图标未在Android应用程序中显示

Question

I am complete newbie when it comes to Android applications. Please bear with me. I am trying to make an menu options bar but somehow the icons are not displaying.

I had looked for answers to this question on stackoverflow and the answer that I came across was "On Android 3.0+, the preferred approach for the options menu (a spillover menu in the action bar) will not show icons. If you have android targetSdkVersion of 11 or higher, icons will never show up in menus on Android 3.0+. The icons will show up if you promote an options menu item to be a toolbar button, and the icons will show up on Android 1.x/2.x devices." I am sorry but I am not sure what that means. Can someone please direct me in the right direction? Any help will be appreciated!

I am not sure what I am doing incorrectly. Here is my code so far.

MainActivity.java

package com.example.useoptionsmenu;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;

public class MainActivity extends Activity {

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

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.main, menu);
    return true;
}

public boolean onOptionsItemSelected(MenuItem item) {
    switch (item.getItemId()) {
    case R.id.about:
    startActivity(new Intent(this, About.class));
    return true;
    case R.id.help:
    startActivity(new Intent(this, Help.class));
    return true;
    default:
    return super.onOptionsItemSelected(item);
    }
}

}

main.xml

<menu xmlns:android="http://schemas.android.com/apk/res/android" >

<item
    android:id="@+id/action_settings"
    android:orderInCategory="100"
    android:showAsAction="never"
    android:title="@string/action_settings"/>
<item
    android:id="@+id/about"
    android:showAsAction="always"
    android:orderInCategory="1"
    android:icon="@drawable/ic_action_about"
    android:title="About"/>
<item
    android:id="@+id/help"
    android:showAsAction="always"
     android:orderInCategory="2"
    android:icon="@drawable/ic_action_help"
    android:title="Help"/>

</menu>

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.useoptionsmenu"
android:versionCode="1"
android:versionName="1.0" >

<uses-sdk
    android:minSdkVersion="8"
    android:targetSdkVersion="18" />

<application
    android:allowBackup="true"
    android:icon="@drawable/ic_launcher"
    android:label="@string/app_name"
    android:theme="@style/AppTheme" >
    <activity
        android:name="com.example.useoptionsmenu.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="com.example.useoptionsmenu.About"
        android:label="@string/title_activity_about" >
    </activity>
    <activity
        android:name="com.example.useoptionsmenu.Help"
        android:label="@string/title_activity_help" >
    </activity>
</application>

</manifest>

Answer 1

You have to add this to the item you want to display in the header:

    android:showAsAction="ifRoom"

so that your menu will be:

<menu xmlns:android="http://schemas.android.com/apk/res/android" >

<item
    android:id="@+id/action_settings"
    android:orderInCategory="100"
    android:showAsAction="ifRoom"
    android:title="@string/action_settings"/>
<item
    android:id="@+id/about"
    android:showAsAction="ifRoom"
    android:orderInCategory="1"
    android:icon="@drawable/ic_action_about"
    android:title="About"/>
<item
    android:id="@+id/help"
    android:showAsAction="ifRoom"
     android:orderInCategory="2"
    android:icon="@drawable/ic_action_help"
    android:title="Help"/>

</menu>

remove the line android:showAsAction="ifRoom" from the item you won't display in your header.