在 Android 中填充 class 按钮时出错

Question

我有一个最小 sdk 16 到 23 的应用程序。我想尽可能地使用 Material 设计。它还必须是全屏应用程序。包含 AppCompat 支持库。现在我可以使用一些按钮登录 activity:

<Button
    android:id="@+id/act_logon_btn_logon"
    style="@style/ButtonDefault"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:text="@string/act_logon_logon" />

样式如下(values/styles.xml):

<style name="Theme.AppCompat.Light.NoActionBar.FullScreen" parent="@style/Theme.AppCompat.Light">
    <item name="windowNoTitle">true</item>
    <item name="windowActionBar">false</item>
    <item name="android:windowFullscreen">true</item>
    <item name="android:windowContentOverlay">@null</item>
</style>

<style name="AppThemeBase" parent="Theme.AppCompat.Light.NoActionBar.FullScreen"></style>

<style name="AppTheme" parent="AppThemeBase"></style>

<style name="ButtonDefault" parent="Widget.AppCompat.Button">
    <item name="android:textSize">?attr/font_medium</item>
</style>

<style name="FontStyle"></style>

<style name="FontStyle.Small">
    <item name="font_small">12sp</item>
    <item name="font_medium">14sp</item>
    <item name="font_large">16sp</item>
</style>

<style name="FontStyle.Medium">
    <item name="font_small">16sp</item>
    <item name="font_medium">18sp</item>
    <item name="font_large">20sp</item>
</style>

<style name="FontStyle.Large">
    <item name="font_small">20sp</item>
    <item name="font_medium">22sp</item>
    <item name="font_large">24sp</item>
</style>

在values/attrs中：

<declare-styleable name="FontStyle">
    <attr name="font_small" format="dimension" />
    <attr name="font_medium" format="dimension" />
    <attr name="font_large" format="dimension" />
</declare-styleable>

属性 font_medium 的定义如 here 所述。我不明白的行为是，当登录 activity 打开时，一切正常，没有例外。但是当我从 Logon activity 打开另一个 activity 并且里面有片段并且片段有一个这种样式的按钮时，我得到一个异常说 "Error inflating class Button"。当我从 ButtonDefault 样式中删除 textSize 属性时，一切正常。为什么它在某处有效而在某处无效？自定义属性有问题吗？

我尝试用那种风格创建 values-v21/styles。xml 但没有效果。

能否请您解释一下以下父样式定义之间的差异？我迷路了。

parent="Widget.AppCompat.Button"
parent="@style/Widget.AppCompat.Button"
parent="android:Widget.Button"
parent="android:Widget.AppCompat.Button"
parent="android:Widget.Material.Button"
parent="android:style/Widget.Material.Button"

