小贝子编程

如何使用sqlite数据库来存储提取数据和检索



我用在线服务器/管理面板构建了一个电视应用程序。我想将提取的数据从服务器保存到应用程序内存。这意味着，如果互联网不可用，应用程序会显示从sqlite数据库检索到的旧数据。请帮我做这件事？。我已经创建了Offline数据库文件，但我不知道如何做。我正在发布Activity、Fragment和Offline数据库的代码。请帮助我配置我的问题。提前一束感谢。。。！！！

public class ActivityDetailCategory extends AppCompatActivity {
private RecyclerView recyclerView;
private AdapterChannel adapterChannel;
private SwipeRefreshLayout swipeRefreshLayout;
private Call<CallbackDetailCategory> callbackCall = null;
private int post_total = 0;
private int failed_page = 0;
private Category category;
private InterstitialAd interstitialAd;
int counter = 1;
private AdView adView;
View view;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_category_details);
view = findViewById(android.R.id.content);
if (Config.ENABLE_RTL_MODE) {
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1) {
getWindow().getDecorView().setLayoutDirection(View.LAYOUT_DIRECTION_RTL);
}
} else {
Log.d("Log", "Working in Normal Mode, RTL Mode is Disabled");
}
loadBannerAd();
loadInterstitialAd();
category = (Category) getIntent().getSerializableExtra(Constant.EXTRA_OBJC);
swipeRefreshLayout = (SwipeRefreshLayout) findViewById(R.id.swipe_refresh_layout);
swipeRefreshLayout.setColorSchemeResources(R.color.orange, R.color.green, R.color.blue, R.color.red);
recyclerView = (RecyclerView) findViewById(R.id.recyclerView);
recyclerView.setLayoutManager(new LinearLayoutManager(this));
recyclerView.setHasFixedSize(true);
//set data and list adapter
adapterChannel = new AdapterChannel(this, recyclerView, new ArrayList<Channel>());
recyclerView.setAdapter(adapterChannel);
// on item list clicked
adapterChannel.setOnItemClickListener(new AdapterChannel.OnItemClickListener() {
@Override
public void onItemClick(View v, Channel obj, int position) {
Intent intent = new Intent(getApplicationContext(), ActivityDetailChannel.class);
intent.putExtra(Constant.KEY_CHANNEL_CATEGORY, obj.category_name);
intent.putExtra(Constant.KEY_CHANNEL_ID, obj.channel_id);
intent.putExtra(Constant.KEY_CHANNEL_NAME, obj.channel_name);
intent.putExtra(Constant.KEY_CHANNEL_IMAGE, obj.channel_image);
intent.putExtra(Constant.KEY_CHANNEL_URL, obj.channel_url);
intent.putExtra(Constant.KEY_CHANNEL_DESCRIPTION, obj.channel_description);
startActivity(intent);
showInterstitialAd();
}
});
// detect when scroll reach bottom
adapterChannel.setOnLoadMoreListener(new AdapterChannel.OnLoadMoreListener() {
@Override
public void onLoadMore(int current_page) {
if (post_total > adapterChannel.getItemCount() && current_page != 0) {
int next_page = current_page + 1;
requestAction(next_page);
} else {
adapterChannel.setLoaded();
}
}
});
// on swipe list
swipeRefreshLayout.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
@Override
public void onRefresh() {
if (callbackCall != null && callbackCall.isExecuted()) {
callbackCall.cancel();
}
adapterChannel.resetListData();
requestAction(1);
}
});
requestAction(1);
setupToolbar();
}
public void setupToolbar() {
final Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
final ActionBar actionBar = getSupportActionBar();
if (actionBar != null) {
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
getSupportActionBar().setHomeButtonEnabled(true);
getSupportActionBar().setTitle(category.category_name);
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem menuItem) {
switch (menuItem.getItemId()) {
case android.R.id.home:
onBackPressed();
return true;
case R.id.search:
Intent intent = new Intent(getApplicationContext(), ActivitySearch.class);
startActivity(intent);
return true;
default:
return super.onOptionsItemSelected(menuItem);
}
}
private void displayApiResult(final List<Channel> channels) {
adapterChannel.insertData(channels);
swipeProgress(false);
if (channels.size() == 0) {
showNoItemView(true);
}
}
private void requestPostApi(final int page_no) {
ApiInterface apiInterface = RestAdapter.createAPI();
