大家好，我已经制作我的应用程序 6 个月了。我一直在研究我的布局和编码等。现在上个月我一直在尝试创建一个数据库。但我就是无法解决这个问题。我已经完成了 android 记事本教程，并且我已经下载了 SQLite 数据库浏览器。即使我有一个来自notepad v3（添加和删除数据）的工作数据库，我只是不知道我是否可以在我的项目中使用这个数据库演示。
我也在一些堆栈溢出页面上（现在找不到它），有人放了一个指向我下载并运行它的数据库演示 zip 文件的链接。它正是我所追求的。希望你们能帮助我，让我知道我是否可以将这个数据库演示用作我自己的..
不要误会我的意思，我不是在寻找一种简单的方法来制作我自己的数据库或学习它。
在安卓世界里有很多东西要学。如果我有一个可以在其他项目中使用的工作数据库，我将一路学习编码。这是数据库演示的 java 代码，如果您想查看我的 XML，粘贴所有这些内容有点重请说..
package mina.android.DatabaseDemo;
import android.app.Activity;
import android.app.Dialog;
import android.database.Cursor;
import android.os.Bundle;
import android.text.Spannable;
import android.view.View;
import android.widget.AdapterView;
import android.widget.EditText;
import android.widget.SimpleCursorAdapter;
import android.widget.Spinner;
import android.widget.TextView;
import android.widget.AdapterView.OnItemSelectedListener;
public class AddEmployee extends Activity {
EditText txtName;
EditText txtAge;
TextView txtEmps;
DatabaseHelper dbHelper;
Spinner spinDept;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.addemployee);
txtName=(EditText)findViewById(R.id.txtName);
txtAge=(EditText)findViewById(R.id.txtAge);
txtEmps=(TextView)findViewById(R.id.txtEmps);
spinDept=(Spinner)findViewById(R.id.spinDept);
}
@Override
public void onStart()
{
try
{
super.onStart();
dbHelper=new DatabaseHelper(this);
txtEmps.setText(txtEmps.getText()+String.valueOf(dbHelper.getEmployeeCount()));
Cursor c=dbHelper.getAllDepts();
startManagingCursor(c);
//SimpleCursorAdapter ca=new
SimpleCursorAdapter(this,android.R.layout.simple_spinner_item, c, new String []
{DatabaseHelper.colDeptName}, new int []{android.R.id.text1});
SimpleCursorAdapter ca=new
SimpleCursorAdapter(this,R.layout.deptspinnerrow, c, new String []
{DatabaseHelper.colDeptName,"_id"}, new int []{R.id.txtDeptName});
//ca.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
spinDept.setAdapter(ca);
spinDept.setOnItemSelectedListener(new OnItemSelectedListener() {
public void onItemSelected(AdapterView<?> parent, View
selectedView,
int position, long id) {
// TODO Auto-generated method stub
}
public void onNothingSelected(AdapterView<?> arg0) {
// TODO Auto-generated method stub
}
});
//never close cursor
}
catch(Exception ex)
{
CatchError(ex.toString());
}
}
public void btnAddEmp_Click(View view)
{
boolean ok=true;
try
{
Spannable spn=txtAge.getText();
String name=txtName.getText().toString();
int age=Integer.valueOf(spn.toString());
int deptID=Integer.valueOf((int)spinDept.getSelectedItemId());
Employee emp=new Employee(name,age,deptID);
dbHelper.AddEmployee(emp);
}
catch(Exception ex)
{
ok=false;
CatchError(ex.toString());
}
finally
{
if(ok)
{
//NotifyEmpAdded();
Alerts.ShowEmpAddedAlert(this);
txtEmps.setText("Number of employees
"+String.valueOf(dbHelper.getEmployeeCount()));
}
}
}
void CatchError(String Exception)
{
Dialog diag=new Dialog(this);
diag.setTitle("Add new Employee");
TextView txt=new TextView(this);
txt.setText(Exception);
diag.setContentView(txt);
diag.show();
}
void NotifyEmpAdded()
{
Dialog diag=new Dialog(this);
diag.setTitle("Add new Employee");
TextView txt=new TextView(this);
txt.setText("Employee Added Successfully");
diag.setContentView(txt);
diag.show();
try {
diag.wait(1000);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
CatchError(e.toString());
}
diag.notify();
diag.dismiss();
}
}
package mina.android.DatabaseDemo;
import android.app.AlertDialog;
import android.app.Dialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.DialogInterface.OnClickListener;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.Spinner;
import android.widget.TextView;
public class Alerts {
public static void ShowEmpAddedAlert(Context con)
{
AlertDialog.Builder builder=new AlertDialog.Builder(con);
builder.setTitle("Add new Employee");
builder.setIcon(android.R.drawable.ic_dialog_info);
DialogListner listner=new DialogListner();
builder.setMessage("Employee Added successfully");
builder.setPositiveButton("ok", listner);
AlertDialog diag=builder.create();
diag.show();
}
public static AlertDialog ShowEditDialog(final Context con,final Employee emp)
{
AlertDialog.Builder b=new AlertDialog.Builder(con);
b.setTitle("Employee Details");
LayoutInflater li=LayoutInflater.from(con);
View v=li.inflate(R.layout.editdialog, null);
b.setIcon(android.R.drawable.ic_input_get);
b.setView(v);
final TextView txtName=(TextView)v.findViewById(R.id.txtDelName);
final TextView txtAge=(TextView)v.findViewById(R.id.txtDelAge);
final Spinner spin=(Spinner)v.findViewById(R.id.spinDiagDept);
Utilities.ManageDeptSpinner(con, spin);
for(int i=0;i<spin.getCount();i++)
{
long id=spin.getItemIdAtPosition(i);
if(id==emp.getDept())
{
spin.setSelection(i, true);
break;
}
}
txtName.setText(emp.getName());
txtAge.setText(String.valueOf(emp.getAge()));
b.setPositiveButton("Modify", new OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
// TODO Auto-generated method stub
emp.setName(txtName.getText().toString());
emp.setAge(Integer.valueOf(txtAge.getText().toString()));
emp.setDept((int)spin.getItemIdAtPosition(spin.getSelectedItemPosition()));
try
{
DatabaseHelper db=new DatabaseHelper(con);
db.UpdateEmp(emp);
}
catch(Exception ex)
{
CatchError(con, ex.toString());
}
}
});
b.setNeutralButton("Delete", new OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
// TODO Auto-generated method stub
DatabaseHelper db=new DatabaseHelper(con);
db.DeleteEmp(emp);
}
});
b.setNegativeButton("Cancel", null);
return b.create();
//diag.show();
}
static public void CatchError(Context con, String Exception)
{
Dialog diag=new Dialog(con);
diag.setTitle("Error");
TextView txt=new TextView(con);
txt.setText(Exception);
diag.setContentView(txt);
diag.show();
}
}
package mina.android.DatabaseDemo
import android.app.TabActivity;
import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.GridView;
import android.widget.TabHost;
import android.widget.TextView;
public class DatabaseDemo extends TabActivity {
DatabaseHelper dbHelper;
GridView grid;
TextView txtTest;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
SetupTabs();
}
@Override
public boolean onCreateOptionsMenu(Menu menu)
{
menu.add(1, 1, 1, "Add Employee");
return true;
}
public boolean onOptionsItemSelected(MenuItem item)
{
switch (item.getItemId())
{
//Add employee
case 1:
Intent addIntent=new Intent(this,AddEmployee.class);
startActivity(addIntent);
break;
}
super.onOptionsItemSelected(item);
return false;
}
void SetupTabs()
{
TabHost host=getTabHost();
TabHost.TabSpec spec=host.newTabSpec("tag1");
Intent in1=new Intent(this, AddEmployee.class);
spec.setIndicator("Add Employee");
spec.setContent(in1);
TabHost.TabSpec spec2=host.newTabSpec("tag2");
Intent in2=new Intent(this, GridList.class);
spec2.setIndicator("Employees");
spec2.setContent(in2);
host.addTab(spec);
host.addTab(spec2);
}
}
package mina.android.DatabaseDemo;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
public class DatabaseHelper extends SQLiteOpenHelper {
static final String dbName="demoDB";
static final String employeeTable="Employees";
static final String colID="EmployeeID";
static final String colName="EmployeeName";
static final String colAge="Age";
static final String colDept="Dept";
static final String deptTable="Dept";
static final String colDeptID="DeptID";
static final String colDeptName="DeptName";
static final String viewEmps="ViewEmps";
public DatabaseHelper(Context context) {
super(context, dbName, null,33);
// TODO Auto-generated constructor stub
}
@Override
public void onCreate(SQLiteDatabase db) {
// TODO Auto-generated method stub
db.execSQL("CREATE TABLE "+deptTable+" ("+colDeptID+ " INTEGER PRIMARY KEY
, "+
colDeptName+ " TEXT)");
db.execSQL("CREATE TABLE "+employeeTable+" ("+colID+" INTEGER PRIMARY KEY
AUTOINCREMENT, "+
colName+" TEXT, "+colAge+" Integer, "+colDept+" INTEGER
NOT NULL ,FOREIGN KEY ("+colDept+") REFERENCES "+deptTable+"
("+colDeptID+"));");
db.execSQL("CREATE TRIGGER fk_empdept_deptid " +
" BEFORE INSERT "+
" ON "+employeeTable+
" FOR EACH ROW BEGIN"+
" SELECT CASE WHEN ((SELECT "+colDeptID+" FROM
"+deptTable+" WHERE "+colDeptID+"=new."+colDept+" ) IS NULL)"+
" THEN RAISE (ABORT,'Foreign Key Violation') END;"+
" END;");
db.execSQL("CREATE VIEW "+viewEmps+
" AS SELECT "+employeeTable+"."+colID+" AS _id,"+
" "+employeeTable+"."+colName+","+
" "+employeeTable+"."+colAge+","+
" "+deptTable+"."+colDeptName+""+
" FROM "+employeeTable+" JOIN "+deptTable+
" ON "+employeeTable+"."+colDept+"
="+deptTable+"."+colDeptID
);
//Inserts pre-defined departments
InsertDepts(db);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// TODO Auto-generated method stub
db.execSQL("DROP TABLE IF EXISTS "+employeeTable);
db.execSQL("DROP TABLE IF EXISTS "+deptTable);
db.execSQL("DROP TRIGGER IF EXISTS dept_id_trigger");
db.execSQL("DROP TRIGGER IF EXISTS dept_id_trigger22");
db.execSQL("DROP TRIGGER IF EXISTS fk_empdept_deptid");
db.execSQL("DROP VIEW IF EXISTS "+viewEmps);
onCreate(db);
}
void AddEmployee(Employee emp)
{
SQLiteDatabase db= this.getWritableDatabase();
ContentValues cv=new ContentValues();
cv.put(colName, emp.getName());
cv.put(colAge, emp.getAge());
cv.put(colDept, emp.getDept());
//cv.put(colDept,2);
db.insert(employeeTable, colName, cv);
db.close();
}
int getEmployeeCount()
{
SQLiteDatabase db=this.getWritableDatabase();
Cursor cur= db.rawQuery("Select * from "+employeeTable, null);
int x= cur.getCount();
cur.close();
return x;
}
Cursor getAllEmployees()
{
SQLiteDatabase db=this.getWritableDatabase();
//Cursor cur= db.rawQuery("Select "+colID+" as _id , "+colName+",
"+colAge+" from "+employeeTable, new String [] {});
Cursor cur= db.rawQuery("SELECT * FROM "+viewEmps,null);
return cur;
}
Cursor getAllDepts()
{
SQLiteDatabase db=this.getReadableDatabase();
Cursor cur=db.rawQuery("SELECT "+colDeptID+" as _id, "+colDeptName+" from
"+deptTable,new String [] {});
return cur;
}
void InsertDepts(SQLiteDatabase db)
{
ContentValues cv=new ContentValues();
cv.put(colDeptID, 1);
