Question

我有以下情况：

我有两项活动（主要活动和产品卡活动）
主要活动有一个包含物品的RecyclerView。（用户可以手动添加项目。例如，他添加3项）
用户点击某个项目并转到ProductCard活动
在ProductCard活动用户中，点击按钮（moneyOk_readylist）并转到主要活动

但是当用户执行最后一步时，RecyclerView变为空白（空）。我知道它与国家有关，但不知道如何。任何人都可以帮助我吗？

MainActivity

import android.content.Intent;
import android.os.Bundle;
import android.os.PersistableBundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.CardView;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.Toolbar;
import android.util.Log;
import android.view.View;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.Toast;

import java.io.Serializable;
import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity {
    private List<Person> persons;
    private RecyclerView rv;
    final String LOG_TAG = "myLogs";

    RVAdapter adapter;
    Person person;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        rv = (RecyclerView)findViewById(R.id.rv);
        rv.setHasFixedSize(true);
        LinearLayoutManager llm = new LinearLayoutManager(this);
        rv.setLayoutManager(llm);
        persons = new ArrayList<>();
        adapter = new RVAdapter(persons);
        rv.setAdapter(adapter);



        if ((savedInstanceState != null) && (savedInstanceState.getSerializable("card") != null)) {
            persons.clear();
            persons.addAll((List<Person>) savedInstanceState.getSerializable("card"));
            adapter.notifyDataSetChanged();
                Log.d(LOG_TAG, "restore card with persons" + persons);
                }



        adapter.setOnItemClickListener(new RVAdapter.MyClickListener() {
            @Override
            public void onItemClick(int position, View v) {
                Toast.makeText(MainActivity.this, "push on item" + position, Toast.LENGTH_SHORT).show();
                Intent intent = new Intent(MainActivity.this, ProductCard.class);
                startActivity(intent);
                Log.d(LOG_TAG, "go to ProductCard class" + persons);
            }

        });
        adapter.setOnItemLongClickListener(new RVAdapter.MyLongClickListener() {
            @Override
            public void onItemLongClick(int position, View v) {
                Toast.makeText(MainActivity.this, "push on item long" + position, Toast.LENGTH_SHORT).show();
                Log.d(LOG_TAG, "Removed " + position);
                persons.remove(position);
                adapter.notifyDataSetChanged();
            }
        });


        setSupportActionBar(toolbar);

        FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
        fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
               person= new Person("Emma Wilson", "23 years old", R.drawable.im_beach);
               persons.add(person);

               Log.d(LOG_TAG, "push add" + persons);
               adapter.notifyDataSetChanged();
            }
        });

    }

    @Override
    protected void onResume() {
        super.onResume();
        adapter = new RVAdapter(persons);
        rv.setAdapter(adapter);
        Log.d(LOG_TAG, "onresume" + persons);
    }
       @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);

        outState.putSerializable("card", (Serializable) persons);
        Log.d(LOG_TAG, "save cards" + persons);
    }

    @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);
    }
}

ProductCard活动

import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView;
import android.widget.Button;
import android.widget.ImageButton;
import android.widget.ImageView;
import android.widget.Toast;

/**
 * Created by Dmitry on 01.11.2015.
 */
public class ProductCard extends AppCompatActivity implements AdapterView.OnItemClickListener {
    final String LOG_TAG = "myLogs";
    Button moneyOk_readylist;
    ImageButton addPhoto;
    ImageView imageView;
    private static int LOAD_IMAGE_RESULTS = 1;
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.product_card);
        moneyOk_readylist=(Button)findViewById(R.id.moneyOk_readylist);
        addPhoto=(ImageButton)findViewById(R.id.add_photo);
        imageView=(ImageView)findViewById(R.id.imageView);
        addPhoto.setOnLongClickListener(new View.OnLongClickListener() {
            @Override
            public boolean onLongClick(View v) {
                return false;
            }
        });
        addPhoto.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent i = new Intent(Intent.ACTION_PICK,
                        android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
                i.setType("image/*");
                //i.setAction(Intent.ACTION_PICK);
                startActivityForResult(Intent.createChooser(i,"Select picture"),1);

            }
        });
        moneyOk_readylist.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent=new Intent(ProductCard.this,MainActivity.class);
                startActivity(intent);
            }
        });

    }

    @Override

    public void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
// Here we need to check if the activity that was triggers was the Image Gallery.
        // If it is the requestCode will match the LOAD_IMAGE_RESULTS value.
        // If the resultCode is RESULT_OK and there is some data we know that an image was picked.
        if (requestCode == 1 && resultCode == RESULT_OK && data != null) {
            // Let's read picked image data - its URI

            imageView.setImageURI(data.getData());
        }


    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, 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();
        switch (id) {
            case R.id.action_save_card:
                Toast.makeText(ProductCard.this, "Карточка сохранена", Toast.LENGTH_SHORT).show();
                Intent intent=new Intent(ProductCard.this,MainActivity.class);
                startActivity(intent);
                Log.d(LOG_TAG, "go to Main class" );
                break;
            case R.id.action_delete_card:
                Toast.makeText(ProductCard.this, "Карточка удалена", Toast.LENGTH_SHORT).show();
                break;

        }
        return true;
    }


    @Override
    public void onItemClick(AdapterView<?> parent, View view, int position, long id) {

    }
}

如何恢复RecyclerView？

0 个答案: