فیلتر جستجو روی Recycler View در اندروید — راهنمای کاربردی

1class SearchAdapter1(private val mutableList: MutableList<SearchModel1>) :
2    DynamicSearchAdapter<SearchModel1>(mutableList) {
3
4
5    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
6        val textView = TextView(parent.context)
7        return ViewHolder(textView)
8    }
9
10    override fun getItemCount(): Int {
11        return mutableList.count()
12    }
13
14    override fun onBindViewHolder(holder: ViewHolder, position: Int) {
15        val tv = holder.containerView as TextView
16        tv.text = mutableList[position].data
17
18    }
19
20
21}
22class SearchAdapter2(private val mutableList: MutableList<SearchModel2>) :
23    DynamicSearchAdapter<SearchModel2>(mutableList) {
24
25    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
26        val textView = TextView(parent.context)
27        return ViewHolder(textView)
28    }
29
30    override fun getItemCount(): Int {
31        return mutableList.count()
32    }
33
34    override fun onBindViewHolder(holder: ViewHolder, position: Int) {
35        val tv = holder.containerView as TextView
36        tv.text = mutableList[position].data
37
38    }
39
40
41}

1abstract class DynamicSearchAdapter<T : DynamicSearchAdapter.Searchable>(private val searchableList: MutableList<T>) :
2        RecyclerView.Adapter<ViewHolder>(), Filterable {
3
4    // Single not-to-be-modified copy of original data in the list.
5    private val originalList = ArrayList(searchableList)
6    // a method-body to invoke when search returns nothing. It can be null.
7    private var onNothingFound: (() -> Unit)? = null
8
9    /**
10     * Searches a specific item in the list and updates adapter.
11     * if the search returns empty then onNothingFound callback is invoked if provided which can be used to update UI
12     * @param s the search query or text. It can be null.
13     * @param onNothingFound a method-body to invoke when search returns nothing. It can be null.
14     */
15    fun search(s: String?, onNothingFound: (() -> Unit)?) {
16        this.onNothingFound = onNothingFound
17        filter.filter(s)
18
19    }
20
21    override fun getFilter(): Filter {
22        return object : Filter() {
23            private val filterResults = FilterResults()
24            override fun performFiltering(constraint: CharSequence?): FilterResults {
25                searchableList.clear()
26                if (constraint.isNullOrBlank()) {
27                    searchableList.addAll(originalList)
28                } else {
29                    val searchResults = originalList.filter { it.getSearchCriteria().contains(constraint) }
30                    searchableList.addAll(searchResults)
31                }
32                return filterResults.also {
33                    it.values = searchableList
34                }
35            }
36
37            override fun publishResults(constraint: CharSequence?, results: FilterResults?) {
38                // no need to use "results" filtered list provided by this method.
39                if (searchableList.isNullOrEmpty())
40                    onNothingFound?.invoke()
41                notifyDataSetChanged()
42
43            }
44        }
45    }
46
47    interface Searchable {
48        /** This method will allow to specify a search string to compare against
49        your search this can be anything depending on your use case.
50         */
51        fun getSearchCriteria(): String
52    }
53
54
55}

1class SearchModel1(val data: String) : DynamicSearchAdapter.Searchable {
2
3
4    override fun getSearchCriteria(): String {
5        return data
6    }
7}
8class SearchModel2(val data: String) : DynamicSearchAdapter.Searchable {
9
10
11    override fun getSearchCriteria(): String {
12        return data
13    }
14}

1class SampleActivity2 : AppCompatActivity(), SearchView.OnQueryTextListener {
2
3
4    private lateinit var searchAdapter3: SearchAdapter3
5
6    override fun onCreate(savedInstanceState: Bundle?) {
7        super.onCreate(savedInstanceState)
8        setContentView(R.layout.fragment_main)
9        rv.layoutManager = LinearLayoutManager(this)
10        searchAdapter3 = SearchAdapter3(mutableListOf<SearchModel3>().populateWithUUIDSM3())
11        rv.adapter = searchAdapter3
12        searchV.setOnQueryTextListener(this)
13
14    }
15
16    override fun onQueryTextChange(newText: String?): Boolean {
17        search(newText)
18        return true
19    }
20
21    override fun onQueryTextSubmit(query: String?): Boolean {
22        search(query)
23        return true
24    }
25
26    private fun search(s: String?) {
27        searchAdapter3.search(s) {
28            // update UI on nothing found
29            Toast.makeText(this, "Nothing Found", Toast.LENGTH_SHORT).show()
30        }
31    }