Android学习笔记2012年(2012-11-23至2012-11-27)

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*********************************************2012-11-23****************************************************

十一、Content provider内容提供者控件

1、作用：内容提供者为数据共享提供统一接口，也是一个常用的控件

2、配置：
a、创建内容提供者类继承ContentProvider类的，并覆写抽象方法

b、配置ContentProvider，在提供方的应用的AndroidManifest.xml中添加配置
android:authorities="com.caiz.android.providers.userProvider" />（ContentProvider的唯一标识uri）

3、uri
content://cn.itcast.provider/person/10

代表含义：scheme(固定)// 主机名或authority /路径（数据）

4、编码实现通过内容提供者给外界程序提供操作数据的接口
a、内容提供者实现类：UserProvider

package caiz.android.dboper;

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;
import caiz.android.dboper.service.DBOpenHelper;

/**
* 内容提供者访问数据库
* @author HuangYucai
*
*/
public class UserProvider extends ContentProvider {
private DBOpenHelper dbOpenHelper;
private static final UriMatcher MATCHER = new UriMatcher(
UriMatcher.NO_MATCH);
private static final int INSERTUSER = 1;
private static final int DELETEUSER = 2;
static {
MATCHER.addURI("com.caiz.android.providers.userProvider", "user",
INSERTUSER);
MATCHER.addURI("com.caiz.android.providers.userProvider", "user/#",
DELETEUSER);
}

@Override
public boolean onCreate() {// 当内容提供者创建时自动调用
dbOpenHelper = new DBOpenHelper(this.getContext());
// TODO Auto-generated method stub
return false;
}

@Override
public Cursor query(Uri uri, String[] projection, String selection,
String[] selectionArgs, String sortOrder) {
SQLiteDatabase db = dbOpenHelper.getWritableDatabase();
Cursor cursor = null;
switch (MATCHER.match(uri)) {
case 1:
cursor = db.query("user", projection, selection, selectionArgs,
null, null, sortOrder);
return cursor;
case 2:
long rowid = ContentUris.parseId(uri);
String where = "uid=" + rowid;
if (selection != null && !"".equals(selection.trim())) {
where = where + " and " + selection;
}
cursor = db.query("user", projection, where, selectionArgs, null,
null, sortOrder);
return cursor;
default:
throw new IllegalArgumentException("The uri'" + uri
+ "' is illegal!");
}
}// 供外部应用查询内容提供者的数据

@Override
public String getType(Uri uri) {// 返回操作数据的类型
// TODO Auto-generated method stub
return null;
}

@Override
public Uri insert(Uri uri, ContentValues values) {// 供外部应用插入内容提供者的数据
// 判断uri专门类
SQLiteDatabase db = dbOpenHelper.getWritableDatabase();

switch (MATCHER.match(uri)) {
case 1:
long rowid = db.insert("user", "uname", values);
Uri insertUri = ContentUris.withAppendedId(uri, rowid);
return insertUri;

default:
throw new IllegalArgumentException("The uri'" + uri
+ "' is illegal!");
}
}

@Override
public int delete(Uri uri, String selection, String[] selectionArgs) {// 供外部应用删除内容提供者的数据
// 判断uri专门类
SQLiteDatabase db = dbOpenHelper.getWritableDatabase();
int rowCounts = 0;
switch (MATCHER.match(uri)) {
case 1:
rowCounts = db.delete("user", selection, selectionArgs);
break;
case 2:
long rowid = ContentUris.parseId(uri);
String where = "uid=" + rowid;
if (selection != null && !"".equals(selection.trim())) {
where = where + " and " + selection;
}
rowCounts = db.delete("user", where, selectionArgs);
break;
default:
throw new IllegalArgumentException("The uri'" + uri
+ "' is illegal!");
}
return rowCounts;
}

@Override
public int update(Uri uri, ContentValues values, String selection,
String[] selectionArgs) {// 供外部应用更新内容提供者的数据
SQLiteDatabase db = dbOpenHelper.getWritableDatabase();
int rowCounts = 0;
switch (MATCHER.match(uri)) {
case 1:
rowCounts = db.update("user", values, selection, selectionArgs);
break;
default:
throw new IllegalArgumentException("The uri'" + uri
+ "' is illegal!");
}
return rowCounts;
}

