Android利用SQLite制作最简单成语小词典

欲忘树

　　UnzipAssets.java

package com.hu.andstar;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.zip.ZipEntry;
import java.util.zip.ZipInputStream;
import android.content.Context;
public class UnzipAssets {
/**
* 解压assets的zip压缩文件到指定目录
* @param context上下文对象
* @param assetName压缩文件名
* @param outputDirectory输出目录
* @param isReWrite是否覆盖
* @throws IOException
*/
public static void unZip(Context context, String assetName,
String outputDirectory,boolean isReWrite) throws IOException {
//创建解压目标目录
File file = new File(outputDirectory);
//如果目标目录不存在，则创建
if (!file.exists()) {
file.mkdirs();
}
//打开压缩文件
InputStream inputStream = context.getAssets().open(assetName);
ZipInputStream zipInputStream = new ZipInputStream(inputStream);
//读取一个进入点
ZipEntry zipEntry = zipInputStream.getNextEntry();
//使用1Mbuffer
byte[] buffer = new byte[1024 * 1024];
//解压时字节计数
int count = 0;
//如果进入点为空说明已经遍历完所有压缩包中文件和目录
while (zipEntry != null) {
//如果是一个目录
if (zipEntry.isDirectory()) {
file = new File(outputDirectory + File.separator + zipEntry.getName());
//文件需要覆盖或者是文件不存在
if(isReWrite || !file.exists()){
file.mkdir();
}
} else {
//如果是文件
file = new File(outputDirectory + File.separator
+ zipEntry.getName());
//文件需要覆盖或者文件不存在，则解压文件
if(isReWrite || !file.exists()){
file.createNewFile();
FileOutputStream fileOutputStream = new FileOutputStream(file);
while ((count = zipInputStream.read(buffer)) > 0) {
fileOutputStream.write(buffer, 0, count);
}
fileOutputStream.close();
}
}
//定位到下一个文件入口
zipEntry = zipInputStream.getNextEntry();
}
zipInputStream.close();
}
}

　　用于第一次运行时解压数据文件到SD卡：
　　MainActivity.java：

package com.hu.andstar;
import java.io.File;
import java.util.ArrayList;
import java.util.List;
import android.app.Activity;
import android.app.AlertDialog.Builder;
import android.content.DialogInterface;
import android.content.Intent;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.text.Editable;
import android.text.TextWatcher;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.EditText;
import android.widget.ImageButton;
import android.widget.ListView;
import android.widget.TextView;
public class MainActivity extends Activity {
// 指定数据库文件所在目录
private final String DATABASE_PATH = android.os.Environment
.getExternalStorageDirectory().getAbsolutePath() + "/andstar";
// 指定数据库文件名
private final String DATABASE_FILENAME = "data.db";
private SQLiteDatabase database = null;
private EditText etInput = null;
private ImageButton ibSearch = null;
private ListView lvWords = null;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// 找到控件
etInput = (EditText) findViewById(R.id.editTextInput);
ibSearch = (ImageButton) findViewById(R.id.imageButtonSearch);
lvWords = (ListView) findViewById(R.id.listViewWords);
initAll();
}
private void initAll() {
// 获取并打开数据库
database = openDatabase();
// 设置ListView数据
lvWords.setAdapter(getIndexs(""));
// 当输入框文本改变时，让ListView现实的数据也随之改变
etInput.addTextChangedListener(new TextWatcher() {
public void onTextChanged(CharSequence s, int start, int before,
int count) {
}
public void beforeTextChanged(CharSequence s, int start, int count,
int after) {
}
public void afterTextChanged(Editable s) {
// 重新设置ListView的数据
lvWords.setAdapter(getIndexs(etInput.getText().toString()));
}
});
// 当ListView子项单击时，让文本框内容变成该项文本
lvWords.setOnItemClickListener(new AdapterView.OnItemClickListener() {
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
etInput.setText(((TextView) view).getText());
etInput.selectAll();
}
});
// 设置查询按钮事件
ibSearch.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
// 查询SQL语句
String sql = "SELECT dContent FROM words WHERE dIndex = @arg";
Cursor cursor = database.rawQuery(sql, new String[] { etInput
.getText().toString() });
// 如果查询有结果，将第一个结果传递给显示结果的Activity
if (cursor.getCount() > 0) {
cursor.moveToFirst();
Intent intent = new Intent();
intent.putExtra("word", etInput.getText().toString());
intent.putExtra("explain", cursor.getString(0));
cursor.close();
intent.setClass(MainActivity.this, ExplainActivity.class);
MainActivity.this.startActivity(intent);
}
}
});
}
// 获取ListView所要显示的数据
ArrayAdapter<String> getIndexs(String input) {
List<String> list = new ArrayList<String>();
// 获取32条大于等于该文本的数据
String sql = "SELECT dIndex FROM words WHERE dIndex >= @arg limit 0,32";
// 执行查询语句
Cursor cursor = database.rawQuery(sql, new String[] { input });
if (cursor.getCount() > 0) {
while (cursor.moveToNext()) {
list.add(cursor.getString(0));
}
cursor.close();
} else {// 如果获取结果为空
list.add(getString(R.string.no_match));
}
return new ArrayAdapter<String>(MainActivity.this,
android.R.layout.simple_list_item_1, list);// 返回ArrayAdapter
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.activity_main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// 退出选项
if (item.getItemId() == R.id.menu_exit) {
Builder builder = new Builder(MainActivity.this);
builder.setMessage("确认退出吗？");
builder.setTitle("提示");
builder.setPositiveButton(R.string.button_positive,
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
System.exit(0);
}
});
builder.setNegativeButton(R.string.button_cancle, null);
builder.show();
} else {
}
return super.onOptionsItemSelected(item);
}
private SQLiteDatabase openDatabase() {// 打开数据库函数
try {
String databaseFilename = DATABASE_PATH + "/" + DATABASE_FILENAME;
File databaseFile = new File(databaseFilename);
// 如果SD卡上数据库文件不存在，则解压数据库文件
if (!databaseFile.exists()) {
UnzipAssets.unZip(MainActivity.this, "data.zip", DATABASE_PATH,
true);
}
// 返回打开的数据库
return SQLiteDatabase.openOrCreateDatabase(databaseFilename, null);
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
}

　　查词界面;
　　

 
　　ExplainActivity.java

package com.hu.andstar;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.webkit.WebView;
import android.widget.TextView;
/*用于显示查询结果
* 使用WebView显示
*/
public class ExplainActivity extends Activity{
private TextView tvWord = null;
private WebView tvExplain = null;
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_explain);
tvWord = (TextView) findViewById(R.id.textViewWord);
tvExplain = (WebView) findViewById(R.id.webViewExplain);
Intent intent = getIntent();
tvWord.setText(intent.getStringExtra("word"));
String htmText = intent.getStringExtra("explain");
tvExplain.loadDataWithBaseURL(null,htmText, "text/html",  "utf-8", null);
}
}

　　用于显示解释: