我想用sqlite开发一个android日记本，并实现增删改查功能。现在大部分功能已经完善，但是在实现删除功能时，总出现问题：delete语句执行后，数据库中的记录删除了，listview中显示的记录却不能同时删除，必须重启软件，listview中才会删除那条记录！哪位高手能指点一下我要如何实现listview与数据库的同步！！！相应代码如下：
package com.example.mydiary;
import android.os.Bundle;
import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.content.Intent;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.support.v4.widget.SimpleCursorAdapter;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.AdapterView.OnItemLongClickListener;
import android.widget.Button;
import android.widget.ListView;
public class MainActivity extends Activity {
private Button addBtn;
private Button delateBtn;
private ListView diaryList;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//找到每个组件的id
findid();
//将数据库的内容在主界面的listview中显示
listview();
//为listview设置监听
listOnClick();
//为主界面上的button设置监听事件
onclicklistenner();
}
//获得数据库的实例
public SQLiteDatabase getdb(){
SQLiteDatabase db;
return (new DiaryDate(MainActivity.this).getWritableDatabase());
}
//获得表中内容并返回一个游标Cursor
public Cursor getcursor(){
SQLiteDatabase db = getdb();
Cursor cursor = db.rawQuery(
"SELECT * FROM diary", null);
return cursor;
}
private void listview() {
// TODO Auto-generated method stub
Cursor cursor = getcursor();
//使用simpleCursorAdapter适配器
SimpleCursorAdapter listAdapter = new SimpleCursorAdapter(MainActivity.this, R.layout.text_01,
cursor,
new String[]{"title","time"},
new int[]{R.id.text_title,R.id.text_time});
diaryList.setAdapter(listAdapter);
}
public void listOnClick(){
//设定listview的点击监听事件
diaryList.setOnItemClickListener(new OnItemClickListener(){
public void onItemClick(AdapterView<?> arg0, View arg1,
int arg2, long arg3) {
// TODO Auto-generated method stub
Cursor cursor = getcursor();
//游标指定到鼠标所在的arg2位置
cursor.moveToPosition(arg2);
Intent intent = new Intent();
intent.setClass(MainActivity.this, C_diary.class);
//为intent绑定数据
intent.putExtra("title",cursor.getString(cursor.getColumnIndex("title")));
intent.putExtra("body",cursor.getString(cursor.getColumnIndex("body")));
intent.putExtra("_id",cursor.getInt(cursor.getColumnIndex("_id")));
startActivity(intent);
}
});
//设定listview的长点击监听事件
diaryList.setOnItemLongClickListener(new OnItemLongClickListener() {
public boolean onItemLongClick(AdapterView<?> arg0, View arg1,
final int arg2, long arg3) {
new AlertDialog.Builder(MainActivity.this)
.setTitle("Message")
.setPositiveButton("删除",new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
// TODO Auto-generated method stub
Cursor cursor = getcursor();
cursor.moveToPosition(arg2);
int i = cursor.getInt(cursor.getColumnIndex("_id"));
Log.i("i", String.valueOf(i));
//删除数据库中的数据
SQLiteDatabase db = getdb();
db.delete("diary", "_id="+i,null);
}
})
.setNegativeButton("取消", null)
.show();
return true;
}
});
}
private void onclicklistenner() {
// TODO Auto-generated method stub
addBtn.setOnClickListener(sbtn1);
delateBtn.setOnClickListener(sbtn2);
}
private void findid() {
// TODO Auto-generated method stub
addBtn = (Button) findViewById(R.id.addBtn);
delateBtn = (Button) findViewById(R.id.delateBtn);
diaryList = (ListView) findViewById(R.id.diaryview);
}
OnClickListener sbtn1 = new OnClickListener() {
public void onClick(View v) {
// TODO Auto-generated method stub
Intent intent = new Intent();
intent.setClass(MainActivity.this, CreatDiary.class);
startActivity(intent);
}
};
OnClickListener sbtn2 = new OnClickListener() {
public void onClick(View v) {
// TODO Auto-generated method stub
}
};
}