}

b、内容通过者的测试类：ContentProviderTest

package caiz.android.xml.test;

import android.content.ContentResolver;
import android.content.ContentValues;
import android.database.Cursor;
import android.net.Uri;
import android.test.AndroidTestCase;
import android.util.Log;

/**
* 内容提供者测试类
* @author HuangYucai
*
*/
public class ContentProviderTest extends AndroidTestCase {

public void testInsert()throws Exception{//测试添加

Uri uri=Uri.parse("content://com.caiz.android.providers.userProvider/user");
ContentResolver resolver=this.getContext().getContentResolver();
ContentValues values=new ContentValues();
values.put("uname", "tqiongqiong");
values.put("phone", "1523798091");
values.put("amount", "5000001");
resolver.insert(uri, values);
}
public void testDelete()throws Exception{//测试删除
Uri uri=Uri.parse("content://com.caiz.android.providers.userProvider/user/44");
ContentResolver resolver=this.getContext().getContentResolver();
int i=resolver.delete(uri, null, null);
Log.i("ContentProvider", "删除了"+i+"条记录");
}
public void testUpdate()throws Exception{//测试更新
Uri uri=Uri.parse("content://com.caiz.android.providers.userProvider/user/");
ContentResolver resolver=this.getContext().getContentResolver();

ContentValues values=new ContentValues();
values.put("uname", "tangqiongqiong");
values.put("amount", "5000002");
int i=resolver.update(uri, values, "uid=?", new String[]{"45"});
Log.i("ContentProvider", "更新了"+i+"条记录");
}
public void testQueryList()throws Exception{//测试查询列表
Uri uri=Uri.parse("content://com.caiz.android.providers.userProvider/user/");
ContentResolver resolver=this.getContext().getContentResolver();
Cursor cursor= resolver.query(uri, null, "uid>?", new String[]{"20"}, "uid desc");
int num=0;
while(cursor.moveToNext()){
String uname= cursor.getString(cursor.getColumnIndex("UNAME"));
Log.i("ContentProvider", "用户"+(++num)+"的姓名："+uname);
}

}
public void testQueryById()throws Exception{//测试查询单个
Uri uri=Uri.parse("content://com.caiz.android.providers.userProvider/user/");
ContentResolver resolver=this.getContext().getContentResolver();

Cursor cursor= resolver.query(uri, null, "uid=?", new String[]{"45"}, "uid desc");
if(cursor.moveToNext()){
String uname= cursor.getString(cursor.getColumnIndex("UNAME"));
Log.i("ContentProvider", "id为45的用户姓名是："+uname);
}

}
}

***********************************************************************************************************

*************************************************2012-11-24************************************************
十一、监听Content provider内容提供者的数据变化

1、作用：两个应用操作使用同一个内容提供者的数据，A应用改变了内容提供者数据，必须通知B应用内容提供者数据
已经改变
A应用---添加数据---》内容提供者---》发出数据变化通知---》B应用（做出响应）

原理：观察者设计模式的应用

2、代码实践：
a、A应用在界面中添加一个按钮，并设置单击事件：

android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >

android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/bnt"
android:onClick="insert"
/>

public class AAppActivity extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
}

//点击按钮时执行的插入数据命令
public void insert(View v) {
Uri uri=Uri.parse("content://com.caiz.android.providers.userProvider/user");
ContentResolver resolver =this.getContentResolver();
ContentValues values=new ContentValues();
values.put("uname", "A_App insert CaiZ");
values.put("phone", "123456789");
values.put("amount", "70000");
resolver.insert(uri, values);
}
}

b、在内容提供者应用的添加数据方法中添加内容更新通知

@Override
public Uri insert(Uri uri, ContentValues values) {// 供外部应用插入内容提供者的数据
SQLiteDatabase db = dbOpenHelper.getWritableDatabase();

switch (MATCHER.match(uri)) {
case 1:
long rowid = db.insert("user", "uname", values);
Uri insertUri = ContentUris.withAppendedId(uri, rowid);
//设置数据更新通知（对于某个uri）
this.getContext().getContentResolver().notifyChange(uri, null);
return insertUri;

