Android 无法使用 attrs 值膨胀布局文件

Question

Android 无法使用 attrs 值膨胀布局文件

Sha*_*ady 3 java xml android android-layout android-night-mode

我正在开发一个可以在夜间模式和白天模式之间切换的应用程序我用这些值创建了一个 attrs 文件

<?xml version="1.0" encoding="utf-8"?>
<resources>

    <declare-styleable name="ds" >

        <attr name="backgroundcolor" format="color"/>
        <attr name="cardbackground" format="color"/>
        <attr name="textcolor" format="color"/>
        <attr name="tintcolor" format="color"/>
        <attr name="buttoncolor" format="color"/>

    </declare-styleable>

</resources>

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我做了相应的两种样式，分别是白天模式和夜间模式

<?xml version="1.0" encoding="utf-8"?>
<resources>

    <!-- Base application theme. -->
    <!-- Light Mode -->
    <style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">
        <!-- Customize your theme here. -->
        <item name="colorPrimary">#2196F3</item>
        <item name="colorPrimaryDark">#1976D2</item>
        <item name="colorAccent">@color/colorAccent</item>
        <item name="backgroundcolor">#fcfcfc</item>
        <item name="cardbackground">#ffffff</item>
        <item name="textcolor">#808080</item>
        <item name="tintcolor">#000000</item>
        <item name="buttoncolor">#2196F3</item>
    </style>

    <!-- Dark Mode -->
    <style name="darktheme" parent="Theme.AppCompat.Light.DarkActionBar">
        <!-- Customize your theme here. -->
        <item name="colorPrimary">#212121</item>
        <item name="colorPrimaryDark">#000000</item>
        <item name="colorAccent">@color/colorAccent</item>
        <item name="backgroundcolor">#303030</item>
        <item name="cardbackground">#424242</item>
        <item name="textcolor">#FFFFFF</item>
        <item name="tintcolor">#FFFFFF</item>
        <item name="buttoncolor">#2196F3</item>
    </style>

</resources>

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我将attrs值添加到布局中以代替背景和textColor属性，以便我可以在它们之间切换

这是布局文件

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:card_view="http://schemas.android.com/apk/res-auto"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:minHeight="500dp"
    android:layout_margin="5dp"
    android:layout_height="match_parent"
    android:background="?attr/backgroundcolor">

    <android.support.v7.widget.CardView
        android:id="@+id/card_view"
        android:layout_gravity="center"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_margin="5dp"
        card_view:cardCornerRadius="7dp"
        card_view:contentPadding="10dp"
        android:background="?attr/cardbackground">

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:orientation="vertical"
            android:background="?attr/backgroundcolor">
            <ImageView
                android:id="@+id/imageView"
                android:layout_width="match_parent"
                android:layout_height="200dp"
                android:src="@drawable/images"
                android:scaleType="centerCrop"/>

            <TextView
                android:id="@+id/header"
                android:layout_width="wrap_content"
                android:padding="2dp"
                android:text="Hello"
                android:textColor="?attr/textcolor"
                android:layout_height="wrap_content"
                android:layout_marginTop="10dp"
                android:textSize="18sp"
                android:textStyle="bold" />

            <TextView
                android:id="@+id/mNews"
                android:layout_width="wrap_content"
                android:padding="2dp"
                android:layout_height="wrap_content"
                android:text="Asam"
                android:layout_marginTop="10dp"
                android:textSize="16sp"
                android:textStyle="italic"
                android:textColor="?attr/textcolor"/>
        </LinearLayout>
    </android.support.v7.widget.CardView>
</LinearLayout>

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我正在实现一个 ViewPager，其中我正在膨胀该布局文件，以前没有实现 attrs，它工作得很好，但是当我现在在布局 xml 文件中使用attrs 值时，它使应用程序崩溃

这是Viewpager 适配器，我在其中填充布局文件

    public class HorizontalPagerAdapter extends PagerAdapter {
    String mResources[] = {"spider man description", "Iron man description", "batman description", "superman description"};
    String mHeader[] = {"Spider-Man", "Iron Man", "BatMan", "Super Man"};
    int mImages[] = {R.drawable.images, R.drawable.ironman, R.drawable.batman, R.drawable.super_man};

    Context mContext;
    LayoutInflater mLayoutInflater;

    public HorizontalPagerAdapter(Context context) {
        mContext = context;
        mLayoutInflater = (LayoutInflater) mContext.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    }

    @Override
    public int getCount() {
        return mResources.length;
    }

    @Override
    public boolean isViewFromObject(View view, Object object) {
        return view == ((LinearLayout) object);
    }

    @Override
    public Object instantiateItem(ViewGroup container, int position) {
        View itemView = mLayoutInflater.inflate(R.layout.content_main, container, false);

        TextView newsHeader = (TextView) itemView.findViewById(R.id.header);
        TextView newsContent = (TextView) itemView.findViewById(R.id.mNews) ;
        ImageView imageView = (ImageView) itemView.findViewById(R.id.imageView);

        newsHeader.setText(mHeader[position]);
        newsContent.setText(mResources[position]);
        imageView.setImageResource(mImages[position]);

        container.addView(itemView);

        return itemView;
    }

    @Override
    public void destroyItem(ViewGroup container, int position, Object object) {
        container.removeView((LinearLayout) object);
    }
}

