[移动开发]Android（12）Preference（三）抽象管理

Android（12）Preference（三）抽象管理

问题发生背景：

假如我们现在有一个设置页面，虽然我们可以通过获取Preference实例去set一些Click、Change监听，但是当我们的业务逻辑增加并且复杂的时候，会发现我们每次都要先去找到一个实例才能去设置，这个时候就需要分离UI逻辑和数据逻辑了，比如我希望点击的时候只是通过传过来的key判断UI的变化，是跳转到下一个设置页面还是弹出一个对话框等；点击Switch改变值的时候通过key判断，意思就是把原来的点击处理一票子逻辑拆分成俩部分方便管理。

开始抽象，准备动手！

• 先抽象出一个PreferenceFragmentCompat容器的Activity。

  • 有对应页面的标题
  • 统一风格的背景和Toobar

  abstract class BaseSettingsActivity: AppCompatActivity() {
  
      // 根Fragment名字
      abstract val hostFragmentName: String
  
      protected val activityLayoutRes = R.layout.activity_main
  
      var hostFragment: BaseSettingsFragment? = null
  
      // Toolbar相关
      protected var actionBar: ActionBar? = null
      protected lateinit var toolBar: Toolbar
      protected var collapsingToolbarLayout: CollapsingToolbarLayout? = null
      protected var appBarLayout: AppBarLayout? = null
  
      override fun onCreate(savedInstanceState: Bundle?) {
          super.onCreate(savedInstanceState)
          setContentView(activityLayoutRes)
  
          // 设置协调布局和toolbar
          toolBar = findViewById(R.id.toolbar)
          setSupportActionBar(toolBar)
          actionBar = supportActionBar
          actionBar?.let {
              it.setDisplayHomeAsUpEnabled(true)
              it.setHomeButtonEnabled(true)
              it.setDisplayShowTitleEnabled(true)
          }
  
          toolBar.apply {
              setNavigationOnClickListener {
                  finishAndRemoveTask()
              }
          }
          collapsingToolbarLayout = findViewById(R.id.collapsing_toolbar)
          appBarLayout = findViewById(R.id.appbar_layout)
          collapsingToolbarLayout?.let {
              it.title = title
          }
         
          val fragment = supportFragmentManager.fragmentFactory.instantiate(
              this.classLoader,
              hostFragmentName
          )
          hostFragment = fragment as BaseSettingsFragment
          supportFragmentManager
              .beginTransaction()
              .replace(
                  R.id.setting_fragment_container,
                  fragment
              ).commit()
      }
  }
  

• 再抽象出一个PreferenceFragmentCompat:

  • 处理UI交互
  • 处理数据逻辑

  abstract class BaseSettingsFragment: PreferenceFragmentCompat() {
  
      // 设置布局资源id
      abstract val xmlRes: Int
  
      // 这个页面上可见的Preference的key
      val preferenceKeys = mutableListOf<String>()
  
      /**
       * 处理UI相关的逻辑
       *
       * @param preference Preference
       * @param prefKey String
       * @return Boolean  是否消费
       */
      abstract fun handleInteractionLogic(preference: Preference, prefKey: String): Boolean
  
      /**
       * 处理数据相关逻辑
       *
       * @param preference Preference
       * @param prefKey String
       */
      abstract fun handleDataLogic(preference: Preference, prefKey: String)
  
      override fun onCreatePreferences(savedInstanceState: Bundle?, rootKey: String?) {
          setPreferencesFromResource(xmlRes, rootKey)
      }
  
      override fun onPreferenceTreeClick(preference: Preference): Boolean {
          return handleInteractionLogic(preference, preference.key)
      }
  }
  

• 搞一个自己的Preference:

  • 在attr.xml中定义自己的属性

  <resources>
      <attr name="myPreferenceStyle" format="reference"/>
  
      <declare-styleable name="MyPreference">
          <attr name="myPfTitleTextColor" format="color"/>
          <attr name="myPfTitleTextSize" format="dimension"/>
      </declare-styleable>
  </resources>
  

