Question

我无法使MenuItem正常工作，我之前创建了其他应用，但由于某种原因它只是没有出现：

MainActivity.java

    package ie.example.artur.adminapp;

    import android.content.Intent;
    import android.os.AsyncTask;
    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.Toolbar;
    import android.view.View;
    import android.view.Menu;
    import android.view.MenuItem;
    import android.view.ViewConfiguration;
    import android.widget.Button;
    import android.widget.EditText;
    import android.widget.TextView;

    import java.lang.reflect.Field;
    import java.sql.Connection;
    import java.sql.DriverManager;
    import java.sql.Statement;

    public class MainActivity extends AppCompatActivity {


        EditText editTextName,editTextEmail,editTextPassword;
        TextView textView;
        private static final String DB_URL = "jdbc:mysql://10.3.2.51/socialmedia_website";
        private static final String USER = "zzz";
        private static final String PASS = "zzz";



        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_register);
            Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
            setSupportActionBar(toolbar);

            textView = (TextView) findViewById(R.id.textView);
            editTextName = (EditText) findViewById(R.id.editTextName);
            editTextEmail = (EditText) findViewById(R.id.editTextEmail);
            editTextPassword = (EditText) findViewById(R.id.editTextPassword);
    ////        try {
    ////            ViewConfiguration config = ViewConfiguration.get(this);
    ////            Field menuKeyField = ViewConfiguration.class.getDeclaredField("sHasPermanentMenuKey");
    ////            if (menuKeyField != null) {
    ////                menuKeyField.setAccessible(true);
    ////                menuKeyField.setBoolean(config, false);
    ////            }
    //        } catch (Exception ignored) {
    //        }


            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();
                }
            });
        }

        public void btnConn(View view) {
            Send objSend = new Send();
            objSend.execute("");


        }







 private class Send extends AsyncTask<String, String, String>

    {
        String msg = "";
        String name = editTextName.getText().toString();
        String email = editTextEmail.getText().toString();
        String password = editTextPassword.getText().toString();

        @Override
        protected void onPreExecute() {
            textView.setText("Please Wait Inserting Data");
        }

        @Override
        protected String doInBackground(String... strings) {
            try {
                Class.forName("com.mysql.jdbc.Driver");
                Connection conn = DriverManager.getConnection(DB_URL, USER, PASS);
                if (conn == null) {
                    msg = "Connection goes wrong";
                } else {
                    String query = "Insert INTO users (name,email,password) VALUES('" + name+"','"+email+"','"+password+"')";
                    Statement stmt = conn.createStatement();
                    stmt.executeUpdate(query);
                    msg = "Inserting Successful!!";

                }

                conn.close();

        }

        catch(
        Exception e
        )

        {
            msg = "Connection goes Wrong";
            e.printStackTrace();

        }

        return msg;


    }



@Override
    protected void onPostExecute(String msg) {textView.setText(msg);}



    }


    @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.
        {
            switch (item.getItemId())
            {
                case R.id.action_settings : startActivity (new Intent(this, ShowUsers.class));
                    break;
            }
            return super.onOptionsItemSelected(item);
        }}

}

menu_main.xml：

 <menu 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"
        tools:context="ie.example.artur.adminapp.MainActivity">



        <item android:id="@+id/action_settings"
            android:title="@string/action_settings"
            android:orderInCategory="100"
            app:showAsAction="ifRoom|withText"/>

    </menu>

的AndroidManifest.xml

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

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

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/Theme.AppCompat.DayNight.NoActionBar">
        <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>
    </application>

</manifest>

我尝试过以下链接来修复我的问题，但没有帮助：

How to force use of overflow menu on devices with menu button

Menu Items are not showing on Action Bar

android - menu item not showing in action bar

Answer 1

在您的活动中添加此内容。

data: data1, data2, data3...

Answer 2

我不知道您发布的MainActivity.java代码是否完整，无论如何看到的是缺少膨胀

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    getMenuInflater().inflate(R.menu.menu_main, menu);
    return true;
}

其中menu_main.xml包含在res文件夹中正确创建的菜单文件夹中。

MenuItem没有显示

2 个答案: