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This article mainly introduces how Kotlin implements object expressions. The article is very detailed and has certain reference value. Interested friends must read it!

Object Expressions

Object Expressions allows defining singletons. For example:

package com.savvyapps.example.utilimport android.os.Handlerimport android.os.Looper// notice that this is object instead of classobject ThreadUtil { fun onMainThread(runnable: Runnable) { val mainHandler = Handler(Looper.getMainLooper()) mainHandler.post(runnable) }}

ThreadUtil can call static class methods directly:

ThreadUtil.onMainThread(runnable)

In a similar way, we create objects instead of anonymous inner classes:

viewPager.addOnPageChangeListener(object : ViewPager.OnPageChangeListener { override fun onPageScrollStateChanged(state: Int) {} override fun onPageScrolled(position: Int, positionOffset: Float, positionOffsetPixels: Int) {} override fun onPageSelected(position: Int) { bindUser(position) }});

Both are basically the same thing-creating a class as a single instance of a declared object.

That's all for "How Kotlin implements object expressions." Thanks for reading! Hope to share the content to help everyone, more relevant knowledge, welcome to pay attention to the industry information channel!

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