自定义 Android 操作栏

Question

我正在尝试自定义我的应用程序的操作栏，但我无法正确执行，我也不知道为什么。

我这样定义我的 themes.xml：

    <?xml version="1.0" encoding="utf-8"?>
<resources>
    <style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">
        <item name="android:actionBarStyle">@style/ActionBar.Solid.Example</item>
    </style>

    <style name = "ActionBar.Solid.Example" parent="@android:style/Widget.Holo.Light.ActionBar.Solid.Inverse">
        <item name="android:background">@drawable/ab_solid_example</item>
    </style>
</resources>

我们称之为样式的AndroidManifest.xml是：

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

    <application
        android:allowBackup="true"
        android:icon="@drawable/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>
    </application>

</manifest>

按理说，我们必须看到紫色的操作栏背景，但我们看到的是她的黑色背景的操作栏

发生了什么事？我做错了什么？

如果我从 AndroidManifest.xml 中删除 android:theme="@style/AppTheme" 并添加 getActionBar().setBackgroundDrawable(new ColorDrawable(getResources().getColor(R.color.background_alert))); 在 onCreate() 方法上我遇到了下一个错误：

02-10 12:50:56.458    2512-2512/coursera.momaproject E/AndroidRuntime﹕ FATAL EXCEPTION: main
    java.lang.RuntimeException: Unable to start activity ComponentInfo{coursera.momaproject/coursera.momaproject.MainActivity}: java.lang.IllegalStateException: You need to use a Theme.AppCompat theme (or descendant) with this activity.
            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2211)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261)
            at android.app.ActivityThread.access0(ActivityThread.java:141)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)
            at android.os.Handler.dispatchMessage(Handler.java:99)
            at android.os.Looper.loop(Looper.java:137)
            at android.app.ActivityThread.main(ActivityThread.java:5103)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:525)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
            at dalvik.system.NativeStart.main(Native Method)
     Caused by: java.lang.IllegalStateException: You need to use a Theme.AppCompat theme (or descendant) with this activity.
            at android.support.v7.app.ActionBarActivityDelegate.onCreate(ActionBarActivityDelegate.java:151)
            at android.support.v7.app.ActionBarActivityDelegateBase.onCreate(ActionBarActivityDelegateBase.java:138)
            at android.support.v7.app.ActionBarActivity.onCreate(ActionBarActivity.java:123)
            at coursera.momaproject.MainActivity.onCreate(MainActivity.java:41)
            at android.app.Activity.performCreate(Activity.java:5133)
            at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2175)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261)
            at android.app.ActivityThread.access0(ActivityThread.java:141)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)
            at android.os.Handler.dispatchMessage(Handler.java:99)
            at android.os.Looper.loop(Looper.java:137)
            at android.app.ActivityThread.main(ActivityThread.java:5103)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:525)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
            at dalvik.system.NativeStart.main(Native Method)

如果我恢复我的 AndroidManifest.xml 并删除 actionBar 自定义，我的应用程序会在我运行时给我一个错误。

AndroidManifest.xml

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

    <uses-sdk
        android:minSdkVersion="13"
        android:targetSdkVersion="18" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/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>
    </application>

</manifest>

Themes.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">

    </style>
</resources>

我遇到了这个错误：

02-10 13:42:33.955    2574-2574/coursera.momaproject E/AndroidRuntime﹕ FATAL EXCEPTION: main
    java.lang.RuntimeException: Unable to start activity ComponentInfo{coursera.momaproject/coursera.momaproject.MainActivity}: java.lang.NullPointerException
            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2211)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261)
            at android.app.ActivityThread.access0(ActivityThread.java:141)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)
            at android.os.Handler.dispatchMessage(Handler.java:99)
            at android.os.Looper.loop(Looper.java:137)
            at android.app.ActivityThread.main(ActivityThread.java:5103)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:525)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
            at dalvik.system.NativeStart.main(Native Method)
     Caused by: java.lang.NullPointerException
            at coursera.momaproject.MainActivity.onCreate(MainActivity.java:44)
            at android.app.Activity.performCreate(Activity.java:5133)
            at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2175)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261)
            at android.app.ActivityThread.access0(ActivityThread.java:141)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)
            at android.os.Handler.dispatchMessage(Handler.java:99)
            at android.os.Looper.loop(Looper.java:137)
            at android.app.ActivityThread.main(ActivityThread.java:5103)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:525)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
            at dalvik.system.NativeStart.main(Native Method)

onCreate() 方法，其中 ** 行产生错误 ...

