[英]Nothing happens when I attempt to search HashMap
我正在尝试实现一项功能,该功能使我可以搜索所有歌曲,这些歌曲都存储在名为songsList的HashMap中。 我已经成功实现了songsList HashMap。 我尝试使用当用户单击搜索图标时输入的由用户键入的字符串来过滤结果,但是没有任何反应。
有什么想法为什么SongsList HashMap没有被过滤?
我尝试区分大小写和不区分大小写的搜索。 我尝试在完整和准确的歌曲标题中搜索几首歌曲。 因此,我认为这不是我要测试的搜索字符串,而是我代码中的某些问题。
PlaylistActivity.java
import android.app.ListActivity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Locale;
public class PlayListActivity extends ListActivity {
private EditText editSearch;
private ImageView searchIcon;
private ListAdapter adapter;
private ArrayList<HashMap<String, String>> songsListData;
private boolean userEnteredSearchString = false;
// Songs playlist_item
public ArrayList<HashMap<String, String>> songsList = new ArrayList<HashMap<String, String>>();
public ArrayList<HashMap<String, String>> filteredSongsList = new ArrayList<HashMap<String, String>>();
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.playlist);
songsListData = new ArrayList<HashMap<String, String>>();
final SongsManager songsManager = new SongsManager();
// get all songs from SD card
this.songsList = songsManager.getPlayList();
createListViewUsingSongs();
// Set up the layout elements for this activity
editSearch = (EditText) findViewById(R.id.search);
searchIcon = (ImageView) findViewById(R.id.search_icon);
// Capture Text in EditText when user clicks search icon
searchIcon.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
String text = editSearch.getText().toString().toLowerCase(Locale.getDefault());
filteredSongsList = songsManager.filter(text);
userEnteredSearchString = true;
createListViewUsingSongs();
}
});
// selecting single ListView item
ListView listView = getListView();
// listening to single playlist_item item click
listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
// getting list item index
int songIndex = position;
// Starting new intent
Intent intent = new Intent(getApplicationContext(), MainActivity.class);
// Sending songIndex to PlayerActivity
intent.putExtra("songIndex", songIndex);
setResult(100, intent);
// Closing PlayListView
finish();
}
}
);
}
private void createListViewUsingSongs() {
if (userEnteredSearchString) {
// looping through playlist
for (int i = 0; i < filteredSongsList.size(); i++){
// creating new HashMap
HashMap<String, String> song = songsList.get(i);
// adding HashList to ArrayList
songsListData.add(song);
}
} else {
// looping through playlist
for (int i = 0; i < songsList.size(); i++){
// creating new HashMap
HashMap<String, String> song = songsList.get(i);
// adding HashList to ArrayList
songsListData.add(song);
}
}
// Adding menuItems to ListView
adapter = new SimpleAdapter(this, songsListData,
R.layout.playlist_item, new String[]{"songTitle"}, new int[]{
R.id.songTitle});
setListAdapter(adapter);
}
}
SongsManager.java
import java.io.File;
import java.io.FilenameFilter;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Locale;
public class SongsManager {
private HashMap<String, String> song;
private String songString;
// SDCard Path
final String MEDIA_PATH = "/storage/extSdCard/music";
private ArrayList<HashMap<String, String>> songsList = new ArrayList<HashMap<String, String>>();
private ArrayList<HashMap<String, String>> filteredSongsList = new ArrayList<HashMap<String, String>>();
// Constructors
public SongsManager(String song) {
this.songString = songString;
}
public SongsManager() {
}
/**
* Function to read all mp3 files from sdcard
* and store the details in ArrayList
*/
public ArrayList<HashMap<String, String>> getPlayList() {
File home = new File(MEDIA_PATH);
if (home.listFiles(new FileExtensionFilter()).length > 0) {
for (File file : home.listFiles(new FileExtensionFilter())) {
HashMap<String, String> song = new HashMap<String, String>();
song.put("songTitle", file.getName().substring(0, (file.getName().length() - 4)));
song.put("songPath", file.getPath());
// Adding each song to SongList
songsList.add(song);
}
}
// return songs playlist_item array
return songsList;
}
public String getSong() {
return this.songString;
}
/**
* Class to filter files which are having .mp3 extension
*/
class FileExtensionFilter implements FilenameFilter {
public boolean accept(File dir, String name) {
return (name.endsWith(".mp3") || name.endsWith(".MP3") || name.endsWith(".wma"));
}
}
// Filter Class
public ArrayList<HashMap<String, String>> filter(String searchString) {
searchString = searchString.toLowerCase(Locale.getDefault());
songsList.clear();
songsList = getPlayList();
//searchString is empty, so show all songs in results
if (searchString.length() == 0) {
if (filteredSongsList != null){
filteredSongsList.clear();
}
filteredSongsList = songsList;
}
//only return songs that match the search string
else {
if (filteredSongsList != null){
filteredSongsList.clear();
}
for (HashMap<String, String> song : songsList) {
if (song != null) {
String songTitle = song.get("songTitle");
if (songTitle.toLowerCase().contains(searchString)) {
filteredSongsList.add(song);
}
}
}
}
return filteredSongsList;
}
}
playList.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<EditText
android:id="@+id/search"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="4"
android:hint="Type song & click search icon"
android:inputType="text"
android:maxLength="40">
<requestFocus />
</EditText>
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/search_icon"
android:layout_weight="1"
android:src="@drawable/ic_search"/>
</LinearLayout>
<ListView
android:id="@android:id/list"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:divider="#242424"
android:dividerHeight="1dp"
android:listSelector="@drawable/list_selector" />
</LinearLayout>
可以在Github上下载完整的代码: https : //github.com/jogold9/Simple_Music_Player
解决:搜索一直songsListData.clear();
都很好,但是我忽略了songsListData.clear();
因此,在刷新适配器时,将显示完整的数据集而不是已过滤的数据集。
不要害怕每个人都使用调试器。 如果我遵循这个简单的建议,我本可以节省几个小时。
import android.app.ListActivity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.Toast;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Locale;
public class PlayListActivity extends ListActivity {
private EditText editSearch; //search text input by user
private ImageView searchIcon;
public SimpleAdapter simpleAdapter;
private ListView listView;
private ArrayList<HashMap<String, String>> songsListData;
public ArrayList<HashMap<String, String>> songsList = new ArrayList<>(); //stores all the songs
public ArrayList<HashMap<String, String>> filteredSongsList = new ArrayList<>(); //stores songs that match search
private int songsAddedCounter = 0; //counter for debugging -> are songs being added to list?
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.playlist);
// Set up the layout elements for this activity
editSearch = (EditText) findViewById(R.id.search);
searchIcon = (ImageView) findViewById(R.id.search_icon);
songsListData = new ArrayList<>(); //Stores all the songs to put into ListView
final SongsManager songsManager = new SongsManager();
// get all songs from SD card
this.songsList = songsManager.getPlayList(); //gets all the songs from the phone and puts them in the HashMap
createListViewUsingSongs(); //draws the ListView on the screen using the songsList HashMap
// selecting single ListView item
listView = getListView();
// listening to single playlist_item item click
listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
int songIndex = position; // getting list item index
// Starting new intent
Intent intent = new Intent(getApplicationContext(), MainActivity.class);
// Sending songIndex to PlayerActivity
intent.putExtra("songIndex", songIndex);
setResult(100, intent);
// Closing PlayListView
finish();
}
}
);
/**
* When user clicks search icon, execute a search, then update the ListView simpleAdapter
*/
searchIcon.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
String text = editSearch.getText().toString().toLowerCase(Locale.getDefault());
filteredSongsList = songsManager.filter(text);
updateListViewUsingSongs();
}
});
}
private void createListViewUsingSongs() {
// looping through playlist
for (int i = 0; i < songsList.size(); i++) {
// creating new HashMap
HashMap<String, String> song = songsList.get(i);
// adding HashList to ArrayList
songsListData.add(song);
}
// Adding menuItems to ListView
simpleAdapter = new SimpleAdapter(this, songsListData,
R.layout.playlist_item, new String[]{"songTitle"}, new int[]{
R.id.songTitle});
setListAdapter(simpleAdapter);
}
private void updateListViewUsingSongs() {
songsAddedCounter = 0;
songsListData.clear(); //super important that we start from zero, and add only the filtered songs!
// looping through playlist
for (int i = 0; i < filteredSongsList.size(); i++) {
// creating new HashMap
HashMap<String, String> song = filteredSongsList.get(i);
// adding HashList to ArrayList
songsListData.add(song);
songsAddedCounter++;
}
Toast.makeText(getApplicationContext(), "Search results: " + songsAddedCounter + " songs", Toast.LENGTH_SHORT).show();
simpleAdapter = null;
simpleAdapter = new SimpleAdapter(this, songsListData,
R.layout.playlist_item, new String[]{"songTitle"}, new int[]{
R.id.songTitle});
setListAdapter(simpleAdapter);
simpleAdapter.notifyDataSetChanged();
}
}
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