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问题描述
我有一个应用程序写入，并从数据库中删除。我有一个从该数据库中的2个不同的列都产生一个2纺纱。我想运行所有从给定的下拉微调匹配所选项目的记录的查询。截至目前一切工作正常但是当我从下拉列表中选择一个项目下来，什么也没有发生。我知道我失去了一些东西只是不知道或者。请帮忙
I have an app that writes to and deletes from a database. I have a 2 spinners that are generated from 2 different columns in that database. I want to run a query for all records matching the selected item from the given drop down spinner. As of right now everything works fine however when I select an item from the drop down, nothing happens. I know I'm missing something just not sure what or where. Please help
下面是我的Dbhelper.Java
Here is my Dbhelper.Java
package com.gamingbrothers.pat.passwordencrypter;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
//table structure
public class Dbhelper extends SQLiteOpenHelper {
public static final String DB_NAME = "LogInInfo.db";
public static final String TABLE_NAME = "LogInInfo_table";
public static final String COL_1 = "ID";
public static final String COL_2 = "USER_NAME";
public static final String COL_3 = "USER_PASSWORD";
public static final String COL_4 = "APPLICATION";
public static final String COL_5 = "CUSTOMER";
public Dbhelper(Context context) {
super(context, DB_NAME, null, 1);
}
c.close();
return notes_array;
}
@Override
public void onCreate (SQLiteDatabase db) {
db.execSQL("create table " + TABLE_NAME + " (ID INTEGER PRIMARY KEY AUTOINCREMENT," +
"USER_NAME TEXT,USER_PASSWORD TEXT," +
"APPLICATION TEXT,CUSTOMER TEXT)");
}
//Query Database with item selected from drop down
public Cursor getChoiceData() {
SQLiteDatabase db = this.getWritableDatabase();
Cursor result = db.rawQuery("select * from LogInInfo_table where CUSTOMER = ?",null);
return result;
}
//Gather Data
public Cursor getAllData() {
SQLiteDatabase db = this.getWritableDatabase();
Cursor result = db.rawQuery("select * from LogInInfo_table",null);
return result;
}
//getting customers for drop down
public List<String> getAllCustomers(){
List<String> customers = new ArrayList<String>();
// Select All Query
String selectQuery = "SELECT * FROM " + TABLE_NAME;
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery(selectQuery, null);
// looping through all rows and adding to list
if (cursor.moveToPosition(0)) {
do {
customers.add(cursor.getString(4));
} while (cursor.moveToNext());
}
// closing connection
cursor.close();
db.close();
// returning customers
return customers;
}
//getting apps for drop down
public List<String> getAllApps(){
List<String> apps = new ArrayList<String>();
// Select All Query
String selectQuery = "SELECT * FROM " + TABLE_NAME;
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery(selectQuery, null);
// looping through all rows and adding to list
if (cursor.moveToPosition(0)) {
do {
apps.add(cursor.getString(3));
} while (cursor.moveToNext());
}
// closing connection
cursor.close();
db.close();
// returning apps
return apps;
}
//creating update data function
public boolean updateData(String ID,String User_Name,String Password,String Application,String Customer){
SQLiteDatabase db = this.getWritableDatabase();
ContentValues contentValues = new ContentValues();
contentValues.put(COL_1,ID);
contentValues.put(COL_2,User_Name);
contentValues.put(COL_3,Password);
contentValues.put(COL_4, Application);
contentValues.put(COL_5,Customer);
db.update(TABLE_NAME,contentValues, "ID = ?",new String[] {ID});
return true;
}
//deleting data
public Integer deleteData (String ID){
SQLiteDatabase db = this.getWritableDatabase();
return db.delete(TABLE_NAME, "ID = ?",new String[]{ID});
}
}
下面是我的MainActivity.Java
Here is my MainActivity.Java
package com.gamingbrothers.pat.passwordencrypter;
//Created by Pat 8/6/15
import android.app.AlertDialog;
import android.database.Cursor;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Spinner;
import android.widget.Toast;
import java.util.List;
public class MainActivity extends AppCompatActivity implements AdapterView.OnItemSelectedListener {
Dbhelper myDB;
Button btnAdd;
Button btnDelete;
Button btnView;
Button btnUpdate;
Spinner spinner;
Spinner spinner2;
String itemSelected;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
myDB = new Dbhelper(this);
//initializing objects
editUserName = (EditText) findViewById(R.id.editText_user);
editPassword = (EditText) findViewById(R.id.editText_pass);
editApplication = (EditText) findViewById(R.id.editText_app);
editID = (EditText) findViewById(R.id.editText_id);
editCustomer = (EditText) findViewById(R.id.editText_customer);
btnAdd = (Button) findViewById(R.id.button_Add);
btnDelete = (Button) findViewById(R.id.button_Delete);
btnView = (Button) findViewById(R.id.button_View);
btnUpdate = (Button) findViewById(R.id.button_update);
spinner = (Spinner) findViewById(R.id.spinner);
spinner2 = (Spinner) findViewById(R.id.spinner2);
AddData();
viewAll();
UpdateData();
DeleteData();
loadSpinnerData();
loadSpinner2Data();
}
public void loadSpinner2Data() {
//db handler
Dbhelper db2 = new Dbhelper(getApplicationContext());
//Spinner drop elem.
