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我有一个独立运行的 ListView，但由于某种原因，添加搜索栏似乎毁了一切。我可以打开 ListView 并单击一个项目以进入一个新页面，但按一个键在搜索栏中键入会导致“不幸的是，myapp 已停止”。我从 logcat 得到 NullPointerException 但我似乎没有做任何修复它。任何帮助将非常感激！

列表视图活动：

public class SecondScreenActivity extends Activity
{

    // Listview Adapter
    ArrayAdapter<String> arrayAdapter;

    // Search EditText
    EditText inputSearch;

        ArrayList<String> RecipeList;
        public void onCreate(Bundle saveInstanceState)
        {
                super.onCreate(saveInstanceState);
                setContentView(R.layout.main);

               // Get the reference of ListViewRecipes
                ListView RecipeListView=(ListView)findViewById(R.id.mainListView);

                 RecipeList = new ArrayList<String>();
                 getRecipeNames();

                 RecipeListView = (ListView) findViewById(R.id.mainListView);
                 inputSearch = (EditText) findViewById(R.id.inputSearch);

                 // Adding items to listview
                 ArrayAdapter<String> arrayAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, RecipeList); 
     //^^^this is the line that seems to be the problem^^^

                 // Set The Adapter
                 RecipeListView.setAdapter(arrayAdapter);


                 //Search
                 inputSearch = (EditText) findViewById(R.id.inputSearch);
                 /**
                  * Enabling Search Filter
                  * */
                 inputSearch.addTextChangedListener(new TextWatcher() {

       @Override
       public void onTextChanged(CharSequence cs, int arg1, int arg2, int arg3) {
       // When user changes the Text
       SecondScreenActivity.this.arrayAdapter.getFilter().filter(cs);   
       }

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

       }

       @Override
       public void afterTextChanged(Editable arg0) {
       // TODO Auto-generated method stub                          
       }
       });

       // register onClickListener to handle click events on each item
       RecipeListView.setOnItemClickListener(new OnItemClickListener()
       {
           public void onItemClick(AdapterView<?> parent, View itemClicked,
                            int position, long id) {

           TextView textView = (TextView) itemClicked;
           String strText = textView.getText().toString();

           Intent intenttwo = new Intent(SecondScreenActivity.this, ThirdScreenActivity.class);
           intenttwo.putExtra("position", strText);
           startActivity(intenttwo);
           }
           });

        }

        void getRecipeNames()
        {
            RecipeList.add("Recipe1");
            RecipeList.add("Recipe2");
            RecipeList.add("Recipe3");
            RecipeList.add("Recipe4");
            RecipeList.add("Recipe5");
            RecipeList.add("Recipe6");
            RecipeList.add("Recipe7");
            RecipeList.add("Recipe8");
            RecipeList.add("Recipe9");
            RecipeList.add("Recipe10");

        }  
}

编辑： 这是一个稍微修改的列表视图活动。这使得搜索栏可以工作，但是当单击 ListView 中的项目时，应用程序被迫关闭，并出现 logcat 错误：java.lang.classcastexception: android.widget.linearlayout cannot be cast to android.widget.textview。这可能有帮助，也可能没有！

import java.util.ArrayList;
import java.util.HashMap;    
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.AdapterView.OnItemClickListener;
import android.text.Editable;
import android.text.TextWatcher;
import android.view.View;

public class SecondScreenActivity extends Activity
{
    // List view
    private ListView lv;

    // Listview Adapter
    ArrayAdapter<String> adapter;

    // Search EditText
    EditText inputSearch;


    // ArrayList for Listview
    ArrayList<HashMap<String, String>> recipeList;

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

        // Listview Data
        String recipes[] = {"Recipe1", "Recipe2", "Recipe3", "Recipe4", "Recipe5",
                             "Recipe6", "Recipe7", "Recipe8", "Recipe9", "Recipe10"};

        lv = (ListView) findViewById(R.id.mainListView);
        inputSearch = (EditText) findViewById(R.id.inputSearch);

        // Adding items to listview
        adapter = new ArrayAdapter<String>(this, R.layout.list_item, R.id.recipe_name, recipes);
        lv.setAdapter(adapter);

        // Enabling search filter
        inputSearch.addTextChangedListener(new TextWatcher() {

            @Override
            public void onTextChanged(CharSequence cs, int arg1, int arg2, int arg3) {
                // When user changed the Text
                SecondScreenActivity.this.adapter.getFilter().filter(cs);   
            }

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

            }

            @Override
            public void afterTextChanged(Editable arg0) {
                // TODO Auto-generated method stub                          
            }
        });

     // register onClickListener to handle click events on each item
        lv.setOnItemClickListener(new OnItemClickListener()
           {


                    // argument position gives the index of item which is clicked
                public void onItemClick(AdapterView<?> parent, View itemClicked,
                int position, long id) {                

                    //TO DO: Send string (position) of recipe name

//                  TextView textView = (TextView) findViewById(itemClicked);
//                  String stringName = textView.getText().toString();
                    String stringName = (String) (lv.getItemAtPosition(position));

            Intent intenttwo = new Intent(SecondScreenActivity.this, ThirdScreenActivity.class);
            intenttwo.putExtra("position", stringName);
            startActivity(intenttwo);
        }
        });
    }
}

