Question

我在两个不同的活动中有两个android spinner下拉列表。但是两个微调器都有来自同一个sourec的相同数据。我想根据第一个活动的位置改变第二个Activity的位置。如何解决这个问题？。

更新代码：

第一项活动：

public class ServiceRequest extends BaseActivity implements OnItemClickListener {
    private List<Item> customerList = new ArrayList<Item>();
    private SpinnerAdapter adapter;
    public static final String EXTRA_INTENT_CUSTOMER_LIST  ="extra_intent_customer_list";

    public static final String EXTRA_INTENT_SELECTED_ITEM = "extra_intent_selected_item";
    private List<Item> items;
    Spinner spin;

    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        getLayoutInflater().inflate(R.layout.service_request, frameLayout);

       ;


    );
                    System.out.println("Selected item "    Button login = (Button) findViewById(R.id.booking);

        final String message = autoCompView.getText().toString();
        //Create the bundle


        login.setOnClickListener(new View.OnClickListener()
        {
            @Override
            public void onClick(View v) {
{

                    if(customerList.isEmpty()) return;
                    Item selectedItem = (Item) spin.getSelectedItem();
                    spin.getSelectedItem().toString(+selectedItem);

              Intent intent = new Intent(ServiceRequest.this, Form.class);
//            intent.putExtra(EXTRA_INTENT_CUSTOMER_LIST, (Serializable) customerList);
                    intent.putExtra("seletedItem", selectedItem);
                    intent.putExtra(EXTRA_INTENT_SELECTED_ITEM, selectedItem);
                    startActivity(intent);
                }
            }

        });

        spin = (Spinner) findViewById(R.id.service_spinner);
        adapter = new SpinnerAdapter((ArrayList<Item>) customerList, this);
        spin.setAdapter(adapter);
    }


    public void onStart(){
        super.onStart();
        BackTask bt=new BackTask();
        bt.execute();
    }
    private class BackTask extends AsyncTask<Void,Void,ArrayList<Item>> {
        ArrayList<String> list;
        protected void onPreExecute(){
            super.onPreExecute();
            list=new ArrayList<>();
        }
        protected ArrayList<Item> doInBackground(Void... params) {
            InputStream is = null;
            String result = "";
            try {
                HttpClient httpclient = new DefaultHttpClient();
                HttpPost httppost = new HttpPost("http://my_url/Service.asmx/GetServiceList");
                HttpResponse response = httpclient.execute(httppost);
                HttpEntity entity = response.getEntity();
                // Get our response as a String.
                is = entity.getContent();
            } catch (IOException e) {
                e.printStackTrace();
            }

            //convert response to string
            try {
                BufferedReader reader = new BufferedReader(new InputStreamReader(is, "utf-8"));
                String line = null;
                while ((line = reader.readLine()) != null) {
                    result += line;
                }
                is.close();
                //result=sb.toString();
            } catch (Exception e) {
                e.printStackTrace();
            }
            // parse json data
            try {
                JSONArray jArray = new JSONArray(result);
                for (int i = 0; i < jArray.length(); i++) {
                    JSONObject obj = jArray.getJSONObject(i);
                    Item customer = new Item();
                    customer.setId(obj.getString("ServiceId"));
                    customer.setName(obj.getString("ServiceName"));

                    // adding movie to movies array
                    customerList.add(customer);
                }
            } catch (JSONException e) {
                e.printStackTrace();
            }
//            adapter.notifyDataSetChanged();
            return null;
        }
        @Override
        protected void onPostExecute(ArrayList<Item> customerList) {
            if(customerList != null && !customerList.isEmpty()){
                adapter.updateDate(customerList);
            }
        }

    }}

第二项活动代码

     public class Form extends BaseActivity {

    //    ArrayList<String> listItems = new ArrayList<>();
//    ArrayAdapter<String> adapter;
    private ArrayList<Item> customerList = new ArrayList<Item>();
    private SpinnerAdapter adapter;
    private List<Item> items;

