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    ▪ContentProvider的根本使用        ContentProvider的基本使用ContentProvider：内容提供者。她主要完成这么一件事：共享数据。将一个应用的数据共享给其他应用 代码如下： 1、SQLiteProvider package com.njupt.practice_contentprovider1.provider; .........
    ▪ elipse手机设备显示Target unknown解决办法        elipse手机设备显示Target unknown解决方法Android Device Chooser中显示Target unknown解决方法 手机插在电脑上准备调试程序来着，通过eclipse运行时，弹出的Android Device Chooser中显示设备名是？？？？.........
    ▪ ListView滑动分页，并加载一部分数据       ListView滑动分页，并加载部分数据       由于要使用SimpleAdapter，所以要新建一个布局文件tab_info.xml   <?xml version="1.0" encoding="utf-8"?> <TableLayout   xmlns:android="http://schemas.android.com/apk/res/a.........

[1]ContentProvider的根本使用
    来源: 互联网  发布时间: 2014-02-18
ContentProvider的基本使用

ContentProvider：内容提供者。她主要完成这么一件事：共享数据。将一个应用的数据共享给其他应用


代码如下：

1、SQLiteProvider

package com.njupt.practice_contentprovider1.provider;

import com.njupt.practice_contentprovider1.dao.DBOpenHelper;

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 SQliteProvider extends ContentProvider{

	private UriMatcher matcher = new UriMatcher(UriMatcher.NO_MATCH);
	private DBOpenHelper helper;
	public static final int PERSON = 1;
	public static final int PERSON_ID = 2;
	
	@Override
	public boolean onCreate() {
		helper = new DBOpenHelper(getContext());
		matcher.addURI("jd_love_ztmm","person",PERSON);
		matcher.addURI("jd_love_ztmm", "person/#", PERSON_ID);
		return true;
	}
	
	@Override
	public Cursor query(Uri uri, String[] projection, String selection,
			String[] selectionArgs, String sortOrder) {
		
		SQLiteDatabase db = helper.getReadableDatabase();
		switch(matcher.match(uri)){
		case PERSON_ID:
			long id = ContentUris.parseId(uri);
			selection = selection == null ? "id = " + id : selection + " AND id = " + id;
		case PERSON:
			return db.query("person", null, selection, selectionArgs, null, null, sortOrder);
		default:
			throw new RuntimeException("Uri不能识别: " + uri);
		}
	}
	
	@Override
	public Uri insert(Uri uri, ContentValues values) {
		SQLiteDatabase db =  helper.getWritableDatabase();
		switch(matcher.match(uri)){
		case PERSON:
			long id = db.insert("person", "id", values);
			return ContentUris.withAppendedId(uri, id);
		default:
			throw new RuntimeException("Uri不能识别: " + uri);
		}
		
	}
	
	@Override
	public int delete(Uri uri, String selection, String[] selectionArgs) {
		
		SQLiteDatabase db = helper.getWritableDatabase();
		switch(matcher.match(uri)){
			case PERSON_ID:
				long id = ContentUris.parseId(uri);
				selection = selection == null ? "id = " + id : selection + " AND id = " + id;
			case PERSON:
				return db.delete("person", selection, selectionArgs);
			default:
				throw new RuntimeException("Uri不能识别: " + uri);
		}
	}
	
	
	@Override
	public int update(Uri uri, ContentValues values, String selection,
			String[] selectionArgs) {
		SQLiteDatabase db = helper.getWritableDatabase();
		switch(matcher.match(uri)){
		case PERSON_ID:
			long id = ContentUris.parseId(uri);
			selection = selection == null ? "id = " + id : selection + "AND id = " + id; 
		case PERSON:
			return db.update("person", values, selection, selectionArgs);
		default:
			throw new RuntimeException("Uri不能识别: " + uri);
		}
	}
	
	
	@Override
	public String getType(Uri uri) {
		// TODO Auto-generated method stub
		return null;
	}
}


2、ProviderTest

测试类

package com.njupt.pc1;

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

public class ProviderTest extends AndroidTestCase{

	public void testQuery(){
		
		ContentResolver resolver = getContext().getContentResolver();
		Uri uri = Uri.parse("content://jd_love_ztmm/person");
		Cursor c = resolver.query(uri,null,null,null,null);
	    
		while(c.moveToNext()){
			Integer id = c.getInt(0);
			String name = c.getString(1);
			Integer balance = c.getInt(2);
			
