Android 手动释放viewpager中的所有fragment

adapter的源码如下，destroyItem回调经过处理，滑动的时候不销毁 ，viewpager所在界面销毁的时候才让super执行：

class FigViewPagerAdapter(
    fm: FragmentManager?,
    fragments: List<Fragment>,
    mtitles: Array<String?>? = null
) : FragmentStatePagerAdapter(fm!!) {
    var mFragments: List<Fragment> =
        ArrayList()

    var isCanRemove = false


    override fun getItem(position: Int): Fragment {
        return mFragments[position]
    }

    override fun getCount(): Int {
        return mFragments.size
    }

    override fun getPageTitle(position: Int): CharSequence? {
        return ""
    }

    override fun destroyItem(container: ViewGroup, position: Int, `object`: Any) {
        //ページは破棄されません
        if (isCanRemove) {
            super.destroyItem(container, position, `object`)
        }
    }

    init {
        mFragments = fragments
    }
}

  通过反射的方法，在内存中找到adapter中所有mFragments变量的具体Fragment，然后销毁：

   override fun onDestroyView() {
        try {
            val field: Field =
                figViewPagerAdapter?.javaClass?.superclass?.getDeclaredField("mFragments")!!
            field.isAccessible = true
            val mFragments: ArrayList<Fragment> =
                field[figViewPagerAdapter] as ArrayList<Fragment> //false 则是不关闭mFragments
            if (mFragments != null) {
                figViewPagerAdapter?.isCanRemove = true
                for (i in mFragments.indices) {
                    figViewPagerAdapter?.destroyItem(
                        dataBinding.viewPager,
                        i,
                        mFragments[i]
                    )
                }
                figViewPagerAdapter?.finishUpdate(dataBinding.viewPager) //提交事务
            }
        } catch (e: Exception) {
        }
        super.onDestroyView()
        figViewModel.clearPartListEvent()
    }

 

本文地址：https://blog.csdn.net/Crystal_xing/article/details/107143033