  • 在theme.xml定义一个style指定myPreferenceStyle，记得<applicatiopn/>的themme要指定为我们的哟

  <resources xmlns:tools="http://schemas.android.com/tools">
      <!-- Base application theme. -->
      <style name="Theme.MyApplication" parent="Theme.AppCompat.DayNight.NoActionBar">
          <!-- Primary brand color. -->
          <item name="colorPrimary">@color/purple_500</item>
          <item name="colorPrimaryVariant">@color/purple_700</item>
          <item name="colorOnPrimary">@color/white</item>
          <!-- Secondary brand color. -->
          <item name="colorSecondary">@color/teal_200</item>
          <item name="colorSecondaryVariant">@color/teal_700</item>
          <item name="colorOnSecondary">@color/black</item>
          <!-- Status bar color. -->
          <item name="android:statusBarColor" tools:targetApi="l">?attr/colorPrimaryVariant</item>
          <!-- Customize your theme here. -->
  
          <item name="myPreferenceStyle">@style/MyPreferenceStyle</item>
      </style>
      
      
      // _-----------------------
  
      // 这里就可以统一设置自己定义的属性拉
      <style name="MyPreferenceStyle">
          <item name="myPfTitleTextColor">#FF4081</item>
          <item name="myPfTitleTextSize">20sp</item>
      </style>
      
      
  
      <style name="CollapsingToolbarTitle.Collapsed" parent="@android:style/TextAppearance.DeviceDefault.Widget.ActionBar.Title">
          <item name="android:textSize">22sp</item>
          <item name="android:textColor">#FF4081</item>
      </style>
  
      <style name="CollapsingToolbarTitle.Expanded" parent="CollapsingToolbarTitle.Collapsed">
          <item name="android:textSize">36sp</item>
          <item name="android:textColor">#536DFE</item>
      </style>
  </resources>
  

• 代码里使用属性：

  class MyPreference(
      context: Context,
      attributeSet: AttributeSet,
      defStyleAttr: Int = R.attr.myPreferenceStyle
  ): Preference(context, attributeSet, defStyleAttr) {
  
      val hostFragment by lazy {
          context.takeIf { it is BaseSettingsActivity }?.let {
              (it as BaseSettingsActivity).hostFragment
          }
      }
  
      private  var titleTextColor = 0
      private  var titleTextSize = 0f
  
      init {
          widgetLayoutResource = R.layout.my_widget
          context.obtainStyledAttributes(
              attributeSet,
              R.styleable.MyPreference, defStyleAttr, 0
          ).apply {
              titleTextColor =
                  getColor(R.styleable.MyPreference_myPfTitleTextColor, Color.BLACK)
              titleTextSize =
                  getDimension(R.styleable.MyPreference_myPfTitleTextSize, 10f)
              recycle()
          }
          hostFragment.takeIf { it is BaseSettingsFragment }?.preferenceKeys?.add(key)
      }
  
      override fun onBindViewHolder(holder: PreferenceViewHolder) {
          super.onBindViewHolder(holder)
          with(holder) {
              findViewById(android.R.id.title).takeIf { it is TextView }?.let {
                  (it as TextView).setTextColor(titleTextColor)
                  it.textSize = titleTextSize
              }
          }
          holder.findViewById(R.id.switchWidget).takeIf { it is Switch }?.let {
              (it as Switch).setOnCheckedChangeListener { buttonView, isChecked ->
                  hostFragment?.handleDataLogic(this, key)
              }
          }
      }
  }
  

使用

在搞完通用的之后了，就可以使用了：

class MyActivity: BaseSettingsActivity() {
    override val hostFragmentName: String
        get() = MyFragemnt::class.java.name
    
    class MyFragemnt: BaseSettingsFragment() {
        override val xmlRes: Int
            get() = R.xml.settings

        /**
         * 处理 UI
         * 
         * @param preference Preference
         * @param prefKey String
         * @return Boolean
         */
        override fun handleInteractionLogic(preference: Preference, prefKey: String): Boolean {
            TODO("Not yet implemented")
        }

        /**
         * 处理 数据
         * 
         * @param preference Preference
         * @param prefKey String
         */
        override fun handleDataLogic(preference: Preference, prefKey: String) {
            TODO("Not yet implemented")
        }
    }
}