【Android】用Kotlin方式使用ActionMode

客官°小女子只卖身不卖艺 2022-12-12 04:49 181阅读 0赞

# ActionMode #

--------------------

ActionMode模式为在页面产生一个悬浮的类似于ActionBar的控件，悬浮在ActionBar之上，可以在不占用页面空间的情况下增加功能入口。ActionMode有两种模式

1.  Primary Action ：控件覆盖出现在上方ActionBar之上
2.  Floating Action：控件浮动出现在任意View的四周

<table> 
 <thead> 
  <tr> 
   <th>Primary Action</th> 
   <th>Floating Action</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td><img src="https://img-blog.csdnimg.cn/20201006102959675.png" width="100%"></td> 
   <td><img src="https://img-blog.csdnimg.cn/2020100610301467.png" width="100%"></td> 
  </tr> 
 </tbody> 
</table>

# 启动方式 #

--------------------

通过Activity或者View的`startActionMode`方法启动，并接受两个参数：`ActionMode.Callback`、`ActionMode.Type`

public ActionMode startActionMode(android.view.ActionMode.Callback callback, int type)

ActionMode.Callback定义了ActionMode的生命周期回调：

public interface Callback { 
        // AcionMode创建
        boolean onCreateActionMode(ActionMode var1, Menu var2);
    
        // AcionMode状态变化时（无效、或者项目更新）
        boolean onPrepareActionMode(ActionMode var1, Menu var2);
    
        // AcionMode菜单项被选中时
        boolean onActionItemClicked(ActionMode var1, MenuItem var2);
    
        // AcionMode销毁
        void onDestroyActionMode(ActionMode var1);
    }

ActionMode.Type定义了前面介绍的两种ActionMode类型

public abstract class ActionMode { 
        public static final int TYPE_FLOATING = 1;
        public static final int TYPE_PRIMARY = 0;
          ︙
    }

# 封装ActionModeController #

--------------------

我们封装ActionModeController类，简化ActionMode使用体验

class ActionModeController(
        // menu的resId
        @MenuRes private val resId: Int,
        // ActionMode 类型
        private val type: Int,
        // menu选择后回调
        private val onAction : (MenuItem) -> Unit
    ) { 
        // 从Activiy启动
        fun startActionMode(activity: Activity) { 
            activity.startActionMode(createActionModeCallback(), type)
        }
    
        // 从View启动
        fun startActionMode(view: View) { 
            view.startActionMode(createActionModeCallback(), type)
        }
    
        private fun createActionModeCallback(): ActionMode.Callback { 
            return object: ActionMode.Callback { 
                override fun onCreateActionMode(mode: ActionMode, menu: Menu): Boolean { 
                    mode.menuInflater.inflate(resId, menu)
                    return true
                }
    
                override fun onPrepareActionMode(mode: ActionMode, menu: Menu): Boolean { 
                    return false
                }
    
                override fun onDestroyActionMode(mode: ActionMode) { 
                }
    
                override fun onActionItemClicked(mode: ActionMode, item: MenuItem): Boolean { 
                    onAction.invoke(item)
    
                    mode.finish()
                    return true
                }
            }
        }
    }

接下来实际看一下使用效果

<?xml version="1.0" encoding="utf-8"?>
    <menu xmlns:android="http://schemas.android.com/apk/res/android">
        <item android:id="@+id/first" android:title="@string/first" android:icon="@drawable/ic_done" />
    
        <item android:id="@+id/second" android:title="@string/second" android:icon="@drawable/ic_close" />
    </menu>

<?xml version="1.0" encoding="utf-8"?>
    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_gravity="center" tools:context=".MainFragment" android:orientation="vertical">
    
            <Button android:id="@+id/primary_action_mode_activity_button" android:layout_width="match_parent" android:layout_height="wrap_content" android:text="PRIMARY ACTION MODE (ACTIVITY)"/>
    
            <Button android:id="@+id/primary_action_mode_view_button" android:layout_width="match_parent" android:layout_height="wrap_content" android:text="PRIMARY ACTION MODE (VIEW)"/>
    
            <Button android:id="@+id/floating_action_mode_activity_button" android:layout_width="match_parent" android:layout_height="wrap_content" android:text="FLOATING ACTION MODE (ACTIVITY)"/>
    
            <Button android:id="@+id/floating_action_mode_view_button" android:layout_width="match_parent" android:layout_height="wrap_content" android:text="FLOATING ACTION MODE (VIEW)"/>
    </LinearLayout>

class MainFragment : Fragment(R.layout.fragment_main) { 
        override fun onViewCreated(view: View, savedInstanceState: Bundle?) { 
            super.onViewCreated(view, savedInstanceState)
    
    		// Primary Action
            val primaryActionModeController = ActionModeController(R.menu.action_menus, ActionMode.TYPE_PRIMARY) { 
    
                when (it.itemId) { 
                    R.id.first -> { 
                        Toast.makeText(context, "FIRST", Toast.LENGTH_SHORT).show()
                    }
                    R.id.second -> { 
                        Toast.makeText(context, "SECOND", Toast.LENGTH_SHORT).show()
                    }
                }
            }
    
            // Floating Action 
            val floatingActionModeController = ActionModeController(R.menu.action_menus, ActionMode.TYPE_FLOATING) { 
                when (it.itemId) { 
                    R.id.first -> { 
                        Toast.makeText(context, "FIRST", Toast.LENGTH_SHORT).show()
                    }
                    R.id.second -> { 
                        Toast.makeText(context, "SECOND", Toast.LENGTH_SHORT).show()
                    }
                }
            }
    
            // Activity 启动 Primary Action
            primary_action_mode_activity_button.setOnClickListener { 
                primaryActionModeController.startActionMode(requireActivity())
            }
    
            // View 启动 Primary Action
            primary_action_mode_view_button.setOnClickListener { 
                primaryActionModeController.startActionMode(it)
            }
    
            // Activity 启动 Floating Action
            floating_action_mode_activity_button.setOnClickListener { 
                floatingActionModeController.startActionMode(requireActivity())
            }
    
            // View 启动 Floating Action
            floating_action_mode_view_button.setOnClickListener { 
                floatingActionModeController.startActionMode(it)
            }
        }
    }

![在这里插入图片描述][20201006111347238.gif_pic_left]

# 更加Kotlin范儿的封装 #

--------------------

ActionModeController适合在Java或者Kotlin中使用，如果我们只面向Kotlin使用，可以在ActionModeController基础上，分装的更加Kotlin范儿：

fun Activity.startActionMode(@MenuRes resId: Int, type: Int, onAction: (MenuItem) -> Unit) =
        ActionModeController(resId, type, onAction).startActionMode(this)

通过扩展函数，完全隐去了对`ActionModeController`的定义和调用，非常简洁。

[20201006111347238.gif_pic_left]: /images/20221123/cffc47c9c8df4486b27959c73339b358.png