Android 向SQLite数据库表添加图像
我是安卓和Java的新手。向SQLite数据库表添加图像时遇到一些问题。以下是我的表格设计:Android 向SQLite数据库表添加图像,android,sqlite,android-sqlite,Android,Sqlite,Android Sqlite,我是安卓和Java的新手。向SQLite数据库表添加图像时遇到一些问题。以下是我的表格设计: private static final String CREATE_GALLERY_TABLE = "CREATE TABLE " + GALLERY_TABLE + "(" + ID + " INTEGER PRIMARY KEY," + IMAGE + " BLOB," + TITLE + " TEXT," + CAPTION + " TEXT" + ")"
private static final String CREATE_GALLERY_TABLE = "CREATE TABLE "
+ GALLERY_TABLE + "("
+ ID + " INTEGER PRIMARY KEY,"
+ IMAGE + " BLOB,"
+ TITLE + " TEXT,"
+ CAPTION + " TEXT" + ")";
这是我将图像
、标题
和标题
添加到库
表中的方法:
public boolean createGallery(byte[] image, String title, String caption) throws SQLiteException {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(IMAGE, image);
values.put(TITLE, title);
values.put(CAPTION, caption);
long result = db.insert(GALLERY_TABLE, null, values);
if (result == -1)
return false;
else
return true;
}
在我的活动中,我有以下方法:
//user selects image from gallery
public void selectImage() {
selectButton.setOnClickListener(
new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent galleryIntent = new Intent(Intent.ACTION_PICK, MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
startActivityForResult(galleryIntent, RESULT_LOAD_IMAGE);
}
}
);
}
//This method is called when user selected image from gallery
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (requestCode == RESULT_LOAD_IMAGE && resultCode == RESULT_OK && data != null) {
Uri selectedImage = data.getData();
viewImage.setImageURI(selectedImage);
}
}
public void uploadImage() {
uploadButton.setOnClickListener(
new View.OnClickListener() {
@Override
public void onClick(View v) {
Bitmap image = ((BitmapDrawable) viewImage.getDrawable()).getBitmap();
ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
image.compress(Bitmap.CompressFormat.JPEG, 100, byteArrayOutputStream);
String encodedImage = Base64.encodeToString(byteArrayOutputStream.toByteArray(), Base64.DEFAULT);
boolean isInserted = myDb.createGallery(
encodedImage.getBytes(),
addTitle.getText().toString(),
addCaption.getText().toString()
);
if (isInserted == true) {
Toast.makeText(gallery.this, "Image uploaded successfully added", Toast.LENGTH_SHORT).show();
} else
Toast.makeText(gallery.this, "Image upload has failed", Toast.LENGTH_SHORT).show();
}
}
);
}
我可以从图库中选择一幅图像,选中后,我有一个名为
viewImage
的ImageView
,它成功地显示了我选择的图像。我还能够成功地插入到数据库中,插入了标题和标题,但图像列为空。知道我哪里出错了吗?如果有任何帮助,我们将不胜感激。为什么要对字节数组进行base64编码,然后将该字符串转换回字节数组?难道你不想把压缩字节数组放到数据库中吗?它会更小更快。另外,在日志中检查它的大小,确保它是有意义的。@DougStevenson我在YouTube上看了一个guys教程,但他发送到了服务器而不是SQLite数据库,所以最终结果不同,所以我只是尝试将encodedImage添加到数据库中。如果我只想将压缩字节数组添加到db中,我的代码应该是什么样子?…对不起,我对android编程非常陌生。您的压缩图像字节位于byteArrayOutputStream.toByteArray()。@DougStevenson所以我只需删除Base64.encodeToString
和,Base64.DEFAULT
?因此它是String encodedImage=byteArrayOutputStream.toByteArray()
删除执行Base64编码的整行,只存储图像压缩的结果。