我创建了一个包含surveyname和image的数据库。图像以正确的字节（BLOB）形式插入到数据库中，但是当我试图检索图像时，它会给出一些随机值。当我使用if条件查找图像时，它返回一个随机值，当我使用它时，它导致随机值无限循环。
public class CaptureSignature extends Fragment implements OnClickListener {
LinearLayout mContent;
signature mSignature;
Button mClear, mGetSign, mCancel;
public static String tempDir;
public int count = 1;
public String current = null;
private Bitmap mBitmap;
View mView;
File mypath;
Context context;
private String uniqueId;
private EditText yourName;
// private DatabaseMethods db;
// private DatabaseHandler db;
DatabaseMethods db=new DatabaseMethods(getActivity());
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
}
//@Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
db=new DatabaseMethods(getActivity());
//db=new DatabaseHandler(getActivity());
//db.open();
//Toast toast = Toast.makeText(context,"hj", Toast.LENGTH_SHORT);
//toast.show();
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View viewFrag = inflater.inflate(R.layout.signature, container, false);
//this.requestWindowFeature(Window.FEATURE_NO_TITLE);
// DatabaseMethods db=new DatabaseMethods(this);
tempDir = Environment.getExternalStorageDirectory() + "/" + getResources().getString(R.string.external_dir) + "/";
ContextWrapper cw = new ContextWrapper(getActivity());
File directory = cw.getDir(getResources().getString(R.string.external_dir), Context.MODE_PRIVATE);
prepareDirectory();
uniqueId = getTodaysDate() + "_" + getCurrentTime() + "_" + Math.random();
current = uniqueId + ".png";
mypath= new File(directory,current);
Log.e("path"," "+mypath);
mContent = (LinearLayout)viewFrag. findViewById(R.id.linearLayout);
mSignature = new signature(getActivity(), null);
mSignature.setBackgroundColor(Color.WHITE);
mContent.addView(mSignature, LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT);
mClear = (Button)viewFrag.findViewById(R.id.clear);
mGetSign = (Button)viewFrag.findViewById(R.id.getsign);
mGetSign.setEnabled(false);
mCancel = (Button)viewFrag.findViewById(R.id.cancel);
mView = mContent;
yourName = (EditText)viewFrag.findViewById(R.id.yourName);
mClear.setOnClickListener(new OnClickListener()
{
public void onClick(View v)
{
Log.v("log_tag", "Panel Cleared");
mSignature.clear();
mGetSign.setEnabled(false);
}
});
mGetSign.setOnClickListener(new OnClickListener()
{
public void onClick(View v)
{
Log.v("log_tag", "Panel Saved");
boolean error = captureSignature();
if(!error){
mView.setDrawingCacheEnabled(true);
mSignature.save(mView);
/*Bundle b = new Bundle();
b.putString("status", "done");
Intent intent = new Intent();
intent.putExtras(b);
setResult(RESULT_OK,intent);
finish();*/
}
}
});
mCancel.setOnClickListener(new OnClickListener()
{
public void onClick(View v)
{
Log.v("log_tag", "Panel Canceled");
/*Bundle b = new Bundle();
b.putString("status", "cancel");
Intent intent = new Intent();
intent.putExtras(b);
setResult(RESULT_OK,intent);
finish();*/
}
});
return viewFrag;
}
/* @Override
protected void onDestroy() {
Log.w("GetSignature", "onDestory");
super.onDestroy();
}*/
private boolean captureSignature() {
boolean error = false;
String errorMessage = "";
if(yourName.getText().toString().equalsIgnoreCase("")){
errorMessage = errorMessage + "Please enter your Name\n";
error = true;
}
if(error){
Toast toast = Toast.makeText(context, errorMessage, Toast.LENGTH_SHORT);
toast.setGravity(Gravity.TOP, 105, 50);
toast.show();
}
return error;
}
private String getTodaysDate() {
final Calendar c = Calendar.getInstance();
int todaysDate = (c.get(Calendar.YEAR) * 10000) +
((c.get(Calendar.MONTH) + 1) * 100) +
(c.get(Calendar.DAY_OF_MONTH));
Log.w("DATE:",String.valueOf(todaysDate));
return(String.valueOf(todaysDate));
}
private String getCurrentTime() {
final Calendar c = Calendar.getInstance();
