我在我的应用中使用了旋转木马。这是该轮播的github链接： https://github.com/ludovicroland/carousel-android
我得到了这个例外：
Fatal Exception: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.graphics.Matrix.mapPoints(float[])' on a null object reference
at fr.rolandl.carousel.CarouselSpinner.pointToPosition(CarouselSpinner.java:269)
at fr.rolandl.carousel.Carousel.onDown(Carousel.java:782)
at android.view.GestureDetector.onTouchEvent(GestureDetector.java:550)
at fr.rolandl.carousel.Carousel.onTouchEvent(Carousel.java:965)
at android.view.View.dispatchTouchEvent(View.java:8808)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2569)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2239)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2581)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2196)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2581)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2196)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2581)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2196)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2581)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2196)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2581)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2196)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2581)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2196)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2581)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2196)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2581)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2196)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2581)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2196)
at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchTouchEvent(PhoneWindow.java:2607)
at com.android.internal.policy.impl.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1779)
at android.app.Activity.dispatchTouchEvent(Activity.java:2846)
at android.support.v7.internal.view.WindowCallbackWrapper.dispatchTouchEvent(WindowCallbackWrapper.java:59)
at android.support.v7.internal.view.WindowCallbackWrapper.dispatchTouchEvent(WindowCallbackWrapper.java:59)
at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:2568)
at android.view.View.dispatchPointerEvent(View.java:9003)
at android.view.ViewRootImpl$ViewPostImeInputStage.processPointerEvent(ViewRootImpl.java:4209)
at android.view.ViewRootImpl$ViewPostImeInputStage.onProcess(ViewRootImpl.java:4072)
at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:3627)
at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:3680)
at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:3646)
at android.view.ViewRootImpl$AsyncInputStage.forward(ViewRootImpl.java:3763)
at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:3654)
at android.view.ViewRootImpl$AsyncInputStage.apply(ViewRootImpl.java:3820)
at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:3627)
at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:3680)
at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:3646)
at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:3654)
at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:3627)
at android.view.ViewRootImpl.deliverInputEvent(ViewRootImpl.java:5910)
at android.view.ViewRootImpl.doProcessInputEvents(ViewRootImpl.java:5884)
at android.view.ViewRootImpl.enqueueInputEvent(ViewRootImpl.java:5855)
at android.view.ViewRootImpl$WindowInputEventReceiver.onInputEvent(ViewRootImpl.java:6000)
at android.view.InputEventReceiver.dispatchInputEvent(InputEventReceiver.java:185)
at android.os.MessageQueue.nativePollOnce(MessageQueue.java)
at android.os.MessageQueue.next(MessageQueue.java:143)
at android.os.Looper.loop(Looper.java:122)
at android.app.ActivityThread.main(ActivityThread.java:5910)
at java.lang.reflect.Method.invoke(Method.java)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1405)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1200)
我的代码是：
final ArrayList<Book> books = new ArrayList<>();
Book book1 = new Book(R.drawable.adabiat_selector, getString(R.string.adabiat));
books.add(book1);
Book book2 = new Book(R.drawable.arabi_selector, getString(R.string.arabi));
books.add(book2);
Book book3 = new Book(R.drawable.english_selector, getString(R.string.english));
books.add(book3);
if (!getResources().getBoolean(R.bool.isTablet)) {
final Carousel carousel = (Carousel) findViewById(R.id.coverflow);
CarouselAdapter carouselAdapter = new BooksAdapter(this, books);
carousel.setAdapter(carouselAdapter);
carousel.setOnItemClickListener(new CarouselBaseAdapter.OnItemClickListener() {
@Override
public void onItemClick(CarouselBaseAdapter<?> carouselBaseAdapter, View view, int position, long l) {
Intent intent = new Intent(getApplicationContext(), TopicActivity.class);
intent.putExtra(getString(R.string.page_name), books.get(position).getName());
intent.putExtra(getString(R.string.book_number), 0);
intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(intent);
}
});
carouselAdapter.notifyDataSetChanged();
这是我的xml（它的一部分）：
<LinearLayout
android:id="@+id/layout"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="0.75">
<carousel.Carousel xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/coverflow"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginTop="0dp"
android:animationDuration="200"
android:clickable="true" />
</LinearLayout>
我不知道如何解决它。如果你有这个旋转木马并遇到这个问题，或者如果你有想法解决它，请帮忙。
感谢。