通函揭示了新活动的过渡

Question 1

根据https://developer.android.com/training/material/animations.html

该ViewAnimationUtils.createCircularReveal()方法使您可以为剪切圆制作动画以显示或隐藏视图。

要使用此效果显示以前不可见的视图：

// previously invisible view
View myView = findViewById(R.id.my_view);

// get the center for the clipping circle
int cx = (myView.getLeft() + myView.getRight()) / 2;
int cy = (myView.getTop() + myView.getBottom()) / 2;

// get the final radius for the clipping circle
int finalRadius = Math.max(myView.getWidth(), myView.getHeight());

// create the animator for this view (the start radius is zero)
Animator anim =
    ViewAnimationUtils.createCircularReveal(myView, cx, cy, 0, finalRadius);

// make the view visible and start the animation
myView.setVisibility(View.VISIBLE);
anim.start();

这是为了揭示视图。如何使用它来循环显示整个活动，而没有任何共享元素？

具体来说，我希望我的searchActivity可以从工具栏中的搜索操作按钮中循环显示出来。

Question 2

寻找了半天没有结果的解决方案后，我想出了自己的实现。我正在使用具有匹配根布局的透明活动。根布局是一个视图，可以使用来显示createCircularReveal()。

我的代码如下所示：

styles.xml中的主题定义

<style name="Theme.Transparent" parent="Theme.AppCompat.Light.NoActionBar">
    <item name="android:windowIsTranslucent">true</item>
    <item name="android:statusBarColor">@android:color/transparent</item>
    <item name="android:windowBackground">@android:color/transparent</item>
</style>

AndroidManifest.xml中的活动定义

<activity
        android:name=".ui.CircularRevealActivity"
        android:theme="@style/Theme.Transparent"
        android:launchMode="singleTask"
        />

然后为我的活动声明一个布局（我选择了DrawerLayout，这样我就可以拥有NavDrawer。每个布局都应该在这里工作。）

<android.support.v4.widget.DrawerLayout
    android:id="@+id/drawer_layout"
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    >

    <FrameLayout
        android:id="@+id/root_layout"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="@color/honey_melon"
        >

        <!-- Insert your actual layout here -->

    </FrameLayout>

</android.support.v4.widget.DrawerLayout>

重要的是带有id的FrameLayout root_layout。该视图将在活动中显示。

最后，我实现CircularRevealActivity并重写onCreate()：

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    overridePendingTransition(R.anim.do_not_move, R.anim.do_not_move);

    setContentView(R.layout.activity_reveal_circular);

    if (savedInstanceState == null) {
        rootLayout.setVisibility(View.INVISIBLE);

        ViewTreeObserver viewTreeObserver = rootLayout.getViewTreeObserver();
        if (viewTreeObserver.isAlive()) {
            viewTreeObserver.addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
                @Override
                public void onGlobalLayout() {
                    circularRevealActivity();
                    if (Build.VERSION.SDK_INT < Build.VERSION_CODES.JELLY_BEAN) {
                        rootLayout.getViewTreeObserver().removeGlobalOnLayoutListener(this);
                    } else {
                        rootLayout.getViewTreeObserver().removeOnGlobalLayoutListener(this);
                    } 
                }
            });
        }
    }
}

放进circularRevealActivity()去很重要OnGlobalLayoutListener，因为需要为动画绘制视图。

circularRevealActivity() 看起来像伊桑的建议：

private void circularRevealActivity() {

    int cx = rootLayout.getWidth() / 2;
    int cy = rootLayout.getHeight() / 2;

    float finalRadius = Math.max(rootLayout.getWidth(), rootLayout.getHeight());

    // create the animator for this view (the start radius is zero)
    Animator circularReveal = ViewAnimationUtils.createCircularReveal(rootLayout, cx, cy, 0, finalRadius);
    circularReveal.setDuration(1000);

    // make the view visible and start the animation
    rootLayout.setVisibility(View.VISIBLE);
    circularReveal.start();
}

