我正在做一个Android应用程序。我试图让数据库的行在文本视图中查看它们。在开始我想采取数据库的第一行。然后我使用陀螺仪在屏幕上滑动引号。但是我得到了这个错误。有人可以帮我吗？非常感谢。
这是SlideShow类
package com.example.prova1;
import java.util.HashMap;
import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.os.Bundle;
import android.widget.TextView;
public class SlideQuote extends Activity implements SensorEventListener
{
//a TextView
private TextView quote;
private TextView author;
//the Sensor Manager
private SensorManager sManager;
float x;
int id;
int total;
String s1,s2;
Database quotedatabase = new Database(this);
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.slide_quote);
//get the TextView from the layout file
quote = (TextView) findViewById(R.id.textView3);
author = (TextView) findViewById(R.id.textView4);
id=1;
//get a hook to the sensor service
sManager= (SensorManager) getSystemService(Context.SENSOR_SERVICE);
if(sManager.getSensorList(Sensor.TYPE_GYROSCOPE).size()!=0){
Sensor s =sManager.getSensorList(Sensor.TYPE_GYROSCOPE).get(o);
sManager.registerListener(this,s ,SensorManager.SENSOR_DELAY_NORMAL);
quotedatabase.getQuote(id, s1, s2);
quote.setText(s1);
author.setText(s2);
}
}
//when this Activity starts
@Override
protected void onResume()
{
super.onResume();
/*register the sensor listener to listen to the gyroscope sensor, use the
callbacks defined in this class, and gather the sensor information as quick
as possible*/
sManager.registerListener(this, sManager.getDefaultSensor(Sensor.TYPE_GYROSCOPE),SensorManager.SENSOR_DELAY_FASTEST);
}
//When this Activity isn't visible anymore
@Override
protected void onStop()
{
//unregister the sensor listener
sManager.unregisterListener(this);
super.onStop();
}
@Override
public void onAccuracyChanged(Sensor arg0, int arg1)
{
//Do nothing.
}
@Override
public void onSensorChanged(SensorEvent event)
{
//if sensor is unreliable, return void
if (event.accuracy == SensorManager.SENSOR_STATUS_UNRELIABLE)
{
return;
}
//else it will output the Roll, Pitch and Yawn values
x=event.values[2];
total=quotedatabase.getQuotesCount();
if(x>25){
if(id==total)
{id=1;
}
else{
id++;
}
quotedatabase.getQuote(id, s1, s2);
quote.setText(s1);
author.setText(s2);
}
if(x<-25){
if(id==1)
{id=total;}
else{
id--;}
quotedatabase.getQuote(id, s1, s2);
quote.setText(s1);
author.setText(s2);
}
}
@Override
public void onBackPressed() {
// TODO Auto-generated method stub
sManager.unregisterListener(this);
Intent backIntent = new Intent(getApplication(), Quote.class);
finish();
startActivity(backIntent);
}
}
这是数据库：
package com.example.prova1;
/**This class is for the database that is used to store quotes*/
import java.util.ArrayList;
import java.util.HashMap;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
public class Database extends SQLiteOpenHelper {
public Database(Context quoteContext){
super(quoteContext, "quoteDB", null, 1);
}
@Override
//Create database
public void onCreate(SQLiteDatabase database) {
String query = "CREATE TABLE quotelist ( quoteId INTEGER PRIMARY KEY, textQuote TEXT ,textAuthor TEXT)";
String query1 = "INSERT INTO quotelist VALUES ( '1', 'RAI', 'uku')";
database.execSQL(query);
database.execSQL(query1);
}
@Override
public void onUpgrade(SQLiteDatabase database, int oldVersion, int newVersion) {
String query = "DROP TABLE IF EXISTS quotelist";
database.execSQL(query);
onCreate(database);
}
//Insert quotes into database
public void insertItem(HashMap<String, String> queryValues){
SQLiteDatabase database = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put("textQuote", queryValues.get("textQuote"));
values.put("textAuthor", queryValues.get("textAuthor"));
database.insert("quotelist", null, values);
database.close();
}
//Update the quotes into the database
public int updateItem(HashMap<String, String> queryValues) {
SQLiteDatabase database = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put("textQuote", queryValues.get("textQuote"));
values.put("textAuthor", queryValues.get("textAuthor"));
return database.update("quotelist", values, "quoteId" + " = ?", new String[] {queryValues.get("quoteId") });
}
//Delete quotes into the database
public void deleteItem(String id){
SQLiteDatabase database = this.getWritableDatabase();
String deleteQuery = "DELETE FROM quotelist WHERE quoteId='" + id + "'";
database.execSQL(deleteQuery);
database.close();
}
public ArrayList<HashMap<String, String>> getAllItems(){
ArrayList<HashMap<String, String>> itemArrayList = new ArrayList<HashMap<String, String>>();
String selectQuery = "SELECT * FROM quotelist";
SQLiteDatabase database = this.getWritableDatabase();
Cursor cursor = database.rawQuery(selectQuery, null);
if(cursor.moveToFirst()){
do{
HashMap<String, String> itemMap = new HashMap<String, String>();
itemMap.put("quoteId", cursor.getString(o));
itemMap.put("textQuote", cursor.getString(1));
itemMap.put("textAuthor", cursor.getString(2));
itemArrayList.add(itemMap);
} while(cursor.moveToNext());
}
database.close();
return itemArrayList;
}
public HashMap<String, String> getItemInfo(String id){
HashMap<String, String> itemMap = new HashMap<String, String>();
SQLiteDatabase database = this.getReadableDatabase();
String selectQuery = "SELECT * FROM quotelist WHERE quoteId='" + id + "'";
Cursor cursor = database.rawQuery(selectQuery, null);
if(cursor.moveToFirst()){
do{
itemMap.put("quoteId", cursor.getString(o));
itemMap.put("textQuote", cursor.getString(1));
itemMap.put("textAuthor", cursor.getString(2));
} while(cursor.moveToNext());
}
return itemMap;
}
public void getQuote(int id, String s1,String s2) {
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.query("quotelist", new String[] { "quoteId",
"textQuote", "textAuthor" }, "quoteId" + "=?",
new String[] { String.valueOf(id) }, null, null, null, null);
if (cursor != null)
cursor.moveToFirst();
s1=cursor.getString(1);
s2=cursor.getString(2);
}
public int getQuotesCount() {
String countQuery = "SELECT * FROM quotelist" ;
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery(countQuery, null);
cursor.close();
// return count
return cursor.getCount();
}
错误是这行：s1 = cursor.getString（1）;在DatabaseClass
和at：quotedatabase.getQuote（id，s1，s2）;在ShowQuote类
答案 0 :(得分：1)
此错误表示光标中没有数据。您的数据库中是否包含数据？此外，您应该检查moveToFirst的结果，因为如果光标为空，则会显示false值。
答案 1 :(得分：0)
错误在于：s1 = cursor.getString（1）;和 S2 = cursor.getString（2）; 如果字符串长度为0，则无法获得第二个字符，并且您将获得outofboundexception。
此操作也无效。在这种情况下，您为您的方法提供一个字符串。方法中的S1与您给方法的字符串不同。通过为方法赋予变量，JAVA会创建此变量的副本。