How to stop an animation (cancel() does not work)

问题:

I need to stop a running translate animation. The .cancel() method of Animation has no effect; the animation goes until the end anyway.

How do you cancel a running animation?

回答1:

Call clearAnimation() on whichever View you called startAnimation().

回答2:

On Android 4.4.4, it seems the only way I could stop an alpha fading animation on a View was calling View.animate().cancel() (i.e., calling .cancel() on the View's ViewPropertyAnimator).

Here's the code I'm using for compatibility before and after ICS:

public void stopAnimation(View v) {
    v.clearAnimation();
    if (canCancelAnimation()) {
        v.animate().cancel();
    }
}

... with the method:

/**
 * Returns true if the API level supports canceling existing animations via the
 * ViewPropertyAnimator, and false if it does not
 * @return true if the API level supports canceling existing animations via the
 * ViewPropertyAnimator, and false if it does not
 */
public static boolean canCancelAnimation() {
    return Build.VERSION.SDK_INT >= Build.VERSION_CODES.ICE_CREAM_SANDWICH;
}

Here's the animation that I'm stopping:

v.setAlpha(0f);
v.setVisibility(View.VISIBLE);
// Animate the content view to 100% opacity, and clear any animation listener set on the view.
v.animate()
    .alpha(1f)
    .setDuration(animationDuration)
    .setListener(null);

回答3:

If you are using the animation listener, set v.setAnimationListener(null). Use the following code with all options.

v.getAnimation().cancel();
v.clearAnimation();
animation.setAnimationListener(null);

回答4:

You must use .clearAnimation(); method in UI thread:

runOnUiThread(new Runnable() {
    @Override
    public void run() {
        v.clearAnimation();
    }
});

回答5:

What you can try to do is get the transformation Matrix from the animation before you stop it and inspect the Matrix contents to get the position values you are looking for.

Here are the api's you should look into

public boolean getTransformation (long currentTime, Transformation outTransformation)

public Matrix getMatrix ()

public void getValues (float[] values)

So for example (some pseudo code. I have not tested this):

Transformation outTransformation = new Transformation();
myAnimation.getTransformation(currentTime, outTransformation);
Matrix transformationMatrix = outTransformation.getMatrix();
float[] matrixValues = new float[9];
transformationMatrix.getValues(matrixValues);
float transX = matrixValues[Matrix.MTRANS_X];
float transY = matrixValues[Matrix.MTRANS_Y];

回答6:

Use the method setAnimation(null) to stop an animation, it exposed as public method in View.java, it is the base class for all widgets, which are used to create interactive UI components (buttons, text fields, etc.). /** * Sets the next animation to play for this view. * If you want the animation to play immediately, use * {@link #startAnimation(android.view.animation.Animation)} instead. * This method provides allows fine-grained * control over the start time and invalidation, but you * must make sure that 1) the animation has a start time set, and * 2) the view's parent (which controls animations on its children) * will be invalidated when the animation is supposed to * start. * * @param animation The next animation, or null. */ public void setAnimation(Animation animation)

回答7:

To stop animation you may set such objectAnimator that do nothing, e.g.

first when manual flipping there is animation left to right:

flipper.setInAnimation(leftIn);
flipper.setOutAnimation(rightOut);

then when switching to auto flipping there's no animation

flipper.setInAnimation(doNothing);
flipper.setOutAnimation(doNothing);

doNothing = ObjectAnimator.ofFloat(flipper, "x", 0f, 0f).setDuration(flipperSwipingDuration);