禁用无边框按钮时如何显示不同的布局？

Question

我正在将无边框按钮的概念应用到我正在开发的应用程序中。我可以编辑我的按钮完美到目前为止与以下问题的帮助：

如何创建标准的无边框按钮（如设计指南中提到的）？

Android绘图分隔符/分隔符线布局？

但是现在我需要显示一个不同的背景图像，或者当按钮由于用户没有填写某些必填字段而未启用时需要强调的内容。

到目前为止，我的代码是：

<RelativeLayout
    android:id="@+id/layoutId"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentBottom="true" >

    <View
        android:layout_width="match_parent"
        android:layout_height="1dip"
        android:layout_marginLeft="4dip"
        android:layout_marginRight="4dip"
        android:background="@android:color/darker_gray"/>

    <Button
        android:id="@+id/buttonId"
        android:layout_width="match_parent"
        android:layout_height="70dp"
        android:background="?android:attr/selectableItemBackground"
        android:onClick="onButtonClicked"
        android:text="@string/someText"
        android:textColor="@color/someColor"
        android:textSize="25sp"
        android:textStyle="bold" />

</RelativeLayout>

现在，我打算在按钮的背景中放置一个带条纹的图像，以显示它何时被禁用。通过阅读下面的问题，我可以定制我的按钮，当它不是无边界的。

不同颜色的标准Android按钮

我试图用这个想法来定制我的无边框按钮，就像下面的代码一样：

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

    <item android:state_enabled="true" 
        android:drawable="?android:attr/selectableItemBackground" >
    </item>

    <item android:state_enabled="false"
        android:drawable="@drawable/stripes"
        android:tileMode="repeat" >
    </item>
</selector>

但似乎不可能，一旦<代码>？android： attr/selectableItembackground中的borderless_button_bg.xml使程序崩溃。

