Activity transition in Android

Question

How can I define the transition between two activities for Android 1.5 and later? I would like an activity to fade in.

Answer 1

Use ActivityCompat.startActivity() works API > 21.

    ActivityOptionsCompat options = ActivityOptionsCompat.makeSceneTransitionAnimation(activity, transitionImage, EXTRA_IMAGE);
    ActivityCompat.startActivity(activity, intent, options.toBundle());

Answer 2

Some versions of Android support custom Activity transitions and some don't (older devices). If you want to use custom transitions it's good practice to check whether the Activity has the overridePendingTransition() method, as on older versions it does not.

To know whether the method exists or not, reflection API can be used. Here is the simple code which will check and return the method if it exists:

Method mOverridePendingTransition;

try {
        mOverridePendingTransition = Activity.class.getMethod(
                "overridePendingTransition", new Class[] { Integer.TYPE, Integer.TYPE } );
        /* success */
    } catch (NoSuchMethodException nsme) {
        /* failure, this version of Android doesn't have this method */
    } 

And then, we can apply our own transition, i.e. use this method if it exists:

if (UIConstants.mOverridePendingTransition != null) {
               try {
                   UIConstants.mOverridePendingTransition.invoke(MainActivity.this, R.anim.activity_fade_in, R.anim.activity_fade_out);
               } catch (InvocationTargetException e) {
                   e.printStackTrace();
               } catch (IllegalAccessException e) {
                   e.printStackTrace();
               }
            }

Here, as an example, simple fade-in and fade-out animations were used for transition demonstration..