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多重搜索算法
In this tutorial, we’ll discuss and implement a search feature that displays the matched results in a drop-down beside allowing to filter the ListView results based on the searched string. This type of UI is commonly seen in Food Delivery apps that have plenty of options to choose from. The user can search based on a certain tag/category to quickly find their desired result.
在本教程中，我们将讨论并实现搜索功能，该功能将在下拉菜单中显示匹配的结果，并允许根据搜索到的字符串过滤ListView结果。 这种界面通常出现在“食物交付”应用程序中，该应用程序有很多可供选择的选项。 用户可以基于某个标签/类别进行搜索以快速找到他们想要的结果。
At the end of this tutorial, you’ll be able to come up with a working application similar to the one given below.
在本教程的最后，您将能够提出一个与下面给出的应用程序相似的工作应用程序。
For the above application, we’ll NOT be using a SearchView. Instead, we’ll be using an EditText wrapped inside a CardView. The dropdown that pops up with a list of suggestions will be a RecyclerView.
对于上述应用程序，我们将不使用SearchView。 相反，我们将使用CardView中包装的EditText。 弹出的建议列表下拉列表将是RecyclerView。
The activity_main.xml layout is given below.
下面是activity_main.xml布局。
In the above code, the CardView is a Custom SearchView UI with a back button on the left. The ListView would display all the restaurants from the adapter.
在上面的代码中，CardView是一个Custom SearchView UI，左侧带有一个后退按钮。 ListView将显示适配器中的所有餐厅。
The Data Source for the restaurants and the type of cuisines is defined in the Model.java file as shown below.
餐厅和菜肴类型的数据源在Model.java文件中定义，如下所示。
package com.journaldev.efficientsearch;import java.util.List;public class Model { public String name; public String id; public List cuisines; public boolean isCuisine; public int numberOfCuisine; public Model(String id, String name, List cuisines, boolean isCuisine, int numberOfCuisine) { this.name = name; this.id = id; this.cuisines = cuisines; this.isCuisine = isCuisine; this.numberOfCuisine = numberOfCuisine; }} The parameter that differentiates between a restaurant and a cuisine is isCuisine which is of type Boolean.
区分餐厅和美食的参数是isCuisine ，其类型为Boolean。
The MainActivity.java is given below.
MainActivity.java在下面给出。
package com.journaldev.efficientsearch;import android.content.Context;import android.os.Bundle;import android.support.v7.app.AppCompatActivity;import android.support.v7.widget.CardView;import android.support.v7.widget.LinearLayoutManager;import android.support.v7.widget.RecyclerView;import android.support.v7.widget.Toolbar;import android.text.Editable;import android.text.TextWatcher;import android.util.Log;import android.view.KeyEvent;import android.view.MenuItem;import android.view.View;import android.view.inputmethod.EditorInfo;import android.view.inputmethod.InputMethodManager;import android.widget.EditText;import android.widget.ImageView;import android.widget.ListView;import android.widget.RelativeLayout;import android.widget.TextView;import android.widget.Toast;import java.util.ArrayList;import java.util.Arrays;import java.util.HashMap;import java.util.List;import java.util.Map;public class MainActivity extends AppCompatActivity implements CuisineSearchAdapter.ItemListener { Toolbar toolbar; private ImageView image_search_back; private RelativeLayout view_search; private EditText edit_text_search; private CardView card_search; private View line_divider, toolbar_shadow; RecyclerView recyclerView; ListView listView; String text = ""; List modelsList, filterModels; List cuisinesModels; ListViewAdapter listViewAdapter; CuisineSearchAdapter cuisineSearchAdapter; ShowSearchView showSearchView; boolean editTextChangedFromClick = false; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); showSearchView = new ShowSearchView(); toolbar = (Toolbar) findViewById(R.id.toolbar); toolbar.inflateMenu(R.menu.menu_main); image_search_back = (ImageView) findViewById(R.id.image_search_back); view_search = (RelativeLayout) findViewById(R.id.view_search); edit_text_search = (EditText) findViewById(R.id.edit_text_search); card_search = (CardView) findViewById(R.id.card_search); line_divider = findViewById(R.id.line_divider); toolbar_shadow = findViewById(R.id.toolbar_shadow); recyclerView = (RecyclerView) findViewById(R.id.recyclerView); listView = (ListView) findViewById(R.id.listView); TextView no_results = (TextView) findViewById(R.id.txtNoResultsFound); listView.setEmptyView(no_results); populateRestaurantsAndCuisines(); image_search_back.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { text = ""; showSearchView.handleToolBar(MainActivity.this, card_search, toolbar, view_search, recyclerView, edit_text_search, line_divider); toolbar_shadow.setVisibility(View.VISIBLE); listViewAdapter = new ListViewAdapter(modelsList); listView.setAdapter(listViewAdapter); } }); edit_text_search.addTextChangedListener(new TextWatcher() { @Override public void beforeTextChanged(CharSequence s, int start, int count, int after) { } @Override public void onTextChanged(CharSequence s, int start, int before, int count) { text = s.toString(); if (editTextChangedFromClick) { editTextChangedFromClick = false; if (recyclerView.getVisibility() == View.VISIBLE) recyclerView.setVisibility(View.GONE); } else { if (recyclerView.getVisibility() != View.VISIBLE) recyclerView.setVisibility(View.VISIBLE); if (s.toString().length() > 0) { performFiltering(filterModels); } else { CuisineSearchAdapter cuisineSearchAdapter = new CuisineSearchAdapter(cuisinesModels, modelsList, MainActivity.this, MainActivity.this, text); cuisineSearchAdapter.notifyDataSetChanged(); recyclerView.setAdapter(cuisineSearchAdapter); listViewAdapter = new ListViewAdapter(modelsList); listView.setAdapter(listViewAdapter); } } } @Override public void afterTextChanged(Editable s) { } }); edit_text_search.setOnEditorActionListener(new TextView.OnEditorActionListener() { @Override public boolean onEditorAction(TextView v, int actionId, KeyEvent event) { if (actionId == EditorInfo.IME_ACTION_SEARCH) { // Your piece of code on keyboard search click recyclerView.setVisibility(View.GONE); ((InputMethodManager) getApplicationContext().getSystemService(Context.INPUT_METHOD_SERVICE)).hideSoftInputFromWindow(view_search.getWindowToken(), 0); listViewAdapter.getFilter().filter(v.getText().toString()); return true; } return false; } }); toolbar.setOnMenuItemClickListener(new Toolbar.OnMenuItemClickListener() { @Override public boolean onMenuItemClick(MenuItem item) { int menuItem = item.getItemId(); switch (menuItem) { case R.id.action_search: recyclerView.setLayoutManager(new LinearLayoutManager(MainActivity.this)); cuisineSearchAdapter = new CuisineSearchAdapter(cuisinesModels, filterModels, MainActivity.this, MainActivity.this, text); recyclerView.setAdapter(cuisineSearchAdapter); showSearchView.handleToolBar(MainActivity.this, card_search, toolbar, view_search, recyclerView, edit_text_search, line_divider); break; default: break; } return false; } }); } private void populateRestaurantsAndCuisines() { modelsList = new ArrayList(); cuisinesModels = new ArrayList(); List cuisinesList = new ArrayList(); for (int i = 0; i < 7; i++) cuisinesList.add("Cafes"); for (int i = 0; i < 4; i++) cuisinesList.add("Burgers"); for (int i = 0; i < 4; i++) cuisinesList.add("Bars"); modelsList.add(new Model("1", "McDonalds", new ArrayList(Arrays.asList("Cafes", "Burgers")), false, -1)); modelsList.add(new Model("2", "KFC", new ArrayList(Arrays.asList("Cafes", "Burgers")), false, -1)); modelsList.add(new Model("3", "Burger King", new ArrayList(Arrays.asList("Cafes", "Burgers")), false, -1)); modelsList.add(new Model("4", "Subway", new ArrayList(Arrays.asList("Burgers")), false, -1)); modelsList.add(new Model("5", "Cafe Coffee Day", new ArrayList(Arrays.asList("Cafes")), false, -1)); modelsList.add(new Model("6", "Costa", new ArrayList(Arrays.asList("Cafes")), false, -1)); modelsList.add(new Model("7", "Coffee Beans", new ArrayList(Arrays.asList("Cafes")), false, -1)); modelsList.add(new Model("8", "Starbucks", new ArrayList(Arrays.asList("Cafes")), false, -1)); modelsList.add(new Model("9", "Blues", new ArrayList(Arrays.asList("Bars")), false, -1)); modelsList.add(new Model("10", "Hard Rock Cafe", new ArrayList(Arrays.asList("Bars", "Cafe")), false, -1)); modelsList.add(new Model("11", "The Backyard Underground", new ArrayList(Arrays.asList("Bars")), false, -1)); modelsList.add(new Model("12", "Downtown", new ArrayList(Arrays.asList("Bars")), false, -1)); Map cuisineMap = new HashMap(); for (String cuisine : cuisinesList) { Integer n = cuisineMap.get(cuisine); n = (n == null) ? 1 : ++n; cuisineMap.put(cuisine, n); } for (Map.Entry entry : cuisineMap.entrySet()) { Model model = new Model("", entry.getKey(), null, true, entry.getValue()); modelsList.add(model); cuisinesModels.add(model); } filterModels = new ArrayList(modelsList); initialiseAdapters(); } private void initialiseAdapters() { listViewAdapter = new ListViewAdapter(filterModels); listView.setAdapter(listViewAdapter); } @Override public void onItemClick(Model model) { editTextChangedFromClick = true; if (model.isCuisine) { edit_text_search.setText(model.name); listViewAdapter.getFilter().filter(model.name); } else { edit_text_search.setText(model.name); showSearchView.handleToolBar(MainActivity.this, card_search, toolbar, view_search, recyclerView, edit_text_search, line_divider); Toast.makeText(getApplicationContext(), model.name + " was selected.", Toast.LENGTH_LONG).show(); } } public void performFiltering(List filteredSuggestions) { filteredSuggestions.clear(); for (Model model : modelsList) { if (model.name.toLowerCase().contains(text.toLowerCase())) { filteredSuggestions.add(model); } } CuisineSearchAdapter cuisineSearchAdapter = new CuisineSearchAdapter(cuisinesModels, filteredSuggestions, MainActivity.this, MainActivity.this, text); cuisineSearchAdapter.notifyDataSetChanged(); recyclerView.setAdapter(cuisineSearchAdapter); }} The Toolbar layout is set from the menu_main.xml file as shown below.
可以从menu_main.xml文件设置工具栏布局，如下所示。
Before analysing the MainActivity.java class in detail, let’s glance at the code for ListViewAdapter with a filter. Something that we’ve already implemented .
在详细分析MainActivity.java类之前，让我们看一下带有过滤器的ListViewAdapter的代码。 我们已经实现一些东西。
The code for the ListViewAdapter.java class is given below.
