Android 数据库没有'；无法检索数据
我想在安卓系统中制作一个应用程序，通过数据库显示公交车、火车和航班。我为此编写了代码，但当我想从数据库检索数据时，只调用为总线编写的方法。其他方法没有给出任何值。 我的代码是： Database_Activity.javaAndroid 数据库没有'；无法检索数据,android,sqlite,android-sqlite,Android,Sqlite,Android Sqlite,我想在安卓系统中制作一个应用程序，通过数据库显示公交车、火车和航班。我为此编写了代码，但当我想从数据库检索数据时，只调用为总线编写的方法。其他方法没有给出任何值。 我的代码是： Database_Activity.java public class Database_Activity { public int id; private DbHelper ourHelper; private Context ourContext; private SQLiteDatabase ourDatabas
public class Database_Activity {
public int id;
private DbHelper ourHelper;
private Context ourContext;
private SQLiteDatabase ourDatabase;
private static class DbHelper extends SQLiteOpenHelper {
// this is database name (change it as you want)
public DbHelper(Context context) {
super(context, "shrirang", null, 1);
}
@Override
// create corrsponding tables
public void onCreate(SQLiteDatabase db) {
db.execSQL("CREATE TABLE travel ( id INTEGER PRIMARY KEY AUTOINCREMENT, src TEXT NOT NULL,dest TEXT NOT NULL,bcost INTEGER NOT NULL,tcost INTEGER,acost INTEGER);");
db.execSQL("CREATE TABLE bus ( bid INTEGER PRIMARY KEY AUTOINCREMENT, bsname TEXT NOT NULL, bsrc TEXT NOT NULL,bdest TEXT NOT NULL,bcost INTEGER NOT NULL,bt1 TEXT NOT NULL,bt2 TEXT NOT NULL);");
db.execSQL("CREATE TABLE train ( tid INTEGER PRIMARY KEY AUTOINCREMENT, trname TEXT NOT NULL, tsrc TEXT NOT NULL,tdest TEXT NOT NULL,tcost INTEGER NOT NULL,tt1 TEXT NOT NULL,tt2 TEXT NOT NULL);");
db.execSQL("CREATE TABLE flight ( fid INTEGER PRIMARY KEY AUTOINCREMENT, flname TEXT NOT NULL, fsrc TEXT NOT NULL,fdest TEXT NOT NULL,fcost INTEGER NOT NULL,ft1 TEXT NOT NULL,ft2 TEXT NOT NULL);");
db.execSQL("CREATE TABLE history ( sid INTEGER PRIMARY KEY AUTOINCREMENT, src TEXT NOT NULL,dest TEXT NOT NULL,budget INTEGER NOT NULL, day INTEGER NOT NULL,mon INTEGER NOT NULL, year INTEGER NOT NULL);");
db.execSQL("CREATE TABLE install (db INTEGER NOT NULL);");
}
@Override
// if tables all ready exist then delete
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL("DROP TABLE IF EXISTS travel");
db.execSQL("DROP TABLE IF EXISTS bus");
db.execSQL("DROP TABLE IF EXISTS train");
db.execSQL("DROP TABLE IF EXISTS flight");
db.execSQL("DROP TABLE IF EXISTS history");
db.execSQL("DROP TABLE IF EXISTS install");
onCreate(db);
}
}
public Database_Activity(Context c) {
ourContext = c;
}
// method for opening database
public Database_Activity open() throws SQLException {
ourHelper = new DbHelper(ourContext);
ourDatabase = ourHelper.getWritableDatabase();
return this;
}
// method for creating entry
public long createentry(String src, String dest, int bcost,int tcost,int acost) {
ContentValues cv = new ContentValues();
cv.put("src", src);
cv.put("dest", dest);
cv.put("bcost", bcost);
cv.put("tcost", tcost);
cv.put("acost", acost);
return ourDatabase.insert("travel", null, cv);
}
// method for adding bus details
public long Add_BUS_Entry(String bname, String bsrc, String bdest, int bcost,String bt1,String bt2) {
ContentValues cv = new ContentValues();
cv.put("bsname", bname);
cv.put("bsrc", bsrc);
cv.put("bdest", bdest);
cv.put("bcost",bcost);
cv.put("bt1", bt1);
cv.put("bt2", bt2);
return ourDatabase.insert("bus", null, cv);
}
// method for add train to database
public long Add_TRAIN_Entry(String trname, String src, String dest, int cost,String t1,String t2) {
ContentValues cv = new ContentValues();
cv.put("trname", trname);
cv.put("tsrc", src);
cv.put("tdest", dest);
cv.put("tcost",cost);
