-            Toast toast = Toast.makeText(this, "Database unavailable", Toast.LENGTH_SHORT);+            Toast toast = Toast.makeText(this, "Database unavailable", 
 +                Toast.LENGTH_SHORT);
             toast.show();             toast.show();
         }         }
Line 418: Line 448:
         try {         try {
             // Gain access to our app's database:             // Gain access to our app's database:
-            SQLiteOpenHelper starbuzzDatabaseHelper = new StarbuzzDatabaseHelper(this);+            SQLiteOpenHelper starbuzzDatabaseHelper = 
 +                new StarbuzzDatabaseHelper(this);
             SQLiteDatabase db = starbuzzDatabaseHelper.getWritableDatabase();             SQLiteDatabase db = starbuzzDatabaseHelper.getWritableDatabase();
  
             // Get the name, description, and image for drinkNo:             // Get the name, description, and image for drinkNo:
             Cursor cursor = db.query ("DRINK",             Cursor cursor = db.query ("DRINK",
-                    new String[] {"NAME", "DESCRIPTION", "IMAGE_RESOURCE_ID", "FAVORITE"},+                    new String[] 
 +                        {"NAME", "DESCRIPTION", "IMAGE_RESOURCE_ID", "FAVORITE"},
                     "_id = ?",                     "_id = ?",
                     new String[] {Integer.toString(drinkNo)},                     new String[] {Integer.toString(drinkNo)},
Line 458: Line 490:
             db.close();             db.close();
         } catch (SQLiteException e) {         } catch (SQLiteException e) {
-            Toast toast = Toast.makeText(this, "Database unavailable", Toast.LENGTH_SHORT);+            Toast toast = Toast.makeText(this, "Database unavailable", 
 +                Toast.LENGTH_SHORT);
             toast.show();             toast.show();
         }         }
Line 479: Line 512:
             drinkValues = new ContentValues();             drinkValues = new ContentValues();
             drinkValues.put("FAVORITE", favorite.isChecked());             drinkValues.put("FAVORITE", favorite.isChecked());
-            Toast.makeText(DrinkActivity.this, "Backgrounding DB operation...", Toast.LENGTH_SHORT).show();+            Toast.makeText(DrinkActivity.this, "Backgrounding DB operation...",  
 +                Toast.LENGTH_SHORT).show();
         }         }
  
Line 485: Line 519:
         protected Boolean doInBackground(Integer... drinks) {         protected Boolean doInBackground(Integer... drinks) {
             int drinkNo = drinks[0];             int drinkNo = drinks[0];
-            SQLiteOpenHelper starbuzzDatabaseHelper = new StarbuzzDatabaseHelper(DrinkActivity.this);+            SQLiteOpenHelper starbuzzDatabaseHelper =  
 +                new StarbuzzDatabaseHelper(DrinkActivity.this);
             try {             try {
                 SQLiteDatabase db = starbuzzDatabaseHelper.getWritableDatabase();                 SQLiteDatabase db = starbuzzDatabaseHelper.getWritableDatabase();
-                db.update("DRINK", drinkValues, "_id = ?", new String[]{Integer.toString(drinkNo)});+                db.update("DRINK", drinkValues, "_id = ?", 
 +                    new String[]{Integer.toString(drinkNo)});
                 db.close();                 db.close();
                 return true;                 return true;
Line 499: Line 535:
         protected void onPostExecute(Boolean success) {         protected void onPostExecute(Boolean success) {
             if (!success) {             if (!success) {
-                Toast.makeText(DrinkActivity.this, "Database unavailable", Toast.LENGTH_SHORT).show();+                Toast.makeText(DrinkActivity.this, "Database unavailable",  
 +                    Toast.LENGTH_SHORT).show();
             } else {             } else {
-                Toast.makeText(DrinkActivity.this, "DB update complete", Toast.LENGTH_SHORT).show();+                Toast.makeText(DrinkActivity.this, "DB update complete", 
 +                    Toast.LENGTH_SHORT).show();
             }             }
         }         }
Line 509: Line 547:
 </file> </file>
  
