implementation 'com.android.support:design:27.1.1'
implementation 'com.android.support:cardview-v7:27.1.1'
implementation 'android.arch.lifecycle:extensions:1.1.1
<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout xmlns:android="https://schemas.android.com/apk/res/android"
xmlns:app="https://schemas.android.com/apk/res-auto"
xmlns:tools="https://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<android.support.design.widget.AppBarLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:theme="@style/AppTheme.AppBarOverlay">
<android.support.v7.widget.Toolbar
android:id="@+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="?attr/colorPrimary"
app:popupTheme="@style/AppTheme.PopupOverlay" />
</android.support.design.widget.AppBarLayout>
<RelativeLayout xmlns:android="https://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="@string/appbar_scrolling_view_behavior">
<android.support.v7.widget.RecyclerView
android:id="@+id/recyclerView"
android:layout_width="match_parent"
android:layout_height="match_parent" />
</RelativeLayout>
<android.support.design.widget.FloatingActionButton
android:id="@+id/fab"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="bottom|end"
android:layout_margin="@dimen/fab_margin"
app:srcCompat="@android:drawable/ic_input_add" />
</android.support.design.widget.CoordinatorLayout>
<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.CardView xmlns:android="https://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:padding="8dp"
android:gravity="center_vertical">
<TextView
android:id="@+id/tvUrl"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentStart="true"
android:autoLink="web"
android:padding="8dp"
android:textColor="@android:color/black"
android:textSize="20sp" />
<TextView
android:id="@+id/tvDate"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_below="@+id/tvUrl" />
<ImageButton
android:id="@+id/btnDelete"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentEnd="true"
android:layout_centerVertical="true"
android:src="@android:drawable/ic_menu_delete" />
</RelativeLayout>
</android.support.v7.widget.CardView>
کد کلاس DbSettings.java در زیر آورده شده است:
package com.sevenlearn.androidlivedata.db;
import android.provider.BaseColumns;
public class DbSettings {
public static final String DB_NAME = "favourites.db";
public static final int DB_VERSION = 1;
public class DBEntry implements BaseColumns {
public static final String TABLE = "fav";
public static final String COL_FAV_URL = "url";
public static final String COL_FAV_DATE = "date";
}
}
The code for FavouritesDbHelper.java class is given below:
package com.journaldev.androidlivedata.db;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
public class FavouritesDBHelper extends SQLiteOpenHelper {
public FavouritesDBHelper(Context context) {
super(context, DbSettings.DB_NAME, null, DbSettings.DB_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db) {
String createTable = "CREATE TABLE " + DbSettings.DBEntry.TABLE + " ( " +
DbSettings.DBEntry._ID + " INTEGER PRIMARY KEY AUTOINCREMENT, " +
DbSettings.DBEntry.COL_FAV_URL + " TEXT NOT NULL, " +
DbSettings.DBEntry.COL_FAV_DATE + " INTEGER NOT NULL);";
db.execSQL(createTable);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL("DROP TABLE IF EXISTS " + DbSettings.DBEntry.TABLE);
onCreate(db);
}
}
package com.sevenlearn.androidlivedata;
public class Favourites {
public long mId;
public String mUrl;
public long mDate;
public Favourites(long id, String name, long date) {
mId = id;
mUrl = name;
mDate = date;
}
public Favourites(Favourites favourites) {
mId = favourites.mId;
mUrl = favourites.mUrl;