cv.put("tt1", t1);
cv.put("tt2", t2);
return ourDatabase.insert("train", null, cv);
}
// method for add flight to databse
public long Add_FLIGHT_Entry(String flname, String src, String dest, int cost,String t1,String t2) {
ContentValues cv = new ContentValues();
cv.put("flname", flname);
cv.put("fsrc", src);
cv.put("fdest", dest);
cv.put("fcost",cost);
cv.put("ft1", t1);
cv.put("ft2", t2);
return ourDatabase.insert("flight", null, cv);
}
// method for closing database
public void close() {
ourHelper.close();
}
// method for showing database entries
public String getData() {
String[] columns = new String[] { "id", "src", "dest", "bcost" , "tcost", "acost"};
Cursor c = ourDatabase.query("travel", columns, null, null, null, null,
null);
String result = "";
int iRow = c.getColumnIndex("id");
int iun = c.getColumnIndex("src");
int ipw = c.getColumnIndex("dest");
int ib = c.getColumnIndex("bcost");
int it = c.getColumnIndex("tcost");
int ia = c.getColumnIndex("acost");
for (c.moveToFirst(); !c.isAfterLast(); c.moveToNext()) {
result = result + c.getString(iRow) + " " + c.getString(iun) + " "
+ c.getString(ipw) + " " + c.getShort(ib) + " " + c.getShort(it)+ " " + c.getShort(ia)+ "\n";
}
return result;
}
// method for adding search entry
public long AddSearch_entry(String s, String d, int b, int day, int mon,
int year) {
ContentValues cv = new ContentValues();
cv.put("src", s);
cv.put("dest", d);
cv.put("budget", b);
cv.put("day", day);
cv.put("mon", mon);
cv.put("year", year);
return ourDatabase.insert("history", null, cv);
}
// method for getting search data
public String getSearchData() {
String[] columns = new String[] { "sid", "src", "dest", "budget" , "day", "mon","year"};
Cursor c = ourDatabase.query("history", columns, null, null, null, null,
null);
String result = "";
int iRow = c.getColumnIndex("sid");
int iun = c.getColumnIndex("src");
int ipw = c.getColumnIndex("dest");
int ib = c.getColumnIndex("budget");
int it = c.getColumnIndex("day");
int ia = c.getColumnIndex("mon");
int ic = c.getColumnIndex("year");
for (c.moveToFirst(); !c.isAfterLast(); c.moveToNext()) {
result = result + c.getString(iRow) + " " + c.getString(iun) + " "
+ c.getString(ipw) + " " + c.getShort(ib) + " " + c.getShort(it)+ "/" + c.getShort(ia)+ "/" + c.getShort(ic)+ "\n";
}
return result;
}
// methods for reading corrosponding database entries
public Cursor GetLatestSearch() {
return ourDatabase.query("history", new String[] {"sid","src","dest","budget","day","mon","year"},null, null, null, null, null);
}
public Cursor Get_BUS_details() {
return ourDatabase.query("bus", new String[] {"bid","bsname","bsrc","bdest","bcost","bt1","bt2"},null, null, null, null, null);
}
public Cursor findBUS(int temp) {
return ourDatabase.query("bus", new String[] {"bid","bsname","bsrc","bdest","bcost","bt1","bt2"},"bid="+temp, null, null, null, null);
}
public Cursor Get_TRAIN_Details() {
return ourDatabase.query("train", new String[] {"tid","trname","tsrc","tdest","tcost","tt1","tt2"},null, null, null, null, null);
}
public Cursor findTRAIN(int temp) {
return ourDatabase.query("train", new String[] {"tid","trname","tsrc","tdest","tcost","tt1","tt2"},"tid="+temp, null, null, null, null);
}
public Cursor findAIR(int temp) {
return ourDatabase.query("flight", new String[] {"fid","flname","fsrc","fdest","fcost","ft1","ft2"},"fid="+temp, null, null, null, null);
}
public Cursor Get_flight_details() {
