android sqlite图片的保存与查询

package com.yiyiweixiao; import java.io.ByteArrayOutputStream; import android.app.Activity; import android.content.ContentValues; import android.database.Cursor; import android.database.sqlite.SQLiteDatabase; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.os.Bundle; import android.view.View; import android.view.View.OnClickListener; import android.widget.Button; import android.widget.ImageView; public class main extends Activity implements OnClickListener { private Button btnsave1, btnsave2, btnquery1, btnquery2; private ImageView iv1, iv2; private MySQLiteOpenHelper mySQLiteOpenHelper = null; private SQLiteDatabase mydb = null; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); // 创建助手类的实例 // CursorFactory的值为null,表示采用默认的工厂类 mySQLiteOpenHelper = new MySQLiteOpenHelper(this, "saveimage.db", null, 1); // 创建一个可读写的数据库 mydb = mySQLiteOpenHelper.getWritableDatabase(); // 创建按钮的实例 btnsave1 = (Button) findViewById(R.id.button1); btnsave2 = (Button) findViewById(R.id.button2); btnquery1 = (Button) findViewById(R.id.button3); btnquery2 = (Button) findViewById(R.id.button4); // 设置其点击方法 btnsave1.setOnClickListener(this); btnsave2.setOnClickListener(this); btnquery1.setOnClickListener(this); btnquery2.setOnClickListener(this); } public void onClick(View v) { if (v == btnsave1) {//保存图片 try { //将图片转化为位图 Bitmap bitmap1=BitmapFactory.decodeResource(getResources(), R.drawable.erweima); int size=bitmap1.getWidth()*bitmap1.getHeight()*4; //创建一个字节数组输出流,流的大小为size ByteArrayOutputStream baos=new ByteArrayOutputStream(size); //设置位图的压缩格式，质量为100%，并放入字节数组输出流中 bitmap1.compress(Bitmap.CompressFormat.PNG, 100, baos); //将字节数组输出流转化为字节数组byte[] byte[] imagedata1=baos.toByteArray(); //将字节数组保存到数据库中 ContentValues cv=new ContentValues(); cv.put("_id", 1); cv.put("image", imagedata1); mydb.insert("imagetable", null, cv); //关闭字节数组输出流 baos.close(); } catch (Exception e) { e.printStackTrace(); } } else if (v == btnsave2) {// 保存图片2 try{ Bitmap bitmap2=BitmapFactory.decodeResource(getResources(), R.drawable.taohua); int size=bitmap2.getWidth()*bitmap2.getHeight()*4; ByteArrayOutputStream baos=new ByteArrayOutputStream(size); bitmap2.compress(Bitmap.CompressFormat.PNG, 100, baos); byte[] imagedata2=baos.toByteArray(); ContentValues cv=new ContentValues(); cv.put("_id", 2); cv.put("image", imagedata2); mydb.insert("imagetable", null, cv); baos.close(); } catch(Exception e){ e.printStackTrace(); } } else if (v == btnquery1) {// 查询图片1 //创建一个指针 Cursor cur=mydb.query("imagetable", new String[]{"_id","image"}, null, null, null, null, null); byte[] imagequery=null; if(cur.moveToNext()){ //将Blob数据转化为字节数组 imagequery=cur.getBlob(cur.getColumnIndex("image")); } //将字节数组转化为位图 Bitmap imagebitmap=BitmapFactory.decodeByteArray(imagequery, 0, imagequery.length); iv1=(ImageView) findViewById(R.id.imageView1); //将位图显示为图片 iv1.setImageBitmap(imagebitmap); } else if (v == btnquery2) {// 查询图片2 Cursor cur=mydb.query("imagetable", new String[]{"_id","image"}, null, null, null, null, null); byte[] imagequery=null; while(cur.moveToNext()){ imagequery=cur.getBlob(cur.getColumnIndex("image")); Bitmap imagebitmap=BitmapFactory.decodeByteArray(imagequery,0,imagequery.length); iv2=(ImageView) findViewById(R.id.imageView2); iv2.setImageBitmap(imagebitmap); } } } public void onDestroy(){ super.onDestroy(); //退出程序时，必须关闭数据库。 mydb.close(); } }