将图像保存到数据库

Question

我想检索联系人和图像并将其显示在列表视图中，并将图像和联系人保存到数据库中，在另一个活动中，我想从数据库中检索包含图像的联系人并将其显示到列表视图中，从而无法检索联系人，但如何将图像保存到数据库中然后如何从数据库中检索图像

我使用这种方法将数据保存到数据库

public void addBlockedNumberWithImage(String number, String name,
        byte[] image) {

    // Add a new blocked number
    SQLiteDatabase db = this.getWritableDatabase();

    ContentValues values = new ContentValues();
    values.put(BLOCKLIST_NUMBER, number);
    values.put(BLOCKLIST_NAME, name);
    values.put(CONTACT_IMAGE, image);

    /* Inserting the entry */
    db.insert(TABLE_BLOCKLISTWITHIMAGE, null, values);
    db.close(); // close the database connection
}



DbHelper db = new DbHelper(this);
db.addBlockedNumberWithImage(phoneNumber, name, image);

Answer 1

与其将图像保存到数据库中，不如将图像保存到设备上的某个位置（最好是SD卡），然后在数据库中保存每个图像的位置

然后，当您要显示它们时，您只需从数据库中检索图像的路径，然后将其加载即可：)

Answer 2

在我的应用程序中，我正在从图库中上传图像，并且上传的图像要存储在数据库中。但是如何将位图存储在数据库中，我正在将位图转换为字符串并保存在数据库中。

Imageupload.class：

public class Imageupload12 extends Activity {
Button buttonLoadImage;
ImageView targetImage;
int i=0;
Database database=new Database(this);
String i1;
String img;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main5);
buttonLoadImage = (Button)findViewById(R.id.loadimage);
targetImage = (ImageView)findViewById(R.id.targetimage);

Bundle b=getIntent().getExtras();
if(b!=null)
{
img=b.getString("image");
targetImage2.setImageURI("image");
//i am getting error as i cant assign string to imageview.

}

buttonLoadImage.setOnClickListener(new Button.OnClickListener(){

public void onClick(View arg0) {
// TODO Auto-generated method stub
Intent intent = new Intent(Intent.ACTION_PICK,
android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
Log.i("photo",""+intent);
startActivityForResult(intent, i);
i=i+1;
}});

}

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {

// TODO Auto-generated method stub
super.onActivityResult(requestCode, resultCode, data);
switch(requestCode) {

case 0:
if (resultCode == RESULT_OK){
Uri targetUri = data.getData();
// textTargetUri.setText(targetUri.toString());
Bitmap bitmap;
try {
bitmap = BitmapFactory.decodeStream(getContentResolver().openInputStream(targetUri));
targetImage.setImageBitmap(bitmap);

i1=bitmap.toString();
Log.i("firstimage........",""+i1);
targetImage.setVisibility(0);

SQLiteDatabase db=database.getWritableDatabase();
db.execSQL("INSERT INTO UPLOAD VALUES('"+i1+"');");

} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
break;

}

}
}

Image.class：

public class Image extends Activity {
Database database=new Database(this);
static EfficientAdapter adapter, adapter1;
static ListView lv1;

static SQLiteDatabase db;
static EfficientAdapter adp;
static Cursor c1;

static Vector<String>IMAGE=new Vector<String>();

@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);

db=database.getReadableDatabase();
c1=db.rawQuery("select * from UPLOAD;", null);

if (c1.moveToFirst()) {

do {
IMAGE.add(c1.getString(0).toString());

} while (c1.moveToNext());

c1.close();
}

lv1=(ListView)findViewById(R.id.List);

adapter=new EfficientAdapter(this);

lv1.setAdapter(adapter);

ImageView add=(ImageView)findViewById(R.id.imv1a);

add.setOnClickListener(new OnClickListener() {

@Override
public void onClick(View v) {
// TODO Auto-generated method stub
IMAGE.clear();

Intent i=new Intent(Image.this,Imageupload12.class);
startActivity(i);

}
});

}

private static class EfficientAdapter extends BaseAdapter{

// protected final Context Context = null;
protected LayoutInflater mLayoutInflater;
AlertDialog.Builder aBuilder;
public EfficientAdapter(Context context) {
// TODO Auto-generated constructor stub
mLayoutInflater=LayoutInflater.from(context);
}

@Override
public int getCount() {
// TODO Auto-generated method stub

return IMAGE.size();
}

@Override
public Object getItem(int position) {
// TODO Auto-generated method stub
return position;
}

