Question

我在AndroidManifest.xml文件中遇到一个奇怪的错误，说＆＃34; MainActivity不公开。验证Android XML文件中的资源引用。＆＃34; 不知道如何解决错误。谁能在这帮助我？

的AndroidManifest.xml

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

    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" >
    </uses-permission>

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name=".MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity
            android:name=".What_is_java"
            android:label="@string/title_activity_what_is_java" >
        </activity>
    </application>

</manifest>

MainActivity.java

    package com.pixalstudio.javaclasses;

import android.content.Intent;
import android.content.res.Configuration;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.os.Bundle;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarActivity;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.widget.Toolbar;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.Toast;


class MainActivity extends ActionBarActivity implements AdapterView.OnItemClickListener {

    private Toolbar toolbar;
    ListView mDrawerList;
    DrawerLayout mDrawerLayout;
    ActionBarDrawerToggle mDrawerToggle;
    String[] mDrawerListItems;
    String[] mDrawerListItems2;

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

        ConnectivityManager cManager = (ConnectivityManager) getSystemService(this.CONNECTIVITY_SERVICE);
        NetworkInfo nInfo = cManager.getActiveNetworkInfo();
        if (nInfo != null && nInfo.isConnected()) {
            Toast.makeText(this, "Newtwrok Available", Toast.LENGTH_LONG).show();
        } else {
            Toast.makeText(this, "Network Not Available", Toast.LENGTH_LONG).show();
        }


        toolbar = (Toolbar) findViewById(R.id.app_bar);
        setSupportActionBar(toolbar);
        LayoutInflater inflater = getLayoutInflater();
        mDrawerLayout = (DrawerLayout) findViewById(R.id.drawerLayout);
        mDrawerList = (ListView) findViewById(R.id.drawerList);
        mDrawerListItems = getResources().getStringArray(R.array.drawer_list);

        ViewGroup header_news = (ViewGroup) inflater.inflate(R.layout.nav_header, mDrawerList, false);
        mDrawerList.addHeaderView(header_news, null, false);


        mDrawerList.setAdapter(new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, mDrawerListItems));
        mDrawerList.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                if (position == 1) {
                    Intent i = new Intent(MainActivity.this, What_is_java.class);
                    startActivity(i);
                }
                mDrawerLayout.closeDrawer(mDrawerList);
            }

        });


        mDrawerToggle = new ActionBarDrawerToggle(this,
                mDrawerLayout,
                toolbar,
                R.string.drawer_open,
                R.string.drawer_close) {
            @Override
            public void onDrawerClosed(View drawerView) {
                super.onDrawerClosed(drawerView);
                invalidateOptionsMenu();
                syncState();
            }

            @Override
            public void onDrawerOpened(View drawerView) {
                super.onDrawerOpened(drawerView);
                invalidateOptionsMenu();
                syncState();
            }
        };
        mDrawerLayout.setDrawerListener(mDrawerToggle);
        setSupportActionBar(toolbar);
        getSupportActionBar().setDisplayHomeAsUpEnabled(true);
        getSupportActionBar().setHomeButtonEnabled(true);
        mDrawerToggle.syncState();
    }

    @Override
    public void onPostCreate(Bundle savedInstanceState) {
        super.onPostCreate(savedInstanceState);
        mDrawerToggle.syncState();
    }

    @Override
    public void onConfigurationChanged(Configuration newConfig) {
        super.onConfigurationChanged(newConfig);
        mDrawerToggle.syncState();
    }

    @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);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {

        switch (item.getItemId()) {
            case android.R.id.home: {
                if (mDrawerLayout.isDrawerOpen(mDrawerList)) {
                    mDrawerLayout.closeDrawer(mDrawerList);
                } else {
                    mDrawerLayout.openDrawer(mDrawerList);
                }
                return true;
            }
            default:
                return super.onOptionsItemSelected(item);
        }


    }

    @Override
    public void onItemClick(AdapterView<?> parent, View view, int position, long id) {

        if (position == 2) {
            Intent i = new Intent(this, What_is_java.class);
            startActivity(i);
        }
        mDrawerLayout.closeDrawer(mDrawerList);
    }
}

activity_main.xml中

    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"

    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <include
        android:id="@+id/app_bar"
        layout="@layout/app_bar">

    </include>


    <android.support.v4.widget.DrawerLayout
        android:id="@+id/drawerLayout"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <FrameLayout
            android:id="@+id/content_frame"
            android:layout_width="match_parent"
            android:layout_height="match_parent">

        </FrameLayout>


        <ListView
            android:id="@+id/drawerList"
            android:layout_width="240dp"
            android:layout_height="match_parent"
            android:layout_gravity="start"
            android:background="#CE93D8">

        </ListView>


    </android.support.v4.widget.DrawerLayout>
</LinearLayout>

Answer 1

在class MainActivity [...]

中将public class MainActivity [...]更改为MainActivity.java

MainActivity不公开

1 个答案: