我是 android 的新手。我有一个关于数据库的查询。我在数据库中插入了一些数据，即我从自定义 datepickerdialog 中选择的 textview 中插入了月份和年份，还插入了日期和一些从 textview 到 database.nw 的信息我想要从数据库中检索基于月份和年份的插入日期和信息，并显示在列表中。下面的代码显示了数据的插入..
package com.example.collegeapp;
import java.lang.reflect.Field;
import java.util.Calendar;
import android.app.Activity;
import android.app.DatePickerDialog;
import android.app.Dialog;
import android.content.ContentValues;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.DatePicker;
import android.widget.EditText;
import android.widget.ImageButton;
import android.widget.Toast;
public class Events1 extends Activity {
int yr,mm,dd;
ImageButton ib;
EditText et1,et2,et3;
String d,c,e;
Button b1;
static final int Date_Dialog_id=1;
Database md=new Database(this);
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_events1);
ib=(ImageButton) findViewById(R.id.imageButton1);
et1=(EditText) findViewById(R.id.editText1);
et2=(EditText) findViewById(R.id.editText2);
et3=(EditText) findViewById(R.id.editText3);
b1=(Button) findViewById(R.id.button1);
md.open();
b1.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
d=et1.getText().toString();
c=et2.getText().toString();
e=et3.getText().toString();
ContentValues cv=new ContentValues();
cv.put("d",d);
cv.put("c",c);
cv.put("e",e);
md.add(cv);
Toast t=Toast.makeText(getApplicationContext(), "Data is inserted",Toast.LENGTH_SHORT);
t.show();
et1.setText("");
et2.setText(" ");
et3.setText(" ");
}
});
ib.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
showDialog(Date_Dialog_id);
}
});
final Calendar c = Calendar.getInstance();
yr = c.get(Calendar.YEAR);
mm = c.get(Calendar.MONTH);
}
DatePickerDialog.OnDateSetListener mDateSetListner = new DatePickerDialog.OnDateSetListener() {
@Override
public void onDateSet(DatePicker view, int year, int monthOfYear,
int dayOfMonth) {
yr= year;
mm = monthOfYear;
dd = dayOfMonth;
updateDate();
}
};
@Override
protected Dialog onCreateDialog(int id) {
switch (id) {
case Date_Dialog_id:
DatePickerDialog datePickerDialog = this.customDatePicker();
return datePickerDialog;
}
return null;
}
protected void updateDate() {
int localMonth = (mm + 1);
String monthString = localMonth < 10 ? "0" + localMonth : Integer
.toString(localMonth);
String localYear = Integer.toString(yr).substring(2);
et1.setText(new StringBuilder()
// Month is 0 based so add 1
.append(monthString).append("/").append(localYear).append(" "));
showDialog(Date_Dialog_id);
}
private DatePickerDialog customDatePicker() {
DatePickerDialog dpd = new DatePickerDialog(this, mDateSetListner,
yr,mm,dd);
try {
Field[] datePickerDialogFields = dpd.getClass().getDeclaredFields();
for (Field datePickerDialogField : datePickerDialogFields) {
if (datePickerDialogField.getName().equals("mDatePicker")) {
datePickerDialogField.setAccessible(true);
DatePicker datePicker = (DatePicker) datePickerDialogField
.get(dpd);
Field datePickerFields[] = datePickerDialogField.getType()
.getDeclaredFields();
for (Field datePickerField : datePickerFields) {
if ("mDayPicker".equals(datePickerField.getName())
|| "mDaySpinner".equals(datePickerField
.getName())) {
datePickerField.setAccessible(true);
Object dayPicker = new Object();
dayPicker = datePickerField.get(datePicker);
((View) dayPicker).setVisibility(View.GONE);
}}}}}
catch (Exception ex) {
}
return dpd;
}
}
现在下面是从数据库中检索数据的代码..
