Question

专家请按照我的查询提出建议。我试图在Android工作室中运行查询。

原样：Spinner根据使用Textwatcher输入的edittext X值显示X值。

要成为：微调器应根据编辑文本中输入的X值显示Y值。

示例：如果我在edittext中输入值“6”，那么我的微调器应该显示vaue“数据结构”

我的数据库如下：

数据库遵循

package com.bar.example.myapplication;


import android.content.ContentValues;
import android.content.Context;
import android.content.res.AssetManager;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.Arrays;

class DBHelper extends SQLiteOpenHelper {

  private Context mContext;

  //TASK: DEFINE THE DATABASE VERSION AND NAME  (DATABASE CONTAINS MULTIPLE TABLES)
  static final String DATABASE_NAME = "OCC";
  private static final int DATABASE_VERSION = 1;

  //TASK: DEFINE THE FIELDS (COLUMN NAMES) FOR THE COURSES TABLE
  public static final String COURSES_TABLE = "Courses";
  public static final String COURSES_KEY_FIELD_ID = "_id";
  public static final String FIELD_ALPHA = "alpha";
  public static final String FIELD_NUMBER = "number";
  public static final String FIELD_TITLE = "title";

  //TASK: DEFINE THE FIELDS (COLUMN NAMES) FOR THE INSTRUCTORS TABLE


  //TASK: DEFINE THE FIELDS (COLUMN NAMES) FOR THE OFFERINGS TABLE
  private static final String OFFERINGS_TABLE = "Offerings";
  private static final String OFFERINGS_KEY_FIELD_ID = "crn";
  private static final String FIELD_SEMESTER_CODE = "semester_code";
  public static final String FIELD_COURSE_ID = "course_id";

  public DBHelper(Context context) {
    super(context, DATABASE_NAME, null, DATABASE_VERSION);
    mContext = context;
  }

  @Override
  public void onCreate(SQLiteDatabase database) {
    String createQuery = "CREATE TABLE " + COURSES_TABLE + "(" +
      COURSES_KEY_FIELD_ID + " INTEGER PRIMARY KEY AUTOINCREMENT, " +
      FIELD_ALPHA + " TEXT, " +
      FIELD_NUMBER + " TEXT, " +
      FIELD_TITLE + " TEXT" + ")";
    database.execSQL(createQuery);



    createQuery = "CREATE TABLE " + OFFERINGS_TABLE + "(" +
      OFFERINGS_KEY_FIELD_ID + " INTEGER PRIMARY KEY AUTOINCREMENT, " +
      FIELD_SEMESTER_CODE + " INTEGER, " +
      FIELD_COURSE_ID + " INTEGER, "

      +
      "FOREIGN KEY(" + FIELD_COURSE_ID + ") REFERENCES "

      +
      COURSES_TABLE + "(" + COURSES_KEY_FIELD_ID + ")" +
      ")";
    database.execSQL(createQuery);
  }

  @Override
  public void onUpgrade(SQLiteDatabase database,
    int oldVersion,
    int newVersion) {
    database.execSQL("DROP TABLE IF EXISTS " + COURSES_TABLE);

    database.execSQL("DROP TABLE IF EXISTS " + OFFERINGS_TABLE);
    onCreate(database);
  }

  //********** COURSE TABLE OPERATIONS:  ADD, GETALL, EDIT, DELETE

  public void addCourse(Course course) {
    SQLiteDatabase db = this.getWritableDatabase();
    ContentValues values = new ContentValues();

    values.put(FIELD_ALPHA, course.getAlpha());
    values.put(FIELD_NUMBER, course.getNumber());
    values.put(FIELD_TITLE, course.getTitle());

    db.insert(COURSES_TABLE, null, values);

