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Android 數(shù)據(jù)庫使用demo

來源：_110 發(fā)布時間：2018-11-30 17:43:08 閱讀量：1147

應用A

package com.example.testc;

import android.content.Context;

import android.database.sqlite.SQLiteDatabase;

import android.database.sqlite.SQLiteDatabase.CursorFactory;

import android.database.sqlite.SQLiteOpenHelper;

public class DatabaseHelper extends SQLiteOpenHelper {

//創(chuàng)建表格名字data 表格里面主鍵 uid int ,total text , name text

private static final String CREATE_TABLE = "create table data(_id INTEGER PRIMARY KEY autoincrement,uid int,total text,name text);";

private Context mContext;

public DatabaseHelper (Context context, String name, CursorFactory factory, int version) {

super(context, name, factory, version);

// TODO Auto-generated constructor stub

mContext = context;

}

@Override

public void onCreate(SQLiteDatabase db) {

// TODO Auto-generated method stub創(chuàng)建數(shù)據(jù)庫后，對數(shù)據(jù)庫的操作

db.execSQL(CREATE_TABLE);

}

@Override

public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

// TODO Auto-generated method stub 更改數(shù)據(jù)庫版本的操作

db.execSQL("drop table if exists peopleinfo");

onCreate(db);

}

package com.example.testc;

import java.util.ArrayList;

import android.net.Uri;

import android.os.Bundle;

import android.annotation.TargetApi;

import android.app.Activity;

import android.content.ContentResolver;

import android.content.ContentValues;

import android.content.Context;

import android.database.Cursor;

import android.database.sqlite.SQLiteDatabase;

import android.util.Log;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.Button;

import android.widget.TextView;

@TargetApi(23)

public class MainActivity extends Activity {

private Context mcontext;

private TextView IEMI;

MapBroadcast mapReceiver;

DatabaseHelper helper;

SQLiteDatabase db;

ArrayList< Appinfo> lists ;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

mcontext = getApplicationContext();

initView();

helper = new DatabaseHelper(MainActivity.this, "mydb.db", null, 1);

db = helper.getWritableDatabase();

lists = new ArrayList<Appinfo>();

/* 創(chuàng)建一個MySQLiteOpenHelper，該語句執(zhí)行是不會創(chuàng)建或打開連接的 */

}

private void initView() {

// TODO Auto-generated method stub

IEMI = (TextView) findViewById(R.id.hello);

Button bt = (Button) findViewById(R.id.bt);

Button bt1 = (Button)findViewById(R.id.bt1);

Button bt2 = (Button)findViewById(R.id.bt3);

bt.setOnClickListener(new OnClickListener() {

@Override

public void onClick(View v) {

db.execSQL("DELETE FROM data"); //插入前清空表格

for (int i = 0; i < 10; i++) {

ContentValues values = new ContentValues();

values.put("uid", i);

values.put("total", "12MB");

values.put("name", "zhangsan");

// 插入數(shù)據(jù)

db.insert("data", null, values);

}

});

bt1.setOnClickListener(new OnClickListener() {

@Override

public void onClick(View v) {

// TODO Auto-generated method stub

//清空表格數(shù)據(jù)

testQuery();

}

});

bt2.setOnClickListener(new OnClickListener() {

@Override

public void onClick(View v) {

// TODO Auto-generated method stub

//查詢數(shù)據(jù)

Cursor cursor = db.query("data", null, null, null, null, null, null);

lists.clear();

while (cursor.moveToNext()) {

String uid = cursor.getString(cursor.getColumnIndex("uid"));

String total = cursor.getString(cursor.getColumnIndex("total"));

String name = cursor.getString(cursor.getColumnIndex("name"));

Appinfo appinfo=new Appinfo(uid, total, name);

/* Log.e("TAG", "[uid]="+uid+"[total]="+total+"[name]="+name);

*/ appinfo.setName(name);

appinfo.setTotal(total);

appinfo.setUid(uid);

lists.add(appinfo);

