在Android中使用RxJava2插入SQLiteDatabase
我正在用android学习RxJava2。有人能告诉我如何使用RxJava2将数据插入SQLiteDatabase吗。 这里是我试图使用的代码示例,但它将数据插入数据库六次 //OnClick在Android中使用RxJava2插入SQLiteDatabase,android,rx-java2,rx-android,Android,Rx Java2,Rx Android,我正在用android学习RxJava2。有人能告诉我如何使用RxJava2将数据插入SQLiteDatabase吗。 这里是我试图使用的代码示例,但它将数据插入数据库六次 //OnClick getCompletableObservable() .subscribeOn(Schedulers.io()) .observeOn(AndroidSchedulers.mainThread())
getCompletableObservable()
.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.subscribe(getCompletableObserver());
//可观察
private Completable getCompletableObservable(){
return Completable.create(new CompletableOnSubscribe() {
@Override
public void subscribe(CompletableEmitter emitter) throws Exception {
addData();
if(!emitter.isDisposed())
emitter.onComplete();
}
});
}
//观察者
CompletableObserver getCompletableObserver(){
return new CompletableObserver() {
@Override
public void onSubscribe(Disposable d) {
}
@Override
public void onComplete() {
showMessage("Student Added Sucessfully");
}
@Override
public void onError(Throwable e) {
showMessage(e.getMessage()+"");
}
};
}
//添加方法
try {
DatabaseHelper db = new DatabaseHelper(DemoRxJava.this);
db.open();
String c = db.AddData(new Student(random.nextInt(1000)+"",SName.getText().toString(),SContact.getText().toString(),SEmail.getText().toString()));
Log.d("StudentData",c);
db.close();
}catch (Exception e){
}
使用。创建它是为了简化与数据库的交互。它支持使用RxJava和LiveData包装数据
检查以开始
基本上,您希望创建一个实体类,它将抽象您的表并表示一个单行对象。例如,这显示了名为users
的表的用户实体和作为PK的uid
@Entity(tableName="users")
public class User {
@PrimaryKey
private int uid;
@ColumnInfo(name = "first_name")
private String firstName;
@ColumnInfo(name = "last_name")
private String lastName;
// Getters and setters are ignored for brevity,
// but they're required for Room to work.
}
然后定义将包含查询定义的DAO类。您将使用此接口的对象进行实际查询。这个房间将为你们提供具体的课程
@Dao
public interface UserDao {
@Query("SELECT * FROM user")
List<User> getAll();
@Query("SELECT * FROM user WHERE uid IN (:userIds)")
List<User> loadAllByIds(int[] userIds);
@Query("SELECT * FROM user WHERE first_name LIKE :first AND "
+ "last_name LIKE :last LIMIT 1")
User findByName(String first, String last);
@Insert
void insertAll(User... users);
@Delete
void delete(User user);
}
现在我想
AppDatabase db = Room.databaseBuilder(getApplicationContext(),
AppDatabase.class, "databaseName.db").build(); //Most of the time I have used this, it is a Singleton.
List<User> users = db.userDao().getAll();
for(User u : users)
{
Log.d("SQLITE_ROOM_DATA", u.firstName);
}
谢谢斯蒂法诺的回答。我会仔细看一看。我已经用一些修改过的示例进行了扩展,这些示例说明了依赖项应用程序需要哪些注释。我很高兴能为您提供帮助!
AppDatabase db = Room.databaseBuilder(getApplicationContext(),
AppDatabase.class, "databaseName.db").build(); //Most of the time I have used this, it is a Singleton.
List<User> users = db.userDao().getAll();
for(User u : users)
{
Log.d("SQLITE_ROOM_DATA", u.firstName);
}
dependencies {
def room_version = "1.1.0" // or, for latest rc, use "1.1.1-rc1"
implementation "android.arch.persistence.room:runtime:$room_version"
annotationProcessor "android.arch.persistence.room:compiler:$room_version"
// optional - RxJava support for Room
implementation "android.arch.persistence.room:rxjava2:$room_version"
// Test helpers
testImplementation "android.arch.persistence.room:testing:$room_version"
}