    // CLOSE THE DATABASE CONNECTION
    db.close();
  }

  public ArrayList < Course > getAllCourses() {
    ArrayList < Course > coursesList = new ArrayList < > ();
    SQLiteDatabase database = this.getReadableDatabase();
    //Cursor cursor = database.rawQuery(queryList, null);
    Cursor cursor = database.query(
      COURSES_TABLE,
      new String[] {
        COURSES_KEY_FIELD_ID,
        FIELD_ALPHA,
        FIELD_NUMBER,
        FIELD_TITLE
      },
      null,
      null,
      null, null, null, null);

    //COLLECT EACH ROW IN THE TABLE
    if (cursor.moveToFirst()) {
      do {
        Course course =
          new Course(cursor.getInt(0),
            cursor.getString(1),
            cursor.getString(2),
            cursor.getString(3));
        coursesList.add(course);
      } while (cursor.moveToNext());
    }
    return coursesList;
  }

  public void deleteCourse(Course course) {
    SQLiteDatabase db = this.getWritableDatabase();

    // DELETE THE TABLE ROW
    db.delete(COURSES_TABLE, COURSES_KEY_FIELD_ID + " = ?",
      new String[] {
        String.valueOf(course.getId())
      });
    db.close();
  }

  public void deleteAllCourses() {
    SQLiteDatabase db = this.getWritableDatabase();
    db.delete(COURSES_TABLE, null, null);
    db.close();
  }

  public void updateCourse(Course course) {
    SQLiteDatabase db = this.getWritableDatabase();
    ContentValues values = new ContentValues();

    values.put(FIELD_ALPHA, course.getAlpha());
    values.put(FIELD_NUMBER, course.getNumber());
    values.put(FIELD_TITLE, course.getTitle());

    db.update(COURSES_TABLE, values, COURSES_KEY_FIELD_ID + " = ?",
      new String[] {
        String.valueOf(course.getId())
      });
    db.close();
  }

  public Course getCourse(int id) {
    SQLiteDatabase db = this.getReadableDatabase();
    Cursor cursor = db.query(
      COURSES_TABLE,
      new String[] {
        COURSES_KEY_FIELD_ID,
        FIELD_ALPHA,
        FIELD_NUMBER,
        FIELD_TITLE
      },
      COURSES_KEY_FIELD_ID + "=?",
      new String[] {
        String.valueOf(id)
      },
      null, null, null, null);

    if (cursor != null)
      cursor.moveToFirst();

    Course course = new Course(
      cursor.getInt(0),
      cursor.getString(1),
      cursor.getString(2),
      cursor.getString(3));

    db.close();
    return course;
  }




  //********** OFFERING TABLE OPERATIONS:  ADD, GETALL, EDIT, DELETE

  public void addOffering(int crn, int semesterCode, int courseId) {
    SQLiteDatabase db = this.getWritableDatabase();
    ContentValues values = new ContentValues();

    values.put(OFFERINGS_KEY_FIELD_ID, crn);
    values.put(FIELD_SEMESTER_CODE, semesterCode);
    values.put(FIELD_COURSE_ID, courseId);


    db.insert(OFFERINGS_TABLE, null, values);

    // CLOSE THE DATABASE CONNECTION
    db.close();
  }

  public ArrayList < Offering > getAllOfferings() {
    ArrayList < Offering > offeringsList = new ArrayList < > ();
    SQLiteDatabase database = this.getReadableDatabase();
    //Cursor cursor = database.rawQuery(queryList, null);
    Cursor cursor = database.query(
      OFFERINGS_TABLE,
      new String[] {
        OFFERINGS_KEY_FIELD_ID,
        FIELD_SEMESTER_CODE,
        FIELD_COURSE_ID
      },
      null,
      null,
      null, null, null, null);

    //COLLECT EACH ROW IN THE TABLE
    if (cursor.moveToFirst()) {
      do {
        Course course = getCourse(cursor.getInt(2));
        //Instructor instructor = getInstructor(cursor.getInt(3));
        Offering offering = new Offering(cursor.getInt(0),
          cursor.getInt(1), course);

        offeringsList.add(offering);
      } while (cursor.moveToNext());
    }
    return offeringsList;
  }

  public void deleteOffering(Offering offering) {
    SQLiteDatabase db = this.getWritableDatabase();

