Sqlite、以及系统常用的几个服务

package com.imooc.sqlitedemo1;import android.os.Bundle;import android.app.Activity;import android.database.Cursor;import android.database.sqlite.SQLiteDatabase;import android.util.Log;import android.view.Menu;public class MainActivity extends Activity {@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);// 创建数据库、打开SQLiteDatabase db = openOrCreateDatabase("user.db", MODE_PRIVATE, null);//执行数据库sql语句db.execSQL("create table if not exists usertb (_id integer primary key autoincrement, name text not null , age integer not null , sex text not null )");db.execSQL("insert into usertb(name,sex,age) values('张三','女',18)");db.execSQL("insert into usertb(name,sex,age) values('李四','女',19)");db.execSQL("insert into usertb(name,sex,age) values('王五','男',20)");//创建Cursor对象--执行查询方法，返回游标Cursor c = db.rawQuery("select * from usertb", null);if (c != null) {while (c.moveToNext()) {//取出数据Log.i("info", "_id:" + c.getInt(c.getColumnIndex("_id")));Log.i("info", "name:" + c.getString(c.getColumnIndex("name")));Log.i("info", "age:" + c.getInt(c.getColumnIndex("age")));Log.i("info", "sex:" + c.getString(c.getColumnIndex("sex")));Log.i("info", "!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!");}c.close();}db.close();}}

************************************************二*******************************************************

package com.imooc.sqlitedemo2;import android.os.Bundle;import android.app.Activity;import android.content.ContentValues;import android.database.Cursor;import android.database.sqlite.SQLiteDatabase;import android.util.Log;import android.view.Menu;public class MainActivity extends Activity {@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);//创建并打开dbSQLiteDatabase db = openOrCreateDatabase("stu.db", MODE_PRIVATE, null);//执行sql语句db.execSQL("create table if not exists stutb(_id integer primary key autoincrement,name text not null,sex text not null,age integer not null)");ContentValues values = new ContentValues();values.put("name", "张三");values.put("sex", "男");values.put("age", 19);db.insert("stutb", null, values);values.clear();values.put("name", "张三丰");values.put("sex", "男");values.put("age", 99);db.insert("stutb", null, values);values.clear();values.put("name", "张三疯");values.put("sex", "男");values.put("age", 59);db.insert("stutb", null, values);values.clear();values.put("name", "张三峰");values.put("sex", "男");values.put("age", 39);db.insert("stutb", null, values);values.clear();values.put("name", "张三封");values.put("sex", "男");values.put("age", 29);db.insert("stutb", null, values);values.clear();values.put("sex", "女");//db.update(table, values, whereClause, whereArgs);db.update("stutb", values, "_id>?", new String[]{"3"});//将全部id>3的人的性别改成女//db.delete(table, whereClause, whereArgs);db.delete("stutb", "name like ?", new String[]{"%丰%"});//删除所有名字中带有丰的人//db.query(table, columns, selection, selectionArgs, groupBy, having, orderBy)Cursor c = db.query("stutb", null, "_id>?", new String[]{"0"}, null, null, "name");if (c!=null) {//取出所有列String [] columns= c.getColumnNames();while (c.moveToNext()) {for (String columnName : columns) {Log.i("info", c.getString(c.getColumnIndex(columnName)));}}c.close();}db.close();}}

*************************************************************三************************************************

package com.imooc.sqlitedemo3;import android.app.Activity;import android.database.Cursor;import android.database.sqlite.SQLiteDatabase;import android.os.Bundle;import android.util.Log;public class MainActivity extends Activity {@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);DBOpenHelper helper =new DBOpenHelper(MainActivity.this, "stu.db");SQLiteDatabase db = helper.getWritableDatabase();//db.query(table, columns, selection, selectionArgs, groupBy, having, orderBy)Cursor c = db.rawQuery("select * from stutb", null);if (c!=null) {String [] cols = c.getColumnNames();while (c.moveToNext()) {for (String ColumnName : cols) {Log.i("info", ColumnName+":"+c.getString(c.getColumnIndex(ColumnName)));}}c.close();}db.close();}}

package com.imooc.sqlitedemo3;import android.content.Context;import android.database.sqlite.SQLiteDatabase;import android.database.sqlite.SQLiteDatabase.CursorFactory;import android.database.sqlite.SQLiteOpenHelper;public class DBOpenHelper extends SQLiteOpenHelper{public DBOpenHelper(Context context, String name) {super(context, name, null, 1);}public DBOpenHelper(Context context, String name, CursorFactory factory,int version) {super(context, name, factory, version);}@Override//首次创建数据库的时候调用 一般可以把建库 建表的操作public void onCreate(SQLiteDatabase db) {db.execSQL("create table if not exists stutb(_id integer primary key autoincrement,name text not null,sex text not null,age integer not null)");db.execSQL("insert into stutb(name,sex,age)values('张三','女',18)");}@Override//当数据库的版本发生变化的时候 会自动执行public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {}}

