122 lines
3.8 KiB
Kotlin
122 lines
3.8 KiB
Kotlin
package com.yingmao.clash.ui.fragment
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import android.os.Bundle
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import android.view.LayoutInflater
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import android.view.View
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import android.view.ViewGroup
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import androidx.fragment.app.Fragment
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import androidx.fragment.app.FragmentActivity
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/**
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*
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* 若需要采用Lazy方式加载的Fragment，初始化内容放到initData实现
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* 若不需要Lazy加载则initData方法内留空,初始化内容放到initViews即可
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*
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* 注意事项 1:
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* 如果是与ViewPager一起使用，调用的是setUserVisibleHint。
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*
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* 注意事项 2:
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* 如果是通过FragmentTransaction的show和hide的方法来控制显示，调用的是onHiddenChanged.
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* 针对初始就show的Fragment 为了触发onHiddenChanged事件 达到lazy效果 需要先hide再show
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*
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* @author tamsiree
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* @date 2015/11/21.
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*/
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abstract class FragmentLazy : Fragment() {
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/**
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* 是否可见状态
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*/
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private var isFragmentVisible: Boolean = false
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/**
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* 标志位，View已经初始化完成。
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*/
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private var isPrepared = false
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/**
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* 是否第一次加载
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*/
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private var isFirstLoad = true
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lateinit var mContext: FragmentActivity
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var rootView: View? = null
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private set
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override fun onCreateView(layoutInflater: LayoutInflater, viewGroup: ViewGroup?, savedInstanceState: Bundle?): View? {
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// 若 viewpager 不设置 setOffscreenPageLimit 或设置数量不够
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// 销毁的Fragment onCreateView 每次都会执行(但实体类没有从内存销毁)
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// 导致initData反复执行,所以这里注释掉
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// isFirstLoad = true;
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// 取消 isFirstLoad = true的注释 , 因为上述的initData本身就是应该执行的
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// onCreateView执行 证明被移出过FragmentManager initData确实要执行.
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// 如果这里有数据累加的Bug 请在initViews方法里初始化您的数据 比如 list.clear();
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mContext = this.activity!!
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isFirstLoad = true
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rootView = inflateView(layoutInflater, viewGroup, savedInstanceState)
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return rootView
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}
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override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
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super.onViewCreated(view, savedInstanceState)
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initView()
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isPrepared = true
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lazyLoad()
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}
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/**
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* 如果是与ViewPager一起使用，调用的是setUserVisibleHint
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*
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* @param isVisibleToUser 是否显示出来了
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*/
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override fun setUserVisibleHint(isVisibleToUser: Boolean) {
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super.setUserVisibleHint(isVisibleToUser)
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if (userVisibleHint) {
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isFragmentVisible = true
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onVisible()
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} else {
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isFragmentVisible = false
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onInvisible()
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}
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}
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/**
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* 如果是通过FragmentTransaction的show和hide的方法来控制显示，调用的是onHiddenChanged.
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* 若是初始就show的Fragment 为了触发该事件 需要先hide再show
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*
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* @param hidden hidden True if the fragment is now hidden, false if it is not
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* visible.
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*/
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override fun onHiddenChanged(hidden: Boolean) {
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super.onHiddenChanged(hidden)
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if (!hidden) {
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isFragmentVisible = true
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onVisible()
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} else {
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isFragmentVisible = false
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onInvisible()
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}
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}
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protected fun onVisible() {
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lazyLoad()
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}
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protected fun onInvisible() {}
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/**
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* 要实现延迟加载Fragment内容,需要在 onCreateView
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* isPrepared = true;
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*/
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protected fun lazyLoad() {
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if (!isPrepared || !isFragmentVisible || !isFirstLoad) {
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return
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}
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isFirstLoad = false
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initData()
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}
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protected abstract fun inflateView(layoutInflater: LayoutInflater, viewGroup: ViewGroup?, savedInstanceState: Bundle?): View
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protected abstract fun initView()
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protected abstract fun initData()
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} |