default:
throw new IllegalArgumentException("The uri'" + uri
+ "' is illegal!");
}
}
c、在应用B中添加应用的事件监听处理方法

package com.caiz.android.bapp;

import android.app.Activity;
import android.database.ContentObserver;
import android.database.Cursor;
import android.net.Uri;
import android.os.Bundle;
import android.os.Handler;
import android.util.Log;

public class BAppActivity extends Activity {
/** Called when the activity is first created. */
public static final String TAG = "BApp";
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Uri uri = Uri.parse("content://com.caiz.android.providers.userProvider/user");
// 注册内容观察者
this.getContentResolver().registerContentObserver(uri, true,
new UserContentObserver(new Handler()));
}

// 内容观察者内部类（继承观察者内部类）
public class UserContentObserver extends ContentObserver {

//构造方法
public UserContentObserver(Handler handler) {
super(handler);

}

// （覆写）数据改变时候调用的方法
@Override
public void onChange(boolean selfChange) {
super.onChange(selfChange);
Log.i(TAG, "OK=OK");
Uri uri = Uri
.parse("content://com.caiz.android.providers.userProvider/user");
Cursor cursor = getContentResolver().query(uri, null, null, null,
"uid desc limit 1");
if (cursor.moveToFirst()) {// 查询出最新记录并打印出来
String uname = cursor.getString(cursor.getColumnIndex("UNAME"));
Log.i(TAG, "uname=" + uname);
}

}
}
}
***********************************************************************************************************

**********************************************2012-11-25***************************************************
十二、访问和添加通讯录内容

1、作用：有些应用要求访问或添加通讯录操作

2、添加权限，在清单文件中添加读写通讯录的权限：

3、代码实现：
/**
* 存取通讯录中信息内容
* @author HuangYucai
*/
public class ContactsTest extends AndroidTestCase {

private String TAG="ContactsTest";
// 测试获取通讯录
public void testGetContacts()throws Exception {
StringBuilder sb=new StringBuilder("DATA:");
Uri uri = Uri.parse("content://com.android.contacts/contacts");
ContentResolver resolver = this.getContext().getContentResolver();
Cursor cursor = resolver.query(uri, new String[] { "_id" }, null, null,
null);
while (cursor.moveToNext()) {
String id=cursor.getString(0);
uri = Uri.parse("content://com.android.contacts/contacts/"+id+"/data");
sb.append("id=").append(id);
resolver = this.getContext().getContentResolver();
Cursor c = resolver.query(uri, new String[] { "data1","data2","mimetype" }, null, null,null);
while(c.moveToNext()){
String type=c.getString(c.getColumnIndex("mimetype"));
String data=c.getString(c.getColumnIndex("data1"));

if(type.equals("vnd.android.cursor.item/name")){
sb.append("name=").append(data);
}
if(type.equals("vnd.android.cursor.item/email_v2")){
sb.append("email=").append(data);
}
if(type.equals("vnd.android.cursor.item/phone_v2")){
sb.append("phone=").append(data);
}
}
}

Log.i(TAG,sb.toString());
}

//测试通过电话号码查询联系人
public void testgetNameByPhone() throws Exception{
StringBuilder sb=new StringBuilder("DATA:");
String number="13533415878";
Uri uri=Uri.parse("content://com.android.contacts/data/phones/filter/"+number);

ContentResolver resolver =this.getContext().getContentResolver();
Cursor cursor=resolver.query(uri, new String[]{"display_name"}, null, null, null);
if(cursor.moveToFirst()){
sb.append("name=").append(cursor.getString(0));
}

Log.i(TAG,sb.toString());
}
//测试通过电话号码查询联系人
public void testAddContacts() throws Exception{

Uri uri=Uri.parse("content://com.android.contacts/raw_contacts/");
ContentResolver resolver =this.getContext().getContentResolver();
ContentValues values =new ContentValues();
long rowid=ContentUris.parseId(resolver.insert(uri, values));

uri=Uri.parse("content://com.android.contacts/data/");
values.put("raw_contact_id", rowid);
values.put("mimetype", "vnd.android.cursor.item/name");
values.put("data2", "黄育才");
resolver.insert(uri, values);

values.clear();
values.put("raw_contact_id", rowid);
values.put("mimetype", "vnd.android.cursor.item/phone_v2");
values.put("data2", "2");
values.put("data1", "12121212");
resolver.insert(uri, values);

values.clear();
values.put("raw_contact_id", rowid);
values.put("mimetype", "vnd.android.cursor.item/email_v2");
values.put("data2", "2");
values.put("data1", "[email protected]");
resolver.insert(uri, values);
}

