一、在AndroidManifest.xml中加入： <provider android:name=".TalkHistoryProvider" android:authorities="com.g.im.talkhistoryprovider" /> 二、自定义ContentProvider类：
public class TalkHistoryProvider extends ContentProvider {
private static UriMatcher mUriMatcher = new UriMatcher(UriMatcher.NO_MATCH);
private static final int TALKHISTORYS = 1; // 集合类型
private static final int TALKHISTORY = 2; // 单个类型
private DBOpenHelper mDBOpenHelper;
static {
mUriMatcher.addURI("com.g.im.talkhistoryprovider", "talkhistory", TALKHISTORYS);
mUriMatcher.addURI("com.g.im.talkhistoryprovider", "talkhistory/#", TALKHISTORY);
}
@Override
public boolean onCreate() {
mDBOpenHelper = DBOpenHelper.getDBOpenHelper(this.getContext().getApplicationContext());
return true;
}
@Override
public String getType(Uri uri) {
switch (mUriMatcher.match(uri)) {
case TALKHISTORYS:
return "vnd.android.cursor.dir/talkhistory"; // 返回集合类型
case TALKHISTORY:
return "vnd.android.cursor.item/talkhistory"; // 返回单个类型
default:
throw new IllegalArgumentException("Unkown Uri:" + uri);
}
}
@Override
public Uri insert(Uri uri, ContentValues values) {
SQLiteDatabase db = mDBOpenHelper.getWritableDatabase();
long id = 0;
switch (mUriMatcher.match(uri)) {
case TALKHISTORYS:
id = db.insert("talkhistory", "user_id", values); // 将数据插入DB中，当values数据为空时，给user_id赋值NULL，返回记录的id
getContext().getContentResolver().notifyChange(uri, null); // 通知外部数据被改变了
return ContentUris.withAppendedId(uri, id); // 返回代表新增记录的Uri
case TALKHISTORY:
id = db.insert("talkhistory", "user_id", values);
String uri1 = uri.toString();
Uri talkhistoryUri = Uri.parse(uri1.substring(0, uri1.lastIndexOf("/")));
getContext().getContentResolver().notifyChange(talkhistoryUri, null);
return ContentUris.withAppendedId(talkhistoryUri, id); // 返回代表新增记录的Uri
default:
throw new IllegalArgumentException("Unkown Uri:" + uri);
}
}
@Override
public int delete(Uri uri, String selection, String[] selectionArgs) {
SQLiteDatabase db = mDBOpenHelper.getWritableDatabase();
int num = 0; // 已删除的条数
switch (mUriMatcher.match(uri)) {
case TALKHISTORYS:
num = db.delete("talkhistory", selection, selectionArgs);
break;
case TALKHISTORY:
long id = ContentUris.parseId(uri);
String where = "user_id=" + id;
if (selection != null && !"".equals(selection)) {
where = where + " and " + selection; // 如user_id=1 and ...
}
num = db.delete("talkhistory", where, selectionArgs);
break;
default:
throw new IllegalArgumentException("Unkown Uri:" + uri);
}
getContext().getContentResolver().notifyChange(uri, null);
return num;
}
@Override
public int update(Uri uri, ContentValues values, String selection, String[] selectionArgs) {
SQLiteDatabase db = mDBOpenHelper.getWritableDatabase();
int num = 0; // 已修改的条数
switch (mUriMatcher.match(uri)) {
case TALKHISTORYS:
num = db.update("talkhistory", values, selection, selectionArgs);
break;
case TALKHISTORY:
long id = ContentUris.parseId(uri);
String where = "user_id=" + id;
if (selection != null && !"".equals(selection)) {
where = where + " and " + selection;
}
num = db.update("talkhistory", values, where, selectionArgs);
break;
default:
throw new IllegalArgumentException("Unkown Uri:" + uri);
}
getContext().getContentResolver().notifyChange(uri, null); // 通知外部数据被改变了
return num;
}
@Override
public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder) {
SQLiteDatabase db = mDBOpenHelper.getReadableDatabase();
switch (mUriMatcher.match(uri)) {
case TALKHISTORYS:
return db.query("talkhistory", projection, selection, selectionArgs, null, null, sortOrder);
case TALKHISTORY:
long id = ContentUris.parseId(uri);
String where = "user_id=" + id;
if (selection != null && !"".equals(selection)) {
where = where + " and " + selection;
}
return db.query("talkhistory", projection, where, selectionArgs, null, null, sortOrder);
default:
throw new IllegalArgumentException("Unkown Uri:" + uri);
}
}
}
三、使用ContentResolver对ContentProvider中的数据进行增删改查：
ContentResolver resolver = getContentResolver();
Uri uri = Uri.parse("content://com.g.im.talkhistoryprovider/talkhistory");
// 增加记录
ContentValues insertValues = new ContentValues();
insertValues.put("name", "姓名1");
insertValues.put("age", 25);
resolver.insert(uri, insertValues);
// 删除记录
Uri deleteUri = ContentUris.withAppendedId(uri, 1); //1为id值
resolver.delete(deleteUri, null, null);
// 修改记录
ContentValues updateValues = new ContentValues();
updateValues.put("name", "姓名2");
Uri updateUri = ContentUris.withAppendedId(uri, 1); //1为id值
resolver.update(updateUri, updateValues, null, null);
// 查找记录
Cursor cursor = resolver.query(uri, null, null, null, "talkhistory desc");
while (cursor.moveToNext()) {
long userId = cursor.getInt(0);
String name = cursor.getString(1);
}
四、使用ContentObserver对数据的更改进行监听：
//true表示以如下Uri开头就触发onChange，false要完全一致才触发
getContentResolver().registerContentObserver(Uri.parse("content://com.g.im.talkhistoryprovider/talkhistory"), true, new ContentObserver(new Handler()) {
@Override
public void onChange(boolean selfChange) {
super.onChange(selfChange);
//处理一些逻辑
}
});
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