    // DELETE THE TABLE ROW
    db.delete(OFFERINGS_TABLE, OFFERINGS_KEY_FIELD_ID + " = ?",
      new String[] {
        String.valueOf(offering.getCRN())
      });
    db.close();
  }

  public void deleteAllOfferings() {
    SQLiteDatabase db = this.getWritableDatabase();
    db.delete(OFFERINGS_TABLE, null, null);
    db.close();
  }

  public void updateOffering(Offering offering) {
    SQLiteDatabase db = this.getWritableDatabase();
    ContentValues values = new ContentValues();

    values.put(FIELD_SEMESTER_CODE, offering.getSemesterCode());
    values.put(FIELD_COURSE_ID, offering.getCourse().getId());


    db.update(OFFERINGS_TABLE, values, OFFERINGS_KEY_FIELD_ID + " = ?",
      new String[] {
        String.valueOf(offering.getCRN())
      });
    db.close();
  }

  public Offering getOffering(int crn) {
    SQLiteDatabase db = this.getReadableDatabase();
    Cursor cursor = db.query(
      OFFERINGS_TABLE,
      new String[] {
        OFFERINGS_KEY_FIELD_ID,
        FIELD_SEMESTER_CODE,
        FIELD_COURSE_ID
      },
      OFFERINGS_KEY_FIELD_ID + "=?",
      new String[] {
        String.valueOf(crn)
      },
      null, null, null, null);

    if (cursor != null)
      cursor.moveToFirst();

    Course course = getCourse(cursor.getInt(2));
    //Instructor instructor = getInstructor(cursor.getInt(3));
    Offering offering = new Offering(cursor.getInt(0),
      cursor.getInt(1), course);


    db.close();
    return offering;
  }

  public Cursor getAllLabelsAsCursor() {
    String[] columns = new String[] {
      "rowid AS _id, *"
    }; // Need _id column for SimpleCursorAdapter
    return this.getWritableDatabase().query(COURSES_TABLE, columns, null, null, null, null, null);
  }



  public boolean importCoursesFromCSV(String csvFileName) {
    AssetManager manager = mContext.getAssets();
    InputStream inStream;
    try {
      inStream = manager.open(csvFileName);
    } catch (IOException e) {
      e.printStackTrace();
      return false;
    }

    BufferedReader buffer = new BufferedReader(new InputStreamReader(inStream));
    String line;
    try {
      while ((line = buffer.readLine()) != null) {
        String[] fields = line.split(",");
        if (fields.length != 4) {
          Log.d("OCC Course Finder", "Skipping Bad CSV Row: " + Arrays.toString(fields));
          continue;
        }
        int id = Integer.parseInt(fields[0].trim());
        String alpha = fields[1].trim();
        String number = fields[2].trim();
        String title = fields[3].trim();
        addCourse(new Course(id, alpha, number, title));
      }
    } catch (IOException e) {
      e.printStackTrace();
      return false;
    }
    return true;
  }



  public boolean importOfferingsFromCSV(String csvFileName) {
    AssetManager am = mContext.getAssets();
    InputStream inStream = null;
    try {
      inStream = am.open(csvFileName);
    } catch (IOException e) {
      e.printStackTrace();
    }

    BufferedReader buffer = new BufferedReader(new InputStreamReader(inStream));
    String line;
    try {
      while ((line = buffer.readLine()) != null) {
        String[] fields = line.split(",");
        if (fields.length != 4) {
          Log.d("OCC Course Finder", "Skipping Bad CSV Row: " + Arrays.toString(fields));
          continue;
        }
        int crn = Integer.parseInt(fields[0].trim());
        int semesterCode = Integer.parseInt(fields[1].trim());
        int courseId = Integer.parseInt(fields[2].trim());

        addOffering(crn, semesterCode, courseId);
      }
    } catch (IOException e) {
      e.printStackTrace();
      return false;
    }
    return true;
  }
}