//测试通过电话号码查询联系人(带事务处理的方法)
public void testAddContactsWithTransaction() throws Exception{
ArrayList operations =new ArrayList();
Uri uri=Uri.parse("content://com.android.contacts/raw_contacts/");
ContentResolver resolver =this.getContext().getContentResolver();

ContentProviderOperation op1=ContentProviderOperation.newInsert(uri)
.withValue("account_name", null)
.build();
operations.add(op1);

uri=Uri.parse("content://com.android.contacts/data/");
ContentProviderOperation op2=ContentProviderOperation.newInsert(uri)
.withValueBackReference("raw_contact_id", 0)
.withValue("mimetype", "vnd.android.cursor.item/name")
.withValue("data2", "2")
.withValue("data1", "刘德华")
.build();

operations.add(op2);

ContentProviderOperation op3=ContentProviderOperation.newInsert(uri)
.withValueBackReference("raw_contact_id", 0)
.withValue("mimetype", "vnd.android.cursor.item/phone_v2")
.withValue("data2", "2")
.withValue("data1", "121212123")
.build();

operations.add(op3);

ContentProviderOperation op4=ContentProviderOperation.newInsert(uri)
.withValueBackReference("raw_contact_id", 0)
.withValue("mimetype", "vnd.android.cursor.item/email_v2")
.withValue("data2", "2")
.withValue("data1", "[email protected]")
.build();

operations.add(op4);

//执行事务方式的保存
resolver.applyBatch("com.android.contacts", operations);
}
}
***********************************************************************************************************

********************************************2012-11-26*****************************************************
十三、网络图片查看器

1、作用：将通过HTTP访问网络图片数据，并将图片数据在android手机应用中显示

2、思路:使用API
ImageView 类 的setImageBitmap(Bitmap bm)

通过URL类 构建一个HttpURLConnection实例

HttpURLConnection 类 getInputStream() 拿到数据流

IO操作把流转换成字节数组
3、实现过程及代码：
a、创建应用的界面，图片显示一般用ImageView控件

b、需要设置访问网络的权限
在清单文件中加入：

c、代码：

/**
* 读取网络图片的主类
* @author HuangYucai
*/
public class NetImageActivity extends Activity {
/** Called when the activity is first created. */
private Button bnt;
private ImageView imgview;
private EditText txtEdit;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
txtEdit=(EditText)this.findViewById(R.id.imagepath);
bnt=(Button)this.findViewById(R.id.bnt);
imgview=(ImageView)this.findViewById(R.id.image);
bnt.setOnClickListener(new BntOnclickListener());
}
//单机按钮的事件监听器实现类
public final class BntOnclickListener implements View.OnClickListener{
public void onClick(View v) {

String url=txtEdit.getText().toString().trim();//获取图片的路径
if(url!=null&&!"".equals(url)){
try {
byte[] data = ImageService.getImageDataByUrl(url);//获取图片的字节数组数据
Bitmap bm=BitmapFactory.decodeByteArray(data, 0, data.length);//Bitmap对象
imgview.setImageBitmap(bm);//设置图片显示
} catch (Exception e) {
Toast.makeText(getApplicationContext(), "图片访问失败", Toast.LENGTH_SHORT).show();
}
}else{
Toast.makeText(getApplicationContext(), "请输入图片路径", Toast.LENGTH_SHORT).show();
}
}

