Question

我在操作栏中有一个带有可折叠视图的编辑文本。当我在编辑文本中输入基于文本观察者的名称时，它必须显示名称。它显示空指针。任何人指导我在哪里犯了错误

MainActivity.java

package com.example.filterlistview;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Locale;

import android.annotation.SuppressLint;
import android.annotation.TargetApi;
import android.app.Activity;
import android.content.Context;
import android.os.Build;
import android.os.Bundle;
import android.text.Editable;
import android.text.TextWatcher;
import android.view.Menu;
import android.view.MenuItem;
import android.view.MenuItem.OnActionExpandListener;
import android.view.inputmethod.InputMethodManager;
import android.view.View;
import android.widget.EditText;
import android.widget.LinearLayout;
import android.widget.ListView;


@SuppressLint("NewApi")
@TargetApi(Build.VERSION_CODES.HONEYCOMB)
public class MainActivity extends Activity{

    ListView lv;
    CustomAdapter adapter;

    ArrayList<String> name;
    ArrayList<String> comp;
    ArrayList<String> mobile;
    ArrayList<String> address,pincode;

    List<HashMap<String, String>> list;

    ArrayList<MyModel> a_list = new ArrayList<MyModel>();
    EditText searchView;

    EditText editsearch;

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

        final LinearLayout rel = (LinearLayout)findViewById(R.id.myrelative);
        rel.setVisibility(View.VISIBLE);

        name = new ArrayList<String>();
        comp = new ArrayList<String>();
        mobile = new ArrayList<String>();
        address = new ArrayList<String>();
        pincode = new ArrayList<String>();

        name.add("Giri");
        name.add("palani");
        name.add("Lawrence");
        name.add("Giri");
        name.add("palani");
        name.add("Lawrence");
        name.add("Giri");
        name.add("palani");
        name.add("Lawrence");


        comp.add("sri ram");
        comp.add("sri ram");
        comp.add("sri ram");
        comp.add("sri ram");
        comp.add("sri ram");
        comp.add("sri ram");
        comp.add("sri ram");
        comp.add("sri ram");
        comp.add("sri ram");

        mobile.add("900121233");
        mobile.add("900121233");
        mobile.add("900121233");

        mobile.add("900121233");
        mobile.add("900121233");
        mobile.add("900121233");

        mobile.add("900121233");
        mobile.add("900121233");
        mobile.add("900121233");



        for(int i=0;i<name.size();i++)
        {
            MyModel mp = new MyModel(name.get(i), comp.get(i), mobile.get(i));
            a_list.add(mp);
        }

        lv = (ListView) findViewById(R.id.list);
        CustomAdapter adapter= new CustomAdapter(MainActivity.this, a_list);
        adapter.notifyDataSetChanged();


        lv.setAdapter(adapter);

        lv.setTextFilterEnabled(true);

    }

    @SuppressLint("NewApi")
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);



        editsearch = (EditText) menu.findItem(R.id.menu_search).getActionView();

        // Capture Text in EditText
        editsearch.addTextChangedListener(textWatcher);

        // Show the search menu item in menu.xml
        MenuItem menuSearch = menu.findItem(R.id.menu_search);

        menuSearch.setOnActionExpandListener(new OnActionExpandListener() {

            // Menu Action Collapse
                        @Override
                        public boolean onMenuItemActionCollapse(MenuItem item) {
                            // Empty EditText to remove text filtering
                            editsearch.setText("");
                            editsearch.clearFocus();
                            return true;
                        }

                        // Menu Action Expand
                        @Override
                        public boolean onMenuItemActionExpand(MenuItem item) {
                            // Focus on EditText
                            editsearch.requestFocus();

                            // Force the keyboard to show on EditText focus
                            InputMethodManager imm = (InputMethodManager) getSystemService(Context.INPUT_METHOD_SERVICE);
                            imm.toggleSoftInput(InputMethodManager.SHOW_FORCED, 0);
                            return true;
                        }
        });




        return super.onCreateOptionsMenu(menu);
    }


        private TextWatcher textWatcher = new TextWatcher() {

            @Override
            public void afterTextChanged(Editable s) {
                // TODO Auto-generated method stub

