Inject database in a ContentProvider with dagger

Question

I want to inject a singleton SqliteOpenHelper in a ContentProvider. However, it seems that the ContentProvider instance is being built bef

Answer 1

As Alex Baker pointed out, the solution of the issue is to defer the injection when an operation (query, insert, update, delete) is called for the first time.

to make an example:

This won't work:

public class YourProviderNull extends ContentProvider {


@Inject
YourSQLHelper yourHelper;


@Override
public boolean onCreate() {
    YourActivity.getComponent().inject(this); //NPE!!!
    //other logic
    return true;
}

@Override
public Cursor query(@NonNull Uri uri, String[] projection, String selection, String[] selectionArgs,
                    String sortOrder) {
    SQLiteDatabase db = yourHelper.getReadableDatabase();
    //other logic
}


@Override
public Uri insert(@NonNull Uri uri, ContentValues values) {
    SQLiteDatabase db = yourHelper.getWritableDatabase();
    //other logic
}

@Override
public int delete(@NonNull Uri uri, String selection, String[] selectionArgs) {
    SQLiteDatabase db = yourHelper.getWritableDatabase();
    //other logic
}

@Override
public int update(@NonNull Uri uri, ContentValues values, String selection, String[] selectionArgs) {
    SQLiteDatabase db = yourHelper.getWritableDatabase();
    //other logicreturn db.update(resolveTableNameForUri(uri), values, selection, selectionArgs);
}

}

but this will work correctly:

public class YourProviderWorking extends ContentProvider {


@Inject
YourSQLHelper yourHelper;


@Override
public boolean onCreate() {

    //other logic
    return true;
}

@Override
public Cursor query(@NonNull Uri uri, String[] projection, String selection, String[] selectionArgs,
                    String sortOrder) {
    if(yourHelper == null){
        deferInit();
    }
    SQLiteDatabase db = yourHelper.getReadableDatabase();
    //other logic
}


@Override
public Uri insert(@NonNull Uri uri, ContentValues values) {
    if(yourHelper == null){
        deferInit();
    }
    SQLiteDatabase db = yourHelper.getWritableDatabase();
    //other logic
}

@Override
public int delete(@NonNull Uri uri, String selection, String[] selectionArgs) {
    if(yourHelper == null){
        deferInit();
    }
    SQLiteDatabase db = yourHelper.getWritableDatabase();
    //other logic
}

@Override
public int update(@NonNull Uri uri, ContentValues values, String selection, String[] selectionArgs) {
    if(yourHelper == null){
        deferInit();
    }
    SQLiteDatabase db = yourHelper.getWritableDatabase();
    //other logicreturn db.update(resolveTableNameForUri(uri), values, selection, selectionArgs);
}

private void deferInit(){
    YourActivity.getComponent().inject(this);
}

}