cv.put(colDeptName, "Sales");
db.insert(deptTable, colDeptID, cv);
cv.put(colDeptID, 2);
cv.put(colDeptName, "IT");
db.insert(deptTable, colDeptID, cv);
cv.put(colDeptID, 3);
cv.put(colDeptName, "HR");
db.insert(deptTable, colDeptID, cv);
db.insert(deptTable, colDeptID, cv);
}
public String GetDept(int ID)
{
SQLiteDatabase db=this.getReadableDatabase();
String[] params=new String[]{String.valueOf(ID)};
Cursor c=db.rawQuery("SELECT "+colDeptName+" FROM"+ deptTable+" WHERE
"+colDeptID+"=?",params);
c.moveToFirst();
int index= c.getColumnIndex(colDeptName);
return c.getString(index);
}
public Cursor getEmpByDept(String Dept)
{
SQLiteDatabase db=this.getReadableDatabase();
String [] columns=new String[]{"_id",colName,colAge,colDeptName};
Cursor c=db.query(viewEmps, columns, colDeptName+"=?", new String[]
{Dept}, null, null, null);
return c;
}
public int GetDeptID(String Dept)
{
SQLiteDatabase db=this.getReadableDatabase();
Cursor c=db.query(deptTable, new String[]{colDeptID+" as
_id",colDeptName},colDeptName+"=?", new String[]{Dept}, null, null, null);
//Cursor c=db.rawQuery("SELECT "+colDeptID+" as _id FROM "+deptTable+"
WHERE "+colDeptName+"=?", new String []{Dept});
c.moveToFirst();
return c.getInt(c.getColumnIndex("_id"));
}
public int UpdateEmp(Employee emp)
{
SQLiteDatabase db=this.getWritableDatabase();
ContentValues cv=new ContentValues();
cv.put(colName, emp.getName());
cv.put(colAge, emp.getAge());
cv.put(colDept, emp.getDept());
return db.update(employeeTable, cv, colID+"=?", new String
[]{String.valueOf(emp.getID())});
}
public void DeleteEmp(Employee emp)
{
SQLiteDatabase db=this.getWritableDatabase();
db.delete(employeeTable,colID+"=?", new String []
{String.valueOf(emp.getID())});
db.close();
}
}
package mina.android.DatabaseDemo;
import android.content.DialogInterface;
public class DialogListner implements
android.content.DialogInterface.OnClickListener {
public DialogListner()
{
}
public void onClick(DialogInterface dialog, int which) {
// TODO Auto-generated method stub
}
}
package mina.android.DatabaseDemo;
import android.content.Context;
public class Employee {
int _id;
String _name;
int _age;
int _dept;
public Employee(String Name,int Age,int Dept)
{
this._name=Name;
this._age=Age;
this._dept=Dept;
}
public Employee(String Name,int Age)
{
this._name=Name;
this._age=Age;
}
public int getID()
{
return this._id;
}
public void SetID(int ID)
{
this._id=ID;
}
public String getName()
{
return this._name;
}
public int getAge()
{
return this._age;
}
public void setName(String Name)
{
this._name=Name;
}
public void setAge(int Age)
{
this._age=Age;
}
public void setDept(int Dept)
{
this._dept=Dept;
}
public String getDeptName(Context con, int Dept)
{
return new DatabaseHelper(con).GetDept(Dept);
}
public int getDept()
{
return this._dept;
}
}
package mina.android.DatabaseDemo;
import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.content.DialogInterface.OnDismissListener;
import android.database.Cursor;
import android.database.sqlite.SQLiteCursor;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.GridView;
import android.widget.SimpleCursorAdapter;
import android.widget.Spinner;
import android.widget.TextView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.AdapterView.OnItemSelectedListener;
public class GridList extends Activity {