            }

            @Override
            public void beforeTextChanged(CharSequence arg0, int arg1, int arg2,int arg3) {
                // TODO Auto-generated method stub

            }

            @Override
            public void onTextChanged(CharSequence arg0, int arg1, int arg2,
                    int arg3) {
                // TODO Auto-generated method stub

                String text = editsearch.getText().toString();

                modellist.clear();
                if (text.length() == 0) {
                    CustomAdapter.modellist.addAll(CustomAdapter.arraylist);
                } 
                else 
                {
                    for (MyModel wp : CustomAdapter.arraylist) 
                    {
                        if (wp.getName().toLowerCase(Locale.getDefault()).contains(text)) 
                        {
                            CustomAdapter.modellist.add(wp);
                        }
                    }
                }
                MainActivity.this.adapter.notifyDataSetChanged();
            }

        };

}

CustomAdapter.java

package com.example.filterlistview;

import java.util.ArrayList;
import java.util.List;
import java.util.Locale;

import android.app.Activity;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.TextView;

public class CustomAdapter extends BaseAdapter{

    ArrayList<String> name,comp,mobile,addr,pin;
    Activity context;
    static List<MyModel> modellist;
    static ArrayList<MyModel> arraylist;

    public CustomAdapter(Activity context,List<MyModel> modellist) {
        super();
        this.context = context;
        this.modellist = modellist;
        this.arraylist = new ArrayList<MyModel>();
        this.arraylist.addAll(modellist);
    }

    private class ViewHolder {
        TextView Name;
        TextView Company;
        TextView Mobile;
        TextView Address;
        TextView Pincode;
    }

    public int getCount() {
        return modellist.size();
    }

    public Object getItem(int position) {
        return modellist.get(position);
    }

    public long getItemId(int position) {
        return 0;
    }

    @Override
    public View getView(final int position, View convertView, ViewGroup parent) {
        final ViewHolder holder;

        LayoutInflater inflater = context.getLayoutInflater();

        if (convertView == null) {
            convertView = inflater.inflate(R.layout.list_row, null);
            holder = new ViewHolder();

            holder.Name = (TextView) convertView.findViewById(R.id.name);
            holder.Company = (TextView) convertView.findViewById(R.id.company);
            holder.Mobile = (TextView) convertView.findViewById(R.id.Mobile);
            holder.Address = (TextView) convertView.findViewById(R.id.Address);
            holder.Pincode = (TextView) convertView.findViewById(R.id.pincode);

            convertView.setTag(holder);


        } else {

            holder = (ViewHolder) convertView.getTag();
        }

        holder.Name.setText(modellist.get(position).getName());
        holder.Company.setText(modellist.get(position).getCom());
        holder.Mobile.setText(modellist.get(position).getMob());
//      holder.Address.setText(addr.get(position));
//      holder.Pincode.setText(pin.get(position));

        return convertView;

    }


    public void filter(String charText) {
        charText = charText.toLowerCase(Locale.getDefault());
//      modellist.clear();
        if (charText.length() == 0) {
            modellist.addAll(arraylist);
        } 
        else 
        {
            for (MyModel wp : arraylist) 
            {
                if (wp.getName().toLowerCase(Locale.getDefault()).contains(charText)) 
                {
                    modellist.add(wp);
                }
            }
        }
        notifyDataSetChanged();
    }

