2024/4/9

跟着教程写todoapplication

package com.example.to_do_application.fragments.list

import android.app.AlertDialog
import android.os.Bundle
import android.view.*
import androidx.appcompat.widget.SearchView
import android.widget.Toast
import androidx.fragment.app.Fragment
import androidx.fragment.app.viewModels
import androidx.lifecycle.Observer
import androidx.recyclerview.widget.*
import com.example.to_do_application.R
import com.example.to_do_application.data.models.ToDoData
import com.example.to_do_application.data.viewmodel.ToDoViewModel
import com.example.to_do_application.databinding.FragmentListBinding
import com.example.to_do_application.fragments.SharedViewModel
import com.example.to_do_application.fragments.list.adapter.ListAdapter
import com.google.android.material.snackbar.Snackbar



class ListFragment : Fragment(), SearchView.OnQueryTextListener {

    private val mToDoViewModel: ToDoViewModel  by   viewModels()
    private val mSharedViewModel: SharedViewModel by viewModels()

    private var _binding: FragmentListBinding? = null
    private val binding get() = _binding!!

   private val  adapter: ListAdapter by lazy { ListAdapter() }

    override fun onCreateView(
        inflater: LayoutInflater, container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View? {
        // Data Binding
       _binding = FragmentListBinding.inflate(inflater,container,false)
        binding.lifecycleOwner = this
        binding.mSharedViewModel = mSharedViewModel

        //SetUp RecyclerView
        setupRecyclerview()

        //Observe LiveData
        mToDoViewModel.getAllData.observe(viewLifecycleOwner, Observer { data ->
            mSharedViewModel.checkIfDatabaseEmpty(data)
            adapter.setData(data)
        })


        //set menu
        setHasOptionsMenu(true)

        return binding.root;
    }

    private fun setupRecyclerview() {
        val recyclerView = binding.recyclerView
        recyclerView.adapter = adapter
        recyclerView.layoutManager = StaggeredGridLayoutManager(2,StaggeredGridLayoutManager.VERTICAL)
        //Swip to Delete
        swipeToDelete(recyclerView)
    }

    private fun swipeToDelete(recyclerView: RecyclerView){
        val swipeToDeleteCallback = object : SwipeToDelete(){
            override fun onSwiped(viewHolder: RecyclerView.ViewHolder, direction: Int) {
                val deleteItem = adapter.dataList[viewHolder.adapterPosition]
                //Delete Item
                mToDoViewModel.deleteData(deleteItem)
                adapter.notifyItemRemoved(viewHolder.adapterPosition)
                Toast.makeText(requireContext(),"Successfully Removed: '${deleteItem.tile}'",Toast.LENGTH_SHORT).show()
                //Restore Delete Item
                restoreDeleteData(viewHolder.itemView,deleteItem)
            }
        }
        val itemTouchHelper = ItemTouchHelper(swipeToDeleteCallback)
        itemTouchHelper.attachToRecyclerView(recyclerView)
    }

    private fun restoreDeleteData(view: View,deleteItem:ToDoData){
        val snackbar = Snackbar.make(
            view,"Delete '${deleteItem.tile}'",
            Snackbar.LENGTH_SHORT
        )
        snackbar.setAction("Undo"){
            mToDoViewModel.insertData(deleteItem)
        }
        snackbar.show()
    }


    override fun onCreateOptionsMenu(menu: Menu, inflater: MenuInflater) {
       inflater.inflate(R.menu.list_fragment_menu,menu)

        val search = menu.findItem(R.id.menu_search)
        val searchView = search.actionView as? SearchView
        searchView?.isSubmitButtonEnabled = true
        searchView?.setOnQueryTextListener(this)
    }

    override fun onOptionsItemSelected(item: MenuItem): Boolean {
        when(item.itemId){
           R.id.menu_delete_all ->  confirmRemoval()
           R.id.menu_priority_high -> mToDoViewModel.sortByHighPriority.observe(this,Observer{adapter.setData(it)})
           R.id.menu_priority_low -> mToDoViewModel.sortByLowPriority.observe(this,Observer{adapter.setData(it)})
        }
        return super.onContextItemSelected(item)
    }

    override fun onQueryTextSubmit(query: String?): Boolean {
        if(query != null){
            searchThroughDatabase(query)
        }
        return true
    }


    override fun onQueryTextChange(query: String?): Boolean {
        if(query != null){
            searchThroughDatabase(query)
        }
        return true
    }

    private fun searchThroughDatabase(query: String) {
        var searchQuery = query
        searchQuery = "%$searchQuery%"

        mToDoViewModel.searchDatabase(searchQuery).observe(this,Observer{list->
            list?.let{
                adapter.setData(it)
            }
        })
    }

    //Show AlertDialog to Confirm Removal All Item from Database Table
    private fun confirmRemoval() {
        val builder = AlertDialog.Builder(requireContext())
        builder.setPositiveButton("Yes"){_,_ ->
            mToDoViewModel.deletaAll()
            Toast.makeText(
                requireContext(),
                "Successfully Removed Everything",
                Toast.LENGTH_SHORT
            ).show()
        }
        builder.setNegativeButton("No"){_,_ ->}
        builder.setTitle("Delete Everything?")
        builder.setMessage("Are you sure you want to remove Everything?")
        builder.create().show()
    }

    override fun onDestroyView() {
        super.onDestroyView()
        _binding = null
    }


}

package com.example.to_do_application.fragments.list


import androidx.recyclerview.widget.ItemTouchHelper
import androidx.recyclerview.widget.RecyclerView

abstract class SwipeToDelete: ItemTouchHelper.SimpleCallback(0,ItemTouchHelper.LEFT){

    override fun onMove(
        recyclerView: RecyclerView,
        viewHolder: RecyclerView.ViewHolder,
        target: RecyclerView.ViewHolder
    ): Boolean {
        return  false
    }

}