在我的活动中，我可以制作签名图，然后使用“saveToDatabase”按钮将其保存在我的 SQLite 数据库中。当我重新打开活动时，我想从我的数据库中加载绘图，但我不知道怎么做！任何人都可以帮忙吗？我已经在“从数据库中添加签名”处解码了位图，但接下来我需要做什么？
这是我的代码：
public class WerkbonDetailsActivity extends Activity{
public Werkbon chosenWorkorder;
Button mClear, mGetSign, saveToDatabase;
LinearLayout mContent;
signature mSignature;
public static String tempDir;
public int count = 1;
public String current = null;
private Bitmap mBitmap;
View mView;
Database db = new Database(this);
int chosenWorkorderposition = 0;
Paint paintPieFill;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.activity_werkbondetails);
tempDir = Environment.getExternalStorageDirectory() + "/" + getResources().getString(R.string.external_dir) + "/";
prepareDirectory();
current = count + ".png";
mContent = (LinearLayout) findViewById(R.id.linearLayout);
mSignature = new signature(this, null);
mSignature.setBackgroundColor(Color.WHITE);
mContent.addView(mSignature, LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT);
mClear = (Button)findViewById(R.id.btn_handtekeningwissen);
mGetSign = (Button)findViewById(R.id.getsign);
saveToDatabase = (Button)findViewById(R.id.save);
mView = mContent;
Bundle extras = getIntent().getExtras();
if (extras != null) {
chosenWorkorderposition = (int)extras.getInt("chosenWorkorderposition");
}
chosenWorkorder = db.getWerkbon(chosenWorkorderposition + 1);
mClear.setOnClickListener(new OnClickListener()
{
public void onClick(View v)
{
Log.v("log_tag", "Panel Cleared");
mSignature.clear();
}
});
mGetSign.setOnClickListener(new OnClickListener()
{
public void onClick(View v)
{
Log.v("log_tag", "Panel Saved");
mView.setDrawingCacheEnabled(true);
mSignature.save(mView);
}
});
saveToDatabase.setOnClickListener(new OnClickListener()
{
public void onClick(View v)
{
mBitmap = Bitmap.createBitmap (mContent.getWidth(), mContent.getHeight(), Bitmap.Config.RGB_565);;
Canvas canvas = new Canvas(mBitmap);
v.draw(canvas);
ByteArrayOutputStream stream = new ByteArrayOutputStream();
mBitmap.compress(Bitmap.CompressFormat.PNG, 100, stream);
byte[] bitmapdata = stream.toByteArray();
chosenWorkorder.setHandtekening(bitmapdata);
db.updateWerkbon(chosenWorkorder);
}
});
//Adding Signature from database
if(chosenWorkorder.getHandtekening() != null){
ByteArrayInputStream stream = new ByteArrayInputStream(chosenWorkorder.getHandtekening());
Bitmap bm = BitmapFactory.decodeStream(stream);
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
private boolean prepareDirectory()
{
try
{
if (makedirs())
{
return true;
} else {
return false;
}
} catch (Exception e)
{
e.printStackTrace();
Toast.makeText(this, "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();
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.BLUE);
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);
String FtoSave = tempDir + current;
File file = new File(FtoSave);
try
{
FileOutputStream mFileOutStream = new FileOutputStream(file);
v.draw(canvas);
mBitmap.compress(Bitmap.CompressFormat.PNG, 90, mFileOutStream);
mFileOutStream.flush();
mFileOutStream.close();
String url = Images.Media.insertImage(getContentResolver(), mBitmap, "title", null);
Log.v("log_tag","url" + url);
}
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();
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);
}
}//signature
}