我进行了三项活动，我捕获了所有数据，但其中一项是从DetailActivity中捕获的，只需单击按钮并使用Room将其保存在数据库中；我的意图是将所有这些数据插入数据库中，并启动ReviewActivity，以便获取评论的数组列表，并将其插入数据库中。在我希望离线查看评论之前，一切似乎都可以正常工作，因为我认为它已保存，因此评论不会加载。 这是我的DetailActivity，
TextView overview_tv; ImageView image_tv; TextView name_tv; TextView ratings; Context context; TextView release_date; ImageView backdrop_poster; private ExpandableHeightListView trailers; public static ArrayList<Youtube> youtube; public static ArrayList<Review> reviews; TrailerViewAdapter adapter; public static DataObject data; DataObject dataObject; ArrayList<Review> savedReview; private static final String IMAGE_URL = "http://image.tmdb.org/t/p/w185/"; private static final String THE_MOVIEDB_URL2 = "https://api.themoviedb.org/3/movie/"; private static final String MOVIE_QUERY2 = "api_key"; private static final String API_KEY2 = "6cc4f47bd4a64e0117e157b79072ae37"; private static String SEARCH_QUERY2 = "videos"; public static int movieId; Button viewReviews; Button favourite; String movieRating; private static final int YOUTUBE_SEARCH_LOADER = 23; private static final int REVIEW_SEARCH_LOADER = 24; File file; String name; String overview; String releaseDate; int switcher; public static ArrayList<Review> favouriteReviews; TextView trev; AppDatabase mDb; //Navigation arrow on the action bar @Override public boolean onOptionsItemSelected(MenuItem item) { int id = item.getItemId(); if (id == android.R.id.home) { NavUtils.navigateUpFromSameTask(this); } return super.onOptionsItemSelected(item); } @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_detail); mDb = AppDatabase.getInstance(getApplicationContext()); youtube = new ArrayList<Youtube>(); reviews = new ArrayList<Review>(); adapter = new TrailerViewAdapter(this, youtube); //Credit to Paolorotolo @github trailers = findViewById(R.id.expandable_list); trailers.setAdapter(adapter); trailers.setExpanded(true); //Navigation arrow on the acton bar; check also override onOptionsItemSelected ActionBar actionBar = this.getSupportActionBar(); if (actionBar != null) { actionBar.setDisplayHomeAsUpEnabled(true); } context = getApplicationContext(); Intent intent = getIntent(); if (intent == null) { closeOnError(); } switcher = getIntent().getIntExtra("switch", 3); overview_tv = findViewById(R.id.overview); image_tv = findViewById(R.id.image); name_tv = findViewById(R.id.name); ratings = findViewById(R.id.ratings); release_date = findViewById(R.id.release_date); backdrop_poster = findViewById(R.id.backdrop_poster); trev = findViewById(R.id.review_show); viewReviews = findViewById(R.id.review_button); favourite = findViewById(R.id.favourite_button); addListenerOnRatingBar(ratings); if (switcher != 2) { favourite.setVisibility(View.INVISIBLE); dataObject = (DataObject) getIntent().getParcelableExtra("array"); final String favouriteName = dataObject.getName(); final String favouriteOverview = dataObject.getOverview(); final String favouriteReleaseDate = dataObject.getReleaseDate(); ArrayList<Youtube> savedTrailer = dataObject.getTrailers(); savedReview = dataObject.getMovieReviews(); movieRating = dataObject.getRating(); name_tv.setText(favouriteName); overview_tv.setText(favouriteOverview); ratings.setText("Rating: " + movieRating); release_date.setText("Release Date: " + favouriteReleaseDate);// Toast.makeText(this, "Testing Reviews " + savedReview.get(0).getAuthor(), Toast.LENGTH_SHORT).show(); String imagePath = name_tv.getText().toString() + "0i"; String backdropPath = name_tv.getText().toString() + "1b"; try { DataObjectAdapter.downloadImage(imagePath, image_tv, this); } catch (Exception e) { e.printStackTrace(); } try { DataObjectAdapter.downloadImage(backdropPath, backdrop_poster, context); } catch (Exception e) { e.printStackTrace(); } if (savedTrailer != null) { TrailerViewAdapter lv = new TrailerViewAdapter(DetailActivity.this, savedTrailer); trailers.setAdapter(lv); switcher = 3; } } else { name = getIntent().getStringExtra("Name"); overview = getIntent().getStringExtra("Overview"); final String image = getIntent().getStringExtra("Image"); movieId = getIntent().getIntExtra("movieId", 1); final String backdrop = getIntent().getStringExtra("backdrop"); releaseDate = getIntent().getStringExtra("releaseDate"); movieRating = getIntent().getStringExtra("rating"); Log.i("this", "switch " + switcher); name_tv.setText(name); overview_tv.setText(overview); ratings.setText("Rating: " + movieRating); release_date.setText("Release Date: " + releaseDate); //load backdrop poster Picasso.with(context) .load(IMAGE_URL + backdrop) .fit() .placeholder(R.drawable.placeholder_image) .error(R.drawable.placeholder_image) .into(backdrop_poster); Picasso.with(context) .load(IMAGE_URL + image) .fit() .placeholder(R.drawable.placeholder_image) .error(R.drawable.placeholder_image) .into(image_tv); getSupportLoaderManager().initLoader(YOUTUBE_SEARCH_LOADER, null, this); //getSupportLoaderManager().initLoader(REVIEW_SEARCH_LOADER, null, this); //loadTrailers(); //loadReviews(); //populateKeys(); } /** * Here manages the views(list) for reviews */ viewReviews.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { if (switcher == 3) { startActivity(new Intent(DetailActivity.this, ReviewActivity.class) .putExtra("switch", 3)); } else { Log.i("this", "I am from initial" + switcher); startActivity(new Intent(DetailActivity.this, ReviewActivity.class).putExtra("id", movieId)); } } } ); favourite.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { data = new DataObject(); data.setName(name); data.setOverview(overview); data.setRating(movieRating); data.setReleaseDate(releaseDate); data.setTrailers(youtube);// data.setMovieReviews(reviews); try { saveImage(name_tv.getText().toString() + "0i", image_tv); saveImage(name_tv.getText().toString() + "1b", backdrop_poster); } catch (IOException e) { e.printStackTrace(); } Toast.makeText(context, "The movie is saved as a favourite", Toast.LENGTH_LONG).show(); AppExecutors.getInstance().diskIO().execute(new Runnable() { @Override public void run() { mDb.dataDao().insertData(data); } }); startActivity(new Intent(DetailActivity.this, ReviewActivity.class).putExtra("id", movieId) .putExtra(ReviewActivity.EXTRA_DATA_ID, 20)); } } ); }
还有我的ReviewActivity
public class ReviewActivity extends AppCompatActivity implements LoaderManager.LoaderCallbacks<ArrayList<Review>>{ public static ArrayList<Review> reviews; public static List<DataObject> favouriteReviews; public static RecyclerView reviewList; ArrayList<Review> r; private static final int REVIEW_SEARCH_LOADER = 24; private static final String MOVIE_QUERY3 = "api_key"; private static final String API_KEY3 = "6cc4f47bd4a64e0117e157b79072ae37"; private static String SEARCH_QUERY3 = "reviews"; private static final String THE_MOVIEDB_URL3 = "https://api.themoviedb.org/3/movie/"; private static int movId; public static final String EXTRA_DATA_ID = "extraDataId"; private static final int DEFAULT_TASK_ID = -1; private int mTaskId = DEFAULT_TASK_ID; DataObject data1; AppDatabase mDb; ReviewAdapter revAdapter; int loaderSwitch; @Override protected void onResume() { super.onResume(); } @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_review); mDb = AppDatabase.getInstance(getApplicationContext()); reviews = new ArrayList<Review>(); favouriteReviews = new ArrayList<DataObject>(); reviewList = findViewById(R.id.review_list); LinearLayoutManager layoutManager = new LinearLayoutManager(getApplicationContext()); reviewList.setLayoutManager(layoutManager); reviewList.setHasFixedSize(true); int switcher = getIntent().getIntExtra("switch", 1); Intent intent = getIntent(); if (intent == null) { finish(); } Log.i("this", "swithcer " + switcher); Log.i("this loader", "Loader " + loaderSwitch); if (switcher == 3){ DataObject dataObject = (DataObject) getIntent().getParcelableExtra("ArrayOfReviews"); if (dataObject != null){ ArrayList<Review> movieReviews = dataObject.getMovieReviews(); Toast.makeText(this, "There are reviews saved", Toast.LENGTH_LONG).show(); revAdapter = new ReviewAdapter(this, movieReviews ); reviewList.setAdapter(revAdapter); } } else { movId = getIntent().getIntExtra("id", 20); revAdapter = new ReviewAdapter(this, reviews); reviewList.setAdapter(revAdapter); loadReviews(); //populateReview(); } DividerItemDecoration decoration = new DividerItemDecoration(this, VERTICAL); reviewList.addItemDecoration(decoration); } @Override protected void onStart() { super.onStart(); //loadReviews(); } public static URL buildUrl3(String stringUrl) { Uri uri = Uri.parse(THE_MOVIEDB_URL3).buildUpon() .appendPath(stringUrl) .appendPath(SEARCH_QUERY3) .appendQueryParameter(MOVIE_QUERY3, API_KEY3) .build(); URL url = null; try { url = new URL(uri.toString()); } catch (MalformedURLException exception) { Log.e(TAG, "Error creating URL", exception); } return url; } public void loadReviews(){ // COMPLETED (19) Create a bundle called queryBundle Bundle queryBundle = new Bundle(); // COMPLETED (20) Use putString with SEARCH_QUERY_URL_EXTRA as the key and the String value of the URL as the value// queryBundle.putString(SEARCH_QUERY_URL_EXTRA, url.toString()); // COMPLETED (21) Call getSupportLoaderManager and store it in a LoaderManager variable LoaderManager loaderManager = getSupportLoaderManager(); // COMPLETED (22) Get our Loader by calling getLoader and passing the ID we specified Loader<ArrayList<Review>> movieReviews = loaderManager.getLoader(REVIEW_SEARCH_LOADER); // COMPLETED (23) If the Loader was null, initialize it. Else, restart it. if (movieReviews == null) { loaderManager.initLoader(REVIEW_SEARCH_LOADER, queryBundle, this); } else { loaderManager.restartLoader(REVIEW_SEARCH_LOADER, queryBundle, this); } } @Override public Loader<ArrayList<Review>> onCreateLoader(int id, Bundle args) { return new AsyncTaskLoader<ArrayList<Review>>(this) { @Override protected void onStartLoading() { super.onStartLoading(); forceLoad(); } @Override public ArrayList<Review> loadInBackground() { String g = String.valueOf(movId); // Create URL object URL url = buildUrl3(g); // Perform HTTP request on the URL and receive a JSON response back String jsonResponse = ""; try { jsonResponse = getResponseFromHttpUrl(url); } catch (Exception e) { e.printStackTrace(); } reviews = MovieJsonUtils.parseReview(jsonResponse); return reviews; } }; } @Override public void onLoadFinished(Loader<ArrayList<Review>> loader, ArrayList<Review> dat) { if (reviews != null) { Intent intent = getIntent(); if (intent != null && intent.hasExtra(EXTRA_DATA_ID)) { //mButton.setText(R.string.update_button); if (mTaskId == DEFAULT_TASK_ID) { mTaskId = intent.getIntExtra(EXTRA_DATA_ID, DEFAULT_TASK_ID); AppExecutors.getInstance().diskIO().execute(new Runnable() { @Override public void run() { data.setMovieReviews(reviews); mDb.dataDao().updateData(data); //mDb.dataDao().insertData(data); final List<DataObject> task = mDb.dataDao().loadById(mTaskId); runOnUiThread(new Runnable() { @Override public void run() { populateUI(task); } }); } }); } } else { ReviewAdapter lv = new ReviewAdapter(ReviewActivity.this, reviews); reviewList.setAdapter(lv); } } } @Override public void onLoaderReset(Loader<ArrayList<Review>> loader) { }
从MainActivity加载数据，保存的数据通过意图作为可拆分捆绑传递给其他活动，传递的数据显示在DetailActivity中，而不显示在ReviewActivity中。
或者，如果我可以从DetailActivity加载评论以及YouTube密钥，我相信我可以从那里处理数据库问题，但是两个加载器不能一起工作，应用程序崩溃；我知道两个AsyncTask同时运行可以解决此问题，但是由于配置更改的性能，我更喜欢使用Loaders