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

        **getActionBar().setBackgroundDrawable(new ColorDrawable(getResources().getColor(R.color.background_alert)));**

        //We add the footer view
        LinearLayout container = (LinearLayout)findViewById(R.id.container);
        View seekBarView = getLayoutInflater().inflate(R.layout.footer_view, null);
        container.addView(seekBarView);

        topLeft = (TextView)findViewById(R.id.topLeft);
        bottomLeft = (TextView)findViewById(R.id.bottomLeft);
        topRight = (TextView)findViewById(R.id.topRight);
        bottomRight = (TextView)findViewById(R.id.bottomRight);

        SeekBar seekBar = (SeekBar)findViewById(R.id.slider);
        seekBar.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
            @Override
            public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {

                Integer newColor = progressColor(progress, ORIGIN_TOP_LEFT_COLOR, TARGET_TOP_LEFT_COLOR);
                topLeft.setBackgroundColor(newColor.intValue());

                newColor = progressColor(progress, ORIGIN_BOTTOM_LEFT_COLOR, TARGET_BOTTOM_LEFT_COLOR);
                bottomLeft.setBackgroundColor(newColor.intValue());

                newColor = progressColor(progress, ORIGIN_TOP_RIGHT_COLOR, TARGET_TOP_RIGHT_COLOR);
                topRight.setBackgroundColor(newColor.intValue());

                newColor = progressColor(progress, ORIGIN_BOTTOM_RIGHT_COLOR, TARGET_BOTTOM_RIGHT_COLOR);
                bottomRight.setBackgroundColor(newColor.intValue());
            }

            @Override
            public void onStartTrackingTouch(SeekBar seekBar) {
                //We don't do anything

            }

            @Override
            public void onStopTrackingTouch(SeekBar seekBar) {
                //We don't do anything
            }
        });

    }

我的文件结构是...

Answer 1

编辑：查看评论

如果您使用 Android Studio 的默认项目模板，material 主题也有 values-v21/styles.xml。您还需要更改它才能在 Lollipop 设备/模拟器上显示。

如果您正在查看 Android Studio 的设计选项卡，您可能希望将 "Android version to use when rendering layouts" 设置为低于 API 21 的版本。

Answer 2

如果你的 minSdkVersion 是 11 或更高 那么写

getActionBar().setBackgroundDrawable(new ColorDrawable("COLOR"));

在您的 .class 文件的 onCreate() 方法中。

现在你的 class 应该看起来像，

Class MyActivity extends Activity{

    @Override
    public void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);
        setContentView(R.layout.layout_activity);

        getActionBar().setBackgroundDrawable(new ColorDrawable("YourColor"));
    }
}

Answer 3

(代表OP发表).

最后，感谢@Maurice Lam，我找到了解决问题的正确方法。

解决方法是：

将 MainActivity 的继承从 ActionBarActivity 更改为 Activity

将AppTheme的样式由Theme.AppCompat.Light.DarkActionBar更改为@android:style/Theme.Holo.Light.DarkActionBar:

themes.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <style name="AppThem" parent="@android:style/Theme.Holo.Light.DarkActionBar"></style>
</resources>

在onCreate()方法中，现在你可以这样定义ActionBar的颜色：

getActionBar().setBackgroundDrawable(new ColorDrawable(getResources().getColor(R.color.background_alert)));

自定义 Android 操作栏

Customizing the Android action bar

android

android-actionbar

android-custom-view