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我正在應用程序，這是一些類似於電子商務應用程序。用戶可以將產品添加到購物車。
我有兩個下面提到的arrayLists。添加到購物車設計在Android工作
public ArrayList<Design> cartList = new ArrayList<Design>();
public ArrayList<Design> designList = new ArrayList<Design>();
一個用於顯示產品列表和其他用於保存用戶添加產品的產品。 我有兩個活動（見圖像）
此活動是爲了顯示recyclerview產品。在這裏，我在購物車中添加了兩件物品。
這是我第二次活動顯示了所有車中的物品。 （用戶可以刪除，增加或從本次活動也減少數量。）
我想現在是什麼，當用戶回來的第一項活動，我想在designList從比較兩個列表更新數量（PCS） cartList。當我按下或重新訪問時，下面的截圖是第一項活動。
此圖像應類似於第一個圖像。我會在這裏分享我的代碼。
Design.java
public class Design implements Serializable {
public int id;
public String qualityId;
public String qualityName;
public String designId;
public String designName;
public String image;
public String name; //use as shade name
public String discPercent;
public String amount;
public int pcs; //consider quantity here.
}
Single_DesignAdapter.java
public class Single_DesignAdapter extends RecyclerView.Adapter<Single_DesignAdapter.ViewHolder> {
public ArrayList<Design> designList;
private Context context;
private LayoutInflater layoutInflater;
public ArrayList<Design> cartList = null;
public Single_DesignAdapter(Context context, ArrayList<Design> designList) {
this.designList = designList;
this.context = context;
this.layoutInflater = LayoutInflater.from(context);
if (cartList != null) {
String cart = getSharePref(context, "cart");
Design[] designs = new Gson().fromJson(cart, Design[].class);
cartList = (ArrayList<Design>) Arrays.asList(designs);
}
}
@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = layoutInflater.inflate(R.layout.single_design, parent, false);
return new ViewHolder(view);
}
@Override
public void onBindViewHolder(final ViewHolder holder, final int position) {
final Design design = designList.get(position);
holder.tvQuality.setText(design.qualityName);
holder.tvDesign.setText(design.designName);
holder.tvShade.setText(design.name);
if (!design.discPercent.equals("0")) {
holder.tvDisPer.setText("-"+design.discPercent+"%");
holder.tvAmount.setPaintFlags(holder.tvAmount.getPaintFlags() | Paint.STRIKE_THRU_TEXT_FLAG);
int a = Integer.parseInt(design.amount);
float b = Float.parseFloat(design.discPercent)/100;
holder.tvAmount.setText("₹ " + design.amount);
int c = (int) (a * b);
int d = a-c;
holder.tvDiscAmt.setText("₹ " +d);
Picasso.with(context).load(design.image).into(holder.ivDesign);
} else {
holder.tvAmount.setText("₹ " + design.amount);
Picasso.with(context).load(design.image).into(holder.ivDesign);
holder.tvDisPer.setVisibility(View.INVISIBLE);
holder.tvDiscAmt.setVisibility(View.INVISIBLE);
}
if (cartList != null) {
for (Design d : cartList) {
if (design.id == d.id) {
design.pcs = d.pcs;
}
}
}
if (design.pcs != 0) {
holder.llAdd.setVisibility(View.GONE);
holder.llPlusMinus.setVisibility(View.VISIBLE);
holder.btPcsCount.setText(Integer.toString(design.pcs));
}
holder.btAdd.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
holder.llAdd.setVisibility(View.GONE);
holder.llPlusMinus.setVisibility(View.VISIBLE);
if (cartList != null) {
if (cartList.contains(design)) {
cartList.remove(design);
design.pcs = 1;
cartList.add(design);
saveSharedPref(context, "cart", new Gson().toJson(cartList));
((Activity) context).invalidateOptionsMenu();
} else {
design.pcs = 1;
cartList.add(design);
saveSharedPref(context, "cart", new Gson().toJson(cartList));
((Activity) context).invalidateOptionsMenu();
}
} else {
cartList = new ArrayList<Design>(Arrays.asList(design));
cartList.remove(design);
design.pcs = 1;
cartList.add(design);
saveSharedPref(context, "cart", new Gson().toJson(cartList));
((Activity) context).invalidateOptionsMenu();
}
}
});
holder.btPlus.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
if (Integer.parseInt(holder.btPcsCount.getText().toString()) >= 1) {
int a = Integer.parseInt(holder.btPcsCount.getText().toString());
a++;
holder.btPcsCount.setText(Integer.toString(a));
if (cartList != null) {
if (cartList.contains(design)) {
cartList.remove(design);
design.pcs = a;
cartList.add(design);
saveSharedPref(context, "cart", new Gson().toJson(cartList));
((Activity) context).invalidateOptionsMenu();
} else {
design.pcs = a;
cartList.add(design);
saveSharedPref(context, "cart", new Gson().toJson(cartList));
((Activity) context).invalidateOptionsMenu();
}
}
}
}
});
