Displaying card flip animation on old android

问题:

We all know this article of how to create "card filp" animations using new api. But how can I make this on apis < 3.0?

Update:

As long as there is good and easy-to-use libraries like android-FlipView I don't think you really need to go through such hard ways ...

回答1:

Found the answer. If you want to do flip animation on ALL ANDROID VERSIONS, use this:

Activity layout file:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/main_activity_root"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="@android:color/transparent" >

<RelativeLayout
android:id="@+id/main_activity_card_face"
android:layout_width="300dp"
android:layout_height="407dp"
android:layout_centerHorizontal="true"
android:layout_centerVertical="true"
android:background="@drawable/front"
android:clickable="true"
android:onClick="onCardClick"
android:padding="5dp" >
</RelativeLayout>

<RelativeLayout
android:id="@+id/main_activity_card_back"
android:layout_width="300dp"
android:layout_height="407dp"
android:layout_centerHorizontal="true"
android:layout_centerVertical="true"
android:background="@drawable/back"
android:clickable="true"
android:onClick="onCardClick"
android:visibility="gone" >
</RelativeLayout>

</RelativeLayout>

As the layout file flips two view groups you could put anything else inside the view group and it should work. Now lets look at the methods inside the activity which handles calling the flip animation code:

public void onCardClick(View view)
{
      flipCard();
}

private void flipCard()
{
    View rootLayout = findViewById(R.id.main_activity_root);
    View cardFace = findViewById(R.id.main_activity_card_face);
    View cardBack = findViewById(R.id.main_activity_card_back);

    FlipAnimation flipAnimation = new FlipAnimation(cardFace, cardBack);

    if (cardFace.getVisibility() == View.GONE)
    {
        flipAnimation.reverse();
    }
    rootLayout.startAnimation(flipAnimation);
}

And finally the FlipAnimation class:

public class FlipAnimation extends Animation
{
    private Camera camera;

    private View fromView;
    private View toView;

    private float centerX;
    private float centerY;

    private boolean forward = true;

    /**
     * Creates a 3D flip animation between two views.
     *
     * @param fromView First view in the transition.
     * @param toView Second view in the transition.
     */
    public FlipAnimation(View fromView, View toView)
    {
        this.fromView = fromView;
        this.toView = toView;

        setDuration(700);
        setFillAfter(false);
        setInterpolator(new AccelerateDecelerateInterpolator());
    }

    public void reverse()
    {
        forward = false;
        View switchView = toView;
        toView = fromView;
        fromView = switchView;
    }

    @Override
    public void initialize(int width, int height, int parentWidth, int parentHeight)
    {
        super.initialize(width, height, parentWidth, parentHeight);
        centerX = width/2;
        centerY = height/2;
        camera = new Camera();
    }

    @Override
    protected void applyTransformation(float interpolatedTime, Transformation t)
    {
        // Angle around the y-axis of the rotation at the given time
        // calculated both in radians and degrees.
        final double radians = Math.PI * interpolatedTime;
        float degrees = (float) (180.0 * radians / Math.PI);

        // Once we reach the midpoint in the animation, we need to hide the
        // source view and show the destination view. We also need to change
        // the angle by 180 degrees so that the destination does not come in
        // flipped around
        if (interpolatedTime >= 0.5f)
        {
            degrees -= 180.f;
            fromView.setVisibility(View.GONE);
            toView.setVisibility(View.VISIBLE);
        }

        if (forward)
            degrees = -degrees; //determines direction of rotation when flip begins

        final Matrix matrix = t.getMatrix();
        camera.save();
        camera.rotateY(degrees);
        camera.getMatrix(matrix);
        camera.restore();
        matrix.preTranslate(-centerX, -centerY);
        matrix.postTranslate(centerX, centerY);
    }

Here is the link for original post: Displaying card flip animation on old android

UPDATE from @FMMobileFelipeMenezes .

if you want the animation with a smooth scale to flip, change this part of code to (applyTransformation) :

final Matrix matrix = t.getMatrix();
camera.save();
camera.translate(0, 0, Math.abs(degrees)*2);
camera.getMatrix(matrix);
camera.rotateY(degrees);
camera.getMatrix(matrix);
camera.restore();
matrix.preTranslate(-centerX, -centerY);
matrix.postTranslate(centerX, centerY);

UPDATE from @Hesam There is good tutorial that I recommend to read it. Although it's not as nice as Android tutorial based on fragments, it's worth to be read and useful if you want to assign animation to layouts and views as well as have it on old APIs.

Use Android's scale animation to simulate a 3D flip

Improved project on github by @LenaBru

回答2:

I used Flextra code below, and if you want the animation with a smooth scale to flip, change this part of code to (applyTransformation) :

    final Matrix matrix = t.getMatrix();
    camera.save();
    camera.translate(0, 0, Math.abs(degrees)*2);
    camera.getMatrix(matrix);
    camera.rotateY(degrees);
    camera.getMatrix(matrix);
    camera.restore();
    matrix.preTranslate(-centerX, -centerY);
    matrix.postTranslate(centerX, centerY);

回答3:

I played with this all day, and finally achieved the ultimate goal - a smooth cardflip like rotation animation of two views!