}

MyModel.java

package com.example.filterlistview;

public class MyModel {

    private String name;
    private String com;
    private String mob;

    public MyModel( String name, String com,String mob)
    {
        this.name = name;
        this.com = com;
        this.mob = mob;
    }

    public String getName() {
        return this.name;
    }

    public String getMob() {
        return this.mob;
    }

    public String getCom() {
        return this.com;
    }
}

错误：

05-14 15:30:02.123: E/AndroidRuntime(21775): FATAL EXCEPTION: main
05-14 15:30:02.123: E/AndroidRuntime(21775): java.lang.NullPointerException
05-14 15:30:02.123: E/AndroidRuntime(21775):    at com.example.filterlistview.MainActivity$1.onTextChanged(MainActivity.java:194)
05-14 15:30:02.123: E/AndroidRuntime(21775):    at android.widget.TextView.sendOnTextChanged(TextView.java:7671)
05-14 15:30:02.123: E/AndroidRuntime(21775):    at android.widget.TextView.handleTextChanged(TextView.java:7718)
05-14 15:30:02.123: E/AndroidRuntime(21775):    at android.widget.TextView$ChangeWatcher.onTextChanged(TextView.java:8081)
05-14 15:30:02.123: E/AndroidRuntime(21775):    at android.text.SpannableStringBuilder.sendTextChange(SpannableStringBuilder.java:892)
05-14 15:30:02.123: E/AndroidRuntime(21775):    at android.text.SpannableStringBuilder.change(SpannableStringBuilder.java:352)
05-14 15:30:02.123: E/AndroidRuntime(21775):    at android.text.SpannableStringBuilder.change(SpannableStringBuilder.java:266)
05-14 15:30:02.123: E/AndroidRuntime(21775):    at android.text.SpannableStringBuilder.replace(SpannableStringBuilder.java:443)
05-14 15:30:02.123: E/AndroidRuntime(21775):    at android.text.SpannableStringBuilder.replace(SpannableStringBuilder.java:420)
05-14 15:30:02.123: E/AndroidRuntime(21775):    at android.text.SpannableStringBuilder.replace(SpannableStringBuilder.java:29)
05-14 15:30:02.123: E/AndroidRuntime(21775):    at android.view.inputmethod.BaseInputConnection.replaceText(BaseInputConnection.java:663)
05-14 15:30:02.123: E/AndroidRuntime(21775):    at android.view.inputmethod.BaseInputConnection.setComposingText(BaseInputConnection.java:425)
05-14 15:30:02.123: E/AndroidRuntime(21775):    at com.android.internal.view.IInputConnectionWrapper.executeMessage(IInputConnectionWrapper.java:333)
05-14 15:30:02.123: E/AndroidRuntime(21775):    at com.android.internal.view.IInputConnectionWrapper$MyHandler.handleMessage(IInputConnectionWrapper.java:77)
05-14 15:30:02.123: E/AndroidRuntime(21775):    at android.os.Handler.dispatchMessage(Handler.java:99)
05-14 15:30:02.123: E/AndroidRuntime(21775):    at android.os.Looper.loop(Looper.java:154)
05-14 15:30:02.123: E/AndroidRuntime(21775):    at android.app.ActivityThread.main(ActivityThread.java:4624)
05-14 15:30:02.123: E/AndroidRuntime(21775):    at java.lang.reflect.Method.invokeNative(Native Method)
05-14 15:30:02.123: E/AndroidRuntime(21775):    at java.lang.reflect.Method.invoke(Method.java:511)
05-14 15:30:02.123: E/AndroidRuntime(21775):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:809)
05-14 15:30:02.123: E/AndroidRuntime(21775):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:576)
05-14 15:30:02.123: E/AndroidRuntime(21775):    at dalvik.system.NativeStart.main(Native Method)

Answer 1

adapter为null，因为您没有初始化它，您有以下代码：

CustomAdapter adapter= new CustomAdapter(MainActivity.this, a_list);
adapter.notifyDataSetChanged();

在上面的代码中，您在本地创建了adapter但是您尝试在onTextChanged的类顶部声明的调用适配器：

  CustomAdapter adapter;

所以改变：

CustomAdapter adapter= new CustomAdapter(MainActivity.this, a_list);

到

adapter= new CustomAdapter(MainActivity.this, a_list);

Listview不会根据编辑文本进行更改

1 个答案: