Android SQLite存储搜索历史记录，List展示

近期学弟问了用SQLite存储List，今天没事，写一下

需求：用一种存储方式，存储搜索历史记录，数据不可重复，以列表形式倒序输出

解决：本篇介绍用SQLite实现，以后会用SharedPreferences等实现

前端页面写的简单一点，布局就不贴出来了，大概就是这个样子：

1、创建数据库，创建表，创建一个类SearchListSQLiteOpenHelper继承SQLiteOpenHelper

public class SearchListSQLiteOpenHelper extends SQLiteOpenHelper {

    private final static String DB_NAME = "keep.db";
    private final static int DB_VERSION = 1;

    public SearchListSQLiteOpenHelper(Context context) {
        super(context, DB_NAME, null, DB_VERSION);
    }
    @Override
    public void onCreate(SQLiteDatabase db) {
        String sqlStr = "CREATE TABLE IF NOT EXISTS building (_id INTEGER PRIMARY KEY AUTOINCREMENT, name TEXT);";//创建存储搜索楼盘的表
        db.execSQL(sqlStr);
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

    }
}

2、创建数据库操作类SearchListDbOperation ,用于对数据进行，增删查等操作

/**
 * 搜素列表数据库操作类
 *
 * tableName 表名
 */
public class SearchListDbOperation {

    SearchListSQLiteOpenHelper searchListSQLiteOpenHelper;
    SQLiteDatabase recordsDb;
    String tableName;

    public SearchListDbOperation(Context context, String tableName){
        searchListSQLiteOpenHelper = new SearchListSQLiteOpenHelper(context);
        this.tableName = tableName;
    }

    //添加搜索记录
    public void addRecords(String record) {

        if (!isHasRecord(record)) {
            recordsDb = searchListSQLiteOpenHelper.getReadableDatabase();
            ContentValues values = new ContentValues();
            values.put("name", record);
            //添加
            recordsDb.insert(tableName, null, values);
            //关闭
            recordsDb.close();
        }
    }

    //判断是否含有该搜索记录
    public boolean isHasRecord(String record) {
        boolean isHasRecord = false;
        recordsDb = searchListSQLiteOpenHelper.getReadableDatabase();
        Cursor cursor = recordsDb.query(tableName, null, null, null, null, null, null);
        while (cursor.moveToNext()) {
            if (record.equals(cursor.getString(cursor.getColumnIndexOrThrow("name")))) {
                isHasRecord = true;
            }
        }
        //关闭数据库
        recordsDb.close();
        return isHasRecord;
    }

    //获取全部搜索记录
    public List<String> getRecordsList() {
        List<String> recordsList = new ArrayList<>();
        recordsDb = searchListSQLiteOpenHelper.getReadableDatabase();
        Cursor cursor = recordsDb.query(tableName, null, null, null, null, null, null);
        while (cursor.moveToNext()) {
            String name = cursor.getString(cursor.getColumnIndexOrThrow("name"));
            recordsList.add(name);
        }
        //关闭数据库
        recordsDb.close();
        return recordsList;
    }

    //清空搜索记录
    public void deleteAllRecords() {
        recordsDb = searchListSQLiteOpenHelper.getWritableDatabase();
        recordsDb.execSQL("delete from "+tableName);

        recordsDb.close();
    }
}

3、使用ListView展示搜索记录列表，创建适配器

public class SearchRecordsListAdaptet extends BaseAdapter {

    private Context context;
    private List<String> searchRecordsList;
    private LayoutInflater inflater;

    public SearchRecordsListAdaptet(Context context, List<String> searchRecordsList) {
        this.context = context;
        this.searchRecordsList = searchRecordsList;
        inflater = LayoutInflater.from(context);
    }

    @Override
    public int getCount() {
        return searchRecordsList.size() == 0 ? 0 : searchRecordsList.size();
    }

    @Override
    public Object getItem(int position) {
        return searchRecordsList.size() == 0 ? null : searchRecordsList.get(position);
    }

    @Override
    public long getItemId(int position) {
        return position;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {

        ViewHolder viewHolder;
        if(null == convertView){
            viewHolder = new ViewHolder();
            //search_records_list_item布局很简单，就一个TextView
            convertView = inflater.inflate(R.layout.search_records_list_item,null);
            viewHolder.search_records_list_tv = (TextView) convertView.findViewById(R.id.search_records_list_tv);

            convertView.setTag(viewHolder);
        }else{
            viewHolder = (ViewHolder) convertView.getTag();
        }
        viewHolder.search_records_list_tv.setText(searchRecordsList.get(position));
        return convertView;
    }

    private class ViewHolder {
        TextView search_records_list_tv;
    }
}

4、在Activity中的使用

public class SearchActivity extends AppCompatActivity {

    private EditText search_et;
    private Button search_bt,search_bt2;
    private ListView search_lv;

    private List<String> searchRecordsList;
    private List<String> tempList;//临时列表
    private SearchListDbOperation searchListDbOperation;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_search);

        initTheView();
    }

    public void initTheView(){
        search_et = (EditText) findViewById(R.id.search_et);
        search_bt = (Button) findViewById(R.id.search_bt);
        search_bt2 = (Button) findViewById(R.id.search_bt2);
        search_lv = (ListView) findViewById(R.id.search_lv);

        searchListDbOperation = new SearchListDbOperation(this,"building");//传入表名，以对表进行操作
        searchRecordsList = new ArrayList<>();
        tempList = new ArrayList<>();
        tempList.addAll(searchListDbOperation.getRecordsList());
        reversedList();//倒序输出
        //设置适配器
        final SearchRecordsListAdaptet adaptet = new SearchRecordsListAdaptet(this,searchRecordsList);
        search_lv.setAdapter(adaptet);

        search_bt.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (search_et.getText().toString().length() > 0) {

                    String record = search_et.getText().toString();

                    //判断数据库中是否存在该记录
                    if (!searchListDbOperation.isHasRecord(record)) {
                        tempList.add(record);
                    }
                    //将搜索记录保存至数据库中
                    searchListDbOperation.addRecords(record);
                    reversedList();
                    adaptet.notifyDataSetChanged();

                } else {
                    MyToast.showToast(SearchActivity.this,"搜索内容不能为空").show();
                }
            }
        });

        //清空所有历史记录
        search_bt2.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                tempList.clear();
                reversedList();
                searchListDbOperation.deleteAllRecords();
                adaptet.notifyDataSetChanged();
            }
        });

    }

    //颠倒list顺序，用户输入的信息会从上依次往下显示
    private void reversedList(){
        searchRecordsList.clear();
        for(int i = tempList.size() - 1 ; i >= 0 ; i --){
            searchRecordsList.add(tempList.get(i));
        }
    }
}

到此就完成了！