}

cursor.close();

if(lists.size() > 0){

for (Appinfo listappinfo : lists) {

Log.e("data", "[info]="+listappinfo.toString());

}

});

}

@Override

protected void onDestroy() {

// TODO Auto-generated method stub

super.onDestroy();

}

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數(shù)據(jù)庫對外提供接口內(nèi)容提供者

package com.example.testc;

import android.content.ContentProvider;

import android.content.ContentUris;

import android.content.ContentValues;

import android.content.UriMatcher;

import android.database.Cursor;

import android.database.sqlite.SQLiteDatabase;

import android.net.Uri;

public class AppTotalContentProvider extends ContentProvider {

private DatabaseHelper dbHelper;

// 若不匹配采用UriMatcher.NO_MATCH(-1)返回

private static final UriMatcher MATCHER = new UriMatcher(UriMatcher.NO_MATCH);

// 匹配碼

private static final int CODE_NOPARAM = 1;

static

{

// 對等待匹配的URI進行匹配操作，必須符合cn.xyCompany.providers.personProvider/person格式

// 匹配返回CODE_NOPARAM，不匹配返回-1

MATCHER.addURI("com.example.testc", "data", CODE_NOPARAM);

}

@Override

public boolean onCreate() {

// TODO Auto-generated method stub

dbHelper = new DatabaseHelper(this.getContext(), "mydb.db", null, 1);

return true;

}

@Override

public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder) {

// TODO Auto-generated method stub

SQLiteDatabase db = dbHelper.getReadableDatabase();

return db.query("data", projection, selection, selectionArgs, null, null, sortOrder);

}

@Override

public String getType(Uri uri) {

// TODO Auto-generated method stub

return null;

}

@Override

public Uri insert(Uri uri, ContentValues values) {

// TODO Auto-generated method stub

SQLiteDatabase db = dbHelper.getWritableDatabase();

// 特別說一下第二個參數(shù)是當name字段為空時，將自動插入一個NULL。

long rowid = db.insert("data", "null", values);

Uri insertUri = ContentUris.withAppendedId(uri, rowid);// 得到代表新增記錄的Uri

this.getContext().getContentResolver().notifyChange(uri, null);

return insertUri;

}

@Override

public int delete(Uri uri, String selection, String[] selectionArgs) {

// TODO Auto-generated method stub

return 0;

}

@Override

public int update(Uri uri, ContentValues values, String selection, String[] selectionArgs) {

// TODO Auto-generated method stub

return 0;

}

//插入數(shù)據(jù)到數(shù)據(jù)庫

ContentResolver contentResolver = getContentResolver();

Uri insertUri = Uri.parse("content://com.example.testc/data");

ContentValues values = new ContentValues();

values.put("name", "wangkuifeng");

values.put("uid", "1111");

values.put("total", "123M");

Uri uri = contentResolver.insert(insertUri, values);

在AndroidManifest.xml 添加

<provider

android:name="com.example.testc.AppTotalContentProvider"

android:authorities="com.example.testc"

android:exported="true" />

測試：應用B

package com.example.testb;

import android.app.Activity;

import android.content.ContentResolver;

import android.database.Cursor;

import android.net.Uri;

import android.os.Bundle;

import android.util.Log;

import android.view.Menu;

import android.view.MenuItem;

public class MainActivity extends Activity {

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

testQuery();

}

public void testQuery(){

Uri uri = Uri.parse("content://com.example.testc/data");

ContentResolver resolver = this.getContentResolver();

Cursor cursor = resolver.query(uri, new String[]{"uid","name","total"}, null, null, null);

while(cursor.moveToNext()){

String uid= cursor.getString(cursor.getColumnIndex("uid"));

String name = cursor.getString(cursor.getColumnIndex("name"));

String total = cursor.getString(cursor.getColumnIndex("total"));

Log.e("TAG", "[uid]="+uid+"[total]="+total +"[name]="+name);

}

cursor.close();

}

---------------------

標簽：數(shù)據(jù)庫

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