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 {
@Override
protected 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 {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//创建并打开db
SQLiteDatabase 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 {
@Override
protected 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;
}
@Override
protected 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wifi
if (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wify
wifiManager.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;
}
}
}