还有我的 logcat（使用第一个活动时）：

06-25 22:37:54.353: E/AndroidRuntime(4646): FATAL EXCEPTION: main
06-25 22:37:54.353: E/AndroidRuntime(4646): java.lang.NullPointerException
06-25 22:37:54.353: E/AndroidRuntime(4646):     at com.example.myapp.SecondScreenActivity$1.onTextChanged(SecondScreenActivity.java:66)
06-25 22:37:54.353: E/AndroidRuntime(4646):     at android.widget.TextView.sendOnTextChanged(TextView.java:7231)
06-25 22:37:54.353: E/AndroidRuntime(4646):     at android.widget.TextView.handleTextChanged(TextView.java:7290)
06-25 22:37:54.353: E/AndroidRuntime(4646):     at android.widget.TextView$ChangeWatcher.onTextChanged(TextView.java:8880)
06-25 22:37:54.353: E/AndroidRuntime(4646):     at android.text.SpannableStringBuilder.sendTextChanged(SpannableStringBuilder.java:962)
06-25 22:37:54.353: E/AndroidRuntime(4646):     at android.text.SpannableStringBuilder.replace(SpannableStringBuilder.java:496)
06-25 22:37:54.353: E/AndroidRuntime(4646):     at android.text.SpannableStringBuilder.replace(SpannableStringBuilder.java:435)
06-25 22:37:54.353: E/AndroidRuntime(4646):     at android.text.SpannableStringBuilder.replace(SpannableStringBuilder.java:30)
06-25 22:37:54.353: E/AndroidRuntime(4646):     at android.text.method.QwertyKeyListener.onKeyDown(QwertyKeyListener.java:222)
06-25 22:37:54.353: E/AndroidRuntime(4646):     at android.text.method.TextKeyListener.onKeyDown(TextKeyListener.java:136)
06-25 22:37:54.353: E/AndroidRuntime(4646):     at android.widget.TextView.doKeyDown(TextView.java:5385)
06-25 22:37:54.353: E/AndroidRuntime(4646):     at android.widget.TextView.onKeyDown(TextView.java:5204)
06-25 22:37:54.353: E/AndroidRuntime(4646):     at android.view.KeyEvent.dispatch(KeyEvent.java:2609)
06-25 22:37:54.353: E/AndroidRuntime(4646):     at android.view.View.dispatchKeyEvent(View.java:7205)
06-25 22:37:54.353: E/AndroidRuntime(4646):     at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1359)
06-25 22:37:54.353: E/AndroidRuntime(4646):     at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1359)
06-25 22:37:54.353: E/AndroidRuntime(4646):     at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1359)
06-25 22:37:54.353: E/AndroidRuntime(4646):     at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1359)
06-25 22:37:54.353: E/AndroidRuntime(4646):     at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchKeyEvent(PhoneWindow.java:1920)
06-25 22:37:54.353: E/AndroidRuntime(4646):     at com.android.internal.policy.impl.PhoneWindow.superDispatchKeyEvent(PhoneWindow.java:1395)
06-25 22:37:54.353: E/AndroidRuntime(4646):     at android.app.Activity.dispatchKeyEvent(Activity.java:2370)
06-25 22:37:54.353: E/AndroidRuntime(4646):     at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchKeyEvent(PhoneWindow.java:1847)
06-25 22:37:54.353: E/AndroidRuntime(4646):     at android.view.ViewRootImpl.deliverKeyEventPostIme(ViewRootImpl.java:3701)
06-25 22:37:54.353: E/AndroidRuntime(4646):     at android.view.ViewRootImpl.handleImeFinishedEvent(ViewRootImpl.java:3651)
06-25 22:37:54.353: E/AndroidRuntime(4646):     at android.view.ViewRootImpl$ViewRootHandler.handleMessage(ViewRootImpl.java:2818)
06-25 22:37:54.353: E/AndroidRuntime(4646):     at android.os.Handler.dispatchMessage(Handler.java:99)
06-25 22:37:54.353: E/AndroidRuntime(4646):     at android.os.Looper.loop(Looper.java:137)
06-25 22:37:54.353: E/AndroidRuntime(4646):     at android.app.ActivityThread.main(ActivityThread.java:5041)
06-25 22:37:54.353: E/AndroidRuntime(4646):     at java.lang.reflect.Method.invokeNative(Native Method)
06-25 22:37:54.353: E/AndroidRuntime(4646):     at java.lang.reflect.Method.invoke(Method.java:511)
06-25 22:37:54.353: E/AndroidRuntime(4646):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
06-25 22:37:54.353: E/AndroidRuntime(4646):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
06-25 22:37:54.353: E/AndroidRuntime(4646):     at dalvik.system.NativeStart.main(Native Method)

谢谢您的帮助！

4

1 回答 1

0

这个答案应该对你有所帮助，它有一个很好的例子。getFilter()我相信如果您使用的是Custom Adapter看起来不像的方法，则需要覆盖适配器中的方法。

在这种情况下，您可以使用setOnQueryTextListener并实现类似

searchField = (SearchView) findViewById(R.id.search_plate);
    searchField.setOnQueryTextListener(new SearchView.OnQueryTextListener() {

        @Override
        public boolean onQueryTextSubmit(String query) {
            return false;
        }

        @Override
        public boolean onQueryTextChange(String newText) {
            // search goes here !!
            setFilters("searchtext", newText);

            return false;
        }
    });

setFilters()你定义的函数在哪里。这是我的一个例子，所以你的变量和这样的变量会有点不同。

您可能还会发现这个答案和这个有用。我希望这有帮助

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于 2013-06-26T00:44:03.443 回答