Question

这是模型类

public class AmountCartModel {

    private String testName;
    private String testPrice;

    public AmountCartModel() {
        this.testName = testName;
        this.testPrice = testPrice;
    }

    public String getTestName() {
        return testName;
    }

    public void setTestName(String testName) {
        this.testName = testName;
    }

    public String getTestPrice() {
        return testPrice;
    }

    public void setTestPrice(String testPrice) {
        this.testPrice = testPrice;
    }
}

这是我的活动

public class AmountCartActivity extends AppCompatActivity

    private RecyclerView recyclerView;
    List<AmountCartModel> mydataList ;
    private MyAdapter madapter;

    Bundle extras ;
    String testName="";
    String testPrice="";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_amount_cart);

        mydataList = new ArrayList<>();
        /*
        * Getting Values From BUNDLE
        * */
        extras = getIntent().getExtras();

        if (extras != null) {
            testName = extras.getString("test_name");
            testPrice = extras.getString("test_price");

            //Just add your data in list
            AmountCartModel mydata = new AmountCartModel();  // object of Model Class
            mydata.setTestName(testName );
            mydata.setTestPrice(testPrice);
            mydataList.add(mydata);
        }

       madapter=new MyAdapter(mydataList);
    madapter.setMyDataList(mydataList);
    recyclerView = (RecyclerView)findViewById(R.id.recyler_amount_cart);
    recyclerView.setHasFixedSize(true);
    RecyclerView.LayoutManager layoutManager = new LinearLayoutManager(getApplicationContext());
    recyclerView.setLayoutManager(layoutManager);
    recyclerView.setAdapter(madapter);

    }

这是我的回收站适配器

public class MyAdapter extends RecyclerView.Adapter<MyAdapter.ViewHolder> {

    private Context context;
    private List<AmountCartModel> myDataList;

    public MyAdapter(Context context) {
        this.context = context;
        myDataList = new ArrayList<>();
    }


    @Override
    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {

        // Replace with your layout
        View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.amount_cart_row, parent, false);
        return new ViewHolder(view);
    }


    @Override
    public void onBindViewHolder(ViewHolder holder, int position) {
        // Set Your Data here to yout Layout Components..

        // to get Amount
        holder.testName.setText(myDataList.get(position).getTestName());
        holder.testPrice.setText(myDataList.get(position).getTestPrice());
    }

    @Override
    public int getItemCount() {

            return myDataList.size();

    }

    public void setMyDataList(List<AmountCartModel> myDataList) {
        // getting list from Fragment.
        this.myDataList = myDataList;
        notifyDataSetChanged();
    }


    public class ViewHolder extends RecyclerView.ViewHolder {

        TextView testName,testPrice;

        public ViewHolder(View itemView) {
            super(itemView);
            // itemView.findViewById

            testName=itemView.findViewById(R.id.test_name_one);
            testPrice=itemView.findViewById(R.id.price_name);

        }
    }
  }
}

Logcat

E / Android运行时：致命异常：主要流程：com.snpinfotech.snp.aoplapp，PID：11874 java.lang.NullPointerException 在com.snpinfotech.snp.aoplapp.aopl.amountCartContent.AmountCartActivity $ MyAdapter.onBindViewHolder（AmountCartActivity.java:374）在com.snpinfotech.snp.aoplapp.aopl.amountCartContent.AmountCartActivity $ MyAdapter.onBindViewHolder（AmountCartActivity.java:343）在android.support.v7.widget.RecyclerView $ Adapter.onBindViewHolder（RecyclerView.java:6482）在android.support.v7.widget.RecyclerView $ Adapter.bindViewHolder（RecyclerView.java:6515）在android.support.v7.widget.RecyclerView $ Recycler.tryBindViewHolderByDeadline（RecyclerView.java:5458）在android.support.v7.widget.RecyclerView $ Recycler.tryGetViewHolderForPositionByDeadline（RecyclerView.java:5724）在android.support.v7.widget.RecyclerView $ Recycler.getViewForPosition（RecyclerView.java:5563）在android.support.v7.widget.RecyclerView $ Recycler.getViewForPosition（RecyclerView.java:5559）在android.support.v7.widget.LinearLayoutManager $ LayoutState.next（LinearLayoutManager.java:2229）在android.support.v7.widget.LinearLayoutManager.layoutChunk（LinearLayoutManager.java:1556）在android.support.v7.widget.LinearLayoutManager.fill（LinearLayoutManager.java:1516）在android.support.v7.widget.LinearLayoutManager.onLayoutChildren（LinearLayoutManager.java:608）在android.support.v7.widget.RecyclerView.dispatchLayoutStep2（RecyclerView.java:3693）在android.support.v7.widget.RecyclerView.dispatchLayout（RecyclerView.java:3410）在android.support.v7.widget.RecyclerView.onLayout（RecyclerView.java:3962）在android.view.View.layout（View.java:15125）在android.view.ViewGroup.layout（ViewGroup.java:4862）在android.widget.RelativeLayout.onLayout（RelativeLayout.java:1160）在android.view.View.layout（View.java:15125）在android.view.ViewGroup.layout（ViewGroup.java:4862）在android.widget.RelativeLayout.onLayout（RelativeLayout.java:1160）在android.view.View.layout（View.java:15125）在android.view.ViewGroup.layout（ViewGroup.java:4862）在android.widget.FrameLayout.layoutChildren（FrameLayout.java:515）在android.widget.FrameLayout.onLayout（FrameLayout.java:450）在android.view.View.layout（View.java:15125）在android.view.ViewGroup.layout（ViewGroup.java:4862）在android.widget.LinearLayout.setChildFrame（LinearLayout.java:1888）在android.widget.LinearLayout.layoutVertical（LinearLayout.java:1742）在android.widget.LinearLayout.onLayout（LinearLayout.java:1651）在android.view.View.layout（View.java:15125）在android.view.ViewGroup.layout（ViewGroup.java:4862）在android.widget.FrameLayout.layoutChildren（FrameLayout.java:515）在android.widget.FrameLayout.onLayout（FrameLayout.java:450）在android.view.View.layout（View.java:15125）在android.view.ViewGroup.layout（ViewGroup.java:4862）在android.widget.LinearLayout.setChildFrame（LinearLayout.java:1888）在android.widget.LinearLayout.layoutVertical（LinearLayout.java:1742）在android.widget.LinearLayout.onLayout（LinearLayout.java:1651）在android.view.View.layout（View.java:15125）在android.view.ViewGroup.layout（ViewGroup.java:4862）在android.widget.FrameLayout.layoutChildren（FrameLayout.java:515）在android.widget.FrameLayout.onLayout（FrameLayout.java:450）在android.view.View.layout（View.java:15125）在android.view.ViewGroup.layout（ViewGroup.java:4862）在android.view.ViewRootImpl.performLayout（ViewRootImpl.java:2317）在android.view.ViewRootImpl.performTraversals（ViewRootImpl.java:2023）在android.view.ViewRootImpl.doTraversal（ViewRootImpl.java:1189）在android.view.ViewRootImpl $ TraversalRunnable.run（ViewRootImpl.java:6223）在android.view.Choreographer $ CallbackRecord.run（Choreographer.java:788）在android.view.Choreographer.doCallbacks（Choreographer.java:591）在android.view.Choreographer.doFrame（Choreographer.java:560）在android.view.Choreographer $ FrameDisplayEventReceiver.run（Choreographer.java:774）在android.os.Handler.handleCallback（Handler.java:808）在android.os.Handler.dispatchMessage（Handler.java:103）在android.os.Looper.loop（Looper.java:193）在Android系统上。

在这里，我正在从“上一个活动回收者”视图中获取值，并且我试图通过此活动中的捆绑包显示它。问题是当我用这种方法做的时候，活动并没有显示我什么东西，而且我在捆绑包中得到了价值，我没有得到什么问题。任何帮助将不胜感激。谢谢

Answer 1

您显然忘记了设置适配器。更改代码

UserForm

到

madapter=new MyAdapter(mydataList);
madapter.setMyDataList(mydataList);
recyclerView = (RecyclerView)findViewById(R.id.recyler_amount_cart);
recyclerView.setHasFixedSize(true);
RecyclerView.LayoutManager layoutManager = new LinearLayoutManager(getApplicationContext());
recyclerView.setLayoutManager(layoutManager);

编辑2：将onBindViewHolder更改为：

madapter=new MyAdapter(mydataList);
madapter.setMyDataList(mydataList);
recyclerView = (RecyclerView)findViewById(R.id.recyler_amount_cart);
recyclerView.setHasFixedSize(true);
RecyclerView.LayoutManager layoutManager = new LinearLayoutManager(getApplicationContext());
recyclerView.setLayoutManager(layoutManager);
recyclerView.setAdapter(madapter);

编辑：作为一个附加的想法，下面的代码与getItemCount（）函数的作用相同。

@Override
public void onBindViewHolder(ViewHolder holder, int position) {
    holder.testName.setText(myDataList.get(position).getTestName());
    holder.testPrice.setText(myDataList.get(position).getTestPrice());
}

显示捆绑包值以供回收者视图

1 个答案: