From: gumartinm <gu.martinm@gmail.com>
Date: Tue, 7 Feb 2012 07:07:09 +0000 (+0100)
Subject: Implementing an Android Provider.
X-Git-Url: https://git.gumartinm.name/?a=commitdiff_plain;h=d9f46b52e71bd6ca617c413f1c59486343bee10e;p=JavaForFun

Implementing an Android Provider.
I would like to have more time to spend working
on this...
---

diff --git a/Android/Testing/Test3/AndroidManifest.xml b/Android/Testing/Test3/AndroidManifest.xml
index 311d2f6..50a95f4 100644
--- a/Android/Testing/Test3/AndroidManifest.xml
+++ b/Android/Testing/Test3/AndroidManifest.xml
@@ -53,10 +53,7 @@
           	android:readPermission="android.permission.READ_MOBIADS"
           	android:syncable="false"
           	android:writePermission="android.permission.WRITE_MOBIADS" >
-            <grant-uri-permission 
-                android:path="string"
-                android:pathPattern="string"
-                android:pathPrefix="string" />
+            <grant-uri-permission android:pathPattern=".*" />
 		</provider>
 		<!--
 		<provider 
diff --git a/Android/Testing/Test3/src/de/android/test3/IndexerOpenHelper.java b/Android/Testing/Test3/src/de/android/test3/IndexerOpenHelper.java
index 4b6269a..e62eb23 100644
--- a/Android/Testing/Test3/src/de/android/test3/IndexerOpenHelper.java
+++ b/Android/Testing/Test3/src/de/android/test3/IndexerOpenHelper.java
@@ -3,8 +3,12 @@ package de.android.test3;
 import android.content.Context;
 import android.database.sqlite.SQLiteDatabase;
 import android.database.sqlite.SQLiteOpenHelper;
+import android.util.Log;
 
 public class IndexerOpenHelper extends SQLiteOpenHelper {
+	// Used for debugging and logging
+    private static final String TAG = "IndexerOpenHelper";
+	
 	private static final String DBNAME = "mobiads";
 	private static final int DATABASE_VERSION = 1;
     private static final String TABLE_NAME = "indexer";
@@ -19,18 +23,34 @@ public class IndexerOpenHelper extends SQLiteOpenHelper {
     }
 
 
-    /*
-     * Creates the data repository. This is called when the provider attempts to open the
-     * repository and SQLite reports that it doesn't exist.
+    /**
+     *
+     * Creates the underlying database with table name and column names taken from the
+     * NotePad class.
      */
-	@Override
+    @Override
 	public void onCreate(SQLiteDatabase db) {
 		db.execSQL(TABLE_CREATE);
 	}
 
-	
+
+    /**
+     *
+     * Demonstrates that the provider must consider what happens when the
+     * underlying datastore is changed. In this sample, the database is upgraded the database
+     * by destroying the existing data.
+     * A real application should upgrade the database in place.
+     */
 	@Override
 	public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
+		// Logs that the database is being upgraded
+        Log.w(TAG, "Upgrading database from version " + oldVersion + " to "
+                + newVersion + ", which will destroy all old data");
+
+        // Kills the table and existing data
+        db.execSQL("DROP TABLE IF EXISTS indexer");
 
+        // Recreates the database with a new version
+        onCreate(db);
 	}
 }
diff --git a/Android/Testing/Test3/src/de/android/test3/IndexerProvider.java b/Android/Testing/Test3/src/de/android/test3/IndexerProvider.java
index a1142e2..52b1a74 100644
--- a/Android/Testing/Test3/src/de/android/test3/IndexerProvider.java
+++ b/Android/Testing/Test3/src/de/android/test3/IndexerProvider.java
@@ -5,6 +5,7 @@ package de.android.test3;
 