callbackCall = apiInterface.getCategoryDetailsByPage(category.cid, page_no, Config.LOAD_MORE);
callbackCall.enqueue(new Callback<CallbackDetailCategory>() {
@Override
public void onResponse(Call<CallbackDetailCategory> call, Response<CallbackDetailCategory> response) {
CallbackDetailCategory resp = response.body();
if (resp != null && resp.status.equals("ok")) {
post_total = resp.count_total;
displayApiResult(resp.posts);
} else {
onFailRequest(page_no);
}
}
@Override
public void onFailure(Call<CallbackDetailCategory> call, Throwable t) {
if (!call.isCanceled()) onFailRequest(page_no);
}
});
}
private void onFailRequest(int page_no) {
failed_page = page_no;
adapterChannel.setLoaded();
swipeProgress(false);
if (NetworkCheck.isConnect(getApplicationContext())) {
showFailedView(true, getString(R.string.failed_text));
} else {
showFailedView(true, getString(R.string.no_internet_text));
}
}
private void requestAction(final int page_no) {
showFailedView(false, "");
showNoItemView(false);
if (page_no == 1) {
swipeProgress(true);
} else {
adapterChannel.setLoading();
}
new Handler().postDelayed(new Runnable() {
@Override
public void run() {
requestPostApi(page_no);
}
}, Constant.DELAY_TIME);
}
private void showFailedView(boolean show, String message) {
View view = (View) findViewById(R.id.lyt_failed);
((TextView) findViewById(R.id.failed_message)).setText(message);
if (show) {
recyclerView.setVisibility(View.GONE);
view.setVisibility(View.VISIBLE);
} else {
recyclerView.setVisibility(View.VISIBLE);
view.setVisibility(View.GONE);
}
((Button) findViewById(R.id.failed_retry)).setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
requestAction(failed_page);
}
});
}
private void showNoItemView(boolean show) {
View view = (View) findViewById(R.id.lyt_no_item);
((TextView) findViewById(R.id.no_item_message)).setText(R.string.no_post_found);
if (show) {
recyclerView.setVisibility(View.GONE);
view.setVisibility(View.VISIBLE);
} else {
recyclerView.setVisibility(View.VISIBLE);
view.setVisibility(View.GONE);
}
}
private void swipeProgress(final boolean show) {
if (!show) {
swipeRefreshLayout.setRefreshing(show);
return;
}
swipeRefreshLayout.post(new Runnable() {
@Override
public void run() {
swipeRefreshLayout.setRefreshing(show);
}
});
}
@Override
public void onDestroy() {
super.onDestroy();
swipeProgress(false);
if (callbackCall != null && callbackCall.isExecuted()) {
callbackCall.cancel();
}
}
public void loadBannerAd() {
if (Config.ENABLE_ADMOB_BANNER_ADS) {
MobileAds.initialize(getApplicationContext(), getResources().getString(R.string.admob_app_id));
adView = (AdView) findViewById(R.id.adView);
adView.loadAd(new AdRequest.Builder().build());
adView.setAdListener(new AdListener() {
@Override
public void onAdClosed() {
}
@Override
public void onAdFailedToLoad(int error) {
adView.setVisibility(View.GONE);
}
@Override
public void onAdLeftApplication() {
}
@Override
public void onAdOpened() {
}
@Override
public void onAdLoaded() {
adView.setVisibility(View.VISIBLE);
}
});
} else {
Log.d("AdMob", "AdMob Banner is Disabled");
}
}
private void loadInterstitialAd() {
if (Config.ENABLE_ADMOB_INTERSTITIAL_ADS) {
interstitialAd = new InterstitialAd(getApplicationContext());
interstitialAd.setAdUnitId(getResources().getString(R.string.admob_interstitial_unit_id));
interstitialAd.loadAd(new AdRequest.Builder().build());
interstitialAd.setAdListener(new AdListener() {
@Override
public void onAdClosed() {
interstitialAd.loadAd(new AdRequest.Builder().build());
}
});
} else {
Log.d("AdMob", "AdMob Interstitial is Disabled");
}
}
private void showInterstitialAd() {
if (Config.ENABLE_ADMOB_INTERSTITIAL_ADS) {
if (interstitialAd != null && interstitialAd.isLoaded()) {
if (counter == Config.ADMOB_INTERSTITIAL_ADS_INTERVAL) {
interstitialAd.show();
counter = 1;
} else {
counter++;
}
} else {
Log.d("AdMob", "Interstitial Ad is Disabled");
}
} else {
Log.d("AdMob", "AdMob Interstitial is Disabled");
}
}
}