下面给出了ListViewAdapter.java类的代码。
package com.journaldev.efficientsearch;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.widget.BaseAdapter;import android.widget.Filter;import android.widget.Filterable;import android.widget.TextView;import java.util.ArrayList;import java.util.List;public class ListViewAdapter extends BaseAdapter implements Filterable { private List modelList; private List mStringFilterList; private ValueFilter valueFilter; private class ViewHolder { TextView vendorName; } public ListViewAdapter(List modelList) { this.modelList = modelList; mStringFilterList = modelList; } @Override public int getCount() { if (modelList != null) return modelList.size(); else return 0; } @Override public Model getItem(int position) { return modelList.get(position); } @Override public long getItemId(int position) { Model object = getItem(position); if (object.isCuisine) { return -1; } else return Integer.parseInt(object.id); } @Override public View getView(int position, View convertView, final ViewGroup parent) { ViewHolder holder = null; Model vendorModel = getItem(position); if (vendorModel.isCuisine) { return LayoutInflater.from(parent.getContext()).inflate(R.layout.row_null, null); } else { if (convertView == null) { convertView = LayoutInflater.from(parent.getContext()).inflate(R.layout.list_row_model, parent, false); holder = new ViewHolder(); holder.vendorName = ((TextView) convertView.findViewById(R.id.txt_vendor_name)); convertView.setTag(holder); } else { if (holder == null) { convertView = LayoutInflater.from(parent.getContext()).inflate(R.layout.list_row_model, parent, false); holder = new ViewHolder(); holder.vendorName = ((TextView) convertView.findViewById(R.id.txt_vendor_name)); convertView.setTag(holder); } else holder = (ViewHolder) convertView.getTag(); } holder.vendorName.setText(vendorModel.name); return convertView; } } @Override public Filter getFilter() { if (valueFilter == null) { valueFilter = new ValueFilter(); } return valueFilter; } private class ValueFilter extends Filter { @Override protected FilterResults performFiltering(CharSequence constraint) { FilterResults results = new FilterResults(); if (constraint != null && constraint.length() > 0) { List filterList = new ArrayList(); for (int i = 0; i < mStringFilterList.size(); i++) { if (!mStringFilterList.get(i).isCuisine) { if (mStringFilterList.get(i).cuisines.contains(constraint)) { Model model = new Model(mStringFilterList.get(i).id, mStringFilterList.get(i).name, mStringFilterList.get(i).cuisines, false, -1); filterList.add(model); } } } if (filterList.size() == 0) { for (int i = 0; i < mStringFilterList.size(); i++) { if ((mStringFilterList.get(i).name.toUpperCase()) .contains(constraint.toString().toUpperCase()) && !mStringFilterList.get(i).isCuisine) { Model model = new Model(mStringFilterList.get(i).id, mStringFilterList.get(i).name, mStringFilterList.get(i).cuisines, false, -1); if (!model.isCuisine) filterList.add(model); } } } results.count = filterList.size(); results.values = filterList; } else { results.count = mStringFilterList.size(); results.values = mStringFilterList; } return results; } @Override protected void publishResults(CharSequence constraint, FilterResults results) { modelList = (List) results.values; notifyDataSetChanged(); } }} In the above class, we check the isCuisine param on each Model instance. If it’s true we add an empty row with 0 height. Else list_row_model.xml is added. The xml code for each of the layouts is given below.
在上面的类中，我们检查每个Model实例上的isCuisine参数。 如果为真，则添加一个高度为0的空行。 否则添加了list_row_model.xml 。 下面给出了每种布局的xml代码。
Clicking the search icon from the Toolbar inflates our custom Search UI and populates the RecyclerView under. To do this, the handleToolbar method is invoked on an instance from the ShowSearchView class.