主要活动。

package com.bar.example.myapplication;


import android.database.Cursor;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;


import android.text.Editable;
import android.text.TextWatcher;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.SimpleCursorAdapter;
import android.widget.Spinner;
import android.widget.Toast;
import android.util.Log;
import java.util.ArrayList;
import java.util.List;

public class CourseSearchActivity extends AppCompatActivity {

  private DBHelper db;
  private List < Course > allCoursesList;
  private List < Offering > allOfferingsList;
  private List < Offering > filteredOfferingsList;
  public Button reset;
  private EditText courseTitleEditText;
  private Spinner ok;
  private ListView offeringsListView;

  // private selectedInstructorName selectedInstructorName;
  private InstructorSpinnerAdapter instructorSpinnerAdapter;
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_course_search);

    deleteDatabase(DBHelper.DATABASE_NAME);
    db = new DBHelper(this);
    db.importCoursesFromCSV("courses.csv");

    db.importOfferingsFromCSV("offerings.csv");
    Button reset = (Button) findViewById(R.id.resetButton);
    allOfferingsList = db.getAllOfferings();
    filteredOfferingsList = new ArrayList < > (allOfferingsList);

    allCoursesList = db.getAllCourses();

    courseTitleEditText = (EditText) findViewById(R.id.courseTitleEditText);
    courseTitleEditText.addTextChangedListener(courseTitleTextWatcher);

    ok = (Spinner) findViewById(R.id.spinner1);


    // offeringListAdapter = new OfferingListAdapter(this, R.layout.offering_list_item, filteredOfferingsList);
    // ok.setAdapter(offeringListAdapter);
    instructorSpinnerAdapter = new InstructorSpinnerAdapter(this, R.layout.offering_list_item, filteredOfferingsList);

    ArrayAdapter < String > instructorSpinnerAdapter = new ArrayAdapter < String >
      (this, android.R.layout.simple_spinner_item, getAllCourse());
    ok.setAdapter(instructorSpinnerAdapter);

    ok.setOnItemSelectedListener(instructorSpinnerListener);


  }


  private String[] getAllCourse1() {
    String[] instructorNames = new String[allCoursesList.size() + 1];
    instructorNames[0] = "[Select Course]";
    for (int i = 1; i < instructorNames.length; i++) {
      instructorNames[i] = allCoursesList.get(i - 1).getTitle();
    }
    return instructorNames;
  }



  private ArrayList < String > getAllCourse() {
    ArrayList < String > instructorNames = new ArrayList < > ();
    instructorNames.add("[Select Course]");
    for (int i = 0; i < allCoursesList.size(); i++) {

      instructorNames.add(allCoursesList.get(i).getTitle());
    }
    return instructorNames;
  }

  public TextWatcher courseTitleTextWatcher = new TextWatcher() {
    @Override
    public void beforeTextChanged(CharSequence charSequence, int i, int i1, int i2) {

    }
    @Override
    public void onTextChanged(CharSequence charSequence, int i, int i1, int i2) {
      String input = charSequence.toString().toLowerCase();
      ArrayAdapter adapter = (ArrayAdapter) ok.getAdapter();
      adapter.clear();
      if (input.equals("")) {
        adapter.addAll(getAllCourse());
      } else {
        Course course;
        for (int j = 0; j < allCoursesList.size(); j++) {
          // If the course title starts with the user input,
          // add it to the listAdapter
          course = allCoursesList.get(j);
          if (course.getTitle().toLowerCase().startsWith(input)) {
            adapter.add(course.getTitle());
          }
        }
      }
      adapter.notifyDataSetChanged();
      if (adapter.getCount() != 0) ok.setSelection(0);
    }
    @Override
    public void afterTextChanged(Editable editable) {