DatabaseHelper dbHelper;
static public GridView grid;
TextView txtTest;
Spinner spinDept1;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.gridview);
grid=(GridView)findViewById(R.id.grid);
txtTest=(TextView)findViewById(R.id.txtTest);
spinDept1=(Spinner)findViewById(R.id.spinDept1);
Utilities.ManageDeptSpinner(this.getParent(),spinDept1);
final DatabaseHelper db=new DatabaseHelper(this);
try
{
http://img856.imageshack.us/img856/446/hoop.png
spinDept1.setOnItemSelectedListener(new OnItemSelectedListener() {
public void onItemSelected(AdapterView<?> arg0, View arg1,
int arg2, long arg3) {
// TODO Auto-generated method stub
LoadGrid();
//sca.notifyDataSetChanged();
}
public void onNothingSelected(AdapterView<?> arg0) {
// TODO Auto-generated method stub
}
});
}
catch(Exception ex)
{
txtTest.setText(ex.toString());
}
try
{
grid.setOnItemClickListener(new OnItemClickListener()
{
public void onItemClick(AdapterView<?> parent, View v, int position,
long id) {
// TODO Auto-generated method stub
try
{
SQLiteCursor
cr=(SQLiteCursor)parent.getItemAtPosition(position);
String
name=cr.getString(cr.getColumnIndex(DatabaseHelper.colName));
int
age=cr.getInt(cr.getColumnIndex(DatabaseHelper.colAge));
String
Dept=cr.getString(cr.getColumnIndex(DatabaseHelper.colDeptName));
Employee emp=new Employee(name, age,db.GetDeptID(Dept));
emp.SetID((int)id);
AlertDialog diag= Alerts.ShowEditDialog(GridList.this,emp);
diag.setOnDismissListener(new OnDismissListener() {
public void onDismiss(DialogInterface dialog) {
// TODO Auto-generated method stub
txtTest.setText("dismissed");
//((SimpleCursorAdapter)grid.getAdapter()).notifyDataSetChanged();
LoadGrid();
}
});
diag.show();
}
catch(Exception ex)
{
Alerts.CatchError(GridList.this, ex.toString());
}
}
}
);
}
catch(Exception ex)
{
}
}
@Override
public void onStart()
{
super.onStart();
//LoadGrid();
}
public void LoadGrid()
{
dbHelper=new DatabaseHelper(this);
try
{
//Cursor c=dbHelper.getAllEmployees();
View v=spinDept1.getSelectedView();
TextView txt=(TextView)v.findViewById(R.id.txtDeptName);
String Dept=String.valueOf(txt.getText());
Cursor c=dbHelper.getEmpByDept(Dept);
startManagingCursor(c);
String [] from=new String
[]{DatabaseHelper.colName,DatabaseHelper.colAge,DatabaseHelper.colDeptName};
int [] to=new int [] {R.id.colName,R.id.colAge,R.id.colDept};
SimpleCursorAdapter sca=new
SimpleCursorAdapter(this,R.layout.gridrow,c,from,to);
grid.setAdapter(sca);
}
catch(Exception ex)
{
AlertDialog.Builder b=new AlertDialog.Builder(this);
b.setMessage(ex.toString());
b.show();
}
}
}
package mina.android.DatabaseDemo;
import android.content.Context;
import android.database.Cursor;
import android.widget.SimpleCursorAdapter;
import android.widget.Spinner;
public class Utilities {
static public void ManageDeptSpinner(Context context,Spinner view)
{
DatabaseHelper dbHelper=new DatabaseHelper(context);
Cursor c=dbHelper.getAllDepts();
//context.startManagingCursor(c);
//SimpleCursorAdapter ca=new
SimpleCursorAdapter(this,android.R.layout.simple_spinner_item, c, new String []
{DatabaseHelper.colDeptName}, new int []{android.R.id.text1});
SimpleCursorAdapter ca=new
SimpleCursorAdapter(context,R.layout.deptspinnerrow,c,
new String [] {DatabaseHelper.colDeptName,"_id"}, new int []{R.id.txtDeptName});
view.setAdapter(ca);
}
}