int currentTime = (c.get(Calendar.HOUR_OF_DAY) * 10000) +
(c.get(Calendar.MINUTE) * 100) +
(c.get(Calendar.SECOND));
Log.w("TIME:",String.valueOf(currentTime));
return(String.valueOf(currentTime));
}
private boolean prepareDirectory()
{
try
{
if (makedirs())
{
return true;
} else {
return false;
}
} catch (Exception e)
{
e.printStackTrace();
Toast.makeText(context, "Could not initiate File System.. Is Sdcard mounted properly?", 1000).show();
return false;
}
}
private boolean makedirs()
{
File tempdir = new File(tempDir);
if (!tempdir.exists())
tempdir.mkdirs();
if (tempdir.isDirectory())
{
File[] files = tempdir.listFiles();
for (File file : files)
{
if (!file.delete())
{
System.out.println("Failed to delete " + file);
}
}
}
return (tempdir.isDirectory());
}
public class signature extends View
{
private static final float STROKE_WIDTH = 5f;
private static final float HALF_STROKE_WIDTH = STROKE_WIDTH / 2;
private Paint paint = new Paint();
private Path path = new Path();
Context context;
private float lastTouchX;
private float lastTouchY;
private final RectF dirtyRect = new RectF();
public signature(Context context, AttributeSet attrs)
{
super(context, attrs);
paint.setAntiAlias(true);
paint.setColor(Color.BLACK);
paint.setStyle(Paint.Style.STROKE);
paint.setStrokeJoin(Paint.Join.ROUND);
paint.setStrokeWidth(STROKE_WIDTH);
}
public void save(View v)
{
Log.v("log_tag", "Width: " + v.getWidth());
Log.v("log_tag", "Height: " + v.getHeight());
if(mBitmap == null)
{
mBitmap = Bitmap.createBitmap (mContent.getWidth(), mContent.getHeight(), Bitmap.Config.RGB_565);;
}
Canvas canvas = new Canvas(mBitmap);
try
{
FileOutputStream mFileOutStream = new FileOutputStream(mypath);
v.draw(canvas);
mBitmap.compress(Bitmap.CompressFormat.PNG, 90, mFileOutStream);
Log.e("imageinto",""+mBitmap);
mFileOutStream.flush();
mFileOutStream.close();
String url = Images.Media.insertImage(getActivity().getContentResolver(), mBitmap, "title", null);
Log.v("log_tag","url: " + url);
ByteArrayOutputStream baos=new ByteArrayOutputStream();
mBitmap.compress(Bitmap.CompressFormat.PNG, 90,baos);
byte[] byteData=baos.toByteArray();
Log.e("imageintobyedata",""+byteData);
Bitmap bmp=BitmapFactory.decodeByteArray(byteData,0,byteData.length);
Log.e("imageretrieved",""+bmp);
db.open();
Log.e("after","database open");
db.storeImage(byteData);
//In case you want to delete the file
//boolean deleted = mypath.delete();
//Log.v("log_tag","deleted: " + mypath.toString() + deleted);
//If you want to convert the image to string use base64 converter
}
catch(Exception e)
{
Log.v("log_tag", e.toString());
}
}
public void clear()
{
path.reset();
invalidate();
}
@Override
protected void onDraw(Canvas canvas)
{
canvas.drawPath(path, paint);
}
@Override
public boolean onTouchEvent(MotionEvent event)
{
float eventX = event.getX();
float eventY = event.getY();
mGetSign.setEnabled(true);
switch (event.getAction())
{
case MotionEvent.ACTION_DOWN:
path.moveTo(eventX, eventY);
lastTouchX = eventX;
lastTouchY = eventY;
return true;
case MotionEvent.ACTION_MOVE:
case MotionEvent.ACTION_UP:
resetDirtyRect(eventX, eventY);
int historySize = event.getHistorySize();
for (int i = 0; i < historySize; i++)
{
float historicalX = event.getHistoricalX(i);
float historicalY = event.getHistoricalY(i);
expandDirtyRect(historicalX, historicalY);
path.lineTo(historicalX, historicalY);
}
path.lineTo(eventX, eventY);
break;
default:
debug("Ignored touch event: " + event.toString());
return false;
}
invalidate((int) (dirtyRect.left - HALF_STROKE_WIDTH),
(int) (dirtyRect.top - HALF_STROKE_WIDTH),
(int) (dirtyRect.right + HALF_STROKE_WIDTH),
(int) (dirtyRect.bottom + HALF_STROKE_WIDTH));
lastTouchX = eventX;
lastTouchY = eventY;
