我遇到有关的奇怪行为android.support.design.widget.FloatingActionButton。我在Google上搜索了一下，但没有发现此组件的此类错误。
仅当我在StrictMode启用android的情况下进行构建时才会发生这种情况。我得到以下异常：
CoordinatorLayout﹕ Default behavior class android.support.design.widget.FloatingActionButton$a could not be instantiated. Did you forget a default constructor?
java.lang.InstantiationException: can't instantiate class android.support.design.widget.FloatingActionButton$a; no empty constructor
at java.lang.Class.newInstanceImpl(Native Method)
at java.lang.Class.newInstance(Class.java:1130)
at android.support.design.widget.CoordinatorLayout.a(CoordinatorLayout.java:503)
at android.support.design.widget.CoordinatorLayout.onMeasure(CoordinatorLayout.java:579)
at android.view.View.measure(View.java:16831)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5245)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
at android.view.View.measure(View.java:16831)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5245)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1410)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:695)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:588)
at android.view.View.measure(View.java:16831)
at android.support.v4.widget.DrawerLayout.onMeasure(DrawerLayout.java:868)
at android.view.View.measure(View.java:16831)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5245)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
at android.view.View.measure(View.java:16831)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5245)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1410)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:695)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:588)
at android.view.View.measure(View.java:16831)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5245)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
at android.support.v7.internal.widget.ContentFrameLayout.onMeasure(ContentFrameLayout.java:124)
at android.view.View.measure(View.java:16831)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5245)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1410)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:695)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:588)
at android.view.View.measure(View.java:16831)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5245)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
at android.view.View.measure(View.java:16831)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5245)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1410)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:695)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:588)
at android.view.View.measure(View.java:16831)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5245)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2586)
at android.view.View.measure(View.java:16831)
at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:2189)
at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1352)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1535)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1249)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:6364)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:791)
at android.view.Choreographer.doCallbacks(Choreographer.java:591)
at android.view.Choreographer.doFrame(Choreographer.java:561)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:777)
at android.os.Handler.handleCallback(Handler.java:730)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:176)
at android.app.ActivityThread.main(ActivityThread.java:5419)
at java.lang.reflect.Method.invokeN
但是，这不会使我的应用程序崩溃或引发任何可见错误。每次创建具有FAB的活动时都将引发该异常，但是FAB会呈现并正常运行。如果我单击它，它会执行onClickListener它应该执行的操作。
这是我的Android支持库依赖项，在我的目录中build.gradle：
compile 'com.android.support:appcompat-v7:22.2.0'
compile 'com.android.support:design:22.2.0'
这就是我在xml布局中使用FAB的方式：
<android.support.design.widget.CoordinatorLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<fragment
android:id="@+id/home_toolbar_wallet"
android:name="my.fragment.class"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
(...)
</LinearLayout>
<android.support.design.widget.FloatingActionButton
android:id="@+id/home_floating_button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@drawable/ic_add_white_18dp"
android:layout_margin="@dimen/action_button_margin"
app:borderWidth="0dp"
app:layout_anchor="@id/home_toolbar_wallet"
app:layout_anchorGravity="bottom|right|end"/>
如果您想知道，这就是我启用的方式StrictMode：
StrictMode.ThreadPolicy.Builder builder = new StrictMode.ThreadPolicy.Builder builder = new StrictMode.ThreadPolicy.Builder()
.detectAll()
.penaltyLog();
if (Utils.hasHoneycomb()) {
builder.penaltyFlashScreen();
}
StrictMode.setThreadPolicy(builder.build());
StrictMode.setVmPolicy(new StrictMode.VmPolicy.Builder().detectAll()
.penaltyLog()
.build());
有人遇到过这个吗？
这可能是由于proguard混淆了您的代码。您是否尝试过将此规则添加到Proguard规则中？
-keepclassmembers class android.support.design.widget.FloatingActionButton$Behavior { public <init>(); }
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我来说两句