/* * Copyright 2017, The Android Open Source Project * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package com.example.android.persistence.codelab.step4; import android.arch.lifecycle.Observer; import android.arch.lifecycle.ViewModelProviders; import android.os.Bundle; import android.support.annotation.NonNull; import android.support.v7.app.AppCompatActivity; import android.view.View; import android.widget.TextView; import com.example.android.codelabs.persistence.R; import com.example.android.persistence.codelab.db.Book; import java.util.List; public class TypeConvertersActivity extends AppCompatActivity { private TypeConvertersViewModel mViewModel; private TextView mBooksTextView; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.db_activity); mBooksTextView = findViewById(R.id.books_tv); // Get a reference to the ViewModel for this screen. mViewModel = ViewModelProviders.of(this).get(TypeConvertersViewModel.class); // Update the UI whenever there's a change in the ViewModel's data. subscribeUiBooks(); } public void onRefreshBtClicked(View view) { mViewModel.createDb(); } private void subscribeUiBooks() { mViewModel.getBooks().observe(this, new Observer<List<Book>>() { @Override public void onChanged(@NonNull final List<Book> books) { showBooksInUi(books); } }); } private void showBooksInUi(final @NonNull List<Book> books) { StringBuilder sb = new StringBuilder(); for (Book book : books) { sb.append(book.title); sb.append("\n"); } mBooksTextView.setText(sb.toString()); } }