 +===== Debug with the system log =====
 +This isn't covered until Chapter 13 in the book, but it's worth using here.
 +
 +In this final version of DrinkActivity, I use the [[android_learning:using_the_system_log|system log]] to output debug information to the console instead of using Toasts for debug messages.
 +
 +<file java DrinkActivity.java>
 +package com.hfad.starbuzz;
 +
 +import android.content.ContentValues;
 +import android.database.Cursor;
 +import android.database.sqlite.SQLiteDatabase;
 +import android.database.sqlite.SQLiteException;
 +import android.database.sqlite.SQLiteOpenHelper;
 +import android.os.AsyncTask;
 +import android.support.v7.app.AppCompatActivity;
 +import android.os.Bundle;
 +import android.util.Log;
 +import android.view.View;
 +import android.widget.CheckBox;
 +import android.widget.ImageView;
 +import android.widget.TextView;
 +import android.widget.Toast;
 +
 +public class DrinkActivity extends AppCompatActivity {
 +
 +    public static final String EXTRA_DRINKNO = "drinkNo";
 +
 +    @Override
 +    protected void onCreate(Bundle savedInstanceState) {
 +        super.onCreate(savedInstanceState);
 +        setContentView(R.layout.activity_drink);
 +
 +        int drinkNo = (Integer)getIntent().getExtras().get(EXTRA_DRINKNO);
 +
 +        //Create a cursor and populate Views from the cursor's data.
 +        try {
 +            // Gain access to our app's database:
 +            SQLiteOpenHelper starbuzzDatabaseHelper = 
 +                new StarbuzzDatabaseHelper(this);
 +            SQLiteDatabase db = starbuzzDatabaseHelper.getWritableDatabase();
 +
 +            // Get the name, description, and image for drinkNo:
 +            Cursor cursor = db.query ("DRINK",
 +                    new String[]
 +                        {"NAME", "DESCRIPTION", "IMAGE_RESOURCE_ID", "FAVORITE"},
 +                    "_id = ?",
 +                    new String[] {Integer.toString(drinkNo)},
 +                    null, null,null);
 +
 +            // Move to the first record in the Cursor
 +            if (cursor.moveToFirst()) {
 +                // Get the drink details from the cursor
 +                String nameText = cursor.getString(0);
 +                String descriptionText = cursor.getString(1);
 +                int photoId = cursor.getInt(2);
 +                boolean isFavorite = (cursor.getInt(3) == 1);
 +
 +                // Populate the drink name
 +                TextView name = (TextView)findViewById(R.id.name);
 +                name.setText(nameText);
 +
 +                // Populate the drink description
 +                TextView description = (TextView)findViewById(R.id.description);
 +                description.setText(descriptionText);
 +
 +                // Populate the drink image
 +                ImageView photo = (ImageView)findViewById(R.id.photo);
 +                photo.setImageResource(photoId);
 +                photo.setContentDescription(nameText);
 +
 +                // Populate the favorite checkbox
 +                CheckBox favorite = (CheckBox)findViewById(R.id.favorite);
 +                favorite.setChecked(isFavorite);
 +            }
 +
 +            // Close up shop.
 +            cursor.close();
 +            db.close();
 +        } catch (SQLiteException e) {
 +            Toast toast = Toast.makeText(this, "Database unavailable",
 +                Toast.LENGTH_SHORT);
 +            toast.show();
 +        }
 +    }
 +
 +    // Update the DB's FAVORITES field for this drink.
 +    public void onFavoriteClicked(View view) {
 +        int drinkNo = (Integer)getIntent().getExtras().get("drinkNo");
 +        new UpdateDrinkTask().execute(drinkNo);
 +    }
 +
 +    // Inner class: a task to update the drink's DB record.
 +    private class UpdateDrinkTask extends AsyncTask <Integer, Void, Boolean> {
 +
 +        ContentValues drinkValues;
 +
 +        @Override
 +        protected void onPreExecute() {
 +            CheckBox favorite = (CheckBox)findViewById(R.id.favorite);
 +            drinkValues = new ContentValues();
 +            drinkValues.put("FAVORITE", favorite.isChecked());
 +            Log.d("DB", "Backgrounding DB operation...");
 +        }
 +
 +        @Override
 +        protected Boolean doInBackground(Integer... drinks) {
 +            int drinkNo = drinks[0];
 +            SQLiteOpenHelper starbuzzDatabaseHelper =
 +                new StarbuzzDatabaseHelper(DrinkActivity.this);
 +            try {
 +                SQLiteDatabase db = starbuzzDatabaseHelper.getWritableDatabase();
 +                db.update("DRINK", drinkValues, "_id = ?",
 +                    new String[]{Integer.toString(drinkNo)});
 +                db.close();
 +                return true;
 +            } catch(SQLiteException e) {
 +                return false;
 +            }
 +        }
 +
 +        @Override
 +        protected void onPostExecute(Boolean success) {
 +            if (!success) {
 +                Toast.makeText(DrinkActivity.this, "Database unavailable",
 +                    Toast.LENGTH_SHORT).show();
 +            } else {
 +                Log.d("DB", "DB update complete");
 +            }
 +        }
 +    }
 +}
 +
 +</file>
android_learning/headfirst_android_development_notes/chapter_12.1461466871.txt.gz · Last modified: 2016/04/24 03:01 by mithat
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