    AdapterView.OnItemSelectedListener listener;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        getLayoutInflater().inflate(R.layout.activity_form, frameLayout);

        if(getIntent().hasExtra(ServiceRequest.EXTRA_INTENT_SELECTED_ITEM)){
            selectedItem = (Item)getIntent().getSerializableExtra(ServiceRequest.EXTRA_INTENT_SELECTED_ITEM);
        }


        service_need = (Spinner) findViewById(R.id.service_need);
        adapter = new SpinnerAdapter(customerList, this);
        service_need.setAdapter(adapter);
       /*  Commented by me
       if(selectedItem != null){
            service_need.setSelection(customerList.indexOf(selectedItem));
        }*/




        /*
        Commented for testing :Praveen
        Bundle bundle = getIntent().getExtras();
        String stuff1 = bundle.getString("local");*/
        autoCompView.setText("stuff1");
//        position = customerList.indexOf(bundle.getString("name"));
//        spin.setSelection(position);
//        adapter.notifyDataSetChanged();
//        adapter.notifyDataSetChanged();

//        String name = bundle.getString("name");
//        adapter.add(name);


    }

    public void onStart() {
        super.onStart();
        BackTask bt = new BackTask();
        bt.execute();
    }

    private class BackTask extends AsyncTask<Void, Void, ArrayList<Item>> {
        ArrayList<String> list;

        protected void onPreExecute() {
            super.onPreExecute();
//            list = new ArrayList<>();

        }

        protected ArrayList<Item> doInBackground(Void... params) {
            InputStream is = null;
            String result = "";
            try {
                HttpClient httpclient = new DefaultHttpClient();
                HttpPost httppost = new HttpPost("http://my_url/Service.asmx/GetServiceList");
                HttpResponse response = httpclient.execute(httppost);
                HttpEntity entity = response.getEntity();
                // Get our response as a String.
                is = entity.getContent();
            } catch (IOException e) {
                e.printStackTrace();
            }

            //convert response to string
            try {
                BufferedReader reader = new BufferedReader(new InputStreamReader(is, "utf-8"));
                String line = null;
                while ((line = reader.readLine()) != null) {
                    result += line;
                }
                is.close();
                //result=sb.toString();
            } catch (Exception e) {
                e.printStackTrace();
            }
            // parse json data
            try {
                JSONArray jArray = new JSONArray(result);
                for (int i = 0; i < jArray.length(); i++) {
                    JSONObject obj = jArray.getJSONObject(i);
                    Item customer = new Item();
                    customer.setId(obj.getString("ServiceId"));
                    customer.setName(obj.getString("ServiceName"));
                    customerList.add(customer);
                }
            } catch (JSONException e) {
                e.printStackTrace();
            }
//            adapter.notifyDataSetChanged();
            return null;
        }

        @Override
        protected void onPostExecute(ArrayList<Item> customerList) {
            if(customerList != null && !customerList.isEmpty()){
                adapter.updateDate(customerList);
                if(selectedItem != null){
                    spin.setSelection(customerList.indexOf(selectedItem));
                }
            }
        }
    }


}

模型类

public class Item implements Serializable {
    String id;
    String name;

    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;

        Item item = (Item) o;

        if (getId() != item.getId()) return false;
        return getName().equals(item.getName());

    }
}

Adapeter班

public class SpinnerAdapter extends BaseAdapter {

    ArrayList<Item> categories = new ArrayList<>();
    Context mContext;

    public SpinnerAdapter(ArrayList<Item> categories, Context context){
        this.categories = categories;
        mContext = context;
    }

    @Override
    public int getCount() {
        return categories.size();
    }

    @Override
    public Object getItem(int i) {
        return categories.get(i);
    }

    @Override
    public long getItemId(int i) {
        return categories.get(i).hashCode();
    }

