Android 无法解析为键入…将搜索功能添加到小部件

在我的小部件中，我有一个listview，它在一个滑动抽屉中收集用户安装的所有应用程序。我想添加一个搜索功能，使用户可以更轻松地在列表中搜索已安装的应用程序，因此我将继续学习本教程。我已经按照此处的定义创建了我的listview：

package com.example.awesomefilebuilderwidget;

import java.util.List;

import android.content.ActivityNotFoundException;
import android.content.Context;
import android.content.Intent;
import android.content.pm.ApplicationInfo;
import android.content.pm.PackageManager;
import android.widget.Toast;

public class Utilities {

/*
 * Get all installed application on mobile and return a list
 * @param   c   Context of application
 * @return  list of installed applications
 */
public static List getInstalledApplication(Context c) {
    return c.getPackageManager().getInstalledApplications(PackageManager.GET_META_DATA);
}

/*
 * Launch an application
 * @param   c   Context of application
 * @param   pm  the related package manager of the context
 * @param   pkgName Name of the package to run
 */
public static boolean launchApp(Context c, PackageManager pm, String pkgName) {
    // query the intent for lauching
    Intent intent = pm.getLaunchIntentForPackage(pkgName);
    // if intent is available
    if(intent != null) {
        try {
            // launch application
            c.startActivity(intent);
            // if succeed
            return true;

        // if fail
        } catch(ActivityNotFoundException ex) {
            // quick message notification
            Toast toast = Toast.makeText(c, "Application Not Found", Toast.LENGTH_LONG);
            // display message
            toast.show();
        }
    }
    // by default, fail to launch
    return false;
}
}

我的列表视图和搜索栏显示在这里：

package com.example.awesomefilebuilderwidget;

import android.app.Activity;
import android.app.ProgressDialog;
import android.content.Intent;
import android.content.pm.ApplicationInfo;
import android.os.Bundle;
import android.text.Editable;
import android.text.TextWatcher;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemLongClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.AdapterView.OnItemClickListener;

public class Drag_and_Drop_App extends Activity {
private ListView mListAppInfo;
// Search EditText
EditText inputSearch;


@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    // set layout for the main screen
    setContentView(R.layout.drag_and_drop_app);
    // import buttons
    Button btnLinkToFeedback = (Button) findViewById(R.id.btnLinkToFeedback);

    // Link to Feedback Screen
    btnLinkToFeedback.setOnClickListener(new View.OnClickListener() {

        public void onClick(View view) {
            Intent i = new Intent(getApplicationContext(),
                    Feedback.class);
            startActivity(i);
            finish();
        }
    });
    // create new adapter
    AppInfoAdapter adapter = new AppInfoAdapter(this, Utilities.getInstalledApplication(this), getPackageManager());
    // load list application
   mListAppInfo = (ListView)findViewById(R.id.lvApps);
    // set adapter to list view
    mListAppInfo.setAdapter(adapter);
    // search bar
    inputSearch = (EditText) findViewById(R.id.inputSearch);

    inputSearch.addTextChangedListener(new TextWatcher() {

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


    // implement event when an item on list view is selected
    mListAppInfo.setOnItemClickListener(new OnItemClickListener() {

        @Override
        public void onItemClick(AdapterView parent, View view, int pos, long id) {
            // get the list adapter
            AppInfoAdapter appInfoAdapter = (AppInfoAdapter)parent.getAdapter();
            // get selected item on the list
            ApplicationInfo appInfo = (ApplicationInfo)appInfoAdapter.getItem(pos);
            // launch the selected application
            Utilities.launchApp(parent.getContext(), getPackageManager(), appInfo.packageName);
        }

    });

    // implement event when an item on list view is selected via long-click for drag and drop
    mListAppInfo.setOnItemLongClickListener(new OnItemLongClickListener(){

        @Override
        public boolean onItemLongClick(AdapterView parent, View view,
                int pos, long id) {
            // TODO Auto-generated method stub
            // get the list adapter
            AppInfoAdapter appInfoAdapter = (AppInfoAdapter)parent.getAdapter();
            // get selected item on the list
            ApplicationInfo appInfo = (ApplicationInfo)appInfoAdapter.getItem(pos);
            // launch the selected application
            Utilities.launchApp(parent.getContext(), getPackageManager(), appInfo.packageName);
            return true;
        }


    });
}
}

我的应用程序运行正常，只是搜索功能不起作用。我在第58行发现这个错误(

)

无论我做什么，我都不知道如何修复这个错误

就这样吧

AppInfoAdapter adapter ;

onCreate(){

---------------

---------------

 adapter  = new AppInfoAdapter(.................

}

---

“适配器”的范围仅限于onCreate方法。您可以尝试在类外部声明它。因为

adapter

在

onCreate

中，而不是在class字段中，所以您只需使用

adapter.getFilter（）.filter（cs）

或者您可以在onCreate方法中将其声明为final我如何扩展限制以达到我的OnTextChanged方法？我试图复制我已经定义的代码，结果却出现了错误。然后，我只是尝试了一个简单的“AppInfoAdapter”；但那没有起作用。如果我只是使用“adapter.getFilter（）.filter（cs）”，“我在“.getFilter”上得到了一个错误，说它是未定义的。如果我误解了，很抱歉，这会消除适配器上的错误，但是现在我在“.getFilter（）上得到了一个新的错误。”说AppInfoAdapterI类型没有定义，我开始了一个新问题

adapter cannot be resolved or is not a field    

AppInfoAdapter adapter ;

onCreate(){

---------------

---------------

 adapter  = new AppInfoAdapter(.................

}