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1.前言：
今天再一次去蹭了一下某老师的android课，这一次讲的是Android的SQLite的使用，老师当场讲解了他自己做的例子。
回来之后，我春心萌动，不得不拿着参考资料再做了一个类似的例子，其实我已经过几遍SQLite的内容了，但是认识还是不深刻。
2.SQLite继承
要想使用SQLite,就必需设计一个相应类，并且继承SQLiteOpenHelper。
基本上要操作的是onCreate函数（注意自动生成，执行语句建议还是单独写），这个函数在数据库被提及时便会执行，所以添加的内容一般就是建表操作。
person.java
package Model; import android.content.Context; import android.database.sqlite.SQLiteDatabase; import android.database.sqlite.SQLiteDatabase.CursorFactory; import android.database.sqlite.SQLiteOpenHelper; public class Person extends SQLiteOpenHelper { public static final String CREATE_BOOK = "create table person(" + "_id integer primary key autoincrement, " + "name text, " + "tel text)"; public Person(Context context, String name, CursorFactory factory, int version) { super(context, name, factory, version); // TODO Auto-generated constructor stub } @Override public void onCreate(SQLiteDatabase db) { // TODO Auto-generated method stub db.execSQL(CREATE_BOOK); //建表 } @Override public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { // TODO Auto-generated method stub } }
3.使用
SQLite的使用其实套路都一样的。
personHelper = new Person(this, "personDB.db", null, 1);//new一个类，注意*.db不能跟类重名
这里因为不理解的原因，“personDB.db”我第一次海用了"person".....
增加：getWritableDatabase在这里我很不理解，getReadDatabase一般还用不到，看了一次百度的一些解答还是不太懂，那就一直用getWritableDatabase吧。
SQLiteDatabase db = personHelper.getWritableDatabase(); String str_name = edit_name.getText().toString(); String str_tel = edit_tel.getText().toString(); ContentValues cv = new ContentValues(); cv.put("name", str_name); cv.put("tel", str_tel); db.insert("person",null,cv);
查询：
SQLiteDatabase db = personHelper.getWritableDatabase(); String result = ""; Cursor cursor = db.rawQuery("select * from person", null); cursor.moveToFirst(); if (cursor.moveToFirst()){ do{ int id = cursor.getInt(0); String nameString = cursor.getString(1); String telString = cursor.getString(2); result += "id="+id+" name:"+nameString+" tel:"+telString+"\n"; Log.d("sql", nameString); //Log.d("sql", id); Log.d("sql", telString); }while(cursor.moveToNext()); } cursor.close();
删除：
SQLiteDatabase db = personHelper.getWritableDatabase(); String str_name = edit_name.getText().toString(); String str_tel = edit_tel.getText().toString(); db.delete("person", "name=? and tel=?", new String[]{str_name,str_tel});
修改：
SQLiteDatabase db = personHelper.getWritableDatabase(); String str_name = edit_name.getText().toString(); String str_tel = edit_tel.getText().toString(); ContentValues cv = new ContentValues(); cv.put("tel", str_tel); db.update("person", cv, "name=?", new String[]{str_name});
Mainactivity.java
package com.sqlitetest.app; import Model.Person; import android.app.Activity; import android.content.ContentValues; import android.database.Cursor; import android.database.sqlite.SQLiteDatabase; import android.os.Bundle; import android.text.method.ScrollingMovementMethod; import android.util.Log; 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 { Button btn_add = null; Button btn_delete = null; Button btn_update = null; Button btn_search = null; EditText edit_name = null; EditText edit_tel = null; TextView txt_result = null; Person personHelper = null; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); personHelper = new Person(this, "personDB.db", null, 1);//new一个类，注意*.db不能跟类重名 btn_add = (Button) findViewById(R.id.btn_add); btn_delete = (Button) findViewById(R.id.btn_delete); btn_search = (Button) findViewById(R.id.btn_search); btn_update = (Button) findViewById(R.id.btn_update); edit_name = (EditText) findViewById(R.id.edit_name); edit_tel = (EditText) findViewById(R.id.edit_number); txt_result = (TextView) findViewById(R.id.txt_result); txt_result.setMovementMethod(new ScrollingMovementMethod()); //使得内容多时textview可以滚动 btn_add.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { // TODO Auto-generated method stub SQLiteDatabase db = personHelper.getWritableDatabase(); String str_name = edit_name.getText().toString(); String str_tel = edit_tel.getText().toString(); ContentValues cv = new ContentValues(); cv.put("name", str_name); cv.put("tel", str_tel); db.insert("person",null,cv); Log.d("sql", str_name); Log.d("sql", str_tel); } }); btn_search.