The code for theShowSearchView.java is given below. 单击工具栏中的搜索图标，将使我们的自定义搜索UI膨胀，并在下面填充RecyclerView。 为此，在ShowSearchView类的实例上调用handleToolbar方法。
下面给出了ShowSearchView.java的代码。 package com.journaldev.efficientsearch;import android.animation.Animator;import android.content.Context;import android.content.res.Resources;import android.os.Build;import android.support.v7.widget.CardView;import android.support.v7.widget.RecyclerView;import android.support.v7.widget.Toolbar;import android.util.DisplayMetrics;import android.view.View;import android.view.ViewAnimationUtils;import android.view.animation.Animation;import android.view.animation.AnimationUtils;import android.view.inputmethod.InputMethodManager;import android.widget.EditText;public class ShowSearchView { public static void handleToolBar(final Context context, final CardView search, Toolbar toolbarMain, final View view, final RecyclerView recyclerView, final EditText editText, final View line_divider) { final Animation fade_in = AnimationUtils.loadAnimation(context.getApplicationContext(), android.R.anim.fade_in); final Animation fade_out = AnimationUtils.loadAnimation(context.getApplicationContext(), android.R.anim.fade_out); if (search.getVisibility() == View.VISIBLE) { if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) { final Animator animatorHide = ViewAnimationUtils.createCircularReveal(search, search.getWidth() - (int) convertDpToPixel(56, context), (int) convertDpToPixel(23, context), (float) Math.hypot(search.getWidth(), search.getHeight()), 0); animatorHide.addListener(new Animator.AnimatorListener() { @Override public void onAnimationStart(Animator animation) { } @Override public void onAnimationEnd(Animator animation) { view.startAnimation(fade_out); view.setVisibility(View.INVISIBLE); search.setVisibility(View.GONE); ((InputMethodManager) context.getSystemService(Context.INPUT_METHOD_SERVICE)).hideSoftInputFromWindow(view.getWindowToken(), 0); recyclerView.setVisibility(View.GONE); } @Override public void onAnimationCancel(Animator animation) { } @Override public void onAnimationRepeat(Animator animation) { } }); animatorHide.setDuration(300); animatorHide.start(); } else { ((InputMethodManager) context.getSystemService(Context.INPUT_METHOD_SERVICE)).hideSoftInputFromWindow(view.getWindowToken(), 0); view.startAnimation(fade_out); view.setVisibility(View.INVISIBLE); search.setVisibility(View.GONE); } editText.setText(""); toolbarMain.getMenu().clear(); toolbarMain.inflateMenu(R.menu.menu_main); search.setEnabled(false); } else { toolbarMain.getMenu().clear(); toolbarMain.setNavigationIcon(null); if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) { final Animator animator = ViewAnimationUtils.createCircularReveal(search, search.getWidth() - (int) convertDpToPixel(56, context), (int) convertDpToPixel(23, context), 0, (float) Math.hypot(search.getWidth(), search.getHeight())); animator.addListener(new Animator.AnimatorListener() { @Override public void onAnimationStart(Animator animation) { } @Override public void onAnimationEnd(Animator animation) { view.setVisibility(View.VISIBLE); view.startAnimation(fade_in); ((InputMethodManager) context.getSystemService(Context.INPUT_METHOD_SERVICE)).toggleSoftInput(InputMethodManager.SHOW_FORCED, InputMethodManager.HIDE_IMPLICIT_ONLY); } @Override public void onAnimationCancel(Animator animation) { } @Override public void onAnimationRepeat(Animator animation) { } }); search.setVisibility(View.VISIBLE); if (search.getVisibility() == View.VISIBLE) { animator.setDuration(300); animator.start(); search.setEnabled(true); } fade_in.setAnimationListener(new Animation.AnimationListener() { @Override public void onAnimationStart(Animation animation) { } @Override public void onAnimationEnd(Animation animation) { editText.requestFocus(); recyclerView.setVisibility(View.VISIBLE); } @Override public void onAnimationRepeat(Animation animation) { } }); } else { search.setVisibility(View.VISIBLE); search.setEnabled(true); recyclerView.setVisibility(View.VISIBLE); editText.requestFocus(); ((InputMethodManager) context.getSystemService(Context.INPUT_METHOD_SERVICE)).showSoftInput(editText, InputMethodManager.SHOW_IMPLICIT); } } } public static float convertDpToPixel(float dp, Context context) { Resources resources = context.getResources(); DisplayMetrics metrics = resources.getDisplayMetrics(); return dp * (metrics.densityDpi / 160f); }} The handleToolbar method shows/hides the custom UI depending upon the search icon/back arrow clicked respectively. The view animates in/out in the form of circular reveal animation.
handleToolbar方法根据分别单击的搜索图标/后退箭头来显示/隐藏自定义UI。 视图以圆形显示动画的形式进行动画进/出。
The RecyclerView is populated with the cuisines as well as restaurants. Though only the cuisines are displayed until the user types anything.
RecyclerView充满了美食和餐厅。 尽管仅显示美食，直到用户键入任何内容。
The adapter for the RecyclerView is defined in the class CuisinesSearchAdapter.java as shown below.
