我尝试了几个代码来将我的自定义视图保存为 .jpg 格式。我正在将视图转换为位图，然后将其保存，如下所示。但每次尝试保存的图像大小始终为 0 Kb，并且文件不包含任何内容。我已经提出以下许可。
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
这是我使用的代码之一；
drawView.setDrawingCacheEnabled(true);
drawView.buildDrawingCache();
Bitmap b = drawView.getDrawingCache();
private void SaveImage(Bitmap finalBitmap) {
String root = Environment.getExternalStorageDirectory().toString();
File myDir = new File(root + "/saved_images");
myDir.mkdirs();
String fname = "Image.jpg";
File file = new File (myDir, fname);
if (file.exists ()) file.delete ();
try {
FileOutputStream out = new FileOutputStream(file);
finalBitmap.compress(Bitmap.CompressFormat.JPEG, 90, out);
out.flush();
out.close();
} catch (Exception e) {
e.printStackTrace();
}
}
我还想明确指出，这段代码的主要思想不是来自我。
整个完整的代码；公共类 DrawPad 扩展视图 {
//drawing path
private Path drawPath;
//drawing and canvas paint
private Paint drawPaint, canvasPaint;
//initial color
private int paintColor =0xff000000;
//canvas
private Canvas drawCanvas;
//canvas bitmap
private Bitmap canvasBitmap;
//erase flag
private boolean erase=false;
public DrawPad(Context context, AttributeSet attrs){
super(context, attrs);
setupDrawing();
}
public Paint getPaint(){
return drawPaint;
}
//setup drawing
private void setupDrawing(){
//prepare for drawing and setup paint stroke properties
drawPath = new Path();
drawPaint = new Paint();
drawPaint.setColor(paintColor);
drawPaint.setAntiAlias(true);
drawPaint.setStrokeWidth(1.0f);
drawPaint.setStyle(Paint.Style.STROKE);
drawPaint.setStrokeJoin(Paint.Join.ROUND);
drawPaint.setStrokeCap(Paint.Cap.ROUND);
canvasPaint = new Paint(Paint.DITHER_FLAG);
}
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);
canvasBitmap = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_8888);
drawCanvas = new Canvas(canvasBitmap);
}
//draw the view - will be called after touch event
@Override
protected void onDraw(Canvas canvas) {
canvas.drawBitmap(canvasBitmap, 0, 0, canvasPaint);
canvas.drawPath(drawPath, drawPaint);
}
//register user touches as drawing action
@Override
public boolean onTouchEvent(MotionEvent event) {
float touchX = event.getX();
float touchY = event.getY();
//respond to down, move and up events
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
drawPath.moveTo(touchX, touchY);
break;
case MotionEvent.ACTION_MOVE:
drawPath.lineTo(touchX, touchY);
break;
case MotionEvent.ACTION_UP:
drawPath.lineTo(touchX, touchY);
drawCanvas.drawPath(drawPath, drawPaint);
drawPath.reset();
break;
default:
return false;
}
//redraw
invalidate();
return true;
}
//update color
public void setColor(String newColor){
invalidate();
paintColor = Color.parseColor(newColor);
drawPaint.setColor(paintColor);
}
//set erase true or false
public void setErase(boolean isErase){
erase=isErase;
if(erase){
drawPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.CLEAR));
drawPaint.setStrokeWidth(15.0f);
}
else {
drawPaint.setStrokeWidth(1.0f);
drawPaint.setXfermode(null);
}
}
//start new drawing
public void startNew(){
drawCanvas.drawColor(0, PorterDuff.Mode.CLEAR);
drawPaint.setStrokeWidth(1.0f);
invalidate();
}
public void SaveImage(Bitmap finalBitmap,String spin) {
if(finalBitmap == null) {
Toast unsavedToast = Toast.makeText(getContext(),
"Oops! Page could not be saved.", Toast.LENGTH_SHORT);
unsavedToast.show();
}
this.setDrawingCacheEnabled(true);
this.buildDrawingCache();
finalBitmap=this.getDrawingCache();
String root = Environment.getExternalStorageDirectory().toString();
File myDir = new File(root + "/answers");
myDir.mkdirs();
String fname = spin+".jpg";
File file = new File (myDir, fname);
if (file.exists ()) file.delete ();
try {
FileOutputStream out = new FileOutputStream(file);
if ( finalBitmap.compress(Bitmap.CompressFormat.JPEG, 90, out)==true){
out.flush();
out.close();
}
if(finalBitmap.compress(Bitmap.CompressFormat.JPEG, 90, out)==false){
Toast fToast = Toast.makeText(getContext(),
"compression failed", Toast.LENGTH_SHORT);
fToast.show();
}
} catch (Exception e) {
e.printStackTrace();
}
}
}