List<String> apps = db2.getAllApps();
//Create adapter for spinner
ArrayAdapter<String> dataAdapter2 = new ArrayAdapter<String>(this,
android.R.layout.simple_spinner_item, apps);
// Drop down layout style - list view with radio button
dataAdapter2
.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
//attaching data adapter
spinner2.setAdapter(dataAdapter2);
}
private void loadSpinnerData() {
// database handler
Dbhelper db = new Dbhelper(getApplicationContext());
// Spinner Drop down elements
List<String> customers = db.getAllCustomers();
// Creating adapter for spinner
ArrayAdapter<String> dataAdapter = new ArrayAdapter<String>(this,
android.R.layout.simple_spinner_item, customers);
// Drop down layout style - list view with radio button
dataAdapter
.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
// attaching data adapter to spinner
spinner.setAdapter(dataAdapter);
}
public void DeleteData() {
btnDelete.setOnClickListener(
new View.OnClickListener() {
@Override
public void onClick(View v) {
Integer deletedRows = myDB.deleteData(editID.getText().toString());
if(deletedRows >0)
Toast.makeText(MainActivity.this, "Data Deleted", Toast.LENGTH_LONG).show();
else
Toast.makeText(MainActivity.this, "Data not Deleted", Toast.LENGTH_LONG).show();
}
}
);
}
//creating update data function
public void UpdateData() {
btnUpdate.setOnClickListener(
new View.OnClickListener() {
@Override
public void onClick(View v) {
boolean isUpdated = myDB.updateData(editID.getText().toString(),
editUserName.getText().toString(),
editPassword.getText().toString(),
editApplication.getText().toString(),
editCustomer.getText().toString());
//Parse update completion
if (isUpdated == true)
Toast.makeText(MainActivity.this, "Data Updated", Toast.LENGTH_LONG).show();
else
Toast.makeText(MainActivity.this, "Data not Updated", Toast.LENGTH_LONG).show();
}
});
}
//add data to database
public void AddData() {
btnAdd.setOnClickListener(
new View.OnClickListener() {
@Override
public void onClick(View v) {
boolean isInserted = myDB.insertData(editUserName.getText().toString(),
editPassword.getText().toString(),
editApplication.getText().toString(),
editCustomer.getText().toString());
//parse add completion
if (isInserted == true)
Toast.makeText(MainActivity.this, "Data Inserted", Toast.LENGTH_LONG).show();
else
Toast.makeText(MainActivity.this, "Data not Inserted", Toast.LENGTH_LONG).show();
}
});
}
//Get results from database when button is clicked
public void viewAll() {
btnView.setOnClickListener(
new View.OnClickListener() {
@Override
public void onClick(View v) {
Cursor result = myDB.getAllData();
//Check if database is empty
if (result.getCount() == 0) {
//Show Message
showMessage("Error", "No Data Found");
return;
}
StringBuffer buffer = new StringBuffer();
while (result.moveToNext()) {
buffer.append("ID:" + result.getString(0) + "\n");
buffer.append("User Name:" + result.getString(1) + "\n");
buffer.append("Password:" + result.getString(2) + "\n");
buffer.append("App:" + result.getString(3) + "\n");
buffer.append("Customer:" + result.getString(4) + "\n\n");
}
//Show all data
showMessage("Data", buffer.toString());
}
}
);
}
//show data
public void showMessage(String title,String Message){
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setCancelable(true);
builder.setTitle(title);
builder.setMessage(Message);
builder.show();
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
@Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
String label = parent.getItemAtPosition(position).toString();
myDB.getChoiceData().toString();
Toast.makeText(parent.getContext(), "Here is your information: "+ label,Toast.LENGTH_LONG).show();
}
@Override
public void onNothingSelected(AdapterView<?> parent) {
}
}
如果你需要我发表我的XML只问，但我并不认为这是neccessary，我没有发表我的logcat的，因为它没有给我一个错误。
If you need me to post my XML just ask, but I didn't think it was neccessary and I didn't post my logcat because it doesn't give me an error.
推荐答案
从code你贴你似乎缺少选择的项目监听器，添加以下，例如，您的onCreate：
From the code you posted you seem to be missing the selected item listener, add the following, for example, to your onCreate:
spinner.setOnItemSelectedListener(this);
spinner2.setOnItemSelectedListener(this);
这篇关于利用下拉微调所选项目数据库查询的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！