谢谢。

编辑 1 - 异常：

12-17 10:56:53.950: E/AndroidRuntime(7251): FATAL EXCEPTION: main
12-17 10:56:53.950: E/AndroidRuntime(7251): Process: test.android, PID: 7251
12-17 10:56:53.950: E/AndroidRuntime(7251): java.lang.RuntimeException: Unable to start activity ComponentInfo{test.dci.android/test.dci.android.view.activity.TransactionActivity}: android.view.InflateException: Binary XML file line #49: Error inflating class Button
12-17 10:56:53.950: E/AndroidRuntime(7251):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2702)
12-17 10:56:53.950: E/AndroidRuntime(7251):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2767)
12-17 10:56:53.950: E/AndroidRuntime(7251):     at android.app.ActivityThread.access0(ActivityThread.java:177)
12-17 10:56:53.950: E/AndroidRuntime(7251):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1449)
12-17 10:56:53.950: E/AndroidRuntime(7251):     at android.os.Handler.dispatchMessage(Handler.java:102)
12-17 10:56:53.950: E/AndroidRuntime(7251):     at android.os.Looper.loop(Looper.java:145)
12-17 10:56:53.950: E/AndroidRuntime(7251):     at android.app.ActivityThread.main(ActivityThread.java:5951)
12-17 10:56:53.950: E/AndroidRuntime(7251):     at java.lang.reflect.Method.invoke(Native Method)
12-17 10:56:53.950: E/AndroidRuntime(7251):     at java.lang.reflect.Method.invoke(Method.java:372)
12-17 10:56:53.950: E/AndroidRuntime(7251):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1400)
12-17 10:56:53.950: E/AndroidRuntime(7251):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1195)
12-17 10:56:53.950: E/AndroidRuntime(7251): Caused by: android.view.InflateException: Binary XML file line #49: Error inflating class Button
12-17 10:56:53.950: E/AndroidRuntime(7251):     at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:770)
12-17 10:56:53.950: E/AndroidRuntime(7251):     at android.view.LayoutInflater.rInflate(LayoutInflater.java:813)
12-17 10:56:53.950: E/AndroidRuntime(7251):     at android.view.LayoutInflater.rInflate(LayoutInflater.java:821)
12-17 10:56:53.950: E/AndroidRuntime(7251):     at android.view.LayoutInflater.inflate(LayoutInflater.java:511)
12-17 10:56:53.950: E/AndroidRuntime(7251):     at android.view.LayoutInflater.inflate(LayoutInflater.java:415)
12-17 10:56:53.950: E/AndroidRuntime(7251):     at test.dci.android.view.fragment.TransactionFragment.onCreateView(TransactionFragment.java:71)
12-17 10:56:53.950: E/AndroidRuntime(7251):     at android.support.v4.app.Fragment.performCreateView(Fragment.java:1962)
12-17 10:56:53.950: E/AndroidRuntime(7251):     at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1036)
12-17 10:56:53.950: E/AndroidRuntime(7251):     at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1226)
12-17 10:56:53.950: E/AndroidRuntime(7251):     at android.support.v4.app.FragmentManagerImpl.addFragment(FragmentManager.java:1328)
12-17 10:56:53.950: E/AndroidRuntime(7251):     at android.support.v4.app.FragmentManagerImpl.onCreateView(FragmentManager.java:2284)
12-17 10:56:53.950: E/AndroidRuntime(7251):     at android.support.v4.app.FragmentController.onCreateView(FragmentController.java:111)
12-17 10:56:53.950: E/AndroidRuntime(7251):     at android.support.v4.app.FragmentActivity.dispatchFragmentsOnCreateView(FragmentActivity.java:314)
12-17 10:56:53.950: E/AndroidRuntime(7251):     at android.support.v4.app.BaseFragmentActivityHoneycomb.onCreateView(BaseFragmentActivityHoneycomb.java:31)
12-17 10:56:53.950: E/AndroidRuntime(7251):     at android.support.v4.app.FragmentActivity.onCreateView(FragmentActivity.java:79)
12-17 10:56:53.950: E/AndroidRuntime(7251):     at test.dci.android.view.activity.TransactionActivity.onCreateView(TransactionActivity.java:1)
12-17 10:56:53.950: E/AndroidRuntime(7251):     at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:740)
12-17 10:56:53.950: E/AndroidRuntime(7251):     at android.view.LayoutInflater.rInflate(LayoutInflater.java:813)
12-17 10:56:53.950: E/AndroidRuntime(7251):     at android.view.LayoutInflater.inflate(LayoutInflater.java:511)
12-17 10:56:53.950: E/AndroidRuntime(7251):     at android.view.LayoutInflater.inflate(LayoutInflater.java:415)
12-17 10:56:53.950: E/AndroidRuntime(7251):     at android.view.LayoutInflater.inflate(LayoutInflater.java:366)
12-17 10:56:53.950: E/AndroidRuntime(7251):     at android.support.v7.app.AppCompatDelegateImplV7.setContentView(AppCompatDelegateImplV7.java:256)
12-17 10:56:53.950: E/AndroidRuntime(7251):     at android.support.v7.app.AppCompatActivity.setContentView(AppCompatActivity.java:109)
12-17 10:56:53.950: E/AndroidRuntime(7251):     at test.dci.android.view.activity.TransactionActivity.onCreate(TransactionActivity.java:31)
12-17 10:56:53.950: E/AndroidRuntime(7251):     at android.app.Activity.performCreate(Activity.java:6289)
12-17 10:56:53.950: E/AndroidRuntime(7251):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1119)
12-17 10:56:53.950: E/AndroidRuntime(7251):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2655)
12-17 10:56:53.950: E/AndroidRuntime(7251):     ... 10 more
12-17 10:56:53.950: E/AndroidRuntime(7251): Caused by: java.lang.RuntimeException: Failed to resolve attribute at index 12
12-17 10:56:53.950: E/AndroidRuntime(7251):     at android.content.res.TypedArray.getDimensionPixelSize(TypedArray.java:582)
12-17 10:56:53.950: E/AndroidRuntime(7251):     at android.widget.TextView.<init>(TextView.java:1400)
12-17 10:56:53.950: E/AndroidRuntime(7251):     at android.widget.Button.<init>(Button.java:115)
12-17 10:56:53.950: E/AndroidRuntime(7251):     at android.widget.Button.<init>(Button.java:108)
12-17 10:56:53.950: E/AndroidRuntime(7251):     at android.support.v7.widget.AppCompatButton.<init>(AppCompatButton.java:62)
12-17 10:56:53.950: E/AndroidRuntime(7251):     at android.support.v7.widget.AppCompatButton.<init>(AppCompatButton.java:58)
12-17 10:56:53.950: E/AndroidRuntime(7251):     at android.support.v7.app.AppCompatViewInflater.createView(AppCompatViewInflater.java:98)
12-17 10:56:53.950: E/AndroidRuntime(7251):     at android.support.v7.app.AppCompatDelegateImplV7.createView(AppCompatDelegateImplV7.java:938)
12-17 10:56:53.950: E/AndroidRuntime(7251):     at android.support.v7.app.AppCompatDelegateImplV7.onCreateView(AppCompatDelegateImplV7.java:992)
12-17 10:56:53.950: E/AndroidRuntime(7251):     at

Answer 1

正如我们在评论部分讨论的那样，问题是充气器不知何故无法识别 ?attr/font_medium，从而引发异常。

您可以使用 dimens.xml 文件指定自定义尺寸，如下所示：

<resources> 
    <dimen name="small">14sp</dimen>
    <dimen name="medium">16sp</dimen>
    <dimen name="large">18sp</dimen>
</resources>

然后在您的 styles.xml 中您这样引用这些值：

<style name="ButtonDefault" parent="Widget.AppCompat.Button">
    <item name="android:textSize">@dimen/medium</item>
</style>

与所有其他资源一样，dimens.xml 可以放置在相应的资源文件夹中以适应特定的设备配置（屏幕尺寸、密度、语言等）。

Answer 2

已解决。问题是充气机的属性未知（或未指定）。解决方案是在膨胀使用属性的视图之前定义属性值。

解决方案1：不仅在activity中必须指定具有该属性的样式，而且在具有该属性的某些视图的片段中也必须指定。因此，将此行添加到片段的 onCreateView() 之前使片段的根视图膨胀的行：

getContext().getTheme().applyStyle(fontStyleResId, true);

解决方案 2：直接在应用程序主题中设置属性值：

<style name="AppThemeBase" parent="Theme.AppCompat.Light.NoActionBar.FullScreen">
    <item name="font_small">@dimen/font_size_medium_small</item>
    <item name="font_medium">@dimen/font_size_medium_medium</item>
    <item name="font_large">@dimen/font_size_medium_large</item>
</style>

Answer 3

我通过为 api 小于 21，

创建自己的 appcompat 样式来修复它

styles.xml

  <style name="ColoredButtonAppcompat">
    <item name="android:textAppearance">@style/ButtonTextStyle</item>
    <item name="android:background">@drawable/colored_button_background</item>
    <item name="android:minHeight">48dip</item>
    <item name="android:minWidth">88dip</item>
    <item name="android:focusable">true</item>
    <item name="android:clickable">true</item>
    <item name="android:gravity">center_vertical|center_horizontal</item>
</style>

<style name="ButtonTextStyle" >
    <item name="android:textSize">14dp</item>
    <item name="android:textColor">@android:color/white</item>
</style>

样式-v21.xml

<style name="ColoredButtonAppcompat" parent="Widget.AppCompat.Button.Colored"/>

Answer 4

将您的图像文件从 "drawable-v24" 文件夹也复制到 "drawable" 文件夹。问题解决了。信用：https://github.com/chrisjenx/Calligraphy/issues/417

Answer 5

我在使用 Kotlin 开发时遇到过类似的情况：为了解决这个问题，将应用程序drawable-24中的内容复制到drawable。这样做是为了支持旧的 Android 设备。

在 Android 中填充 class 按钮时出错

Error inflating class Button in Android

android

android-styles

android-inflate

inflate-exception

android-attributes