holder.btMinus.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
if (Integer.parseInt(holder.btPcsCount.getText().toString()) <= 1) {
holder.llAdd.setVisibility(View.VISIBLE);
holder.llPlusMinus.setVisibility(View.GONE);
cartList.remove(design);
saveSharedPref(context, "cart", new Gson().toJson(cartList));
((Activity) context).invalidateOptionsMenu();
} else {
int a = Integer.parseInt(holder.btPcsCount.getText().toString());
a--;
holder.btPcsCount.setText(Integer.toString(a));
cartList.remove(design);
design.pcs = a;
cartList.add(design);
saveSharedPref(context, "cart", new Gson().toJson(cartList));
((Activity) context).invalidateOptionsMenu();
}
}
});
}
@Override
public int getItemCount() {
return designList.size();
}
public class ViewHolder extends RecyclerView.ViewHolder {
public LinearLayout llPer, llAdd, llPlusMinus;
public Button btPlus, btMinus, btPcsCount, btAdd;
public ImageView ivDesign;
public TextView tvDesign, tvQuality, tvShade, tvAmount, tvDiscAmt, tvDisPer;
public ViewHolder(View itemView) {
super(itemView);
llAdd = (LinearLayout) itemView.findViewById(R.id.llAdd);
llPlusMinus = (LinearLayout) itemView.findViewById(R.id.llPlusMinus);
btPlus = (Button) itemView.findViewById(R.id.btPlus);
btAdd = (Button) itemView.findViewById(R.id.btAdd);
//other findViewByIds
}
}
}
MainActivity.java
public class MainActivity extends AppCompatActivity {
private RecyclerView recyclerView;
private Single_DesignAdapter adapter;
private ArrayList<Design> designList;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
recyclerView = (RecyclerView) findViewById(R.id.recycler_view);
}
@Override
protected void onResume() {
super.onResume();
designList = new ArrayList<Design>();
designList = list();
/*if (cartList != null) {
String cart = getSharePref(MainActivity.this, "cart");
Design[] designs = new Gson().fromJson(cart, Design[].class);
cartList = (ArrayList<Design>) Arrays.asList(designs);
}*/
recyclerView.setLayoutManager(new LinearLayoutManager(MainActivity.this));
recyclerView.setHasFixedSize(true);
adapter = new Single_DesignAdapter(MainActivity.this, designList);
recyclerView.setAdapter(adapter);
invalidateOptionsMenu();
}
public ArrayList<Design> list() {
ArrayList<Design> arrayList = new ArrayList<Design>();
Design design = new Design();
design.id = 1;
design.name = "Black";
design.image = "http://linksolutions.in/Demo/images/1.jpg";
design.designName = "11001";
design.qualityName = "Cotton";
design.amount = "1000";
design.discPercent = "5";
Design design2 = new Design();
design2.id = 2;
design2.name = "Green";
design2.image = "http://linksolutions.in/Demo/images/2.jpg";
design2.designName = "11001";
design2.qualityName = "Cotton";
design2.amount = "900";
design2.discPercent = "9";
Design design3 = new Design();
design3.id = 3;
design3.name = "Green";
design3.image = "http://linksolutions.in/Demo/images/2.jpg";
design3.designName = "11002";
design3.qualityName = "Satin";
design3.amount = "1200";
design3.discPercent = "12";
arrayList.add(design);
arrayList.add(design2);
arrayList.add(design3);
return arrayList;
}
public static void setBadgeCount(Context context, LayerDrawable icon, int count) {
BadgeDrawable badge;
// Reuse drawable if possible
Drawable reuse = icon.findDrawableByLayerId(R.id.ic_badge);
if (reuse != null && reuse instanceof BadgeDrawable) {
badge = (BadgeDrawable) reuse;
} else {
badge = new BadgeDrawable(context);
}
badge.setCount(count);
icon.mutate();
icon.setDrawableByLayerId(R.id.ic_badge, badge);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.cart_menu, menu);
MenuItem itemCart = menu.findItem(R.id.menu_cart);
LayerDrawable icon = (LayerDrawable) itemCart.getIcon();
String list = getSharePref(MainActivity.this, "cart");
if (list != null) {
Design[] designs = new Gson().fromJson(list, Design[].class);
int count = designs.length;
setBadgeCount(MainActivity.this, icon, count);
}
return super.onCreateOptionsMenu(menu);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case R.id.menu_cart:
Intent intent = new Intent(MainActivity.this, CheckOutActivity.class);
startActivity(intent);
return false;
default:
break;
}
return false;
}
}
我認爲這段代碼可以工作，但它沒有。請有任何其他方式來解決這個問題。
Plz調試並檢查是否在適配器中獲得了更新設計和購物車清單。 – rajesh
不，我沒有得到更新的designList。我總是得到cartList爲null。 –