android将图片转换存到数据库再从数据库读取转换成图片实现代码(2)-木庄网络博客

代码如下:

ByteArrayOutputStream os = new ByteArrayOutputStream();
bitmap.compress(CompressFormat.PNG, 100, os);
return os.toByteArray();

之后将字符数组存入到类型为blob的数据库中去。

代码如下:

ContentValues cv = new ContentValues();
cv.put(PictureColumns.PICTURE, getPicture(drawable));
db.insert(TABLE_NAME, null, cv);

之后在代码中从数据库中取出byte[]，然后转换成Drawable，设置图片即可。

代码如下：

代码如下:

package com.android.test;

import java.util.ArrayList;

import android.app.Activity;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;
import android.os.Bundle;
import android.widget.ImageView;

public class TestPicture extends Activity {

    @Override
    protected void onCreate (Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        ImageView iv = new ImageView(this);
        if(getDrawable().size() != 0) {
            iv.setImageDrawable(getDrawable().get(0));
        }
        setContentView(iv);
    }


    private ArrayList<Drawable> getDrawable() {
        PictureDatabase pd = new PictureDatabase(this);
        SQLiteDatabase sd = pd.getWritableDatabase();

        ArrayList<Drawable> drawables = new ArrayList<Drawable>();

        //查询数据库
        Cursor c = sd.query("picture", null, null, null, null, null, null);

        //遍历数据
        if(c != null && c.getCount() != 0) {
            while(c.moveToNext()) {
                //获取数据
                byte[] b = c.getBlob(c.getColumnIndexOrThrow(PictureDatabase.PictureColumns.PICTURE));
                //将获取的数据转换成drawable
                Bitmap bitmap = BitmapFactory.decodeByteArray(b, 0, b.length, null);
                BitmapDrawable bitmapDrawable = new BitmapDrawable(bitmap);
                Drawable drawable = bitmapDrawable;
                drawables.add(drawable);
            }
        }
        return drawables;
    }
}

重点注意如何将数据库中取出的byte[]转换成drawable：

代码如下:

Bitmap bitmap = BitmapFactory.decodeByteArray(b, 0, b.length, null);
BitmapDrawable bitmapDrawable = new BitmapDrawable(bitmap);
Drawable drawable = bitmapDrawable;

运行效果如下：

标签：SQLite

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