mDate = favourites.mDate;
}
}
package com.sevenlearn.androidlivedata;
import android.app.Application;
import android.arch.lifecycle.AndroidViewModel;
import android.arch.lifecycle.MutableLiveData;
import android.content.ContentValues;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import com.journaldev.androidlivedata.db.DbSettings;
import com.journaldev.androidlivedata.db.FavouritesDBHelper;
import java.util.ArrayList;
import java.util.List;
public class FavouritesViewModel extends AndroidViewModel {
private FavouritesDBHelper mFavHelper;
private MutableLiveData<List<Favourites>> mFavs;
FavouritesViewModel(Application application) {
super(application);
mFavHelper = new FavouritesDBHelper(application);
}
public MutableLiveData<List<Favourites>> getFavs() {
if (mFavs == null) {
mFavs = new MutableLiveData<>();
loadFavs();
}
return mFavs;
}
private void loadFavs() {
List<Favourites> newFavs = new ArrayList<>();
SQLiteDatabase db = mFavHelper.getReadableDatabase();
Cursor cursor = db.query(DbSettings.DBEntry.TABLE,
new String[]{
DbSettings.DBEntry._ID,
DbSettings.DBEntry.COL_FAV_URL,
DbSettings.DBEntry.COL_FAV_DATE
},
null, null, null, null, null);
while (cursor.moveToNext()) {
int idxId = cursor.getColumnIndex(DbSettings.DBEntry._ID);
int idxUrl = cursor.getColumnIndex(DbSettings.DBEntry.COL_FAV_URL);
int idxDate = cursor.getColumnIndex(DbSettings.DBEntry.COL_FAV_DATE);
newFavs.add(new Favourites(cursor.getLong(idxId), cursor.getString(idxUrl), cursor.getLong(idxDate)));
}
cursor.close();
db.close();
mFavs.setValue(newFavs);
}
public void addFav(String url, long date) {
SQLiteDatabase db = mFavHelper.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(DbSettings.DBEntry.COL_FAV_URL, url);
values.put(DbSettings.DBEntry.COL_FAV_DATE, date);
long id = db.insertWithOnConflict(DbSettings.DBEntry.TABLE,
null,
values,
SQLiteDatabase.CONFLICT_REPLACE);
db.close();
List<Favourites> favourites = mFavs.getValue();
ArrayList<Favourites> clonedFavs;
if (favourites == null) {
clonedFavs = new ArrayList<>();
} else {
clonedFavs = new ArrayList<>(favourites.size());
for (int i = 0; i < favourites.size(); i++) {
clonedFavs.add(new Favourites(favourites.get(i)));
}
}
Favourites fav = new Favourites(id, url, date);
clonedFavs.add(fav);
mFavs.setValue(clonedFavs);
}
public void removeFav(long id) {
SQLiteDatabase db = mFavHelper.getWritableDatabase();
db.delete(
DbSettings.DBEntry.TABLE,
DbSettings.DBEntry._ID + " = ?",
new String[]{Long.toString(id)}
);
db.close();
List<Favourites> favs = mFavs.getValue();
ArrayList<Favourites> clonedFavs = new ArrayList<>(favs.size());
for (int i = 0; i < favs.size(); i++) {
clonedFavs.add(new Favourites(favs.get(i)));
}
int index = -1;
for (int i = 0; i < clonedFavs.size(); i++) {
Favourites favourites = clonedFavs.get(i);
if (favourites.mId == id) {
index = i;
}
}
if (index != -1) {
clonedFavs.remove(index);
}
mFavs.setValue(clonedFavs);
}
}
package com.sevenlearn.androidlivedata;
import android.arch.lifecycle.Observer;
import android.arch.lifecycle.ViewModelProviders;
import android.content.DialogInterface;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.design.widget.FloatingActionButton;
import android.support.v7.app.AlertDialog;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.util.DiffUtil;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.EditText;
import android.widget.ImageButton;
import android.widget.TextView;
import java.util.Date;
import java.util.List;
public class MainActivity extends AppCompatActivity {
private FavAdapter mFavAdapter;
private FavouritesViewModel mFavViewModel;
private List<Favourites> mFav;
FloatingActionButton fab;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
fab = findViewById(R.id.fab);
final RecyclerView recyclerView = findViewById(R.id.recyclerView);
recyclerView.setLayoutManager(new LinearLayoutManager(this));
mFavViewModel = ViewModelProviders.of(this).get(FavouritesViewModel.class);
final Observer<List<Favourites>> favsObserver = new Observer<List<Favourites>>() {
@Override
public void onChanged(@Nullable final List<Favourites> updatedList) {
if (mFav == null) {
mFav = updatedList;
mFavAdapter = new FavAdapter();
recyclerView.setAdapter(mFavAdapter);
} else {
DiffUtil.DiffResult result = DiffUtil.calculateDiff(new DiffUtil.Callback() {
@Override
public int getOldListSize() {
return mFav.size();
}
@Override
public int getNewListSize() {
return updatedList.size();
}
@Override
public boolean areItemsTheSame(int oldItemPosition, int newItemPosition) {
return mFav.get(oldItemPosition).mId ==
updatedList.get(newItemPosition).mId;
}
@Override
public boolean areContentsTheSame(int oldItemPosition, int newItemPosition) {
Favourites oldFav = mFav.get(oldItemPosition);
Favourites newFav = updatedList.get(newItemPosition);
return oldFav.equals(newFav);
}
});
result.dispatchUpdatesTo(mFavAdapter);
mFav = updatedList;
}
}
};
fab.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
final EditText inUrl = new EditText(MainActivity.this);
AlertDialog dialog = new AlertDialog.Builder(MainActivity.this)
.setTitle("New favourite")
.setMessage("Add a url link below")
.setView(inUrl)
.setPositiveButton("Add", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
String url = String.valueOf(inUrl.getText());
long date = (new Date()).getTime();
mFavViewModel.addFav(url, date);
}
})
.setNegativeButton("Cancel", null)
.create();
dialog.show();
}
});
mFavViewModel.getFavs().observe(this, favsObserver);
}
public class FavAdapter extends RecyclerView.Adapter<FavAdapter.FavViewHolder> {
@Override
public FavViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View itemView = LayoutInflater.from(parent.getContext()).inflate(R.layout.list_item_row, parent, false);
return new FavViewHolder(itemView);
}
@Override
public void onBindViewHolder(FavViewHolder holder, int position) {
Favourites favourites = mFav.get(position);
holder.mTxtUrl.setText(favourites.mUrl);
holder.mTxtDate.setText((new Date(favourites.mDate).toString()));
}
@Override
public int getItemCount() {
return mFav.size();
}
class FavViewHolder extends RecyclerView.ViewHolder {
TextView mTxtUrl;
TextView mTxtDate;
FavViewHolder(View itemView) {
super(itemView);
mTxtUrl = itemView.findViewById(R.id.tvUrl);
mTxtDate = itemView.findViewById(R.id.tvDate);
ImageButton btnDelete = itemView.findViewById(R.id.btnDelete);
btnDelete.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
int pos = getAdapterPosition();
Favourites favourites = mFav.get(pos);
mFavViewModel.removeFav(favourites.mId);
}
});
}
}
}
}
در کد بالا، ما کلاس Adapter را برای RecyclerView در Activity تعریف کردهایم.
اگر به یادگیری بیشتر در زمینهی اندروید علاقه داری، با شرکت در دورهی آموزش برنامه نویسی اندروید در کمتر از یکسال به یک توسعهدهنده اندروید همه فن حریف تبدیل میشوی که آمادهی استخدام، دریافت پروژه و حتی پیادهسازی اپلیکیشن خودت هستی.
ممنون از مطلب مفیدتون .لینکی که برای دانلود برنامه گذاشتین کار نمیکنه میشه بررسی کنین و دذستش کنین؟
درود. لینک رو با vpn باز کنید، محتوا دانلود میشه. این مشکل به این دلیل ایجاد شده که ما به دلیل حق کپی رایت باید سورس رو از سایت انگلیسی که منبع این مقاله هست، لینک میکردیم.
با سلام، این بستگی به پروژه و خود شما داره میتونین از هر کدوم که خواستین استفاده کنین، هر کدوم مزیتهای خودشون رو دارن و من به شخصه از RxJava استفاده میکنم