    @Override
    public View getView(int i, View view, ViewGroup viewGroup) {

        Item item = categories.get(i);
        ViewHolder holder = null;
        if(view == null){
            view = LayoutInflater.from(mContext).inflate(R.layout.spin_row, null);
            holder = new ViewHolder();
            holder.name = (TextView) view.findViewById(R.id.name);
            view.setTag(holder);
        } else {
            holder = (ViewHolder) view.getTag();
        }
        holder.name.setText(item.getName());
        return view;
    }

    static class ViewHolder{
        TextView name;
    }

}

JSON响应

[{"ServiceId":"1","ServiceName":"AC"},
{"ServiceId":"5","ServiceName":"Plumbing"},
{"ServiceId":"3","ServiceName":"Refrigerator"},
{"ServiceId":"7","ServiceName":"Appliances"},
{"ServiceId":"27","ServiceName":"Others"}]

Answer 1

您可以使用2个主题解决此问题。

SharePrefernce



意图

<强> SharePrefernce

存储Spinner数组的位置。

获取位置并在再次使用时设置为Spinner。

实施例： -

用于保存或将位置存储到SharePrefernce中。

int position = spin.getSelectedItemPosition() ;
PreferenceManager.getDefaultSharedPreferences(this).edit().putInt("position",position ).commit();

从SharePrefernce获取或设置值到Spinner。

int position = PreferenceManager.getDefaultSharedPreferences(this).getInt("position", 0);
spin.setSelection(position);

<强>意图

将Spinner数组的位置存储在意图中。

获取位置并在再次使用意图时设置为Spinner。

实施例： -

用于保存或将位置存储到意图中。

int position = spin.getSelectedItemPosition() ;
Intent myIntent = new Intent(A.this, B.class);
myIntent.putExtra("position", position);
startActivity(myIntent);

从Intent获取或设置值到Spinner。

Intent mIntent = getIntent();
int position = mIntent.getIntExtra("position", 0);
spin.setSelection(position);

这两个都有效。我已经检查过了。

Answer 2

private List<Item> customerList = new ArrayList<Item>();

客户列表是数据模型“Item”的列表，一个pojo类。

position = customerList.indexOf(bundle.getString("name"));

在这一行中，您试图通过传递字符串来获取所选项目的索引。数组列表将无法比较两种不同类型的对象。你必须传递一个“item”实例： position = customerList.indexOf（item）;

你必须使用类的一些独特属性覆盖Item类中的“equals”方法。这个equals方法将用于比较两个对象和list将返回列表中存在的对象索引。请查看this和this以获取说明。

数据模态类

public class Item implements Serializable {
int id;
String name;

public int getId() {
    return id;
}

public void setId(int id) {
    this.id = id;
}

public String getName() {
    return name;
}

public void setName(String name) {
    this.name = name;
}

@Override
public boolean equals(Object o) {
    if (this == o) return true;
    if (o == null || getClass() != o.getClass()) return false;

    Item item = (Item) o;

    if (getId() != item.getId()) return false;
    return getName().equals(item.getName());

}

}

活动类

 package spinner.sample.spinnerexample;

 import android.content.Intent;
 import android.os.Bundle;
 import android.support.v7.app.AppCompatActivity;
 import android.view.View;
 import android.widget.Spinner;

 import java.util.ArrayList;

 public class MainActivity extends AppCompatActivity {

private Spinner spinner;
ArrayList<Item> customerList = new ArrayList<>();
SpinnerAdapter spinnerAdapter;
public static final String EXTRA_INTENT_CUSTOMER_LIST  ="extra_intent_customer_list";

public static final String EXTRA_INTENT_SELECTED_ITEM = "extra_intent_selected_item";

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    spinner = (Spinner)findViewById(R.id.spinner);
    createList();
    spinnerAdapter = new SpinnerAdapter(customerList, this);
    spinner.setAdapter(spinnerAdapter);
}


private void createList(){

    Item item1 = new Item();
    item1.setId(14);
    item1.setName("Automobile");