    }
  };

  public AdapterView.OnItemSelectedListener instructorSpinnerListener = new AdapterView.OnItemSelectedListener() {
    @Override
    public void onItemSelected(AdapterView << ? > adapterView, View view, int i, long l) {
      String selectedInstructorName = adapterView.getItemAtPosition(i).toString();
      if (selectedInstructorName.equals("[Select Instructor]")) {
        instructorSpinnerAdapter.clear();
        for (Offering offering: allOfferingsList)
          instructorSpinnerAdapter.add(offering);


      } else {

        instructorSpinnerAdapter.clear();

      }

    }


    @Override
    public void onNothingSelected(AdapterView << ? > adapterView) {
      adapterView.setSelection(0);

      // Toast.makeText(getApplicationContext(), "Why?", Toast.LENGTH_SHORT).show();
    }
  };




}

Activity_course_search.xml

<< ? xml version = "1.0"
encoding = "utf-8" ? >
  <
  LinearLayout
xmlns: android = "http://schemas.android.com/apk/res/android"
xmlns: tools = "http://schemas.android.com/tools"
android: id = "@+id/activity_course_search"
android: layout_width = "match_parent"
android: layout_height = "match_parent"
android: orientation = "vertical"
android: paddingBottom = "@dimen/activity_vertical_margin"
android: paddingLeft = "@dimen/activity_horizontal_margin"
android: paddingRight = "@dimen/activity_horizontal_margin"
android: paddingTop = "@dimen/activity_vertical_margin"
tools: context = "com.bar.example.myapplication.CourseSearchActivity" >

  <
  LinearLayout
android: orientation = "horizontal"
android: layout_width = "match_parent"
android: layout_height = "wrap_content" >

  <
  TextView
android: text = "Filter By  Instructor"
android: layout_width = "wrap_content"
android: layout_height = "wrap_content"
android: id = "@+id/textView" /
  >

  <
  Spinner
android: id = "@+id/instructorSpinner"
android: layout_width = "wrap_content"
android: layout_height = "wrap_content"
android: layout_weight = "1" / >

  <
  /LinearLayout>

  <
  LinearLayout
android: orientation = "horizontal"
android: layout_width = "match_parent"
android: layout_height = "wrap_content" >

  <
  TextView
android: text = "Filter By Course Title"
android: layout_width = "wrap_content"
android: layout_height = "wrap_content"
android: id = "@+id/textView2" /
  >

  <
  EditText
android: id = "@+id/courseTitleEditText"
android: layout_width = "wrap_content"
android: layout_height = "wrap_content"
android: inputType = "textPersonName"
android: ems = "10" /
  >

  <
  /LinearLayout>

  <
  LinearLayout
android: orientation = "horizontal"
android: layout_width = "match_parent"
android: layout_height = "wrap_content" >

  <
  Button
android: text = "@string/reset_button_text"
android: layout_width = "wrap_content"
android: layout_height = "wrap_content"
android: layout_weight = "1"
android: id = "@+id/resetButton" /
  >

  <
  /LinearLayout>

  <
  ListView
android: id = "@+id/offeringsListView"
android: layout_width = "match_parent"
android: layout_height = "18dp" >

  <
  /ListView>

  <
  Spinner
android: id = "@+id/spinner1"
android: layout_width = "341dp"
android: layout_height = "93dp"
android: layout_weight = "1" / >
  <
  /LinearLayout>

offering_list_item.xml

<< ? xml version = "1.0"
encoding = "utf-8" ? >
  <
  LinearLayout xmlns : android = "http://schemas.android.com/apk/res/android"
android: layout_width = "match_parent"
android: layout_height = "wrap_content"

android: id = "@+id/offeringListLinearLayout" >

  <
  LinearLayout
android: orientation = "vertical"
android: layout_width = "match_parent"
android: layout_height = "match_parent" >

  <
  TextView
android: text = "TextView"
android: layout_width = "match_parent"
android: layout_height = "wrap_content"
android: textSize = "20sp"
android: id = "@+id/offeringListFullNameTextView" / >


  <
  /LinearLayout>


  <
  /LinearLayout>

主屏幕1：

要求1 :(工作正常）从数据库中选择微调器。

要求2：工作但需要另一种方式。使用textwacher基于edittext条目从数据库显示微调器。我想要的是，如果输入“数字A170然后我的微调器应该显示”标题“Java编程1从数据库

当前屏幕显示

我想以这种方式......