+++++++++++++++++++++++++++++++++++系统常用的几个服务********************************

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=".MainActivity" >    <Button        android:id="@+id/network"        android:onClick="doClick"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_alignParentLeft="true"        android:layout_alignParentRight="true"        android:layout_alignParentTop="true"        android:text="判断网络是否连接" />    <Button        android:id="@+id/enableOrDisable_WIFI"        android:layout_width="wrap_content"         android:onClick="doClick"        android:layout_height="wrap_content"        android:layout_alignLeft="@+id/network"        android:layout_alignRight="@+id/network"        android:layout_below="@+id/network"        android:text="开关WIFI" />    <Button        android:id="@+id/getvoice"         android:onClick="doClick"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_alignLeft="@+id/enableOrDisable_WIFI"        android:layout_alignRight="@+id/enableOrDisable_WIFI"        android:layout_below="@+id/enableOrDisable_WIFI"        android:text="获取系统的音量" />    <Button        android:id="@+id/getPackagename"                 android:onClick="doClick"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_alignLeft="@+id/getvoice"        android:layout_alignRight="@+id/getvoice"        android:layout_below="@+id/getvoice"        android:text="获取当前进程包名" /></RelativeLayout>

MainActivity

package comimooc.systemservicedemo;import android.app.Activity;import android.app.ActivityManager;import android.content.Context;import android.media.AudioManager;import android.net.ConnectivityManager;import android.net.NetworkInfo;import android.net.wifi.WifiManager;import android.os.Bundle;import android.view.LayoutInflater;import android.view.View;import android.widget.Toast;public class MainActivity extends Activity {// 判断网络是不是链接状态public boolean isNetWorkConnected(Context context) {if (context != null) {// 连接管理器ConnectivityManager mConnectivityManager = (ConnectivityManager) context.getSystemService(CONNECTIVITY_SERVICE);// 通过管理器，获取活跃的网络信息NetworkInfo mNetWorkInfo = mConnectivityManager.getActiveNetworkInfo();// 如果网络信息不为空if (mNetWorkInfo != null) {return mNetWorkInfo.isAvailable();}}return false;}@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);LayoutInflater inflater = (LayoutInflater) MainActivity.this.getSystemService(LAYOUT_INFLATER_SERVICE);View view = inflater.inflate(R.layout.activity_main, null);setContentView(view);}public void doClick(View v) {switch (v.getId()) {case R.id.network:if (isNetWorkConnected(MainActivity.this) == true) {Toast.makeText(MainActivity.this, "网络已经打开", Toast.LENGTH_SHORT).show();} else {Toast.makeText(MainActivity.this, "网络未连接", Toast.LENGTH_SHORT).show();}break;case R.id.enableOrDisable_WIFI:WifiManager wifiManager = (WifiManager) MainActivity.this.getSystemService(WIFI_SERVICE);// 如果wifi可用，那么就关闭wifiif (wifiManager.isWifiEnabled()) {wifiManager.setWifiEnabled(false);Toast.makeText(MainActivity.this, "WIFI已经关闭",Toast.LENGTH_SHORT).show();} else {// 如果wifi不可用，那么就打开wifywifiManager.setWifiEnabled(true);Toast.makeText(MainActivity.this, "WIFI已经打开",Toast.LENGTH_SHORT).show();}break;case R.id.getvoice:// 音量管理器AudioManager mAudioManager = (AudioManager) MainActivity.this.getSystemService(AUDIO_SERVICE);// 获取最大音量、当前音量int max = mAudioManager.getStreamMaxVolume(AudioManager.STREAM_SYSTEM);int current = mAudioManager.getStreamVolume(AudioManager.STREAM_RING);Toast.makeText(MainActivity.this,"系统的最大音量为：" + max + ",当前音量是：" + current, Toast.LENGTH_SHORT).show();break;case R.id.getPackagename:ActivityManager activityManager = (ActivityManager) MainActivity.this.getSystemService(ACTIVITY_SERVICE);String packageName = activityManager.getRunningTasks(1).get(0).topActivity.getPackageName();Toast.makeText(MainActivity.this, "当前运行的Activity包名：" + packageName,Toast.LENGTH_SHORT).show();break;}}}