			System.out.println(new Person(id,name,balance));
		}
	}
	
	public void testDelete(){
		
	   ContentResolver resolver =  getContext().getContentResolver();
	   Uri uri = Uri.parse("content://jd_love_ztmm/person/1");
	   resolver.delete(uri, null, null);
	}
	
	public void testUpdate(){
		ContentResolver resolver = getContext().getContentResolver();
		Uri uri = Uri.parse("content://jd_love_ztmm/person/2");
		ContentValues values = new ContentValues();
		values.put("name", "刘诗诗是java程序员的女神");
		values.put("balance", "65000");
		resolver.update(uri, values, null, null);
	}
	
	public void testInsert(){
		
		ContentResolver resolver =  getContext().getContentResolver();
		Uri uri = Uri.parse("content://jd_love_ztmm/person");
		ContentValues values = new ContentValues();
		values.put("name","刘诗诗是C++程序员的女神" );
		values.put("balance", "70000");
		resolver.insert(uri, values);
	}
}


3、DBTest

package com.njupt.practice_contentprovider1.dao;

import java.util.List;
import java.util.Random;

import com.njupt.practice_contentprovider1.domain.Person;

import android.test.AndroidTestCase;

public class DBTest extends AndroidTestCase {

	public void testCreateDataBase() {
		DBOpenHelper helper = new DBOpenHelper(getContext());
		helper.getWritableDatabase();
	}

	public void testInsert() {
		PersonDao dao = new PersonDao(getContext());
		Person p = new Person("我爱章泽天", 55000);
		dao.insert(p);
	}

	public void testDelete() {
		PersonDao dao = new PersonDao(getContext());
		dao.delete(104);
	}

	public void testUpdate() {
		PersonDao dao = new PersonDao(getContext());
		Person p = new Person(105, "章泽天爱我", 46000);
		dao.update(p);
	}

	public void testQuery() {
		PersonDao dao = new PersonDao(getContext());
		Person p = dao.query(105);
		System.out.println(p);
	}

	public void testInsertMany() {

		PersonDao dao = new PersonDao(getContext());
		String strs[] = new String[]{"天天","章泽天","我爱天天","天天爱我"};
		
		for(int i = 0 ; i < 100 ; ++i){
			dao.insert(new Person(strs[new Random().nextInt(50) %4]+ i , new Random().nextInt(10000)));
		}
	}
	
	public void testQueryAll(){
		PersonDao dao = new PersonDao(getContext());
		
		List<Person> persons = dao.queryAll();
		
	   for(Person p : persons){
		   System.out.println(p);
	   }
	}
	
	public void testQueryCount(){
		PersonDao dao = new PersonDao(getContext());
		
		System.out.println(dao.queryCount());
	}
	
	public void testQueryPage(){
		PersonDao dao = new PersonDao(getContext());
		
		List<Person> persons = dao.queryPage(2, 20);
		
		for(Person p : persons){
			System.out.println(p);
		}
	}
	
	public void testRemit(){
		PersonDao dao = new PersonDao(getContext());
		dao.remit(4, 3, 3000);
	}
}

4、AndroidManifest.xml

在编写完ContentProvider的代码以后，别忘了在清单文件AndroidManifest.xml中进行注册

<provider android:name="com.njupt.practice_contentprovider1.provider.SQliteProvider"
            android:authorities="jd_love_ztmm"
            android:exported="true"/>



    
[2] elipse手机设备显示Target unknown解决办法
    来源: 互联网  发布时间: 2014-02-18
elipse手机设备显示Target unknown解决方法

Android Device Chooser中显示Target unknown解决方法


手机插在电脑上准备调试程序来着，通过eclipse运行时，弹出的Android Device Chooser中显示设备名是？？？？？，Target未知，无法继续运行。

可以通过以下步骤解决（Ubuntu)：

1. 查看设备的vendor ID：

ubuntu@ubuntu:~$ lsusb
Bus 005 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 003 Device 002: ID 24ae:2000  
Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 002 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 001 Device 004: ID 0bb4:0cfe High Tech Computer Corp. 
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

很容易根据名字认出来手机是哪个，我的手机对应的ID是0bb4。

2.添加手机设备到usb列表中

ubuntu@ubuntu:~$ sudo vim /etc/udev/rules.d/51-android.rules

输入：

SUBSYSTEM=="usb", SYSFS{idVendor}=="0bb4", MODE="0666", GROUP="plugdev"
SUBSYSTEM=="usb", ATTR{idVendor}=="0bb4", MODE="0666", GROUP="plugdev"

3. 保存，在命令行中运行：

ubuntu@ubuntu:~$ sudo chmod a+r /etc/udev/rules.d/51-android.rules
ubuntu@ubuntu:~$ sudo service udev reload

然后再重启一下eclipse，右键运行，问题解决了。



    
[3] ListView滑动分页，并加载一部分数据
    来源: 互联网  发布时间: 2014-02-18
ListView滑动分页，并加载部分数据



 

 

 

由于要使用SimpleAdapter，所以要新建一个布局文件tab_info.xml

 

