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Android乐学成语的实现分析
package cn.deu.bztc.happyidiom.db;import java.io.File;
import java.io.FileOutputStream;
import java.io.InputStream;import cn.deu.bztc.happyidiom.activity.R;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.os.Environment;public class DBOpenHelper {private final int BuFFWER_SIZE=400000;//缓冲区大小public static final String DB_NAME="idioms.db";//保存的数据库文件名public static final String PACKAGE_Name="cn.deu.bztc.happyidiom.activity";//应用的包名public static final String DB_PATH="/data"+Environment.getDataDirectory().getAbsolutePath()+"/"+PACKAGE_Name+"/databases";//在手机里存放数据库的位置private Context context;public DBOpenHelper(Context context) {super();this.context = context;}public SQLiteDatabase openDatabase(){try{File myDataPath=new File(DB_PATH);if(!myDataPath.exists()){myDataPath.mkdirs(); //如果没有这个目录则创建}String dbfile=myDataPath+"/"+DB_NAME;if(!(new File(dbfile).exists())){//判断数据库文件是否存在,若不存在则执行导入,否则直接打开数据库InputStream is=context.getResources().openRawResource(R.raw.idioms);FileOutputStream fos=new FileOutputStream(dbfile);byte[] buffer=new byte[BuFFWER_SIZE];int count=0;while((count=is.read(buffer))>0){fos.write(buffer, 0, count);}fos.close();is.close();}SQLiteDatabase db=SQLiteDatabase.openOrCreateDatabase(dbfile, null);return db;}catch (Exception e) {// TODO: handle exceptione.printStackTrace();}return null;}
}
上面的代码实现功能主要是使用输入输出流将idioms.db复制到手机中默认存放 数据库的位置
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"package="cn.deu.bztc.happyidiom.activity"android:versionCode="1"android:versionName="1.0" ><uses-sdkandroid:minSdkVersion="17"android:targetSdkVersion="17" /><applicationandroid:allowBackup="true"android:icon="@drawable/logo"android:label="@string/app_name"android:screenOrientation="portrait"android:theme="@android:style/Theme.Translucent.NoTitleBar" ><span style="color:#ff0000;"> <uses-library android:name="android.test.runner" /></span><activityandroid:name="cn.deu.bztc.happyidiom.activity.MainActivity"android:label="@string/app_name" ><intent-filter><action android:name="android.intent.action.MAIN" /><category android:name="android.intent.category.LAUNCHER" /></intent-filter></activity><activityandroid:name="cn.deu.bztc.happyidiom.activity.StudyAnimalActivity"android:label="@string/app_name" ></activity><activityandroid:name="cn.deu.bztc.happyidiom.util.DialogUtil"android:label="@string/app_name" ></activity><activityandroid:name="cn.deu.bztc.happyidiom.activity.StudyActivity"android:label="@string/app_name" ></activity><activityandroid:name="com.tangsci.android.example.ttsdemo.TtsDemoActivity"android:label="@string/app_name" ></activity></application><span style="color:#ff0000;"><instrumentationandroid:name="android.test.InstrumentationTestRunner"android:targetPackage="cn.deu.bztc.happyidiom.activity" ></instrumentation></span></manifest>
package cn.deu.bztc.happyidiom.test;import java.util.List;import cn.deu.bztc.happyidiom.dao.AnimalDao;
import cn.deu.bztc.happyidiom.db.DBOpenHelper;
import cn.deu.bztc.happyidiom.entity.Animal;
import android.test.AndroidTestCase;public class DBOpenHelpTest extends AndroidTestCase {public void testDBCOpy(){DBOpenHelper dbopenHelper=new DBOpenHelper(getContext());dbopenHelper.openDatabase();}public void testGetAllAnimals(){AnimalDao animalDao=AnimalDao.getInstance(getContext());List<Animal> animals=animalDao.getAllAnimals();System.out.println(animals.size());for(Animal animal:animals){System.out.println(animal.getName());}}
}
然后你会发现在raw目录下多个数据库
cn.deu.bztc.happyidiom.entity建立实体类
package cn.deu.bztc.happyidiom.entity;public class Animal {private int id; private String name;//成语名称private String pronounce;//成语发音private String explain;//成语解释private String antonym;//反义词private String homoionym;//同义词private String derivation;//源自private String examples;//例子public int getId() {return id;}public void setId(int id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}public String getPronounce() {return pronounce;}public void setPronounce(String pronounce) {this.pronounce = pronounce;}public String getExplain() {return explain;}public void setExplain(String explain) {this.explain = explain;}public String getAntonym() {return antonym;}public void setAntonym(String antonym) {this.antonym = antonym;}public String getHomoionym() {return homoionym;}public void setHomoionym(String homoionym) {this.homoionym = homoionym;}public String getDerivation() {return derivation;}public void setDerivation(String derivation) {this.derivation = derivation;}public String getExamples() {return examples;}public void setExamples(String examples) {this.examples = examples;}}
然后在数据库管理层 (Dao 层)建立操作类AnimalDao.java
package cn.deu.bztc.happyidiom.dao;import java.util.ArrayList;
import java.util.List;import cn.deu.bztc.happyidiom.db.DBOpenHelper;
