Android使用SQLiteDatabase直接存取数据与图像

Android使用SQLiteDatabase直接存取数据与图像的简单方法如下：

package com.test;import java.io.ByteArrayOutputStream;import java.io.File;import java.io.IOException;import java.text.SimpleDateFormat;import com.test.R;import android.app.Activity;import android.content.ContentValues;import android.content.Context;import android.database.Cursor;import android.database.sqlite.SQLiteDatabase;import android.graphics.Bitmap;import android.graphics.BitmapFactory;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Paint;import android.graphics.Bitmap.Config;import android.os.Bundle;import android.view.View;import android.widget.Button;import android.widget.ImageView;import android.widget.TextView;public class SQLiteDatabaseTest extends Activity {/** Called when the activity is first created. */private Button btnSave;private Button btnLoad;private Button btnClear;private ImageView imgView;private ImageView imgView2;private TextView txtView;private Bitmap bmp;private static SQLiteDatabase db;private Context mContext;@Overridepublic void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.main);btnSave = (Button) findViewById(R.id.btnSave);btnLoad = (Button) findViewById(R.id.btnLoad);btnClear = (Button) findViewById(R.id.btnClear);imgView = (ImageView) findViewById(R.id.imgView);imgView2 = (ImageView) findViewById(R.id.imgView2);txtView = (TextView) findViewById(R.id.txtView);btnSave.setOnClickListener(new ClickEvent());btnLoad.setOnClickListener(new ClickEvent());btnClear.setOnClickListener(new ClickEvent());imgView2.setImageBitmap(BitmapFactory.decodeResource(getResources(),R.drawable.bg));mContext = SQLiteDatabaseTest.this;// 创建数据库文件File path = mContext.getDir("databases", Context.MODE_WORLD_WRITEABLE);path = new File(path, "test.db");int flag = SQLiteDatabase.OPEN_READWRITE;flag = flag | SQLiteDatabase.CREATE_IF_NECESSARY;flag = flag | SQLiteDatabase.NO_LOCALIZED_COLLATORS;                  db = SQLiteDatabase.openDatabase(path.getAbsolutePath(), null, flag);                  // 创建表String sql = "create table if not exists info("+ "id integer primary key autoincrement,name varchar(20),"+ "time varchar(20),img BLOB)";                 db.execSQL(sql);}@Overrideprotected void onDestroy() {// TODO Auto-generated method stubsuper.onDestroy();if (db.isOpen()) {      db.close();}if(!bmp.isRecycled()){     bmp.recycle();}}class ClickEvent implements View.OnClickListener {@Overridepublic void onClick(View v) {// TODO Auto-generated method stubif (v == btnSave) {Cursor c = db.rawQuery("select * from info", null);ContentValues values = new ContentValues();c.moveToFirst();values.put("name", "test" + (c.getCount() + 1));SimpleDateFormat sDateFormat = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss");String time = sDateFormat.format(new java.util.Date());values.put("time", time);    Bitmap bmp = BitmapFactory.decodeResource(getResources(),R.drawable.bg);    if (null != bmp) {//在Bitmap上绘制标签Bitmap drawBmp = Bitmap.createBitmap(bmp.getWidth(), bmp.getHeight(), Config.ARGB_8888);Canvas cvs = new Canvas(drawBmp);Paint p = new Paint();p.setColor(Color.RED);p.setTextSize(22);cvs.drawBitmap(bmp, 0, 0, p);cvs.drawText("test" + (c.getCount() + 1), 10, 20,p);    //将绘制后Bitmap转为Byte[]并加入valuesvalues.put("img", bmpToByteArray(drawBmp));drawBmp.recycle();}db.insert("info", null, values);c.close();bmp.recycle();} else if (v == btnLoad) {Cursor c = db.rawQuery("select * from info", null);c.moveToLast();if (c.isLast()) {       String name = c.getString(c.getColumnIndex("name"));       txtView.setText("name:" + name + " 共计：" + c.getCount()+ " 条");       bmp = cursorToBmp(c, c.getColumnIndex("img"));       imgView.setImageBitmap(bmp);}c.close();} else if (v == btnClear) {imgView.setImageBitmap(null);}}}// Bitmap to byte[]public byte[] bmpToByteArray(Bitmap bmp) {    // Default size is 32 bytes    ByteArrayOutputStream bos = new ByteArrayOutputStream();try {bmp.compress(Bitmap.CompressFormat.JPEG, 100, bos);bos.close();} catch (IOException e) {e.printStackTrace();}return bos.toByteArray();}// Cursor to bitmapBitmap cursorToBmp(Cursor c, int columnIndex) {byte[] data = c.getBlob(columnIndex);try {return BitmapFactory.decodeByteArray(data, 0, data.length);} catch (Exception e) {return null;}}}

main.xml

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"android:layout_width="fill_parent" android:layout_height="fill_parent"android:orientation="horizontal">  <ImageView android:id="@+id/imgView"android:layout_width="640dip" android:layout_height="fill_parent"/>       <LinearLayout       android:id="@+id/LinearLayout01"      android:layout_width="150dip"       android:layout_height="fill_parent"      android:layout_marginLeft="5dip"      android:layout_marginRight="5dip"      android:orientation="vertical">                 <ImageView          android:id="@+id/imgView2"android:layout_width="fill_parent" android:layout_height="150dip"android:layout_marginTop="10dip"/>         <Button     android:id="@+id/btnSave"     android:layout_width="fill_parent"    android:layout_height="wrap_content"     android:text="保存图像"/><Button     android:id="@+id/btnLoad"     android:layout_width="fill_parent"    android:layout_height="wrap_content"     android:text="载入图像"/><Button    android:id="@+id/btnClear"    android:layout_width="fill_parent"    android:layout_height="wrap_content"    android:text="清除图像"/><TextView     android:id="@+id/txtView"    android:layout_width="fill_parent"    android:layout_height="wrap_content"    android:textColor="#FFFFFF"    android:textSize="22sp"    android:text="..."/>   </LinearLayout></LinearLayout>

开发环境：XP3+Eclipse+Android2.2+JDK6.0
测试环境：Android2.2，5寸屏，分辨率640X480
源代码：http://download.csdn.net/detail/xinzheng_wang/4420817

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