@Override
public long getItemId(int position) {
// TODO Auto-generated method stub
return position;
}

@Override
public View getView(final int position, View convertView, ViewGroup parent) {
// TODO Auto-generated method stub

final ViewHolder mVHolder;
if(convertView == null){
convertView=mLayoutInflater.inflate(R.layout.pjtlistdetails, parent, false);

mVHolder=new ViewHolder();

mVHolder.t1=(TextView)convertView.findViewById(R.id.pjtdetails);
mVHolder.time=(TextView)convertView.findViewById(R.id.name);

mVHolder.imv=(ImageButton)convertView.findViewById(R.id.editic);
mVHolder.imvd=(ImageView)convertView.findViewById(R.id.delete);
mVHolder.imvf=(ImageView)convertView.findViewById(R.id.fwd);

mVHolder.imv.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {

String img=IMAGE.elementAt(position);
Log.i("image...",""+img);

Context ctx=v.getContext();
Intent myIntent = new Intent();
ctx = v.getContext();
myIntent.setClass(ctx, Imageupload12.class);
myIntent.putExtra("image", img);

ctx.startActivity(myIntent);

IMAGE.clear();

}
});
static class ViewHolder{

ImageButton imv;
ImageView imvd,imvf;
}

从数据库检索图像

public Bitmap getImage(int i){

String qu = "select img from table where feedid=" + i ;
Cursor cur = db.rawQuery(qu, null);

if (cur.moveToFirst()){
byte[] imgByte = cur.getBlob(0);
cur.close();
return BitmapFactory.decodeByteArray(imgByte, 0, imgByte.length);
}
if (cur != null && !cur.isClosed()) {
cur.close();
}

return null ;
}

它是一个非常老的代码，检查是否有效:)

Answer 3

使用Base64类，可以将位图编码为字符串，然后将其存储到数据库。

可以使用以下示例代码：

Bitmap bitmapOrg =get bitmap from image;

ByteArrayOutputStream bao = new ByteArrayOutputStream();

bitmapOrg.compress(Bitmap.CompressFormat.JPEG, 90, bao);

byte[] ba = bao.toByteArray();

String ba1 = Base64.encodeBytes(ba);

现在解码该字符串以使用图像。

Answer 4

使用SQLiteOpenHelper类从数据库存储和检索图像的示例代码

package com.aliahmad.store_retrive_image;


import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;


public class DataManager extends SQLiteOpenHelper 
{
    public final static String tab="image";
    public final static String col1="iname";
    public final static String col2="id";
    public DataManager(Context context)
    {
        super(context, "MyData", null, 1);
    }
    @Override
    public void onCreate(SQLiteDatabase db) 
    {
        db.execSQL("create table image (iname text,id blob)");
    }
    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        // TODO Auto-generated method stub
        Log.w(DataManager.class.getName(), "Upgrading database from version "+oldVersion+" to"+newVersion+", which will destroy all old data");
        db.execSQL("DROP TABLE IF EXISTS "+tab);
        onCreate(db);
    }

}

单击存储按钮时调用此功能

public void onStore(View v)
{
    try
    {
        ByteArrayOutputStream baos=new ByteArrayOutputStream();
        //image is object of Bitmap that you want to store
        image.compress(CompressFormat.PNG, 100, baos);
        byte[] data=baos.toByteArray();
        SQLiteDatabase db=new DataManager(this).getWritableDatabase();
        ContentValues cv=new ContentValues();
        cv.put(DataManager.col1, et.getText().toString());
        cv.put(DataManager.col2, data);
        db.insert(DataManager.tab, null, cv);
    }
    catch (Exception e) {
        Toast.makeText(this, "Errro - "+e,1 ).show();
    }       
}

检索图像调用此函数

public void onRet(View v)
{
    SQLiteDatabase db=new DataManager(this).getReadableDatabase();
    Cursor cr=db.query(DataManager.tab, new String[]{DataManager.col2}, DataManager.col1+"= ?", new String[]{str[which]}, null, null, null);
    if(cr.moveToFirst())
    {
        byte [] b=cr.getBlob(4);
        ByteArrayInputStream imageStream = new ByteArrayInputStream(b); 
        image= BitmapFactory.decodeStream(imageStream);
        iv.setImageBitmap(image);
    }
    else
    {
        Toast.makeText(this, "not found", 1).show();
    }
    db.close();
}