Events.java
package com.example.collegeapp;
import java.lang.reflect.Field;
import java.util.Calendar;
import android.app.Activity;
import android.app.DatePickerDialog;
import android.app.Dialog;
import android.content.ContentValues;
import android.database.Cursor;
import android.os.Bundle;
import android.support.v4.widget.SimpleCursorAdapter;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.DatePicker;
import android.widget.EditText;
import android.widget.ImageButton;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
public class Events extends Activity {
ImageButton ib;
Button b1;
EditText et1;
int yr,mm,dd;
Cursor y;
ListView lv;
String m;
static final int Date_Dialog_id=1;
Database md=new Database(this);
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_events);
ib=(ImageButton) findViewById(R.id.imageButton1);
b1=(Button) findViewById(R.id.button1);
et1=(EditText) findViewById(R.id.editText1);
lv=(ListView) findViewById(R.id.listView1);
md.open();
b1.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
go();
}
});
ib.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
showDialog(Date_Dialog_id);
}
});
final Calendar c = Calendar.getInstance();
yr = c.get(Calendar.YEAR);
mm = c.get(Calendar.MONTH);
}
protected void go() {
// TODO Auto-generated method stub
m=et1.getText().toString();
y=md.get(m);
if (y.moveToFirst())
{
do {
DisplayCmpTitle(y);
} while (y.moveToNext());
}
}
private void DisplayCmpTitle(Cursor y2) {
// TODO Auto-generated method stub
SimpleCursorAdapter cursorAdapter;
String []from={"d","c","e"};
int []to={R.id.textView1,R.id.textView2,R.id.textView3};
cursorAdapter=new SimpleCursorAdapter(this,R.layout.activity_event3,y,from,to,0);
lv.setAdapter(cursorAdapter);
}
DatePickerDialog.OnDateSetListener mDateSetListner = new DatePickerDialog.OnDateSetListener() {
@Override
public void onDateSet(DatePicker view, int year, int monthOfYear,
int dayOfMonth) {
yr= year;
mm = monthOfYear;
dd = dayOfMonth;
updateDate();
}
};
@Override
protected Dialog onCreateDialog(int id) {
switch (id) {
case Date_Dialog_id:
/*
* return new DatePickerDialog(this, mDateSetListner, mYear, mMonth,
* mDay);
*/
DatePickerDialog datePickerDialog = this.customDatePicker();
return datePickerDialog;
}
return null;
}
protected void updateDate() {
int localMonth = (mm + 1);
String monthString = localMonth < 10 ? "0" + localMonth : Integer
.toString(localMonth);
String localYear = Integer.toString(yr).substring(2);
et1.setText(new StringBuilder()
// Month is 0 based so add 1
.append(monthString).append("/").append(localYear).append(" "));
showDialog(Date_Dialog_id);
}
private DatePickerDialog customDatePicker() {
DatePickerDialog dpd = new DatePickerDialog(this, mDateSetListner,
yr,mm,dd);
try {
Field[] datePickerDialogFields = dpd.getClass().getDeclaredFields();
for (Field datePickerDialogField : datePickerDialogFields) {
if (datePickerDialogField.getName().equals("mDatePicker")) {
datePickerDialogField.setAccessible(true);
DatePicker datePicker = (DatePicker) datePickerDialogField
.get(dpd);
Field datePickerFields[] = datePickerDialogField.getType()
.getDeclaredFields();
for (Field datePickerField : datePickerFields) {
if ("mDayPicker".equals(datePickerField.getName())
|| "mDaySpinner".equals(datePickerField
.getName())) {
datePickerField.setAccessible(true);
Object dayPicker = new Object();
dayPicker = datePickerField.get(datePicker);
((View) dayPicker).setVisibility(View.GONE);
}}}}}
catch (Exception ex) {
}
return dpd;
}
}
事件.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent" >
<TextView
android:id="@+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:layout_marginTop="18dp"
android:gravity="center"
android:text="Events"
android:textAppearance="?android:attr/textAppearanceLarge" />
<Button
android:id="@+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_marginBottom="44dp"
android:text="Button" />
<EditText
android:id="@+id/editText1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:layout_below="@+id/textView1"
android:ems="10" />
<ImageButton
android:id="@+id/imageButton1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignTop="@+id/editText1"
android:background="@drawable/ic_launcher" />
<ListView
android:id="@+id/listView1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/editText1"
android:layout_below="@+id/imageButton1"
android:layout_marginTop="74dp" >
</ListView>
</RelativeLayout>
数据库.java
package com.example.collegeapp;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteDatabase.CursorFactory;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;
import android.widget.Toast;
public class Database
{
public static final String MY_db="testDB";
//private static final String Table_name="stu";
private static final String Key_id="_id";
private static final String Key_mnth_yr="d";
private static final String Key_date="c";
private static final String Key_data="e";
MyHelper1 mh;
Context myCon;
SQLiteDatabase sdb;
public Database(Context c){
myCon=c;
mh=new MyHelper1(myCon,MY_db, null,1);
}
public Database open() throws SQLException{
sdb=mh.getWritableDatabase();
return this;
}
public class MyHelper1 extends SQLiteOpenHelper{
public MyHelper1(Context context, String name, CursorFactory factory,
int version) {
super(context, name, factory, version);
// TODO Auto-generated constructor stub
}
public void onCreate(SQLiteDatabase db) {
try{
// TODO Auto-generated method stub
db.execSQL("cretae table s(_id integer primary key autoincrement,d text,c text,e text);");
}
catch(SQLException e){
e.printStackTrace();
}
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// TODO Auto-generated method stub
}
}
public void add(ContentValues cv){
// SQLiteDatabase sdb = this.getWritableDatabase();
sdb.insert("s", null, cv);
}
public Cursor get(String dtr) {
// TODO Auto-generated method stub
Cursor f=sdb.query("s",new String[] {"d","c","e" },"d" + "=" + dtr,
new String [] { "dtr" },null,null,null,null);
return f;
}
}
logcat 中显示的错误是-无法在索引 1 处绑定参数，因为索引超出范围。语句有 0 参数。