Shawn的開發記錄

java 

public class CrossfadeActivity extends Activity {

    private View mContentView;
    private View mLoadingView;
    private int mShortAnimationDuration;

    ...

    private void crossfade() {

        // Set the content view to 0% opacity but visible, so that it is visible
        // (but fully transparent) during the animation.
        mContentView.setAlpha(0f);
        mContentView.setVisibility(View.VISIBLE);

        // Animate the content view to 100% opacity, and clear any animation
        // listener set on the view.
        mContentView.animate()
                .alpha(1f)
                .setDuration(mShortAnimationDuration)
                .setListener(null);

        // Animate the loading view to 0% opacity. After the animation ends,
        // set its visibility to GONE as an optimization step (it won't
        // participate in layout passes, etc.)
        mLoadingView.animate()
                .alpha(0f)
                .setDuration(mShortAnimationDuration)
                .setListener(new AnimatorListenerAdapter() {
                    @Override
                    public void onAnimationEnd(Animator animation) {
                        mLoadingView.setVisibility(View.GONE);
                    }
                });
    }
}

 

kotlin

class CrossfadeActivity : Activity() {

    private lateinit var mContentView: View
    private lateinit var mLoadingView: View
    private var mShortAnimationDuration: Int = 0

    ...

    private fun crossfade() {
        mContentView.apply {
            // Set the content view to 0% opacity but visible, so that it is visible
            // (but fully transparent) during the animation.
            alpha = 0f
            visibility = View.VISIBLE

            // Animate the content view to 100% opacity, and clear any animation
            // listener set on the view.
            animate()
                    .alpha(1f)
                    .setDuration(mShortAnimationDuration.toLong())
                    .setListener(null)
        }
        // Animate the loading view to 0% opacity. After the animation ends,
        // set its visibility to GONE as an optimization step (it won't
        // participate in layout passes, etc.)
        mLoadingView.animate()
                .alpha(0f)
                .setDuration(mShortAnimationDuration.toLong())
                .setListener(object : AnimatorListenerAdapter() {
                    override fun onAnimationEnd(animation: Animator) {
                        mLoadingView.visibility = View.GONE
                    }
                })
    }
}