Android開發之路十三———–ContentProvider串連

ContentProvider

1、PersonProvider

package cn.class3g.db;   import cn.class3g.service.DatabaseHelper; import android.content.ContentProvider; import android.content.ContentUris; import android.content.ContentValues; import android.content.UriMatcher; import android.database.Cursor; import android.database.sqlite.SQLiteDatabase; import android.net.Uri;   public class PersonProvider extends ContentProvider {        private static UriMatcher matcher = new UriMatcher(UriMatcher.NO_MATCH);          private static final int PERSONS = 1;        private static final int PERSON = 2;          private DatabaseHelper dbHelper;          static {               matcher.addURI("cn.class3g.providers.personprovider", "person", PERSONS);               matcher.addURI("cn.class3g.providers.personprovider", "person/#",                             PERSON);        }          public boolean onCreate() {               dbHelper = new DatabaseHelper(this.getContext());               return true;        }          //  content://cn.itcast.provides.personprovider/person        public Uri insert(Uri uri, ContentValues values) {               SQLiteDatabase db = dbHelper.getWritableDatabase();               long rowId;                 switch (matcher.match(uri)) {               case PERSONS: //向表中添加新紀錄並返回其行號                      rowId = db.insert("person", "personid", values);                      return ContentUris.withAppendedId(uri, rowId);               default:                      throw new IllegalArgumentException("Unknow Uri:" + uri);               }        }          public Cursor query(Uri uri, String[] projection, String selection,                      String[] selectionArgs, String sortOrder) {               SQLiteDatabase db = dbHelper.getReadableDatabase();               switch (matcher.match(uri)) {               case PERSONS:                      return db.query("person", projection, selection, selectionArgs, null, null, sortOrder);               case PERSON:                      long personid = ContentUris.parseId(uri);                      String where = "personid="+ personid;                      if(selection!=null && !"".equals(selection)){                             where = where + " and "+ selection;                      }                      return db.query("person", projection, where, selectionArgs, null, null, sortOrder);                                    default:                      throw new IllegalArgumentException("Unknown Uri:"+ uri);               }        }          //  content://cn.itcast.provides.personprovider/person 更新表中的所有記錄        //  content://cn.itcast.provides.personprovider/person/10 更新表中指定id的記錄        public int update(Uri uri, ContentValues values, String selection,                      String[] selectionArgs) {               SQLiteDatabase db = dbHelper.getWritableDatabase();               int num;               switch(matcher.match(uri)){               case PERSONS: //更新指定記錄                      num = db.update("person", values, selection, selectionArgs);                      break;               case PERSON:                      long personid = ContentUris.parseId(uri);                      String where = "personid=" + personid;                      if(selection != null){                             where += " and " + selection;                      }                      num = db.update("person", values, where, selectionArgs);                      break;               default:                      throw new IllegalArgumentException("Unknow Uri"+uri);               }               return num;        }          public int delete(Uri uri, String selection, String[] selectionArgs) {               SQLiteDatabase db = dbHelper.getWritableDatabase();               int num = 0;               switch (matcher.match(uri)) {               case PERSONS:                      num = db.delete("person", selection, selectionArgs);                      break;               case PERSON:                      long personid = ContentUris.parseId(uri);                      String where = "personid="+ personid;                      if(selection!=null && !"".equals(selection)){                             where = where + " and "+ selection;                      }                      num = db.delete("person", where, selectionArgs);                      break;                   default:                      throw new IllegalArgumentException("Unknown Uri:"+ uri);               }               return num;        }          public String getType(Uri uri) {               switch (matcher.match(uri)) {               case PERSONS:                      return "vnd.android.cursor.dir/person";               case PERSON:                      return "vnd.android.cursor.item/person";               default:                      throw new IllegalArgumentException("Unknown Uri:"+ uri);               }        } }

2、配置

<provider             android:authorities="cn.class3g.providers.personprovider"             android:name="PersonProvider" >         </provider>

3、建立測試工程編寫測試代碼

package cn.class3g.visitor;   import android.content.ContentResolver; import android.content.ContentValues; import android.database.Cursor; import android.net.Uri; import android.test.AndroidTestCase; import android.util.Log;   public class AccessContentProviderTest extends AndroidTestCase {         public void testSave() throws Throwable{        ContentResolver resolver = this.getContext().getContentResolver();        Uri insertUri = Uri.parse("content://cn.class3g.providers.personprovider/person");        ContentValues values = new ContentValues();        values.put("name", "laozhang");        values.put("age", "50");        Uri uri = resolver.insert(insertUri, values);        Log.i("TAG", uri.toString());     }         public void testQuery() throws Throwable{        ContentResolver resolver = this.getContext().getContentResolver();        Uri uri = Uri.parse("content://cn.class3g.providers.personprovider/person");               Cursor cursor = resolver.query(uri, null, null, null, "personid asc");               while(cursor.moveToNext()){            int personid = cursor.getInt(cursor.getColumnIndex("personid"));            String name = cursor.getString(cursor.getColumnIndex("name"));                       Log.i("TAG", "personid="+ personid + ",name="+ name);        }        cursor.close();     }         public void testUpdate() throws Throwable{        ContentResolver contentResolver = this.getContext().getContentResolver();        Uri updateUri = Uri.parse("content://cn.class3g.providers.personprovider/person/5");        ContentValues values = new ContentValues();        values.put("name", "蔣介石");        contentResolver.update(updateUri, values, null, null);     }     public void testDelete() throws Throwable{        ContentResolver contentResolver = this.getContext().getContentResolver();        Uri uri = Uri.parse("content://cn.class3g.providers.personprovider/person/5");        contentResolver.delete(uri, null, null);     }   }

 

4、測試（注意需要先將provider擁有者工程部署到裝置上）

5、ContentProvider的監聽器