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所以当运行应用程序时它给了我这个错误

E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.slimshady.newsreaderfinal, PID: 5440
    android.view.InflateException: Binary XML file line #2: Binary XML file line #2: Error inflating class <unknown>
    Caused by: android.view.InflateException: Binary XML file line #2: Error inflating class <unknown>
    Caused by: java.lang.reflect.InvocationTargetException
        at java.lang.reflect.Constructor.newInstance0(Native Method)
        at java.lang.reflect.Constructor.newInstance(Constructor.java:334)
        at android.view.LayoutInflater.createView(LayoutInflater.java:647)
        at com.android.internal.policy.PhoneLayoutInflater.onCreateView(PhoneLayoutInflater.java:58)
        at android.view.LayoutInflater.onCreateView(LayoutInflater.java:720)
        at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:788)
        at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:730)
        at android.view.LayoutInflater.inflate(LayoutInflater.java:492)
        at android.view.LayoutInflater.inflate(LayoutInflater.java:423)
        at com.example.slimshady.newsreaderfinal.HorizontalPagerAdapter.instantiateItem(HorizontalPagerAdapter.java:40)
        at android.support.v4.view.ViewPager.addNewItem(ViewPager.java:1010)
        at android.support.v4.view.ViewPager.populate(ViewPager.java:1158)
        at android.support.v4.view.ViewPager.populate(ViewPager.java:1092)
        at android.support.v4.view.ViewPager.onMeasure(ViewPager.java:1622)
        at android.view.View.measure(View.java:22071)
        at android.widget.RelativeLayout.measureChildHorizontal(RelativeLayout.java:715)
        at android.widget.RelativeLayout.onMeasure(RelativeLayout.java:461)
        at android.view.View.measure(View.java:22071)
        at android.support.v4.widget.DrawerLayout.onMeasure(DrawerLayout.java:1119)
        at android.view.View.measure(View.java:22071)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6602)
        at android.widget.FrameLayout.onMeasure(FrameLayout.java:185)
        at android.support.v7.widget.ContentFrameLayout.onMeasure(ContentFrameLayout.java:143)
        at android.view.View.measure(View.java:22071)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6602)
        at android.support.v7.widget.ActionBarOverlayLayout.onMeasure(ActionBarOverlayLayout.java:401)
        at android.view.View.measure(View.java:22071)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6602)
        at android.widget.FrameLayout.onMeasure(FrameLayout.java:185)
        at android.view.View.measure(View.java:22071)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6602)
        at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1514)
        at android.widget.LinearLayout.measureVertical(LinearLayout.java:806)
        at android.widget.LinearLayout.onMeasure(LinearLayout.java:685)
        at android.view.View.measure(View.java:22071)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6602)
        at android.widget.FrameLayout.onMeasure(FrameLayout.java:185)
        at com.android.internal.policy.DecorView.onMeasure(DecorView.java:724)
        at android.view.View.measure(View.java:22071)
        at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:2422)
        at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1504)
        at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1761)
        at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1392)
        at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:6752)
        at android.view.Choreographer$CallbackRecord.run(Choreographer.java:911)
        at android.view.Choreographer.doCallbacks(Choreographer.java:723)
        at android.view.Choreographer.doFrame(Choreographer.java:658)
        at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:897)
        at android.os.Handler.handleCallback(Handler.java:790)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        at android.os.Looper.loop(Looper.java:164)
        at android.app.ActivityThread.main(ActivityThread.java:6494)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:438)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:807)
     Caused by: java.lang.UnsupportedOperationException: Failed to resolve attribute at index 13: TypedValue{t=0x2/d=0x7f030036 a=-1}
        at android.content.res.TypedArray.getDrawableForDensity(TypedArray.java:944)
        at android.content.res.TypedArray.getDrawable(TypedArray.java:928)
        at android.view.View.<init>(View.java:4768)
        at android.view.ViewGroup.<init>(ViewGroup.java:597)
        at android.widget.LinearLayout.<init>(LinearLayout.java:234)
        at android.widget.LinearLayout.<init>(LinearLayout.java:230)
        at android.widget.LinearLayout.<init>(LinearLayout.java:226)
            ... 55 more
Application terminated.

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我在这里做错了什么？在网上找不到正确的解决方案，所以我正在创建这个线程。

Answer 1

Mik*_* M. 8

当膨胀Views 时，相关属性和值将从所使用的Theme中提取。在这种情况下，很明显，传递给的内容没有正确的信息，如消息所示。ContextLayoutInflaterContextHorizontalPagerAdapterThemeFailed to resolve attribute

当应用程序Context用于创建 UI 组件时，通常会发生这种情况。默认情况下，应用程序Context实际上并没有Theme附加 a，即使android:theme在清单<application>元素上指定了 a。Theme这只是为类设置默认值Activity。

通常，您只想使用 currentActivity作为Context任何View相关的内容，事实上，这就是这里的解决方案。将附加Activity适当的Theme内容，然后在扩展Adapter.

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