<?xml version="1.0" encoding="utf-8"?>

<TableLayout

  xmlns:android="http://schemas.android.com/apk/res/android"

  android:id="@+id/mylayout"

  android:orientation="vertical"

  android:layout_width="fill_parent"

  android:layout_height="fill_parent">

  <TableRow>

     <TextView

       android:id="@+id/id"

       android:textSize="30px"

       android:layout_height="wrap_content"

       android:layout_width="50px"/>

     <TextView

       android:id="@+id/name"

       android:textSize="30px"

       android:layout_height="wrap_content"

       android:layout_width="130px"/>

     <TextView

       android:id="@+id/birthday"

       android:textSize="30px"

       android:layout_height="wrap_content"

       android:layout_width="180px"/>

  </TableRow>

</TableLayout>

 

 

 

 

在main.xml中：

 

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout

  xmlns:android="http://schemas.android.com/apk/res/android"

  android:id="@+id/mylayout"

  android:orientation="vertical"

  android:layout_width="fill_parent"

  android:layout_height="fill_parent">

</LinearLayout>

 

 

 

 

在MySQLiteDemo.java中

 

package com.li.sqlite;

 

import java.util.List;

import java.util.Map;

 

import android.app.Activity;

import android.database.sqlite.SQLiteOpenHelper;

import android.os.Bundle;

import android.view.Gravity;

import android.widget.AbsListView;

import android.widget.AbsListView.OnScrollListener;

import android.widget.LinearLayout;

import android.widget.LinearLayout.LayoutParams;

import android.widget.ListView;

import android.widget.SimpleAdapter;

import android.widget.TextView;

 

public class MySQLiteDemo extends Activity {

  private ListView listView ;

  private SimpleAdapter simpleAdapter = null ;

  private LinearLayout loadLayout = null ;  // 读取的脚标的视图

  private TextView loadInfo = null ; // 进行信息提示

  private List<Map<String,Object>> all = null ;

  private LayoutParams layoutParams = new LinearLayout.LayoutParams(

       LinearLayout.LayoutParams.FILL_PARENT,

       LinearLayout.LayoutParams.WRAP_CONTENT);  // 表示新组件的布局参数

  private SQLiteOpenHelper helper = null ;

  private LinearLayout mylayout = null ;

  private int currentPage = 1 ;

  private int lineSize = 15 ;

  private int allRecorders = 0 ;

  private int pageSize = 1 ;  // 默认在一共只有1页

  private int lastItem = 0 ;  // 保存最后一项

  @Override

  public void onCreate(Bundle savedInstanceState) {

     super.onCreate(savedInstanceState);

     super.setContentView(R.layout.main);

     this.mylayout = (LinearLayout) super.findViewById(R.id.mylayout) ;

     this.loadLayout = new LinearLayout(this) ;  // 定义脚标的线性布局管理器

     this.loadInfo = new TextView(this) ; // 文本组件

     this.loadInfo.setText("数据加载中ing...") ;  // 定义提示文字

     this.loadInfo.setGravity(Gravity.CENTER) ;  // 文字居中显示

     this.loadInfo.setTextSize(30.0f) ; // 文字大小

     this.loadLayout.addView(this.loadInfo,this.layoutParams) ;  // 增加组件

     this.loadLayout.setGravity(Gravity.CENTER) ;

     this.showAllData() ; // 数据显示

     this.pageSize = (this.allRecorders + this.lineSize - 1)

         / this.lineSize; // 计算总页数

     System.out.println("pageSize = " + this.pageSize) ;

     System.out.println("allRecorders = " + this.allRecorders);

  }

  private void showAllData(){ // 读取全部的数据

     MySQLiteDemo.this.helper = new MyDatabaseHelper(MySQLiteDemo.this);

     MytabCursor cur = new MytabCursor( // 实例化查询

         MySQLiteDemo.this.helper.getReadableDatabase()) ;  // 取得SQLiteDatabase对象

     this.allRecorders = cur.getCount() ; // 取得全部记录数

     this.listView = new ListView(MySQLiteDemo.this) ;

     MySQLiteDemo.this.all = cur.find(MySQLiteDemo.this.currentPage,MySQLiteDemo.this.lineSize) ;

     this.listView.addFooterView(this.loadLayout) ; // 增加读取数据的布局文件

     this.simpleAdapter = new SimpleAdapter(MySQLiteDemo.this,   // 上下文对象

         MySQLiteDemo.this.all,      // 所有要操作的数据

         R.layout.tab_info,        // 布局管理器

         new String[] { "id", "name", "birthday" },  // map中的key

         new int[] { R.id.id, R.id.name, R.id.birthday }) ;

     this.listView.setAdapter(this.simpleAdapter);  // 布局管理中的id

     this.listView.setOnScrollListener(new OnScrollListenerImpl()) ;

     this.mylayout.addView(listView) ;

