android增删改查sqlite数据库

在网上一直没找到带界面的，或者代码是断断续续的，不如自己写一个。

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >

<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content" >

<Button
android:id="@+id/insertButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="插入" />

<EditText
android:id="@+id/insertEditText"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:ems="10" >

<requestFocus />
</EditText>

</LinearLayout>

<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content" >

<Button
android:id="@+id/deleteButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="删除" />

<EditText
android:id="@+id/deleteEditText"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:ems="10" />

</LinearLayout>

<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content" >

<Button
android:id="@+id/updateButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="修改" />

<EditText
android:id="@+id/oldEditText"
android:layout_width="119dp"
android:layout_height="wrap_content"
android:ems="10" />

<TextView
android:id="@+id/textView3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="改为" />

<EditText
android:id="@+id/newEditText"
android:layout_width="92dp"
android:layout_height="wrap_content"
android:ems="10" />

</LinearLayout>

<Button
android:id="@+id/selectButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="查询" />

<TextView
android:id="@+id/resultTextView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="结果" />

</LinearLayout>

package com.example.sqlite_1;
//
//import com.example.andtest_2.MainActivity;
//import com.example.andtest_2.StuDBHelper;

import android.app.Activity;
import android.content.ContentValues;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class MainActivity extends Activity {

private Button insertButton, updateButton, deleteButton, selectButton;
private EditText insertEditText, oldEditText, newEditText, deleteEditText;
private TextView resultTextView;
private StringBuilder sb = new StringBuilder();

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
insertButton = (Button) findViewById(R.id.insertButton);
deleteButton = (Button) findViewById(R.id.deleteButton);
updateButton = (Button) findViewById(R.id.updateButton);
selectButton = (Button) findViewById(R.id.selectButton);

insertEditText = (EditText) findViewById(R.id.insertEditText);
oldEditText = (EditText) findViewById(R.id.oldEditText);
newEditText = (EditText) findViewById(R.id.newEditText);
deleteEditText = (EditText) findViewById(R.id.deleteEditText);

resultTextView = (TextView) findViewById(R.id.resultTextView);

// //增
insertButton.setOnClickListener(new OnClickListener() {

@Override
public void onClick(View v) {
// TODO 自动生成的方法存根
CityDBHelper dbHelper = new CityDBHelper(MainActivity.this,
"city_db_2", null, 1);

SQLiteDatabase db = dbHelper.getWritableDatabase();
ContentValues cv = new ContentValues();
cv.put("city", insertEditText.getText().toString());
db.insert("city_table", null, cv);
db.close();

resultTextView.setText("");
}
});
// 删

deleteButton.setOnClickListener(new OnClickListener() {

@Override
public void onClick(View v) {
// TODO 自动生成的方法存根

Log.i("删除开始", "删除开始");

CityDBHelper dbHelper = new CityDBHelper(MainActivity.this,
"city_db_2", null, 1);

SQLiteDatabase db = dbHelper.getReadableDatabase();
String whereClauses = "city=?";
Log.i(" deleteEditText.getText().toString()",  deleteEditText.getText().toString());

String[] whereArgs = { deleteEditText.getText().toString()};
db.delete("city_table", whereClauses, whereArgs);

Log.i("删除结束", "删除结束");

}
});

// //改

updateButton.setOnClickListener(new OnClickListener() {

@Override
public void onClick(View v) {
// TODO 自动生成的方法存根

// db.update(table, values, whereClause, whereArgs)
CityDBHelper dbHelper = new CityDBHelper(MainActivity.this,
"city_db_2", null, 1);

SQLiteDatabase db = dbHelper.getWritableDatabase();

ContentValues cv = new ContentValues();
cv.put("city", newEditText.getText().toString());
String whereClauses = "city=?";
String[] whereArgs = { oldEditText.getText().toString() };
db.update("city_table", cv, whereClauses, whereArgs);

}
});

// //查
selectButton.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO 自动生成的方法存根
CityDBHelper dbHelper = new CityDBHelper(MainActivity.this,
"city_db_2", null, 1);

SQLiteDatabase db = dbHelper.getWritableDatabase();
Cursor cursor = db.query("city_table", new String[] { "city" },
null, null, null, null, null, null);

sb.delete(0, sb.length());
while (cursor.moveToNext()) {

sb.append("城市:"
+ cursor.getString(cursor.getColumnIndex("city"))
+ "\n");
}
resultTextView.setText(sb.toString());
db.close();

}
});

}// /onCreate
}