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
Fragment.getView()
but then it comes to an error if I start the animation. – Abramabramo