  }

  private class OnScrollListenerImpl implements OnScrollListener{

 

     public void onScroll(AbsListView view, int firstVisibleItem,

         int visibleItemCount, int totalItemCount) {

       MySQLiteDemo.this.lastItem = firstVisibleItem + visibleItemCount - 1 ; // 统计是否到最后

     }

 

     public void onScrollStateChanged(AbsListView view, int scrollState) {

       if (MySQLiteDemo.this.lastItem == MySQLiteDemo.this.simpleAdapter

            .getCount()// 已经是最底部

            && MySQLiteDemo.this.currentPage < MySQLiteDemo.this.pageSize // 还有数据没读取完

           && scrollState == OnScrollListener.SCROLL_STATE_IDLE ) { // 不再滑动

         MySQLiteDemo.this.currentPage ++ ;

         MySQLiteDemo.this.listView.setSelection(MySQLiteDemo.this.lastItem) ; // 设置显示位置

         MySQLiteDemo.this.appendData() ; // 增加数据

       }

     }

    

  }

 

  private void appendData(){  // 增加数据

     MytabCursor cur = new MytabCursor( // 实例化查询

         MySQLiteDemo.this.helper.getReadableDatabase()) ;  // 取得SQLiteDatabase对象

     List<Map<String, Object>> newData = cur.find(this.currentPage,

         this.lineSize);

     this.all.addAll(newData) ;  // 集合改变

     this.simpleAdapter.notifyDataSetChanged() ; // 通知记录改变

  }

}

 

 

 

 

在MytabCursor.java中

 

package com.li.sqlite;

 

import java.util.ArrayList;

import java.util.HashMap;

import java.util.List;

import java.util.Map;

 

import android.database.Cursor;

import android.database.sqlite.SQLiteDatabase;

 

public class MytabCursor {

  private static final String TABLENAME = "mytab" ;

  private SQLiteDatabase db = null ;

  public MytabCursor(SQLiteDatabase db) {

     this.db = db ;

  }

 

  public int getCount() { // 返回记录数

     int count = 0;

     String sql = "SELECT COUNT(id) FROM " + TABLENAME; // 查询SQL

     Cursor result = this.db.rawQuery(sql, null);

     for (result.moveToFirst(); !result.isAfterLast(); result.moveToNext()) { // 采用循环的方式检索数据

       count = result.getInt(0);

     }

     return count;

  }

 

  public List<Map<String,Object>> find(int currentPage,int lineSize){

     List<Map<String,Object>> all = new ArrayList<Map<String,Object>>() ;

     String sql = "SELECT id,name,birthday FROM " + TABLENAME

         + " LIMIT ?,?";

     String args[] = new String[] {

         String.valueOf((currentPage - 1) * lineSize),

         String.valueOf(lineSize) }; // 是设置参数

     Cursor result = this.db.rawQuery(sql, args); // 执行查询语句

     for (result.moveToFirst(); !result.isAfterLast(); result.moveToNext()) { // 采用循环的方式检索数据

       Map<String,Object> map = new HashMap<String,Object>() ;

       map.put("id", result.getInt(0)) ;

       map.put("name", result.getString(1)) ;

       map.put("birthday",result.getString(2)) ;

       all.add(map) ;

     }

     this.db.close() ;

     return all ;

  }

 

}

 

 

 

 

 

 

 

在MyDatabaseHelper.java中

 

package com.li.sqlite;

//数据库的辅助操作类

import android.content.Context;

import android.database.sqlite.SQLiteDatabase;

import android.database.sqlite.SQLiteOpenHelper;

 

public class MyDatabaseHelper extends SQLiteOpenHelper {

  private static final String DATABASENAME = "liyewen.db" ;

  private static final int DATABASERVERSION = 1 ;  // 设置数据库的版本

  private static final String TABLENAME = "mytab" ;

 

  public MyDatabaseHelper(Context context) {  // 用户最关心的也肯定只是Context

     super(context, DATABASENAME, null, DATABASERVERSION);

  }

 

  @Override

  public void onCreate(SQLiteDatabase db) { // 创建数据表

     String sql = "CREATE TABLE " + TABLENAME + "("

         + "id    INTEGER       PRIMARY KEY ,"   // 在SQLite中设置为Integer、PRIMARY KEY则ID自动增长

         + "name   VARCHAR(50)   NOT NULL ,"

         + "birthday DATE NOT    NULL" + ")";

     db.execSQL(sql) ;  // 执行SQL

     System.out.println("****************** 创建：onCreate()。");

  }

 

  @Override

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

     String sql = "DROP TABLE IF EXISTS " + TABLENAME ;

     db.execSQL(sql) ;

     System.out.println("****************** 更新：onUpgrade()。");

     this.onCreate(db) ;

  }

 

}

 


    
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