    Item item2 = new Item();
    item2.setId(15);
    item2.setName("Business Services");

    Item item3 = new Item();
    item3.setId(16);
    item3.setName("Business");


    Item item4 = new Item();
    item4.setId(17);
    item4.setName("Computers");


    Item item5 = new Item();
    item5.setId(18);
    item5.setName("Computers Acc");

    Item item6 = new Item();
    item6.setId(19);
    item6.setName("Education");

    Item item7 = new Item();
    item7.setId(20);
    item7.setName("Personal");

    customerList.add(item1);
    customerList.add(item2);
    customerList.add(item3);
    customerList.add(item4);
    customerList.add(item5);
    customerList.add(item6);
    customerList.add(item7);

}

public void onClick(View view){
    if(customerList.isEmpty()) return;
    Item selectedItem = (Item) spinner.getSelectedItem();
    System.out.println("Selected item "+selectedItem);

    Intent intent = new Intent(this, SecondActivity.class);
    intent.putExtra(EXTRA_INTENT_CUSTOMER_LIST, customerList);
    intent.putExtra(EXTRA_INTENT_SELECTED_ITEM, selectedItem);
    startActivity(intent);
}

}

活动2

     package spinner.sample.spinnerexample;

        import android.os.Bundle;
        import android.support.v7.app.AppCompatActivity;
        import android.widget.Spinner;

        import java.util.ArrayList;

        public class SecondActivity extends AppCompatActivity {

        private Spinner spinner;
        ArrayList<Item> customerList = new ArrayList<>();
        SpinnerAdapter spinnerAdapter;
        Item selectedItem;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_second);
        if(getIntent().hasExtra(MainActivity.EXTRA_INTENT_CUSTOMER_LIST)){
            customerList = (ArrayList<Item>) getIntent().getSerializableExtra(MainActivity.EXTRA_INTENT_CUSTOMER_LIST);
        }

        if(getIntent().hasExtra(MainActivity.EXTRA_INTENT_SELECTED_ITEM)){
            selectedItem = (Item)getIntent().getSerializableExtra(MainActivity.EXTRA_INTENT_SELECTED_ITEM);
        }


        spinner = (Spinner)findViewById(R.id.spinner);

        if(customerList.isEmpty()) return;
        spinnerAdapter = new SpinnerAdapter(customerList, this);
        spinner.setAdapter(spinnerAdapter);
        if(selectedItem != null){
            spinner.setSelection(customerList.indexOf(selectedItem));
        }
    }
}

Adapter :

        package spinner.sample.spinnerexample;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.TextView;

import java.util.ArrayList;

/**
 * Created by praveen on 17/8/16.
 */

public class SpinnerAdapter extends BaseAdapter {

    ArrayList<Item> categories = new ArrayList<>();
    Context mContext;

    public SpinnerAdapter(ArrayList<Item> categories, Context context){
        this.categories = categories;
        mContext = context;
    }

    @Override
    public int getCount() {
        return categories.size();
    }

    @Override
    public Object getItem(int i) {
        return categories.get(i);
    }

    @Override
    public long getItemId(int i) {
        return categories.get(i).hashCode();
    }

    @Override
    public View getView(int i, View view, ViewGroup viewGroup) {

        Item item = categories.get(i);
        ViewHolder holder = null;
        if(view == null){
            view = LayoutInflater.from(mContext).inflate(R.layout.spinner_item, null);
            holder = new ViewHolder();
            holder.name = (TextView) view.findViewById(R.id.txt_view_spinner_item);
            view.setTag(holder);
        } else {
            holder = (ViewHolder) view.getTag();
        }
        holder.name.setText(item.getName());
        return view;
    }

    static class ViewHolder{
        TextView name;
    }

}

Answer 3

我可以找到解决方案。尝试使用此更改您的两个活动代码，

public class MainActivity extends AppCompatActivity{


private ArrayList<Item> customerList = new ArrayList<Item>();
private SpinnerAdapter adapter;
public static final String EXTRA_INTENT_CUSTOMER_LIST  ="extra_intent_customer_list";

public static final String EXTRA_INTENT_SELECTED_ITEM = "extra_intent_selected_item";
private List<Item> items;
Spinner spin;

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
   // getLayoutInflater().inflate(R.layout.activity_main, null);

    Button login = (Button) findViewById(R.id.login);
    spin = (Spinner) findViewById(R.id.service_spinner);

    assert login != null;
    login.setOnClickListener(new View.OnClickListener()
    {
        @Override
        public void onClick(View v) {

           if (spin.getSelectedItemPosition() == 0) {

               Toast.makeText(MainActivity.this, "Please Select item", Toast.LENGTH_SHORT).show();

            }
            else {

                if(customerList.isEmpty()) return;
                Item selectedItem = (Item) spin.getSelectedItem();
                Intent intent = new Intent(MainActivity.this, SecondActivity.class);
                intent.putExtra(EXTRA_INTENT_SELECTED_ITEM, spin.getSelectedItemPosition());
                startActivity(intent);
            }
        }

    });

    for (int i = 0; i < 1; i++) {

        Item customer = new Item();
        customer.setId(""+i);
        customer.setName("Select Obj");

        // adding movie to movies array
        customerList.add(customer);
    }

    adapter = new SpinnerAdapter((ArrayList<Item>) customerList, this);
    spin.setAdapter(adapter);


}

public void onStart(){
    super.onStart();
    BackTask bt=new BackTask();
    bt.execute();

}
private class BackTask extends AsyncTask<Void,Void,ArrayList<Item>> {

    protected void onPreExecute(){
        super.onPreExecute();

    }
    protected ArrayList<Item> doInBackground(Void... params) {
        InputStream is = null;
        String result = "";
        try {
            HttpClient httpclient = new DefaultHttpClient();
            HttpPost httppost = new HttpPost("http://my_url/json");
            HttpResponse response = httpclient.execute(httppost);
            HttpEntity entity = response.getEntity();
            // Get our response as a String.
            is = entity.getContent();
        } catch (IOException e) {
            e.printStackTrace();
        }

        //convert response to string
        try {
            BufferedReader reader = new BufferedReader(new InputStreamReader(is, "utf-8"));
            String line = null;
            while ((line = reader.readLine()) != null) {
                result += line;
            }
            is.close();
            //result=sb.toString();
        } catch (Exception e) {
            e.printStackTrace();
        }
        // parse json data
        try {
            JSONArray jArray = new JSONArray(result);
            for (int i = 0; i < jArray.length(); i++) {
                JSONObject obj = jArray.getJSONObject(i);
                Item customer = new Item();
                customer.setId(obj.getString("ServiceId"));
                customer.setName(obj.getString("ServiceName"));

                // adding movie to movies array
                customerList.add(customer);
            }
        } catch (JSONException e) {
            e.printStackTrace();
        }
        return customerList;
    }
    @Override
    protected void onPostExecute(ArrayList<Item> customerList) {
        if(customerList != null && !customerList.isEmpty()){
           // adapter.updateDate(customerList);
            adapter.notifyDataSetChanged();
        }
    }

}}

和SecondActivity：

public class SecondActivity extends AppCompatActivity {

private static final String REGISTER_URL = "http://my_url/Service.asmx/GenerateTicket";

public static final String PREFS_NAME = "MyPrefsFile";

public static final String CUSTOMERID = "customerId";
public static final String USERNAME = "name";
public static final String HOUSENO = "houseNo";
public static final String LOCALITY = "areaName";
public static final String SERVICE = "serviceId";
public static final String MOBILE = "mobile";
public static final String EMAIL = "email";
public static final String PROBLEM = "jobBrief";
private ProgressDialog pDialog;
Spinner spin;
String service;
Item selectedItem;
// flag for Internet connection status
Boolean isInternetPresent = false;

private ArrayList<Item> customerList = new ArrayList<Item>();
private SpinnerAdapter adapter;
private List<Item> items;

