【发布时间】：2017-02-04 10:02:38
【问题描述】：
背景：
您好，我正在开发一个电子商务食品应用程序。对于应用程序的一部分，我想创建一个收藏夹列表，用户可以在列表视图中收藏他们选择的食物，并且收藏的食物将被添加到收藏夹列表中。现在，我可以通过在我的产品列表适配器类中设置图像资源来更改图像按钮状态。但是，在会话关闭或重新打开后，我无法保持状态。我认为它需要一些数据保存机制，例如保存的首选项？所以我的问题是：
如何在适配器类中保存图像按钮状态
以下是我的部分代码，顺便说一下，我使用 sqlite 来存储我的食物，也就是产品
ListProductListAdapter 类：
public class ListProductListAdapter extends BaseAdapter {
private Context context;
private int layout;
private ArrayList<Product> productList2;
@Override
public int getCount() {
return productList2.size();
}
@Override
public Object getItem(int position) {
return productList2.get(position);
}
public ListProductListAdapter(Context context, int layout, ArrayList<Product> productList) {
this.context = context;
this.layout = layout;
this.productList2 = productList;
}
@Override
public long getItemId(int position) {
return position;
}
private class ViewHolder2 {
ImageView imageView;
TextView textName, textStall, textPrice;
Button addCartButton;
ImageButton favBtn;
}
@Override
public View getView(final int position, View view, ViewGroup viewGroup) {
View row = view;
ListProductListAdapter.ViewHolder2 holder = new ListProductListAdapter.ViewHolder2();
if (row == null) {
LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
row = inflater.inflate(layout, null);
holder.imageView = (ImageView) row.findViewById(R.id.listFoodImage);
holder.textName = (TextView) row.findViewById(R.id.listProductName);
holder.textStall = (TextView) row.findViewById(R.id.listProductStall);
holder.textPrice = (TextView) row.findViewById(R.id.listProductPrice);
holder.addCartButton = (Button) row.findViewById(R.id.addToCartButton);
holder.favBtn = (ImageButton)row.findViewById(R.id.favouriteButton);
row.setTag(holder);
} else {
holder = (ListProductListAdapter.ViewHolder2) row.getTag();
}
Product product = productList2.get(position);
holder.textName.setText(product.getProductName());
holder.textStall.setText(product.getProductStall());
holder.textPrice.setText(product.getProductPrice());
byte[] productImage = product.getProductImage();
Bitmap bitmap = BitmapFactory.decodeByteArray(productImage, 0, productImage.length);
holder.imageView.setImageBitmap(bitmap);
// favorite button
holder.favBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View favBtn) {
favBtn.setSelected(!favBtn.isSelected());
if(favBtn.isSelected()){
((ImageButton)favBtn).setImageResource(R.drawable.heart_red);
Toast.makeText(context, "Added to Favorites", Toast.LENGTH_SHORT).show();
}else{
((ImageButton)favBtn).setImageResource(R.drawable.heart_grey);
Toast.makeText(context, "Removed from Favorites", Toast.LENGTH_SHORT).show();
}
}
});
// cart button
holder.addCartButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent i = new Intent(context, AdministratorActivity.class);
context.startActivity(i);
}
});
holder.favBtn.setTag(productList2.get(position));
return row;
}
ListActivity 类：（带有标准的 android 抽屉活动）
public class ListActivity extends AppCompatActivity
implements NavigationView.OnNavigationItemSelectedListener {
GridView gridView;
ArrayList<Product>list;
ListProductListAdapter adapter = null;
@Override
protected void onCreate( Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_list);
gridView = (GridView) findViewById(R.id.gridView);
list = new ArrayList<>();
adapter = new ListProductListAdapter(this, R.layout.list_product_item, list);
gridView.setAdapter(adapter);
//get data from sqlite
Cursor cursor = LoginActivity.sqLiteHelper.getData("select * from product");
list.clear();
while (cursor.moveToNext()){
int id = cursor.getInt(0);
byte[] image = cursor.getBlob(1);
String name = cursor.getString(2);
String stall = cursor.getString(3);
String price = cursor.getString(4);
list.add(new Product(image,id,name,stall,"S$ "+price));
}
adapter.notifyDataSetChanged();
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
drawer.setDrawerListener(toggle);
toggle.syncState();
NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
navigationView.setNavigationItemSelectedListener(this);
}
@Override
public void onBackPressed() {
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
if (drawer.isDrawerOpen(GravityCompat.START)) {
drawer.closeDrawer(GravityCompat.START);
} else {
super.onBackPressed();
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.list, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
@SuppressWarnings("StatementWithEmptyBody")
@Override
public boolean onNavigationItemSelected(MenuItem item) {
// Handle navigation view item clicks here.
int id = item.getItemId();
if (id == R.id.nav_cart) {
// Handle the camera action
} else if (id == R.id.nav_favourites) {
} else if (id == R.id.nav_trackOrder) {
} else if (id == R.id.nav_share) {
} else if (id == R.id.nav_about) {
} else if (id == R.id.nav_logOut) {
}
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
drawer.closeDrawer(GravityCompat.START);
return true;
}
我花了数小时研究，但无济于事，无法找到适合我情况的解决方案。任何帮助将不胜感激！
【问题讨论】：
-
使用 sqlite 数据库
-
您可以使用 SharedPreferences 来永久保存状态，而不是使用数据库。
-
您是否使用 sqlite 数据库来存储产品？
-
@Shruti sharedpref 用于小数据。 sqlite 是最好的选择
-
@Divyesh 真的！但他只是想保存按钮状态，这不是大数据。
标签： android sqlite listview sharedpreferences