 import android.content.ContentProvider;
 import android.content.ContentValues;
+import android.content.UriMatcher;
 import android.database.Cursor;
 import android.database.sqlite.SQLiteDatabase;
 import android.net.Uri;
@@ -13,21 +14,108 @@ import android.net.Uri;
  *
  */
 public class IndexerProvider extends ContentProvider {
-	// Holds the database object
-    private SQLiteDatabase db;
-    /*
-     * Defines a handle to the database helper object. The MainDatabaseHelper class is defined
-     * in a following snippet.
-     */
+    // Creates a UriMatcher object.
+    private static final UriMatcher sUriMatcher;
+    
+    // Handle to a new DatabaseHelper.
     private IndexerOpenHelper mOpenHelper;
-
-	
-	/* (non-Javadoc)
-	 * @see android.content.ContentProvider#delete(android.net.Uri, java.lang.String, java.lang.String[])
+    
+    // The incoming URI matches the Notes URI pattern
+    private static final int INDEXER = 1;
+    
+    // The incoming URI matches the Note ID URI pattern
+    private static final int INDEXER_ID = 2;
+    
+    static {
+    	
+    	/*
+         * Creates and initializes the URI matcher
+         */
+        // Create a new instance
+        sUriMatcher = new UriMatcher(UriMatcher.NO_MATCH);
+        
+        // Add a pattern that routes URIs terminated with "notes" to a NOTES operation
+        sUriMatcher.addURI("de.android.test3.provider", "indexer", INDEXER);
+        
+        // Add a pattern that routes URIs terminated with "notes" plus an integer
+        // to a note ID operation
+        sUriMatcher.addURI("de.android.test3.provider", "indexer/#", INDEXER_ID);
+    }
+ 
+    
+    
+    /**
+	 *
+	 * Initializes the provider by creating a new DatabaseHelper. onCreate() is called
+	 * automatically when Android creates the provider in response to a resolver request from a
+	 * client.
 	 */
 	@Override
+	public boolean onCreate() {
+		
+      // Creates a new helper object. Note that the database itself isn't opened until
+      // something tries to access it, and it's only created if it doesn't already exist.
+      mOpenHelper = new IndexerOpenHelper(getContext());
+
+      // Assumes that any failures will be reported by a thrown exception.
+      return true;
+	}
+    
+	
+    /**
+     * This is called when a client calls
+     * {@link android.content.ContentResolver#delete(Uri, String, String[])}.
+     * Deletes records from the database. If the incoming URI matches the note ID URI pattern,
+     * this method deletes the one record specified by the ID in the URI. Otherwise, it deletes a
+     * a set of records. The record or records must also match the input selection criteria
+     * specified by where and whereArgs.
+     *
+     * If rows were deleted, then listeners are notified of the change.
+     * @return If a "where" clause is used, the number of rows affected is returned, otherwise
+     * 0 is returned. To delete all rows and get a row count, use "1" as the where clause.
+     * @throws IllegalArgumentException if the incoming URI pattern is invalid.
+     */
+    @Override
 	public int delete(Uri uri, String selection, String[] selectionArgs) {
-		// TODO Auto-generated method stub
+    	// Opens the database object in "write" mode.
+        SQLiteDatabase db = mOpenHelper.getWritableDatabase();
+    	
+        String finalWhere;
+
+        int count;
+
+        // Does the delete based on the incoming URI pattern.
+        switch (sUriMatcher.match(uri)) {
+        case INDEXER_ID:
+        	/*
+             * Starts a final WHERE clause by restricting it to the
+             * desired note ID.
+             */
+            finalWhere =
+                    NotePad.Notes._ID +                              // The ID column name
+                    " = " +                                          // test for equality
+                    uri.getPathSegments().                           // the incoming note ID
+                        get(NotePad.Notes.NOTE_ID_PATH_POSITION)
+            ;
+
+            // If there were additional selection criteria, append them to the final
+            // WHERE clause
+            if (where != null) {
+                finalWhere = finalWhere + " AND " + where;
+            }
+
+            // Performs the delete.
+            count = db.delete(
+                NotePad.Notes.TABLE_NAME,  // The database table name.
+                finalWhere,                // The final WHERE clause
+                whereArgs                  // The incoming where clause values.
+            );
+            break;
+
+        default:
+            throw new IllegalArgumentException("Unknown URI " + uri);
+        }
+    	
 		return 0;
 	}
 
@@ -53,15 +141,8 @@ public class IndexerProvider extends ContentProvider {
 
 		return null;
 	}
-
-	/* (non-Javadoc)
-	 * @see android.content.ContentProvider#onCreate()
-	 */
-	@Override
-	public boolean onCreate() {
-		// TODO Auto-generated method stub
-		return false;
-	}
+	
+	
 
 	/* (non-Javadoc)
 	 * @see android.content.ContentProvider#query(android.net.Uri, java.lang.String[], java.lang.String, java.lang.String[], java.lang.String)
diff --git a/Android/Testing/Test3/src/de/android/test3/MobieAdHttpClient.java b/Android/Testing/Test3/src/de/android/test3/MobieAdHttpClient.java
index becd13f..9055d26 100644
--- a/Android/Testing/Test3/src/de/android/test3/MobieAdHttpClient.java
+++ b/Android/Testing/Test3/src/de/android/test3/MobieAdHttpClient.java
@@ -84,15 +84,13 @@ public class MobieAdHttpClient implements Runnable
 				   //So AndroidHttpClient infinite timeout
 				   //and the connection can be kept forever.
 				   StringBuilder builder = httpClient.execute(httpGet, handler);
-				   if (builder != null) {
-					   JSONTokener tokener = new JSONTokener(builder.toString());
-					   JSONArray finalResult = new JSONArray(tokener);
-					   for (int i = 0; i < finalResult.length(); i++) {
-						   JSONObject objects = finalResult.getJSONObject(i);
-						   //Find out if that id is in the SQLite database.
-						   downloadAds((Integer) objects.get("id"), (String)objects.get("domain"), (String)objects.get("link"));   
-					   }	
-				   }  
+				   JSONTokener tokener = new JSONTokener(builder.toString());
+				   JSONArray finalResult = new JSONArray(tokener);
+				   for (int i = 0; i < finalResult.length(); i++) {
+					   JSONObject objects = finalResult.getJSONObject(i);
+					   //Find out if that id is in the SQLite database.
+					   downloadAds((Integer) objects.get("id"), (String)objects.get("domain"), (String)objects.get("link"));   
+				   }	
 			   } catch (URISyntaxException e) {
 				   Log.e(TAG, "Error while creating URI from URL.", e);  
 			   } catch (ClientProtocolException e) {
@@ -109,6 +107,7 @@ public class MobieAdHttpClient implements Runnable
 				   //NextActivity.this.httpClient.close();
 			   }   
 		   } catch (Throwable e) {
+			   //Not sure if it is "legal" to catch Throwable...
 			   Log.e(TAG, "Caught exception, something went wrong", e);
 		   }
 	   }
@@ -143,13 +142,12 @@ public class MobieAdHttpClient implements Runnable
 				   break;				
 			   case HttpStatus.SC_UNAUTHORIZED:
 				   //ERROR IN USERNAME OR PASSWORD
-				   break;				
+				   throw new SecurityException("Unauthorized access: error in username or password.");
 			   case HttpStatus.SC_BAD_REQUEST:
 				   //WHAT THE HECK ARE YOU DOING?
-				   break;				
+				   throw new IllegalArgumentException("Bad request.");			
 			   default:
-				   Log.e(TAG, "Error while retrieving the HTTP status line.");
-				   break;	
+	               throw new IllegalArgumentException("Error while retrieving the HTTP status line.");
 			   }   
 		   }