}
}

/**
* 读取图片的service类
* @author HuangYucai
*/
public class ImageService {
public static byte[] getImageDataByUrl(String path) throws Exception {
URL url=new URL(path);//根据路径初始化URL对象
HttpURLConnection conn=(HttpURLConnection) url.openConnection();//根据URL获取HttpURLConnection
conn.setConnectTimeout(5000);//设置HttpURLConnection请求时间为5秒
conn.setRequestMethod("GET");//设置HttpURLConnection请求方式为“GET”
if(conn.getResponseCode()==200){//当请求状态为200，即为请求成功时则获取输入流
InputStream inStream=conn.getInputStream();//获取输入流
return StreamTool.readBytes(inStream);//处理输入流
}else{
throw new Exception();
}
}

}

/**
*输入流转换为字节数组的工具类
* @author HuangYucai
*/
public class StreamTool {

public static byte[] readBytes(InputStream inStream) throws Exception {
ByteArrayOutputStream bis=new ByteArrayOutputStream();//字节输出流对象
byte[] buffer=new byte[1024];
int len=0;
while((len=inStream.read(buffer))!=-1){//读到buffer
bis.write(buffer,0,len);//写buffer到字节输出流对象bis
}

return bis.toByteArray();//从内存中拿到然后转为字节数组返回
}

}

4、注意项
在访问本机的url时，一般用http://localhost:8080/web/me.jpg或者http://127.0.0.1:8080/web/me.jpg
但是，该环境中，android和windows是两个不同的系统，故不能用
而只能用本机的IP（局域网中的IP地址）：如http://192.168.0.186:8080/web/me.jpg

备注：使用ipconfig命令查看本机IP
查看本机IP的方法：在开始——》搜索程序——》输入cmd——》输入ipconfig命令——》查看本机的IP地址
***********************************************************************************************************

********************************************2012-11-27*****************************************************
十四、Android获取html网页代码

1、通过Connection从网络上获取HTML代码，并显示在TextView控件中

2、步骤：
a、设计界面，为了让TextView可滚动，将其放在一个ScrollView控件中，这样文字就可以滚动了
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
android:id="@+id/viewer"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
/>

b、代码：
/**
* 主程序类
* @author HuangYucai
*/
public class HtmlViewerActivity extends Activity {
/** Called when the activity is first created. */
private EditText pathText;
private Button viewBnt;
private TextView txtViewer;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
pathText= (EditText)this.findViewById(R.id.path);
viewBnt=(Button)this.findViewById(R.id.bnt);
txtViewer=(TextView)this.findViewById(R.id.viewer);
viewBnt.setOnClickListener(new BntOnclickListener());
}

public final class BntOnclickListener implements View.OnClickListener{

public void onClick(View v) {
String path=pathText.getText().toString();
String html;
try {//获取字符数据设置到TextView空间
html = PageService.getPageStr(path);
txtViewer.setText(html);
} catch (Exception e) {
e.printStackTrace();
Toast.makeText(getApplicationContext(), "获取网页失败", Toast.LENGTH_SHORT).show();
}
}

}
}
/**
*获取html代码数据的service类
* @author HuangYucai
*/
public class PageService {

public static String getPageStr(String path) throws Exception {
String html="";
URL url=new URL(path);
HttpURLConnection conn=(HttpURLConnection) url.openConnection();
conn.setConnectTimeout(5000);
conn.setRequestMethod("GET");
if(conn.getResponseCode()==200){//请求状态成功时
InputStream inStream= conn.getInputStream();
byte[] data=StreamTool.getBytesByStream(inStream);
html=new String(data,"UTF-8");//网页编码格式为"UTF-8"
}

return html;
}

}

/**
* 流处理的工具类
* @author HuangYucai
*/
public class StreamTool {

public static byte[] getBytesByStream(InputStream inStream) throws Exception {
ByteArrayOutputStream baos=new ByteArrayOutputStream();
byte[] buffer= new byte[1024];

int len=0;
while((len=inStream.read(buffer))!=-1){
baos.write(buffer,0,len);
}
return baos.toByteArray();
}

}
4、注意项
a、在访问本机的url时，一般用http://localhost:8080/web/index.jsp或者http://127.0.0.1:8080/web/index.jsp
但是，该环境中，android和windows是两个不同的系统，故不能用
而只能用本机的IP（局域网中的IP地址）：如http://192.168.0.186:8080/web/index.jsp
b、在将字节数组转换为字符串数据时，要指定编码格式，而且要与网页的编码一致，否则出现乱码

***********************************************************************************************************