修改了onTextChanged代码。

public TextWatcher courseTitleTextWatcher = new TextWatcher() {
  @Override
  public void beforeTextChanged(CharSequence charSequence, int i, int i1, int i2) {

  }
  @Override
  public void onTextChanged(CharSequence charSequence, int i, int i1, int i2) {
    String input = charSequence.toString().toLowerCase();
    ArrayAdapter adapter = (ArrayAdapter) ok.getAdapter();
    adapter.clear();
    if (input.equals("")) {
      adapter.addAll(getAllCourse());
    } else {
      Course course;

      for (int j = 0; j < CoursesList.size(); j++) {
        // If the course title starts with the user input,
        // add it to the listAdapter
        // course = allCoursesList.get(j);
        if (courseTitleEditText.getText().equals(CoursesList.get(j).get("number"))) {
          //adapter.add(course.getTitle());
          ok.setSelection(j);

        }
      }
    }
    // adapter.notifyDataSetChanged();
    //if(adapter.getCount() != 0)
    // ok.setSelection(i);
  }
  @Override
  public void afterTextChanged(Editable editable) {


  }
};

Answer 1

试试这个。它应该解决你的问题。

替换if (course.getTitle().toLowerCase().startsWith(input)) {

if (course.getNumber().toLowerCase().startsWith(input)) {。

Answer 2

我想我认为你需要什么

实际上这很简单我尝试使用你的代码，但不是像你一样的建模方式它将通过hashmap数组

首先我们需要使用此代码从您的sqlite获取数据

课程DBHelper中的这个

import java.util.HashMap;
import java.util.Map;

这是你需要的导入

public ArrayList<Map<String, String>> getCourses()
{
    ArrayList<Map<String, String>> array_list = new ArrayList<>();

    SQLiteDatabase db = this.getReadableDatabase();
    Cursor res =  db.rawQuery("select * from " + COURSES_TABLE, null);
    res.moveToFirst();

    while(res.isAfterLast() == false){
        Map<String, String> datanum = new HashMap<String, String>();
        datanum.put("id", res.getString(res.getColumnIndex(COURSES_KEY_FIELD_ID)));
        datanum.put("alpha", res.getString(res.getColumnIndex(FIELD_ALPHA)));
        datanum.put("number", res.getString(res.getColumnIndex(FIELD_NUMBER)));
        datanum.put("title", res.getString(res.getColumnIndex(FIELD_TITLE)));
        array_list.add(datanum);
        res.moveToNext();
    }
    return array_list;
}

这里的代码将完美无缺，您无需编辑我的课程

现在你需要在你的课程中调用这个方法

课堂上的这个课程搜索活动

DBHelper DB;
ArrayList<Map<String, String>> CoursesList = new ArrayList<Map<String, String>>();

on create

    DB = new DBHelper(this);
    CoursesList= DB.getCourses();

现在你已经拥有了CoursesList中的所有内容，现在你需要弄清楚你想要选择哪个微调器位置

所以

你要循环它

Textlistener中的这个

    for(int i = 0 ; i < CoursesList.size() ; i++){
        if(courseTitleEditText.getText().equals(CoursesList.get(i).get("number"))){//ex.A170
// you must to be filled your spinner from same courses db and here you gonna to set your selection by iteration
            ok.setSelection(i);
        } 
    }

也许这对你的代码来说不是正确的，因为我看到你在你的代码中使用建模而我使用Hashmap但我认为从你的代码中看到相同的建模方式很有用我没有测试它我直接写了这么测试并告诉我发生了什么希望我帮忙

使用Sqlite将Edittext输入中的数据填充到Spinner Display

2 个答案: