在监控数据库在线原创文章是非常小的变化，基本上没有找到一个实际的问题。所以，如果你看到一个有点蓝牙源代码，写一个Demo。在这里，供大家参考，查看源代码：
src有三个文件MyDataProvider、MainActivity和MyBean。看以下：
MyDataProvider.java:
public class MyDataProvider extends ContentProvider{ // public static final String SCHEME = "test"; public static final String SCHEME = "content"; // 源代码里面规定这样写，所以这个地方改变不了 public static final String HOST = "com.zyj"; public static final String PORT = "497393102"; public static final String PATH = "simple"; public static final int ALARMS = 1; public static final String SHARE_LIST_TYPE = "com.zyj.test.dir/"; public static final int ALARMS_ID = 2; public static final String SHARE_TYPE = "com.zyj.test.item/"; private static final UriMatcher sURIMatcher = new UriMatcher(UriMatcher.NO_MATCH); private SQLiteOpenHelper mDB = null; // ===content://com.zyj:497393102/simple public static final Uri CONTENT_URI = Uri.parse(SCHEME + "://" + HOST + ":" + PORT + "/" + PATH); // 加入Uri的匹配方式，返回的就是上面自己定义的整数类型。1代表操作的是一个批量，2操作的是单独的一个对象 static { sURIMatcher.addURI(HOST + ":" + PORT, PATH, ALARMS); sURIMatcher.addURI(HOST + ":" + PORT, PATH + "/#", ALARMS_ID); } @Override public boolean onCreate() { mDB = new MyDB(getContext()); // 获取数据库的引用 return mDB != null; } @Override public String getType(Uri uri) { // 得到我们自己定义的Uri的类型。看上面你自己的定义 int match = sURIMatcher.match(uri); switch (match) { case ALARMS: { return SHARE_LIST_TYPE; } case ALARMS_ID: { return SHARE_TYPE; } default: { throw new IllegalArgumentException("Unknown URI: " + uri); } } } @Override public Uri insert(Uri uri, ContentValues values) { // 首先是看Uri和我们自己定义的是否匹配。，匹配则将数据属性插入到数据库中并同志更新 SQLiteDatabase db = mDB.getWritableDatabase(); if (sURIMatcher.match(uri) != ALARMS) { throw new IllegalArgumentException("Unknown/Invalid URI " + uri); } ContentValues filteredValues = new ContentValues(); filteredValues.put(MyDB.BEAN_ID, values.getAsInteger(MyDB.BEAN_ID)); filteredValues.put(MyDB.MESSAGE, values.getAsString(MyDB.MESSAGE)); filteredValues.put(MyDB.TASK_PROGRESS, values.getAsFloat(MyDB.TASK_PROGRESS)); long rowID = db.insert(MyDB.TABLET, null, filteredValues); if (rowID != -1) { getContext().getContentResolver().notifyChange(uri, null); } return CONTENT_URI; } @Override public int delete(Uri uri, String selection, String[] selectionArgs) { // 首先是看Uri和我们自己定义的是否匹配，，匹配则进行删除 SQLiteDatabase db = mDB.getWritableDatabase(); int count = 0; int match = sURIMatcher.match(uri); switch (match) { case ALARMS: case ALARMS_ID: String where = null; // 这里对selection进行匹配操作，看你传递的是一个批量还是一个单独的文件 if (selection != null) { if (match == ALARMS) { where = "( " + selection + " )"; } else { where = "( " + selection + " ) AND "; } } else { where = ""; } if (match == ALARMS_ID) { // 假设你传递的是一个单独的文件，也就是Uri后面加入了/item的，那么在这里把该值与数据库中的属性段进行比較，返回sql语句中的where String segment = uri.getPathSegments().get(1); long rowId = Long.parseLong(segment); where += " ( " + MyDB.BEAN_ID + " = " + rowId + " ) "; } count = db.delete(MyDB.TABLET, where, selectionArgs); break; default: throw new UnsupportedOperationException("Cannot delete URI: " + uri); } getContext().getContentResolver().notifyChange(uri, null); return count; } @Override public int update(Uri uri, ContentValues values, String selection, String[] selectionArgs) { // 基本同上了 SQLiteDatabase db = mDB.getWritableDatabase(); int count; long rowId = 0; int match = sURIMatcher.match(uri); switch (match) { case ALARMS: case ALARMS_ID: { String myWhere; if (selection != null) { if (match == ALARMS) { myWhere = "( " + selection + " )"; } else { myWhere = "( " + selection + " ) AND "; } } else { myWhere = ""; } if (match == ALARMS_ID) { String segment = uri.getPathSegments().get(1); rowId = Long.parseLong(segment); myWhere += " ( " + MyDB.BEAN_ID + " = " + rowId + " ) "; } if (values.size() > 0) { count = db.update(MyDB.TABLET, values, myWhere, selectionArgs); } else { count = 0; } break; } default: { throw new UnsupportedOperationException("Cannot update URI: " + uri); } } getContext().getContentResolver().notifyChange(uri, null); return count; } @Override public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder) { SQLiteDatabase db = mDB.getReadableDatabase(); SQLiteQueryBuilder qb = new SQLiteQueryBuilder(); //SQLiteQueryBuilder是一个构造SQL查询语句的辅助类 int match = sURIMatcher.match(uri); switch (match) { case ALARMS: { qb.setTables(MyDB.TABLET); break; } case ALARMS_ID: { qb.setTables(MyDB.TABLET); qb.appendWhere(MyDB.BEAN_ID + "="); qb.appendWhere(uri.getPathSegments().get(1)); break; } default: throw new IllegalArgumentException("Unknown URI: " + uri); } Cursor ret = qb.query(db, projection, selection, selectionArgs, null, null, sortOrder); if (ret != null) { ret.setNotificationUri(getContext().getContentResolver(), uri); Log.d("zyj", "created cursor " + ret + " on behalf of "); } else { Log.d("zyj", "query failed in downloads database"); } return ret; } private static class MyDB extends SQLiteOpenHelper { // 这里就是数据库了，数据库字段、名称、表名等... private static final String DATABASE = "test_database"; public static final String TABLET = "test_table"; public static String ID = "_id"; public static String BEAN_ID = "_bean_id"; public static String MESSAGE = "_message"; public static String TASK_PROGRESS = "_progress"; private SQLiteDatabase mDB = null; private final String msql = "CREATE TABLE IF NOT EXISTS " + TABLET + "( " + ID + " INTEGER PRIMARY KEY AUTOINCREMENT, " + BEAN_ID + " TEXT, " + MESSAGE + " TEXT, " + TASK_PROGRESS + " TEXT )"; private MyDB(Context context) { super(context, DATABASE, null, 1); } @Override public void onCreate(SQLiteDatabase db) { mDB = db; mDB.execSQL(msql); } @Override public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { // 升级。自己能够去实现 } }} MyBean.java一个实例对象
public class MyBean{ public int id = 0; public String message = null; public float progress = 0.0f; public MyBean(int id) { this.id = id; } } MainActivity.java主界面了
public class MainActivity extends Activity{ TextView mMessage = null; private ContentObserver mDatabaseListener = null; private Handler mHand = null; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); mMessage = (TextView) findViewById(R.id.message); init(); // 注冊数据库的监听。相应的是特定的Uri getContentResolver().registerContentObserver(MyDataProvider.CONTENT_URI, true, mDatabaseListener); } @Override protected void onDestroy() { super.onDestroy(); // 注销掉监听 getContentResolver().unregisterContentObserver(mDatabaseListener); } private void init() { mHand = new Handler(); // 数据库变动时的回调 mDatabaseListener = new ContentObserver(mHand) { @Override public boolean deliverSelfNotifications() { System.out.println("deliverSelfNotifications ---------------- "); return super.deliverSelfNotifications(); } @Override public void onChange(boolean selfChange, Uri uri) { System.out.println("onChange ---------------- " + uri.toString()); super.onChange(selfChange, uri); } @Override public void onChange(boolean selfChange) { System.out.println("onChange ---------------- ..."); super.onChange(selfChange); } }; } private int count = 0; public void onViewClick(View view) { switch (view.getId()) { case R.id.add: // 插入数据 ContentValues calues = new ContentValues(); calues.put("_bean_id", count++); calues.put("_message", "AAAAAAAAAAAAAAAAAAAAA"); calues.put("_progress", 0.0f); getContentResolver().insert(MyDataProvider.CONTENT_URI, calues); break; case R.id.del: // 假设找不到指定的_bean_id=1、2、3的，则数据库不进行增减。但还是会调用回调方法 getContentResolver().delete(Uri.parse(MyDataProvider.CONTENT_URI.toString() + "/1"), null, null); getContentResolver().delete(Uri.parse(MyDataProvider.CONTENT_URI.toString() + "/2"), null, null); getContentResolver().delete(Uri.parse(MyDataProvider.CONTENT_URI.toString() + "/3"), null, null); break; case R.id.modify: ContentValues values = new ContentValues(); values.put("_message", "ZZZZZZZZZZZZZZZZZZZZZ"); // 这两中方法一样，这样就能够更加明确Uri中在后面加入的/item了数字的意思了 getContentResolver() .update(Uri.parse(MyDataProvider.CONTENT_URI.toString() + "/5"), values, null, null); getContentResolver().update(MyDataProvider.CONTENT_URI, values, "_bean_id=? ", new String[] { "6" }); break; case R.id.query: showMessage(getContentResolver().query(MyDataProvider.CONTENT_URI, null, null, null, null)); break; } } private void showMessage(Cursor c) { if (c == null) { return; } final StringBuffer sb = new StringBuffer(); if (c.getCount() > 0) { while (c.moveToNext()) { MyBean bean = new MyBean(c.getInt(c.getColumnIndex("_bean_id"))); bean.message = c.getString(c.getColumnIndex("_message")); bean.progress = c.getFloat(c.getColumnIndex("_progress")); sb.append(bean.id + "\t\t\t:" + bean.message + "\t\t\t,progress = " + bean.progress + "\n"); } } c.close(); mHand.post(new Runnable() { public void run() { mMessage.setText(sb.toString()); } }); } }
activity_main.xml 上面就是四个button，以下就是一个TextView显示控件最后就是AndroidManifest.xml了。和平时一样的，仅仅只是在里面将你自定义的ContentProvider写上，类似我的这样：
<provider
android:name="com.example.databasetest.MyDataProvider" android:authorities="com.zyj:497393102" /> 上面的authorities属性是一定要写的。它就是上面MyDataProvider.java里面的CONTENT_URI的HOST + ":" + PORT，能够看以下画的。就比較清楚了。content://com.example.project:200/folder/subfolder/etc
\---------/ \---------------------------/ \---/ \--------------------------/ scheme host port path \--------------------------------/ authority然后就没有了，能够自己执行，感受一下Uri和数据库的监听。
有错误我希望你能来部出，谢谢！！
！
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