return true;
}
private void debug(String string){
}
private void expandDirtyRect(float historicalX, float historicalY)
{
if (historicalX < dirtyRect.left)
{
dirtyRect.left = historicalX;
}
else if (historicalX > dirtyRect.right)
{
dirtyRect.right = historicalX;
}
if (historicalY < dirtyRect.top)
{
dirtyRect.top = historicalY;
}
else if (historicalY > dirtyRect.bottom)
{
dirtyRect.bottom = historicalY;
}
}
private void resetDirtyRect(float eventX, float eventY)
{
dirtyRect.left = Math.min(lastTouchX, eventX);
dirtyRect.right = Math.max(lastTouchX, eventX);
dirtyRect.top = Math.min(lastTouchY, eventY);
dirtyRect.bottom = Math.max(lastTouchY, eventY);
}
}
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
}
}
public class DatabaseMethods {
private static final String databaseName = "Demo11";
private static final int databaseVersion = 10;
private static final String imagestable =
"CREATE TABLE IF NOT EXISTS image (SURVEYNAME TEXT,IMAGE BLOB);";
private final Context context;
private DatabaseHelper DBHelper;
private SQLiteDatabase db;
Cursor cursor;
int count;
boolean isProjectNamePresent=false;
boolean isProfileNamePresent = false;
public DatabaseMethods(Context ctx)
{
Log.e("inside","database method");
this.context = ctx;
DBHelper = new DatabaseHelper(context);
}
private static class DatabaseHelper extends SQLiteOpenHelper
{
public DatabaseHelper(Context context)
{
super(context, databaseName, null, databaseVersion);
}
@Override
public void onCreate(SQLiteDatabase db)
{
Log.e("insideOnCreate","database method1");
db.execSQL(imagestable);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion,int newVersion)
{
db.execSQL("DROP TABLE IF EXISTS image");
onCreate(db);
}
}
//---opens the database---
public DatabaseMethods open() throws SQLException
{
db = DBHelper.getWritableDatabase();
return this;
}
//---closes the database---
public void close()
{
DBHelper.close();
}
public void getAllRecords()
{
String survey="mobile";
String query="SELECT IMAGE FROM image WHERE SURVEYNAME='"+survey+"'";
//SQLiteDatabase db=this.getWritableDatabase();
Cursor c=db.rawQuery(query,null);
int col=c.getColumnIndex("IMAGE");
Log.e("columnindex",""+col);
if(c.moveToFirst())
{
byte[] blobData=c.getBlob(col);
Log.e("cursorimage",""+blobData);
}
}
public void storeImage(byte[] imgData)
{
String query;
String image1=imgData.toString();
String survey="mobile";
Log.e("imagename",image1);
query = "INSERT INTO image (SURVEYNAME,IMAGE)
VALUE('"+survey+"','"+imgData+"')";
Toast.makeText(context,"ImageInserted",Toast.LENGTH_LONG).show();
db.execSQL(query);
}
}
答案 0 :(得分：1)
我找到了我的问题的altaernate解决方案我使用base64解码了我的图像并将其保存为varchar然后再次编码。它为我工作...... 1.我的捕获图像文件
ByteArrayOutputStream baos=new ByteArrayOutputStream();
mBitmap.compress(Bitmap.CompressFormat.PNG, 90,baos);
byte[] byteData=baos.toByteArray();
String imageEncoded=Base64.encodeToString(byteData,Base64.DEFAULT);
数据库文件
private static final String imagestable =
“CREATE TABLE IF NOT NOT EXISTS image（SURVEYNAME TEXT，IMAGE VARCHAR2（500））;”;
public void storeImage（byte [] imgData）
{
字符串查询;
String image1 = imgData.toString（）;
字符串调查=“移动”;
Log.e（ “imagename”，图像1）;
query =“INSERT INTO image（SURVEYNAME，IMAGE）VALUES（'”survey +“'，'”+ imgData +“'）”;
Toast.makeText（上下文中， “ImageInserted”，Toast.LENGTH_LONG）.show（）;
db.execSQL（查询）;
}
解码
byte [] decodeByteArray = Base64.decode（image，0）; 位图bmp = BitmapFactory.decodeByteArray（decodeByteArray，0，decodeByteArray.length）; Log.e（ “BITMAPCONVERSION”， “” + BMP）; img.setImageBitmap（BMP）;
答案 1 :(得分：0)
要从字节中取回图像，您需要将字节转换为位图，如：
byte[] imgBytes; Bitmap bm = BitmapFactory.decodeByteArray(imgBytes, 0, imgBytes.length); imageView.setImageBitmap(bm);
//其中imgBytes是来自数据库的字节
答案 2 :(得分：0)
这是另一种方法。在设备上下载图像并将图像路径保存在数据库中，并在需要时使用该路径。