我正在嘗試使用 RxJava 在后臺線程上使用我的 RoomDatabase。我的 DAO 類：import android.arch.persistence.room.Dao;import android.arch.persistence.room.Insert;import java.util.List;@Daopublic interface MeasurementDAO{ @Insert public void insertMeasurements(Measurements m);}我的實體類（為簡潔起見省略了 getter 和 setter 方法）：import android.arch.persistence.room.Entity;import android.arch.persistence.room.PrimaryKey;import android.support.annotation.NonNull;@Entitypublic class Measurements{ @NonNull @PrimaryKey public String mId; public String finalResultIn; public String finalResultFt; public String lengthFt; public String widthFt; public String heightFt; public String lengthIn; public String widthIn; public String heightIn; public Measurements(String finalResultFt, String finalResultIn, String lengthFt, String widthFt, String heightFt, String lengthIn, String widthIn, String heightIn) { this.finalResultFt = finalResultFt; this.finalResultIn = finalResultIn; this.lengthFt = lengthFt; this.widthFt = widthFt; this.heightFt = heightFt; this.lengthIn = lengthIn; this.widthIn = widthIn; this.heightIn = heightIn; } }最后，這是我的 MeasurementDatabase 類：@Database(entities = {Measurements.class}, version = 1)public abstract class MeasurementDatabase extends RoomDatabase{ private static final String DB_NAME = "measurement_db"; private static MeasurementDatabase instance; public static synchronized MeasurementDatabase getInstance(Context context) { if(instance == null) { instance = Room.databaseBuilder(context.getApplicationContext(), MeasurementDatabase.class, DB_NAME) .fallbackToDestructiveMigration() .build(); } return instance; } public abstract MeasurementDAO measurementDAO();}
3 回答
慕絲7291255
TA貢獻1859條經驗 獲得超6個贊
創建一個 Observable 并在其中編寫您的邏輯。您可以訂閱可觀察對象并獲取布爾值。
public Observable<Boolean> insertObject(Measurements m) {
return Observable.create(new ObservableOnSubscribe<Boolean>() {
@Override
public void subscribe(ObservableEmitter<Boolean> e) {
appDb.measurementDAO().insertMeasurements(m);
e.onNext(true);
e.onComplete();
}
}).subscribeOn(Schedulers.io());
}
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TA貢獻1865條經驗 獲得超7個贊
我知道你有答案，但你永遠不知道這是否失敗。我確定您的 dao 插入方法可以返回一個long[]（插入行的 ID）。
你可以輕松地做到：
Completable.fromCallable(() ->
appDb.measurementDAO().insertMeasurements(m).length != 0 ?
Completable.complete() :
Completable.error(new IllegalStateException("Error inserting " + m.toString())))
.subscribeOn(Schedulers.io())
.subscribe(() -> { }, Throwable::printStackTrace);
回首憶惘然
TA貢獻1847條經驗 獲得超11個贊
我找到了我丟失的部分：
Completable.fromAction(() -> appDb.measurementDAO().insertMeasurements(m)) .subscribeOn(Schedulers.io()) .subscribe();
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