我的代码有什么问题？我想在 Android 中制作 'card-flip' 动画

Question

这是我的主要Activity:

public class Main extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        if (savedInstanceState == null) {
            getFragmentManager()
                    .beginTransaction()
                    .add(R.id.container, new CardFrontFragment())
                    .commit();
        }

    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();
        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }


    /**
     * A fragment representing the front of the card.
     */
    public class CardFrontFragment extends Fragment {
        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container,
                                 Bundle savedInstanceState) {
            return inflater.inflate(R.layout.layout_front_card, container, false);
        }
    }

    /**
     * A fragment representing the back of the card.
     */
    public class CardBackFragment extends Fragment {
        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container,
                                 Bundle savedInstanceState) {
            return inflater.inflate(R.layout.layout_back_card, container, false);
        }
    }

    private void flipCard() {
        if (mShowingBack) {
            getFragmentManager().popBackStack();
            return;
        }

        // Flip to the back.

        mShowingBack = true;

        // Create and commit a new fragment transaction that adds the fragment for the back of
        // the card, uses custom animations, and is part of the fragment manager's back stack.

        getFragmentManager()
                .beginTransaction()

                        // Replace the default fragment animations with animator resources representing
                        // rotations when switching to the back of the card, as well as animator
                        // resources representing rotations when flipping back to the front (e.g. when
                        // the system Back button is pressed).
                .setCustomAnimations(
                        R.animator.card_flip_right_in, R.animator.card_flip_right_out,
                        R.animator.card_flip_left_in, R.animator.card_flip_left_out)

                        // Replace any fragments currently in the container view with a fragment
                        // representing the next page (indicated by the just-incremented currentPage
                        // variable).
                .replace(R.id.container, new CardBackFragment())

                        // Add this transaction to the back stack, allowing users to press Back
                        // to get to the front of the card.
                .addToBackStack(null)

                        // Commit the transaction.
                .commit();
    }

}

这是我的 主 Activity XML 文件:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">

<TextView
    android:text="@string/hello_world"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content" />

<FrameLayout
    android:id="@+id/container"
    android:layout_width="match_parent"
    android:layout_height="match_parent" />

</LinearLayout>

这是我的 layout_front_card.xml:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:background="#a6c"
    android:padding="16dp"
    android:gravity="bottom">

    <TextView android:id="@android:id/text1"
        style="?android:textAppearanceLarge"
        android:textStyle="bold"
        android:textColor="#fff"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="HI" />

    <TextView style="?android:textAppearanceSmall"
        android:textAllCaps="true"
        android:textColor="#80ffffff"
        android:textStyle="bold"
        android:lineSpacingMultiplier="1.2"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="How are u?" />

</LinearLayout>

这是我的 layout_back_card.xml:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:background="#a6c"
    android:padding="16dp"
    android:gravity="bottom">

    <TextView android:id="@android:id/text1"
        style="?android:textAppearanceLarge"
        android:textStyle="bold"
        android:textColor="#fff"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="HI" />

    <TextView style="?android:textAppearanceSmall"
        android:textAllCaps="true"
        android:textColor="#80ffffff"
        android:textStyle="bold"
        android:lineSpacingMultiplier="1.2"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="How are u?" />

</LinearLayout>

我无法运行我的项目！

错误:

Error:(24, 21) error: no suitable method found for add(int,Main.CardFrontFragment)
method FragmentTransaction.add(int,Fragment,String) is not applicable
(actual and formal argument lists differ in length)
method FragmentTransaction.add(int,Fragment) is not applicable
(actual argument Main.CardFrontFragment cannot be converted to Fragment by method invocation conversion)
method FragmentTransaction.add(Fragment,String) is not applicable
(actual argument int cannot be converted to Fragment by method invocation conversion)

Error:(73, 13) error: cannot find symbol variable mShowingBack

Error:(80, 9) error: cannot find symbol variable mShowingBack

Error:(99, 17) error: no suitable method found for replace(int,Main.CardBackFragment)
method FragmentTransaction.replace(int,Fragment,String) is not applicable
(actual and formal argument lists differ in length)
method FragmentTransaction.replace(int,Fragment) is not applicable
(actual argument Main.CardBackFragment cannot be converted to Fragment by method invocation conversion)

Error:Execution failed for task ':app:compileDebugJava'.
> Compilation failed; see the compiler error output for details.

因为我是一个初学者，我很难找出这里的错误。

请帮帮我！

如有任何帮助，我们将不胜感激。

提前致谢。

Answer 1

尝试将嵌套的类声明为 static:

public static class CardFrontFragment extends Fragment {...}
public static class CardBackFragment extends Fragment {...}

Answer 2

如果您使用的是支持片段android.support.v4.app.Fragment;，那么您必须使用getSupportFragmentManager()

我的代码有什么问题？我想在 Android 中制作 'card-flip' 动画

What is wrong with my code? I want to make a 'card-flip' animation in Android

java

xml

android

runtime-error

android-animation