05-28 17:44:54.139: W/dalvikvm(31664): threadid=1: thread exiting with uncaught exception (group=0x40bc61f8)
05-28 17:44:54.154: E/AndroidRuntime(31664): FATAL EXCEPTION: main
05-28 17:44:54.154: E/AndroidRuntime(31664): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.Company.productname/com.Company.productname.myActivity}: android.view.InflateException: Binary XML file line #310: Error inflating class <unknown>
05-28 17:44:54.154: E/AndroidRuntime(31664):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1970)
05-28 17:44:54.154: E/AndroidRuntime(31664):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1995)
05-28 17:44:54.154: E/AndroidRuntime(31664):    at android.app.ActivityThread.access$600(ActivityThread.java:128)
05-28 17:44:54.154: E/AndroidRuntime(31664):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1161)
05-28 17:44:54.154: E/AndroidRuntime(31664):    at android.os.Handler.dispatchMessage(Handler.java:99)
05-28 17:44:54.154: E/AndroidRuntime(31664):    at android.os.Looper.loop(Looper.java:137)
05-28 17:44:54.154: E/AndroidRuntime(31664):    at android.app.ActivityThread.main(ActivityThread.java:4514)
05-28 17:44:54.154: E/AndroidRuntime(31664):    at java.lang.reflect.Method.invokeNative(Native Method)
05-28 17:44:54.154: E/AndroidRuntime(31664):    at java.lang.reflect.Method.invoke(Method.java:511)
05-28 17:44:54.154: E/AndroidRuntime(31664):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:790)
05-28 17:44:54.154: E/AndroidRuntime(31664):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:557)
05-28 17:44:54.154: E/AndroidRuntime(31664):    at dalvik.system.NativeStart.main(Native Method)
05-28 17:44:54.154: E/AndroidRuntime(31664): Caused by: android.view.InflateException: Binary XML file line #310: Error inflating class <unknown>
05-28 17:44:54.154: E/AndroidRuntime(31664):    at android.view.LayoutInflater.createView(LayoutInflater.java:606)
05-28 17:44:54.154: E/AndroidRuntime(31664):    at com.android.internal.policy.impl.PhoneLayoutInflater.onCreateView(PhoneLayoutInflater.java:56)
05-28 17:44:54.154: E/AndroidRuntime(31664):    at android.view.LayoutInflater.onCreateView(LayoutInflater.java:653)
05-28 17:44:54.154: E/AndroidRuntime(31664):    at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:678)
05-28 17:44:54.154: E/AndroidRuntime(31664):    at android.view.LayoutInflater.rInflate(LayoutInflater.java:739)
05-28 17:44:54.154: E/AndroidRuntime(31664):    at android.view.LayoutInflater.rInflate(LayoutInflater.java:742)
05-28 17:44:54.154: E/AndroidRuntime(31664):    at android.view.LayoutInflater.inflate(LayoutInflater.java:489)
05-28 17:44:54.154: E/AndroidRuntime(31664):    at android.view.LayoutInflater.inflate(LayoutInflater.java:396)
05-28 17:44:54.154: E/AndroidRuntime(31664):    at android.view.LayoutInflater.inflate(LayoutInflater.java:352)
05-28 17:44:54.154: E/AndroidRuntime(31664):    at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:273)
05-28 17:44:54.154: E/AndroidRuntime(31664):    at android.app.Activity.setContentView(Activity.java:1835)
05-28 17:44:54.154: E/AndroidRuntime(31664):    at com.Company.productname.myActivity.onCreate(TelaCaminhao.java:41)
05-28 17:44:54.154: E/AndroidRuntime(31664):    at android.app.Activity.performCreate(Activity.java:4465)
05-28 17:44:54.154: E/AndroidRuntime(31664):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1053)
05-28 17:44:54.154: E/AndroidRuntime(31664):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1934)
05-28 17:44:54.154: E/AndroidRuntime(31664):    ... 11 more
05-28 17:44:54.154: E/AndroidRuntime(31664): Caused by: java.lang.reflect.InvocationTargetException
05-28 17:44:54.154: E/AndroidRuntime(31664):    at java.lang.reflect.Constructor.constructNative(Native Method)
05-28 17:44:54.154: E/AndroidRuntime(31664):    at java.lang.reflect.Constructor.newInstance(Constructor.java:417)
05-28 17:44:54.154: E/AndroidRuntime(31664):    at android.view.LayoutInflater.createView(LayoutInflater.java:586)
05-28 17:44:54.154: E/AndroidRuntime(31664):    ... 25 more
05-28 17:44:54.154: E/AndroidRuntime(31664): Caused by: android.content.res.Resources$NotFoundException: File res/drawable-ldpi/borderless_button_bg.xml from drawable resource ID #0x7f020000
05-28 17:44:54.154: E/AndroidRuntime(31664):    at android.content.res.Resources.loadDrawable(Resources.java:1958)
05-28 17:44:54.154: E/AndroidRuntime(31664):    at android.content.res.TypedArray.getDrawable(TypedArray.java:601)
05-28 17:44:54.154: E/AndroidRuntime(31664):    at android.view.View.<init>(View.java:2832)
05-28 17:44:54.154: E/AndroidRuntime(31664):    at android.widget.TextView.<init>(TextView.java:558)
05-28 17:44:54.154: E/AndroidRuntime(31664):    at android.widget.Button.<init>(Button.java:108)
05-28 17:44:54.154: E/AndroidRuntime(31664):    at android.widget.Button.<init>(Button.java:104)
05-28 17:44:54.154: E/AndroidRuntime(31664):    ... 28 more
05-28 17:44:54.154: E/AndroidRuntime(31664): Caused by: org.xmlpull.v1.XmlPullParserException: Binary XML file line #7: <item> tag requires a 'drawable' attribute or child tag defining a drawable
05-28 17:44:54.154: E/AndroidRuntime(31664):    at android.graphics.drawable.StateListDrawable.inflate(StateListDrawable.java:178)
05-28 17:44:54.154: E/AndroidRuntime(31664):    at android.graphics.drawable.Drawable.createFromXmlInner(Drawable.java:867)
05-28 17:44:54.154: E/AndroidRuntime(31664):    at android.graphics.drawable.Drawable.createFromXml(Drawable.java:804)
05-28 17:44:54.154: E/AndroidRuntime(31664):    at android.content.res.Resources.loadDrawable(Resources.java:1955)
05-28 17:44:54.154: E/AndroidRuntime(31664):    ... 33 more

所以，我的问题是：我需要使用无边框按钮，我需要明确按钮何时被禁用。我有什么选择？

Answer 1

这就是我解决问题的方法：

public class MyScreen extends Activity {
    private Button btnNext;
    private Drawable background;

    btnNext = (Button) this.findViewById(R.id.btnNext);
    background = btnNext.getBackground(); //stores the original Drawable characteristic

    ...

    //disable button
    if (!canGoNext) {
        btnNext.setEnabled(false);
        btnNext.setBackgroundResource(R.drawable.gray); //make it gray
    }
    //enable button
    else {
        btnNext.setEnabled(true);
        btnNext.setBackgroundDrawable(background); //make it selectableItemBackground again
    }
}