return ourDatabase.query("flight", new String[] {"fid","flname","fsrc","fdest","fcost","ft1","ft2"},null, null, null, null, null);
}
public Cursor GetHistorySearch(long schid) {
return ourDatabase.query("history", new String[] {"sid","src","dest","budget","day","mon","year"},"sid="+schid, null, null, null, null);
}
// method for deleting history
public void DeleteHistory() {
ourDatabase.delete("history", null, null);
}
public int getM() {
String[] columns = new String[] { "id", "src", "dest", "bcost" , "tcost", "acost"};
Cursor c = ourDatabase.query("travel", columns, null, null, null, null,
null);
int iRow = c.getColumnIndex("id");
return iRow;
}
public int Install() {
int t;
String[] columns = new String[]{"db"};
Cursor c = ourDatabase.query("install", columns,null, null, null, null, null);
if (c != null){
c.moveToFirst();
t = c.getInt(0);
return t;
}
return 0;
}
public long AddDB() {
ContentValues cv = new ContentValues();
cv.put("db", "1");
return ourDatabase.insert("install", null, cv);
}
}
public class Train extends ListActivity{
LayoutInflater mInflater;
static Object[] wer;
static Object searchid;
Dialog dialog = null;
String s1="",s2="",s3="",info="";
private long schid = 0;
String title = "",url="";
String f="",t="",b="",a="",d="",n="";
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
try{
// set screen 'srchres.xml'
setContentView(R.layout.bus);
List<String> strings; // create string list to store search entry
final List<String> listid; // create string list for store list id's
strings = new ArrayList<String>();
listid = new ArrayList<String>();
super.onCreate(savedInstanceState);
Database_Activity db_obj = new Database_Activity(this);
// Define strings to store database entries
@SuppressWarnings("unused")
String temp0="",t="",temp1="", temp2="", temp3="" ,temp4="";
@SuppressWarnings("unused")
String bt0="",bt="",bt1="", bt2="", bt3="" ,bt4="";
@SuppressWarnings("unused")
String at0="",at="",at1="", at2="", at3="" ,at4="";
db_obj.open(); // open database
// ** check for who is starting activity either MainActivity.java (or) History.java **
if(getIntent().getExtras() != null)// if this is true it is from History.java
{
// Get a History list index which we have selected
Bundle bun2 = getIntent().getExtras();
if (null == bun2) return;
this.schid = bun2.getLong("uid");
Cursor c2 = db_obj.GetHistorySearch(schid); // get search history from database
if (c2.moveToFirst())
{
s1=c2.getString(1); // get source
s2=c2.getString(2); // get destination
s3=c2.getString(3); // get budget
}
}
else // if not then it is from MainActivity.java
{
Cursor c1 = db_obj.GetLatestSearch(); // Get search which is searched now
if (c1.moveToFirst())
{
s1=c1.getString(1); // get source
s2=c1.getString(2); // get destination
s3=c1.getString(3); // get budget
}
}
int co = Integer.parseInt(s3.toString());
Cursor c = db_obj.Get_TRAIN_Details();
if(c.moveToFirst()){
// Retrive train information from database
bt0 = c.getString(0);
title = c.getString(1);
bt = c.getString(2);
bt1 = c.getString(3);
bt2 = c.getString(4);
int cost2 = Integer.parseInt(bt2.toString());
bt3 = c.getString(5);
bt4 = c.getString(6);
// Compare given source, destination and budget with database entries
if(s1.equalsIgnoreCase(bt) && s2.equalsIgnoreCase(bt1) && co>=cost2)
{
// ** if searched entry available in database show data
info = bt+" to "+bt1+" in "+bt2+" at "+bt3;
listid.add("B"+bt0);
strings.add(info);
}