public class FragmentCategory extends Fragment {
private View root_view, parent_view;
private RecyclerView recyclerView;
private SwipeRefreshLayout swipeRefreshLayout;
private AdapterCategory adapterCategory;
public static final String EXTRA_OBJC = "key.EXTRA_OBJC";
private Call<CallbackCategories> callbackCall = null;
private StaggeredGridLayoutManager gaggeredGridLayoutManager;
DatabaseHandlerFavorite databaseHandler;
private InterstitialAd interstitialAd;
private Offlinedatabase databaseHelper;
int counter = 1;
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
root_view = inflater.inflate(R.layout.fragment_category, null);
parent_view = getActivity().findViewById(R.id.main_content);
databaseHelper          = new Offlinedatabase(getActivity());
loadInterstitialAd();
swipeRefreshLayout = (SwipeRefreshLayout) root_view.findViewById(R.id.swipe_refresh_layout_category);
swipeRefreshLayout.setColorSchemeResources(R.color.orange, R.color.green, R.color.blue, R.color.red);
recyclerView = (RecyclerView) root_view.findViewById(R.id.recyclerViewCategory);
recyclerView.setHasFixedSize(true);
gaggeredGridLayoutManager = new StaggeredGridLayoutManager(1, 1);
recyclerView.setLayoutManager(gaggeredGridLayoutManager);

//set data and list adapter
adapterCategory = new AdapterCategory(getActivity(), new ArrayList<Category>());
recyclerView.setAdapter(adapterCategory);
// on item list clicked
adapterCategory.setOnItemClickListener(new AdapterCategory.OnItemClickListener() {
@Override
public void onItemClick(View v, Category obj, int position) {
Intent intent = new Intent(getActivity(), ActivityDetailCategory.class);
intent.putExtra(EXTRA_OBJC, obj);
startActivity(intent);
showInterstitialAd();
}
});
// on swipe list
swipeRefreshLayout.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
@Override
public void onRefresh() {
adapterCategory.resetListData();
requestAction();
}
});
requestAction();
return root_view;
}
private void displayApiResult(final List<Category> categories) {
adapterCategory.setListData(categories);
swipeProgress(false);
if (categories.size() == 0) {
showNoItemView(true);
}
}
private void requestCategoriesApi() {
ApiInterface apiInterface = RestAdapter.createAPI();
callbackCall = apiInterface.getAllCategories();
callbackCall.enqueue(new Callback<CallbackCategories>() {
@Override
public void onResponse(Call<CallbackCategories> call, Response<CallbackCategories> response) {
CallbackCategories resp = response.body();
if (resp != null && resp.status.equals("ok")) {
displayApiResult(resp.categories);
} else {
onFailRequest();
}
}
@Override
public void onFailure(Call<CallbackCategories> call, Throwable t) {
if (!call.isCanceled()) onFailRequest();
}
});
}
private void onFailRequest() {
swipeProgress(false);
if (NetworkCheck.isConnect(getActivity())) {
showFailedView(true, getString(R.string.failed_text));
} else {
showFailedView(true, getString(R.string.no_internet_text));
}
}
private void requestAction() {
showFailedView(false, "");
swipeProgress(true);
showNoItemView(false);
new Handler().postDelayed(new Runnable() {
@Override
public void run() {
requestCategoriesApi();
}
}, Constant.DELAY_TIME);
}
@Override
public void onDestroy() {
super.onDestroy();
swipeProgress(false);
if(callbackCall != null && callbackCall.isExecuted()){
callbackCall.cancel();
}
}
private void showFailedView(boolean flag, String message) {
View lyt_failed = (View) root_view.findViewById(R.id.lyt_failed_category);
((TextView) root_view.findViewById(R.id.failed_message)).setText(message);
if (flag) {
recyclerView.setVisibility(View.GONE);
lyt_failed.setVisibility(View.VISIBLE);
} else {
recyclerView.setVisibility(View.VISIBLE);
lyt_failed.setVisibility(View.GONE);
}
((Button) root_view.findViewById(R.id.failed_retry)).setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
requestAction();
}
});
}
private void showNoItemView(boolean show) {
View lyt_no_item = (View) root_view.findViewById(R.id.lyt_no_item_category);
((TextView) root_view.findViewById(R.id.no_item_message)).setText(R.string.no_category_found);
if (show) {
recyclerView.setVisibility(View.GONE);
lyt_no_item.setVisibility(View.VISIBLE);
} else {
recyclerView.setVisibility(View.VISIBLE);
lyt_no_item.setVisibility(View.GONE);
}
}
private void swipeProgress(final boolean show) {
if (!show) {
swipeRefreshLayout.setRefreshing(show);
return;
}
swipeRefreshLayout.post(new Runnable() {
@Override
public void run() {
swipeRefreshLayout.setRefreshing(show);
}
});
}
private int dpToPx(int dp) {
Resources r = getResources();
return Math.round(TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, dp, r.getDisplayMetrics()));
}
private void loadInterstitialAd() {
if (Config.ENABLE_ADMOB_INTERSTITIAL_ADS) {
interstitialAd = new InterstitialAd(getActivity());
interstitialAd.setAdUnitId(getResources().getString(R.string.admob_interstitial_unit_id));
interstitialAd.loadAd(new AdRequest.Builder().build());
interstitialAd.setAdListener(new AdListener() {
@Override
public void onAdClosed() {
interstitialAd.loadAd(new AdRequest.Builder().build());
}
});
} else {
Log.d("AdMob", "AdMob Interstitial is Disabled");
}
}
private void showInterstitialAd() {
if (Config.ENABLE_ADMOB_INTERSTITIAL_ADS) {
if (interstitialAd != null && interstitialAd.isLoaded()) {
if (counter == Config.ADMOB_INTERSTITIAL_ADS_INTERVAL) {
interstitialAd.show();
counter = 1;
} else {
counter++;
}
} else {
Log.d("AdMob", "Interstitial Ad is Disabled");
}
} else {
Log.d("AdMob", "AdMob Interstitial is Disabled");
}
}}