import cn.deu.bztc.happyidiom.entity.Animal;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;public class AnimalDao {private static AnimalDao animalDao;private static SQLiteDatabase db;/*** 将构造方法私有化*/public AnimalDao(Context context) {DBOpenHelper dbHelper=new DBOpenHelper(context);db=dbHelper.openDatabase();}/*** 获取AnimalDao实例*/public synchronized static AnimalDao getInstance(Context context){if(animalDao==null){animalDao=new AnimalDao(context);}return animalDao;}/*** 从数据库读取所有的动物类成语*/ public static List<Animal> getAllAnimals(){List<Animal> list=new ArrayList<Animal>();Cursor cursor=db.query("animal", null, null, null, null,null,null);if(cursor.moveToFirst()){do{Animal animal=new Animal();animal.setId(cursor.getInt(cursor.getColumnIndex("_id")));animal.setName(cursor.getString(cursor.getColumnIndex("name")));animal.setPronounce(cursor.getString(cursor.getColumnIndex("pronounce")));animal.setAntonym(cursor.getString(cursor.getColumnIndex("antonym")));animal.setHomoionym(cursor.getString(cursor.getColumnIndex("homoionym")));animal.setDerivation(cursor.getString(cursor.getColumnIndex("derivation")));animal.setExamples(cursor.getString(cursor.getColumnIndex("examples")));list.add(animal);}while(cursor.moveToNext());}return list;}
}
下面进行单元测试
public void testGetAllAnimals(){AnimalDao animalDao=AnimalDao.getInstance(getContext());List<Animal> animals=animalDao.getAllAnimals();System.out.println(animals.size());for(Animal animal:animals){System.out.println(animal.getName());}
测试如下
测试成功后,实现功能
<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"tools:context=".MainActivity"android:background="@drawable/bg_animal" ><TabHostandroid:id="@android:id/tabhost"android:layout_width="match_parent"android:layout_height="match_parent"android:layout_alignParentLeft="true"android:layout_alignParentTop="true" ><LinearLayoutandroid:layout_width="match_parent"android:layout_height="match_parent"android:orientation="vertical" ><FrameLayoutandroid:id="@android:id/tabcontent"android:layout_width="match_parent"android:layout_height="match_parent"android:layout_weight="1" ><LinearLayoutandroid:id="@+id/tab2"android:layout_width="match_parent"android:layout_height="match_parent"android:orientation="vertical" ></LinearLayout><LinearLayoutandroid:id="@+id/tab3"android:layout_width="match_parent"android:layout_height="match_parent"android:orientation="vertical" ></LinearLayout></FrameLayout><TabWidgetandroid:id="@android:id/tabs"android:layout_width="match_parent"android:layout_height="wrap_content" ></TabWidget></LinearLayout></TabHost></RelativeLayout>
TabHost组件可以在界面中存放多个选项卡, 很多软件都使用了改组件进行设计;
1. TabHost常用组件
TabWidget : 该组件就是TabHost标签页中上部 或者 下部的按钮, 可以点击按钮切换选项卡;
TabSpec : 代表了选项卡界面, 添加一个TabSpec即可添加到TabHost中;
-- 创建选项卡 : newTabSpec(String tag), 创建一个选项卡;
-- 添加选项卡 : addTab(tabSpec);
<string-array name="category"><item>动物类</item><item>自然类</item><item>人物类</item><item>季节类</item><item>数字类</item><item>寓言类</item><item>其他类</item></string-array>
接下来cn.deu.bztc.happyidiom.activity中建立MainActivity.java
package cn.deu.bztc.happyidiom.activity;import android.os.Bundle;
import android.app.Activity;
import android.app.TabActivity;
import android.content.Intent;
import android.view.Menu;
import android.view.Window;
import android.widget.TabHost;public class MainActivity extends TabActivity {private TabHost tabHost;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);requestWindowFeature(Window.FEATURE_NO_TITLE);//取消标题栏setContentView(R.layout.activity_main);tabHost=getTabHost();addTab("study", R.string.title_study, R.drawable.study,StudyActivity.class);addTab("search", R.string.title_search, R.drawable.search, StudyActivity.class);addTab("study", R.string.title_game, R.drawable.game, StudyActivity.class);addTab("save", R.string.title_save, R.drawable.save, StudyActivity.class);addTab("help", R.string.title_help, R.drawable.search, StudyActivity.class);}private void addTab(String tag,int title_introduction,int title_icon,Class ActivityClass){tabHost.addTab(tabHost.newTabSpec(tag).setIndicator(getString(title_introduction),getResources().getDrawable(title_icon)).setContent(new Intent(this,ActivityClass)));}@Overridepublic boolean onCreateOptionsMenu(Menu menu) {// Inflate the menu; this adds items to the action bar if it is present.getMenuInflater().inflate(R.menu.main, menu);return true;}}
在这个类里调用TabHost组件, 然后调用了抽取出来的自定义的方法addTob()添加了五个选项卡,方法的四个参数分别为每个选项卡的tag,指示器上显示的标题。,指示器上显示的图片,选项卡对应的内容。
下面我就不一一介绍了,我会把源码地址分享给大家。
出现以下错误: 这是不能实例类
java.lang.RuntimeException: Unable to instantiate activity ComponentInfo
不能实例化activity有如下二种情况:
1.没有在Manifest.xml 清单中注册该activity,或者在创建完activity后,修改了包名或者activity的类名,而配置清单中没有修改,造成不能实例化
2.自己新建一个包,而配置的时候,使用默认包
详细介绍请看:http://blog.csdn.net/zhupengqq/article/details/51591964
下面是项目源码:http://download.csdn.net/detail/zhupengqq/9559487
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