AdapterView.OnItemSelectedListener listener;

Spinner service_need;
AutoCompleteTextView autoCompView;
String obj;
int pos;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_second);
    //getLayoutInflater().inflate(R.layout.activity_second, null);

    if(getIntent().hasExtra(MainActivity.EXTRA_INTENT_SELECTED_ITEM)){
        pos = getIntent().getIntExtra(MainActivity.EXTRA_INTENT_SELECTED_ITEM,0);

    }

    service_need = (Spinner) findViewById(R.id.service_need);

    for (int i = 0; i < 1; i++) {

        Item customer = new Item();
        customer.setId(""+i);
        customer.setName("Select Obj");

        // adding movie to movies array
        customerList.add(customer);
    }


    adapter = new SpinnerAdapter(customerList, this);

    service_need.setAdapter(adapter);

}

public void onStart() {
    super.onStart();
    BackTask bt = new BackTask();
    bt.execute();
}

private class BackTask extends AsyncTask<Void, Void, ArrayList<Item>> {
    ArrayList<String> list;

    protected void onPreExecute() {
        super.onPreExecute();


    }

    protected ArrayList<Item> doInBackground(Void... params) {
        InputStream is = null;
        String result = "";
        try {
            HttpClient httpclient = new DefaultHttpClient();
            HttpPost httppost = new HttpPost("http://my_url/json");
            HttpResponse response = httpclient.execute(httppost);
            HttpEntity entity = response.getEntity();
            // Get our response as a String.
            is = entity.getContent();
        } catch (IOException e) {
            e.printStackTrace();
        }

        //convert response to string
        try {
            BufferedReader reader = new BufferedReader(new InputStreamReader(is, "utf-8"));
            String line = null;
            while ((line = reader.readLine()) != null) {
                result += line;
            }
            is.close();
            //result=sb.toString();
        } catch (Exception e) {
            e.printStackTrace();
        }
        // parse json data
        try {
            JSONArray jArray = new JSONArray(result);
            for (int i = 0; i < jArray.length(); i++) {
                JSONObject obj = jArray.getJSONObject(i);
                Item customer = new Item();
                customer.setId(obj.getString("ServiceId"));
                customer.setName(obj.getString("ServiceName"));
                customerList.add(customer);
            }
        } catch (JSONException e) {
            e.printStackTrace();
        }

        return customerList;
    }

    @Override
    protected void onPostExecute(ArrayList<Item> customerList) {
        if(customerList != null && !customerList.isEmpty()){

            service_need.setSelection(pos);

        }

    }
}}

问题1：由于null对象微调器导致SecondActivity中出现NullPointerException。第二个活动中的微调器ID是Service_need。

问题2：SecondActivity中的Back_task DoInBackground方法返回null，它必须返回ArrayList以在OnPostExecute中进行验证。

感谢。

希望有所帮助。

Answer 4

尝试通过第二项活动中的List获取所选名称在第一项活动中的位置。

position = customerList.indexOf(bundle.getString("name"));
spin.setSelection(position,false);

Answer 5

获取第一个微调器位置并通过意图传递另一个活动，并将第一个微调器位置设置为第二个微调器。（第二个微调器必须像spinner一样使用edittext进行自定义）。

Answer 6

我们假设您的position是正确的，但您可以使用简单的Log.d(tag, "pos:"+position)进行验证，并且您的微调器正在使用customerList正确填充（您可以直观地验证或{{1} }或Log.d(tag, "size:"+adapter.getCount())）

尝试两件事（或两件事）：

您spin.getCount()应该在adapter.notifyDataSetChanged()之后立即到来。如果你在那之前做customerList.addAll(position,customerList)，那么你的微调器仍然是空的。
你的微调器ui还没有准备就绪，所以这样做：
```
setSelection
```

如何根据其他微调器在两个不同活动中的位置来改变微调器的位置

6 个答案: