java - Android Studio : SearchView: error in searchView. setSearchableInfo(searchManager.getSearchableInfo(cn));

Question

我是一名开发 Android 应用程序的新手，以下是该应用程序的第一个屏幕。我希望我的应用程序使用该搜索对话框执行搜索。

为此，我关注了http://developer.android.com/guide/topics/search/search-dialog.html

但是我收到以下错误:日志猫:

 FATAL EXCEPTION: main
 Process: com.example.shalini.circlelayout, PID: 19330
                                                  java.lang.NullPointerException
 at com.example.shalini.circlelayout.MainActivity.onCreateOptionsMenu(MainActivity.java:69)

MainActivity.java 中第 69 行的位置是:

ComponentName cn = new ComponentName(this, SearchResultsActivity.class);
    searchView.setSearchableInfo(searchManager.getSearchableInfo(cn));

我提到过这个 Cannot get searchview in actionbar to work并进行了更改，但同样的问题仍然存在。我的问题是为什么它在 searchView.setSearchableInfo(searchManager.getSearchableInfo(cn)); 行中显示错误。我无法弄清楚，我仍然认为错误是由于代码的其他部分引起的，可能是 searchresultsactivity.xml 或 SearchResultsActivity.java。任何帮助深表感谢。谢谢。代码如下:

MainActivity.java

package com.example.shalini.circlelayout;

import android.app.SearchManager;
import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.SearchView;
import android.support.v7.widget.Toolbar;
import android.view.MenuInflater;
import android.view.View;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.EditText;
import android.widget.ImageButton;

public class MainActivity extends AppCompatActivity {

  EditText e1;
  ImageButton imageButton;

    @Override
    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        e1 = (EditText) findViewById(R.id.search);
        addListenerOnButton();

        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
        fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                        .setAction("Action", null).show();
            }
        });
    }

private void addListenerOnButton() {
    imageButton = (ImageButton) findViewById(R.id.imageButton);
    imageButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Intent i = new Intent(getApplicationContext(), SymptomsList.class);
            startActivity(i);
        }
    });

}


@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);
    MenuInflater inflater = getMenuInflater();
    inflater.inflate(R.menu.menu_main, menu);
    // Associate searchable configuration with the SearchView
    SearchManager searchManager = (SearchManager) getSystemService(Context.SEARCH_SERVICE);
    SearchView searchView = (SearchView) menu.findItem(R.id.search).getActionView();
    ComponentName cn = new ComponentName(this, SearchResultsActivity.class);
    searchView.setSearchableInfo(searchManager.getSearchableInfo(cn));
    //call to getSearchableInfo()
    //SearchableInfo object
    //SearchView starts an activity with the ACTION_SEARCH intent when a user submits a query
    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();

    //noinspection SimplifiableIfStatement
    if (id == R.id.action_settings) {
        return true;
    }

    return super.onOptionsItemSelected(item);
}
}

SearchResultsActivity.java

package com.example.shalini.circlelayout;

import android.app.ListActivity;
import android.app.SearchManager;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;

public class SearchResultsActivity extends ListActivity {

  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    handleIntent(getIntent());

  }

  @Override
  public void onNewIntent(Intent intent) {
    super.onNewIntent(intent);
    handleIntent(intent);

  }
  private void handleIntent(Intent intent) {

    if (Intent.ACTION_SEARCH.equals(intent.getAction())) {
        String query = intent.getStringExtra(SearchManager.QUERY);
        doMySearch(query);
        //use the query to search your data somehow
    }
  }
  private void doMySearch(String query) {
    Log.d("Event", query);
  }
}

content_main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"

xmlns:tools="http://schemas.android.com/tools"
xmlns:app="http://schemas.android.com/apk/res-auto" android:layout_width="match_parent"
android:layout_height="wrap_content" android:padding="@dimen/activity_horizontal_margin"
app:layout_behavior="@string/appbar_scrolling_view_behavior"
tools:showIn="@layout/activity_main" tools:context=".MainActivity"
android:background="@drawable/blue_bluecrop1">

<EditText
    android:layout_width="160dp"
    android:layout_height="60dp"
    android:id="@+id/search"
    android:inputType="text"
    android:hint="@string/sym"
    android:drawableStart="@drawable/search_s2"
    android:drawableLeft="@drawable/search_s2"

    android:padding="20dp"
    android:gravity="center_vertical|center_horizontal"
    android:layout_alignParentTop="true"
    android:layout_alignParentLeft="true"
    android:layout_alignParentStart="true"
    android:layout_alignParentRight="true"
    android:layout_alignParentEnd="true"
    android:layout_marginLeft="5dp"
    android:layout_marginRight="5dp"
    android:layout_marginTop="5dp"
    android:ellipsize="end"
    android:background="@drawable/roundededittext"/>

<ImageButton
    android:layout_width="40dp"
    android:layout_height="45dp"
    android:contentDescription="@string/symbutton"
    android:id="@+id/imageButton"
    android:background="#00000000"
    android:layout_marginLeft="160dp"
    android:layout_marginStart="160dp"
    android:layout_marginTop="270dp"
    android:clickable="true"
   />

searchresultsactivity.xml

<ListView
android:layout_width="match_parent"
android:layout_height="match_parent"
xmlns:android="http://schemas.android.com/apk/res/android">

@xml/可搜索

<?xml version="1.0" encoding="utf-8"?>
<searchable xmlns:android="http://schemas.android.com/apk/res/android"
android:label="@string/app_name"
android:hint="@string/search_searchable">

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.shalini.circlelayout" >

<application
    android:allowBackup="true"
    android:fullBackupContent="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:supportsRtl="true"
    android:theme="@style/AppTheme" >
    <activity
        android:name=".MainActivity"

        android:label="@string/app_name"
        android:theme="@style/AppTheme.NoActionBar" >
    <intent-filter>
            <action android:name="android.intent.action.MAIN" />
        <action android:name="android.intent.action.VIEW" />
            <category android:name="android.intent.category.BROWSABLE"     />
        <data android:scheme="http"
            android:host="www.example.com"
            android:pathPrefix="/doraemon" />

    </intent-filter>
        <meta-data
            android:name="android.app.default_searchable"
            android:value=".SearchResultsActivity" />


    </activity>
    <activity android:name=".SearchResultsActivity">
        <intent-filter>
            <action android:name="android.intent.action.SEARCH" />
        </intent-filter>
        <meta-data android:name="android.app.searchable"
            android:resource="@xml/searchable" />
    </activity> 
</application>

Answer 1

您的 searchView 似乎为空。你是怎么做到的？