编辑1

的定义R.anim.do_not_move已添加。但是，如果您的设计没有为活动指定默认过渡，那么它也应该没有该行。让我知道

R.anim.do_not_move：

<set xmlns:android="http://schemas.android.com/apk/res/android">
<translate
    android:fromYDelta="0"
    android:toYDelta="0"
    android:duration="@android:integer/config_mediumAnimTime"
    />
</set>

Question 3

如果要反转离开活动时的圆形显示，请对onBackPressed（）使用以下修改。

@Override
public void onBackPressed() {

    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
        int cx = rootLayout.getWidth();
        int cy = 0;
        float finalRadius = Math.max(rootLayout.getWidth(), rootLayout.getHeight());
        Animator circularReveal = ViewAnimationUtils.createCircularReveal(rootLayout, cx, cy, finalRadius, 0);

        circularReveal.addListener(new Animator.AnimatorListener() {
            @Override
            public void onAnimationStart(Animator animator) {

            }

            @Override
            public void onAnimationEnd(Animator animator) {
                rootLayout.setVisibility(View.INVISIBLE);
                finish();
            }

            @Override
            public void onAnimationCancel(Animator animator) {

            }

            @Override
            public void onAnimationRepeat(Animator animator) {

            }
        });
        circularReveal.setDuration(400);
        circularReveal.start();
    }else{
        super.onBackPressed();
    }
}

Question 4

要反转CircularReveal动画，请交换startRadius和endRadius参数。另外，您需要设置AnimatorListener和onAnimationEnd()，您可以在回调方法中进行调用finishAfterTransition()。这是在您按up navigation或单击时使用的back button。

Question 5

我认为您可以使用ActivityOptionsCompat.makeClipRevealAnimation。

[ https://developer.android.com/reference/android/support/v4/app/ActivityOptionsCompat.html#makeClipRevealAnimation(android.view.View，INT，INT，INT，INT）]（https://developer.android .com / reference / android / support / v4 / app / ActivityOptionsCompat.html＃makeClipRevealAnimation（android.view.View，int，int，int，int））

Question 6

您必须绘制圆形视图，然后再为其创建动画。

创建圆视图：

public class Circle extends View {

    private static final int START_ANGLE_POINT = 90;

    private final Paint paint;
    private final RectF rect;

    private float angle;

    public Circle(Context context, AttributeSet attrs) {
        super(context, attrs);

        final int strokeWidth = 40;

        paint = new Paint();
        paint.setAntiAlias(true);
        paint.setStyle(Paint.Style.STROKE);
        paint.setStrokeWidth(strokeWidth);
        //Circle color
        paint.setColor(Color.RED);

        //size 200x200 example
        rect = new RectF(strokeWidth, strokeWidth, 200 + strokeWidth, 200 + strokeWidth);

        //Initial Angle (optional, it can be zero)
        angle = 120;
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        canvas.drawArc(rect, START_ANGLE_POINT, angle, false, paint);
    }

    public float getAngle() {
        return angle;
    }

    public void setAngle(float angle) {
        this.angle = angle;
    }
}

创建动画类以设置新角度：

public class CircleAngleAnimation extends Animation {

    private Circle circle;

    private float oldAngle;
    private float newAngle;

    public CircleAngleAnimation(Circle circle, int newAngle) {
        this.oldAngle = circle.getAngle();
        this.newAngle = newAngle;
        this.circle = circle;
    }

    @Override
    protected void applyTransformation(float interpolatedTime, Transformation transformation) {
        float angle = oldAngle + ((newAngle - oldAngle) * interpolatedTime);

        circle.setAngle(angle);
        circle.requestLayout();
    }
}

将圆圈放入布局中：

<com.package.Circle
    android:id="@+id/circle"
    android:layout_width="300dp"
    android:layout_height="300dp" />

最后开始动画：

Circle circle = (Circle) findViewById(R.id.circle);

CircleAngleAnimation animation = new CircleAngleAnimation(circle, 240);
animation.setDuration(1000);
circle.startAnimation(animation);