用于RecyclerView适配器在该类中定义CuisinesSearchAdapter.java如下所示。
package com.journaldev.efficientsearch;import android.content.Context;import android.graphics.Color;import android.support.v7.widget.RecyclerView;import android.text.Spannable;import android.text.SpannableString;import android.text.style.ForegroundColorSpan;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.widget.ImageView;import android.widget.TextView;import java.text.Normalizer;import java.util.List;import java.util.Locale;public class CuisineSearchAdapter extends RecyclerView.Adapter { Context mContext; ItemListener mListener; String prefix = ""; private List allVendors, cuisines; public CuisineSearchAdapter(List cuisines, List vendorModels, Context context, ItemListener itemListener, String text) { this.allVendors = vendorModels; this.cuisines = cuisines; this.mContext = context; this.mListener = itemListener; prefix = text; } public class MyViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener { ImageView icon; TextView textView; View parent; Model vendorModel; MyViewHolder(View itemView) { super(itemView); this.parent = itemView.findViewById(R.id.parentView); this.textView = (TextView) itemView.findViewById(R.id.textView); this.icon = (ImageView) itemView.findViewById(R.id.imageView); itemView.setOnClickListener(this); } void setData(Model model, MyViewHolder holder) { textView = holder.textView; icon = holder.icon; this.vendorModel = model; if (prefix.length() > 0) { if (model.isCuisine) { textView.setText(highlight(prefix, model.name + " (" + model.numberOfCuisine + ")")); icon.setImageResource(R.mipmap.ic_local_offer); } else { textView.setText(highlight(prefix, model.name)); icon.setImageResource(R.mipmap.ic_local_dining); } } else { if (model.isCuisine) { textView.setText(model.name + " (" + model.numberOfCuisine + ")"); icon.setImageResource(R.mipmap.ic_local_offer); } } } @Override public void onClick(View view) { if (mListener != null) { mListener.onItemClick(vendorModel); } } } @Override public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) { final View view = LayoutInflater.from(parent.getContext()) .inflate(R.layout.recyclerview_list_row, parent, false); MyViewHolder myViewHolder = new MyViewHolder(view); return myViewHolder; } @Override public void onBindViewHolder(final MyViewHolder holder, final int listPosition) { if (prefix.length() > 0) holder.setData(allVendors.get(holder.getAdapterPosition()), holder); else holder.setData(cuisines.get(holder.getAdapterPosition()), holder); } @Override public int getItemCount() { if (prefix.length() > 0) return allVendors.size(); else return cuisines.size(); } private static CharSequence highlight(String search, String originalText) { // ignore case and accents // the same thing should have been done for the search text String normalizedText = Normalizer .normalize(originalText, Normalizer.Form.NFD) .replaceAll("\\p{InCombiningDiacriticalMarks}+", "") .toLowerCase(Locale.ENGLISH); int start = normalizedText.indexOf(search.toLowerCase(Locale.ENGLISH)); if (start = 0) { int spanStart = Math.min(start, originalText.length()); int spanEnd = Math.min(start + search.length(), originalText.length()); highlighted.setSpan(new ForegroundColorSpan(Color.BLUE), spanStart, spanEnd, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE); start = normalizedText.indexOf(search, spanEnd); } return highlighted; } } public interface ItemListener { void onItemClick(Model model); }} The layout for each row of the RecyclerView is defined in the xml code below.
RecyclerView每行的布局在下面的xml代码中定义。
MainActivity.java class. The substrings in the RecyclerView rows that match the typed text are then highlighted. 当用户输入文本时，将从MainActivity.java类中的performFiltering方法中过滤RecyclerView数据。 然后，RecyclerView行中与键入的文本匹配的子字符串将突出显示。 This brings an end to this tutorial. You can download the Android EfficientSearch Project from the link below.
本教程到此结束。 您可以从下面的链接下载Android EfficientSearch项目 。
翻译自:
多重搜索算法
转载地址：http://symzd.baihongyu.com/