public class Offlinedatabase extends SQLiteOpenHelper {
private static final int DATABASE_VERSION = 1;
private static final String DATABASE_NAME = "db_channel_favorite";
private static final String TABLE_NAME = "tbl_channel_favorite";
private static final String KEY_ID = "id";
private static final String KEY_CAT_NAME = "CAT_NAME";
private static final String KEY_CHANNEL_ID = "channel_id";
private static final String KEY_CHANNEL_NAME = "channel_name";
private static final String KEY_CHANNEL_IMAGE = "channel_image";
private static final String KEY_CHANNEL_URL = "channel_url";
private static final String KEY_CHANNEL_DESCRIPTION = "channel_description";
public Offlinedatabase(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
//Create tables
@Override
public void onCreate(SQLiteDatabase db) {
String CREATE_TABLE_CONTACTS="CREATE TABLE " + TABLE_NAME + "("
+ KEY_ID + " INTEGER PRIMARY KEY,"
+ KEY_CAT_NAME + " TEXT,"
+ KEY_CHANNEL_ID + " TEXT,"
+ KEY_CHANNEL_NAME + " TEXT,"
+ KEY_CHANNEL_IMAGE + " TEXT,"
+ KEY_CHANNEL_URL + " TEXT,"
+ KEY_CHANNEL_DESCRIPTION + " TEXT"
+ ")";
db.execSQL(CREATE_TABLE_CONTACTS);
}
// Upgrading database
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// Drop older table if existed
db.execSQL("DROP TABLE IF EXISTS " + TABLE_NAME);
// Create tables again
onCreate(db);
}
//Insert values to the table contacts
public void addtodatabase(Channel pj){
SQLiteDatabase db = this.getReadableDatabase();
ContentValues values=new ContentValues();
values.put(KEY_CAT_NAME, pj.getCategory_name());
values.put(KEY_CHANNEL_ID, pj.getChannel_id());
values.put(KEY_CHANNEL_NAME, pj.getChannel_name());
values.put(KEY_CHANNEL_IMAGE, pj.getChannel_image());
values.put(KEY_CHANNEL_URL, pj.getChannel_url());
values.put(KEY_CHANNEL_DESCRIPTION, pj.getChannel_description());
db.insert(TABLE_NAME, null, values);
db.close();
}
}

推荐的方法是使用Room持久性库。查看谷歌代码实验室：https://codelabs.developers.google.com/codelabs/android-persistence/#0https://codelabs.developers.google.com/codelabs/android-room-with-a-view/#0

如果您使用的Sqlite没有文件室支持，请查看此项Sqlite Android

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