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { // TODO Auto-generated method stub SQLiteDatabase db = personHelper.getWritableDatabase(); String result = ""; Cursor cursor = db.rawQuery("select * from person", null); cursor.moveToFirst(); if (cursor.moveToFirst()){ do{ int id = cursor.getInt(0); String nameString = cursor.getString(1); String telString = cursor.getString(2); result += "id="+id+" name:"+nameString+" tel:"+telString+"\n"; Log.d("sql", nameString); //Log.d("sql", id); Log.d("sql", telString); }while(cursor.moveToNext()); } cursor.close(); txt_result.setText(result); } }); btn_delete.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { // TODO Auto-generated method stub SQLiteDatabase db = personHelper.getWritableDatabase(); String str_name = edit_name.getText().toString(); String str_tel = edit_tel.getText().toString(); db.delete("person", "name=? and tel=?", new String[]{str_name,str_tel}); } }); btn_update.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { // TODO Auto-generated method stub SQLiteDatabase db = personHelper.getWritableDatabase(); String str_name = edit_name.getText().toString(); String str_tel = edit_tel.getText().toString(); ContentValues cv = new ContentValues(); cv.put("tel", str_tel); db.update("person", cv, "name=?", new String[]{str_name}); } }); } }
activity_main.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" android:paddingBottom="@dimen/activity_vertical_margin" android:paddingLeft="@dimen/activity_horizontal_margin" android:paddingRight="@dimen/activity_horizontal_margin" android:paddingTop="@dimen/activity_vertical_margin" tools:context="com.sqlitetest.app.MainActivity" > <TextView android:id="@+id/txt_name" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignParentLeft="true" android:layout_alignParentTop="true" android:layout_marginLeft="20dp" android:layout_marginTop="20dp" android:text="@string/name" android:textSize="20sp" /> <EditText android:id="@+id/edit_name" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignBaseline="@+id/txt_name" android:layout_alignBottom="@+id/txt_name" android:layout_marginLeft="21dp" android:layout_toRightOf="@+id/txt_name" android:ems="10" android:inputType="textPersonName" /> <EditText android:id="@+id/edit_number" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignBottom="@+id/txt_number" android:layout_alignLeft="@+id/edit_name" android:ems="10" android:inputType="number" /> <TextView android:id="@+id/txt_number" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_below="@+id/edit_name" android:layout_marginTop="18dp" android:layout_toLeftOf="@+id/edit_name" android:text="@string/phonenumber" android:textSize="20sp" /> <ScrollView android:id="@+id/scrollView1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignRight="@+id/btn_update" android:layout_below="@+id/btn_update" > </ScrollView> <Button android:id="@+id/btn_add" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignRight="@+id/edit_number" android:layout_below="@+id/edit_number" android:layout_marginRight="47dp" android:text="@string/add" /> <Button android:id="@+id/btn_delete" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_above="@+id/btn_update" android:layout_toRightOf="@+id/txt_number" android:text="@string/delete" /> <TextView android:id="@+id/txt_result" android:layout_width="wrap_content" android:layout_height="match_parent" android:layout_alignTop="@+id/scrollView1" android:layout_toRightOf="@+id/txt_number" android:maxLines = "1000"//这个滚动要加上去，最大怎么表示不清楚 android:scrollbars = "vertical"//这个也是滚动必须加的 android:text="@string/result" /> <Button android:id="@+id/btn_update" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignLeft="@+id/btn_add" android:layout_below="@+id/btn_add" android:layout_marginTop="16dp" android:text="@string/update" /> <Button android:id="@+id/btn_search" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_above="@+id/txt_result" android:layout_alignLeft="@+id/txt_result" android:text="@string/search" /> </RelativeLayout>
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原文地址：http://www.cnblogs.com/ljy-1471914707/p/5444531.html