mInflater = (LayoutInflater)getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}
db_obj.close(); // close database
// Add search result to list
setListAdapter(new ArrayAdapter<String>(this, R.layout.wtlist_item1, strings)
{
@Override
public View getView(int position, View convertView, ViewGroup parent)
{
View row;
if (null == convertView)
{
row = mInflater.inflate(R.layout.wtlist_item1, null);
} else
{
row = convertView;
}
TextView tv = (TextView) row.findViewById(android.R.id.text1);
tv.setText(getItem(position));
return row;
}
});
ListView lv = getListView();
//** Add action for click on search result **
lv.setOnItemClickListener(new OnItemClickListener()
{
@SuppressWarnings("deprecation")
public void onItemClick(AdapterView<?> parent, View view,int position, long id)
{
wer = listid.toArray();
searchid = wer[(int)id]; // add id to list
// Show small dialog box
showDialog(7);
}
});
}catch(Exception e)
{
Toast.makeText(getApplicationContext(), "Error"+e, Toast.LENGTH_LONG).show();
}
}
公共类列车扩展列表活动{
拉平机；
静态对象；
静态对象搜索ID；
Dialog=null；
字符串s1=“”，s2=“”，s3=“”，info=“”；
私有长schid=0；
字符串title=“”，url=“”；
字符串f=“”，t=“”，b=“”，a=“”，d=“”，n=“”；
@凌驾
创建时受保护的void（Bundle savedInstanceState）{
//TODO自动生成的方法存根
super.onCreate（savedInstanceState）；
试一试{
//设置屏幕“srchres.xml”
setContentView（R.layout.bus）；
列表字符串；//创建字符串列表以存储搜索项
最终列表listid；//为存储列表id创建字符串列表
strings=newarraylist（）；
listid=newarraylist（）；
super.onCreate（savedInstanceState）；
Database_Activity db_obj=新数据库_Activity（此）；
//定义用于存储数据库项的字符串
@抑制警告（“未使用”）
字符串temp0=“”，t=“”，temp1=“”，temp2=“”，temp3=“”，temp4=“”；
@抑制警告（“未使用”）
字符串bt0=”，bt=”，bt1=”，bt2=”，bt3=”，bt4=”；
@抑制警告（“未使用”）
字符串at0=”、at=”、at1=”、at2=、at3=、at4=”；
db_obj.open（）；//打开数据库
//**检查谁正在启动活动MainActivity.java（或）History.java**
if（getIntent（）.getExtras（）！=null）//如果这是真的，则来自History.java
{
//获取我们选择的历史记录列表索引
Bundle bun2=getIntent（）.getExtras（）；
如果（null==bun2）返回；
this.schid=bun2.getLong（“uid”）；
游标c2=db_obj.GetHistorySearch（schid）；//从数据库获取搜索历史
if（c2.moveToFirst（））
{
s1=c2.getString（1）；//获取源代码
s2=c2.getString（2）；//获取目的地
s3=c2.getString（3）；//获取预算
}
}
else//如果不是，则来自MainActivity.java
{
游标c1=db_obj.GetLatestSearch（）；//获取现在搜索的搜索
if（c1.moveToFirst（））
{
s1=c1.getString（1）；//获取源代码
s2=c1.getString（2）；//获取目的地
s3=c1.getString（3）；//获取预算
}
}
int co=Integer.parseInt（s3.toString（））；
光标c=db_obj.Get_TRAIN_Details（）；
如果（c.moveToFirst（））{
//从数据库中检索列车信息
bt0=c.getString（0）；
title=c.getString（1）；
bt=c.getString（2）；
bt1=c.getString（3）；
bt2=c.getString（4）；
int cost2=Integer.parseInt（bt2.toString（））；
bt3=c.getString（5）；
bt4=c.getString（6）；
//将给定的源、目标和预算与数据库条目进行比较
如果（s1.等信号案例（bt）和s2.等信号案例（bt1）和co>=成本2）
{
//**如果数据库中有可用的搜索条目，则显示数据
info=bt+“至”+bt1+“在”+bt3的“+bt2+”中；
添加（“B”+bt0）；
字符串。添加（信息）；
}
mInflater=（LayoutInflater）getSystemService（Context.LAYOUT\u INFLATER\u SERVICE）；
}
db_obj.close（）；//关闭数据库
//将搜索结果添加到列表
setListAdapter（新的ArrayAdapter（this，R.layout.wtlist_item1，strings）
{
@凌驾
公共视图getView（int位置、视图转换视图、视图组父视图）
{
查看行；
if（null==convertView）
{
row=mInflater.充气（R.layout.wtlist_item1，空）；
}否则
{
行=转换视图；
}
TextView tv=（TextView）row.findViewById（android.R.id.text1）；
tv.setText（getItem（position））；
返回行；
}
});
ListView lv=getListView（）；
//**添加单击搜索结果的操作**
lv.setOnItemClickListener（新的OnItemClickListener（）
{
@抑制警告（“弃用”）
public void onItemClick（AdapterView父对象、视图、整型位置、长id）
{
wer=listid.toArray（）；
searchid=wer[（int）id]；//将id添加到列表中
//显示小对话框
展示对话（7）；
}
});
}捕获（例外e）
{
Toast.makeText（getApplicationContext（），“Error”+e，Toast.LENGTH_LONG.show（）；
}
}