[英]Adding image to android SQLite Database
I tried my best to solve this problem, but can't figure it out. 我尽力解决了这个问题,但无法解决。
I have spinner with image and text, which is connected to SQLite database. 我有带图片和文本的微调框,它已连接到SQLite数据库。 Basically when I click save button, I want selected spinner image to save in database. 基本上,当我单击“保存”按钮时,我希望所选的微调器图像保存在数据库中。 But it is not happening as expected. 但这并没有按预期发生。
Below is the code. 下面是代码。 Any help is appreciated. 任何帮助表示赞赏。
MainActivity code: MainActivity代码:
public void saveTask(){
if(i == 0){
Bitmap im = BitmapFactory.decodeResource(getResources(), R.drawable.red);
ByteArrayOutputStream stream = new ByteArrayOutputStream();
im.compress(Bitmap.CompressFormat.PNG, 100, stream);
byte[] imageinByte = stream.toByteArray();
long id = mDbHelper.addImage(imageinByte);
if(id > 0){
mRowId = id;
}
}
}
DATABASE CODE: 数据库代码:
private static final String DATABASE_NAME = "Spinnner";
private static final String DATABASE_TABLE = "spin";
private static final int DATABASE_VERSION = 1;
public static final String KEY_ROWID = "_id";
public static final String KEY_IMAGE = "image";
private static final String TAG = "SPINNERERROR";
private DatabaseHelper mDbHelper;
private SQLiteDatabase mDb;
private static final String DATABASE_CREATE =
"CREATE TABLE IF NOT EXISTS " + DATABASE_TABLE + " ("
+ KEY_ROWID + " integer primary key autoincrement, "
+ KEY_IMAGE + " BLOB);";
private final Context mCtx;
private static class DatabaseHelper extends SQLiteOpenHelper{
DatabaseHelper(Context context){
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
public void onCreate(SQLiteDatabase db){
db.execSQL(DATABASE_CREATE);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// TODO Auto-generated method stub
Log.w(TAG, "Upgrading database from version " + oldVersion + " to "
+ newVersion + ", which will destroy all old data");
db.execSQL("DROP TABLE IF EXISTS " + DATABASE_TABLE);
onCreate(db);
}
}
public Database(Context ctx){
this.mCtx = ctx;
}
public Database open() throws SQLException{
mDbHelper = new DatabaseHelper(mCtx);
mDb = mDbHelper.getWritableDatabase();
return this;
}
public void close(){
mDbHelper.close();
}
public long addImage(byte[] image){
ContentValues cv = new ContentValues();
cv.put(KEY_IMAGE, image);
return mDb.insert(DATABASE_TABLE, null, cv);
}
Log cat: 日志猫:
09-14 00:28:29.228: E/AndroidRuntime(30838): FATAL EXCEPTION: main
09-14 00:28:29.228: E/AndroidRuntime(30838): java.lang.NullPointerException
09-14 00:28:29.228: E/AndroidRuntime(30838): at com.example.spinnerimage.Database.addImage(Database.java:62)
09-14 00:28:29.228: E/AndroidRuntime(30838): at com.example.spinnerimage.MainActivity.saveTask(MainActivity.java:114)
09-14 00:28:29.228: E/AndroidRuntime(30838): at com.example.spinnerimage.MainActivity.onClick(MainActivity.java:102)
change from this: 从此更改:
private ContentValues createContentValues(byte[] Image) {
ContentValues values = new ContentValues();
values.put(KEY_IMAGE, Image);
return values;
}
public long addImage(byte[] image){
ContentValues cv = createContentValues(image);
return mDb.insert(DATABASE_TABLE, null, cv);
}
It's likely that your mDb
database variable has not been initialized correctly, viz your database provider is null. 您的mDb
数据库变量可能未正确初始化,即您的数据库提供程序为null。 I normally separate the Helper
and DataProvider
classes rather than merge them into one class as you have done. 我通常将Helper
和DataProvider
类分开,而不是像您那样将它们合并为一个类。
I would recommend you follow the same methodology as show in Lars Vogel's excellent SQLite tutorial . 我建议您采用与Lars Vogel出色的SQLite教程中显示的方法相同的方法。
Hope this helps. 希望这可以帮助。
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