I put demo project here

public class FlipAnimation extends Animation {
    private Camera camera;

    private View fromView;
    private View toView;

    private float centerX;
    private float centerY;

    private boolean forward = true;


    /**
     * Creates a 3D flip animation between two views.
     * 
     * @param fromView
     *            First view in the transition.
     * @param toView
     *            Second view in the transition.
     */
    public FlipAnimation(View fromView, View toView) {
        this.fromView = fromView;
        this.toView = toView;

        setDuration(1500);
        setFillAfter(false);
        // setInterpolator(new AccelerateDecelerateInterpolator());
        setInterpolator(new LinearInterpolator());
    }

    public void reverse() {

        if (forward) {
            View switchView = toView;
            toView = fromView;
            fromView = switchView;
        }
        forward = false;
    }

    @Override
    public void initialize(int width, int height, int parentWidth, int parentHeight) {
        super.initialize(width, height, parentWidth, parentHeight);
        centerX = width / 2;
        centerY = height / 2;
        camera = new Camera();
    }


    @Override
    protected void applyTransformation(float interpolatedTime, Transformation t) {
        // Angle around the y-axis of the rotation at the given time
        // calculated both in radians and degrees.
        final double radians = Math.PI * interpolatedTime;
        float degrees = (float) (180.0 * radians / Math.PI);


        //scale down the views a bit, so that they would look nice when the rotation begins

        if (interpolatedTime <= 0.05f) {
            fromView.setScaleX(1 - interpolatedTime);
            fromView.setScaleY(1 - interpolatedTime);
            toView.setScaleX(1 - interpolatedTime);
            toView.setScaleY(1 - interpolatedTime);
        }

        // Once we reach the midpoint in the animation, we need to hide the
        // source view and show the destination view. We also need to change
        // the angle by 180 degrees so that the destination does not come in
        //It is very important to call "toView.bringToFront()" and not play with the
        // visibility of the views, because if you apply this animation more than once,
        //the subsequent calls may fail
        if (interpolatedTime >= 0.5f) {
            degrees -= 180.f;
            toView.bringToFront();
          //these two lines force a layout redraw
          ((View)toView.getParent()).requestLayout();
          ((View)toView.getParent()).invalidate();


        }

        //scale the views back to their original size (Assuming original size was 1)
        if (interpolatedTime >= 0.95f) {
            fromView.setScaleX(interpolatedTime);
            fromView.setScaleY(interpolatedTime);
            toView.setScaleX(interpolatedTime);
            toView.setScaleY(interpolatedTime);
        }

        if (forward)
            degrees = -degrees; // determines direction of rotation when flip
                                // begins

        final Matrix matrix = t.getMatrix();
        camera.save();
        camera.translate(0, 0, Math.abs(degrees) * 2);
        camera.getMatrix(matrix);
        camera.rotateY(degrees);
        camera.getMatrix(matrix);
        camera.restore();
        matrix.preTranslate(-centerX, -centerY);
        matrix.postTranslate(centerX, centerY);
    }
}

and call it like this

import android.content.Context;
import android.os.Bundle;
import android.os.Handler;
import android.support.v4.app.FragmentActivity;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Toast;

public class MainActivity extends FragmentActivity {

private boolean showingBack;
private FragmentLeft left = new FragmentLeft();
private FragmentRight right = new FragmentRight();
private Context context;
private Handler handler;
private FlipAnimation flipAnimation;
private FlipAnimation backFlip;

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

    context = this;
    handler = new Handler(getMainLooper());

    getSupportFragmentManager().beginTransaction().add(R.id.fragment_container, right, "fragmentRight").commit();
    getSupportFragmentManager().beginTransaction().add(R.id.fragment_container, left, "fragmentLeft").commit();
    findViewById(R.id.flip).setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {
            flipAnimation = new FlipAnimation(left.getView(), right.getView());
            backFlip = new FlipAnimation(left.getView(), right.getView());
            handler.removeCallbacks(rotate);
            handler.postDelayed(rotate, 100);
        }

    });
}

    private Runnable rotate = new Runnable() {

        @Override
        public void run() {
           //put a variable showingBack, do not rely on view properties to flip
            if (!showingBack) {
                //very important to flip both views, so that when the
                //left view goes to back and right view goes to front,
                //the right view finishes the rotation
                left.getView().startAnimation(flipAnimation);
                right.getView().startAnimation(flipAnimation);
                Toast.makeText(context, "flip", Toast.LENGTH_LONG).show();
                showingBack = true;
            } else {
                showingBack = false;
                backFlip.reverse();
                Toast.makeText(context, "backflip", Toast.LENGTH_LONG).show();
                //very important to flip both views, so that when the
                //right view goes to back and right view goes to front,
                //the left view finishes the rotation
                left.getView().startAnimation(backFlip);
                right.getView().startAnimation(backFlip);

            }
        }
    };

}

These are the fragments

import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

public class FragmentRight extends Fragment {


    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        return inflater.inflate(R.layout.fragment_right, container,false);
    }
}

import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

public class FragmentLeft extends Fragment {


    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        return inflater.inflate(R.layout.fragment_left, container,false);
    }
}

and finally the view itself

activity_main.xml

<RelativeLayout 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:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:background="#ff151515"
    tools:context="com.example.flipviewtest.MainActivity" >

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

    <FrameLayout
        android:id="@+id/fragment_container"
        android:layout_width="200dp"
        android:layout_height="200dp"
        android:layout_centerInParent="true" >
    </FrameLayout>

    <Button
        android:id="@+id/flip"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:text="flip" />

</RelativeLayout>

fragment_left.xml

<?xml version="1.0" encoding="utf-8"?>
<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="#ffff0000"
     >

    <View
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="#ff0ffff0"
        android:layout_margin="20dp" />

</LinearLayout>

fragment_right.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#ff00ff00"
    android:orientation="vertical" >

    <View
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_margin="10dp"
        android:background="#ff0000ff" />

</LinearLayout>

note some of the code taken from Flextra's and @FMMobileFelipeMenezes answers

回答4:

There is good tutorial that I recommend to read it. Although it's not as nice as Android tutorial based on fragments, it's worth to be read and useful if you want to assign animation to layouts and views as well as have it on old APIs.

Use Android's scale animation to simulate a 3D flip