java - 在画布上绘制线条并在绘制后修改位置
问题描述
我需要这件事的帮助
我在画布上画线,我需要能够在绘制后修改位置。我搜索并尝试了很多东西,但似乎没有一个有效
我想选择线的一端并将它们拖到另一个位置
有人可以给我和建议吗?
解决方案
请试试这个。在这个你可以绘制和编辑线。
class Drawing extends View{
private Canvas mCanvas = null;
private Path mPath = null;
private Paint mBitmapPaint = null;
private Bitmap mBitmap = null;
private Bitmap bit=null;
private Paint mPaint = null;
private MainActivity baseMainActivity = null;
public interface onDrawingViewSingleTap{
void onDrawingViewTap(float x , float y);
}
public Drawing(Context c) {
super(c);
baseMainActivity=(MainActivity) c;
mPaint = new Paint();
mPaint.setAntiAlias(true);
mPaint.setDither(true);
mPaint.setColor(Color.YELLOW);
mPaint.setStyle(Paint.Style.STROKE);
mPaint.setStrokeJoin(Paint.Join.ROUND);
mPaint.setStrokeCap(Paint.Cap.ROUND);
mPaint.setStrokeWidth(6);//This sets the width of signature
Display display =baseMainActivity.getWindowManager().getDefaultDisplay();
mBitmap = Bitmap.createBitmap(display.getWidth(), display.getHeight(), Bitmap.Config.ARGB_8888);// 320*480 // For setting size of screen to draw Bitmap
mPath = new Path();
mBitmapPaint = new Paint(Paint.DITHER_FLAG);
mCanvas = new Canvas(mBitmap);
onDraw(mCanvas);
}
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);
}
@Override
protected void onDraw(Canvas canvas) {
try{
canvas.drawColor(Color.TRANSPARENT);//Color.WHITE //To change background color of Application
if(bit!=null)
canvas.drawBitmap(bit, 0, 0, mBitmapPaint);
else
canvas.drawBitmap(mBitmap, 0, 0, mBitmapPaint);
}catch(Exception e){}
if(bit==null)
canvas.drawPath(mPath, mPaint);
bit=null;
}
private float mX, mY;
private void touch_start(float x, float y) {
mPath.reset();
mPath.moveTo(x, y);
mX = x+1;
mY = y+1;
}
private void touch_upline(float x,float y) {
mPath.lineTo(mX, mY);
mCanvas.drawLine(mX, mY, x, y, mPaint);
mPath.reset();
}
@Override
public boolean onTouchEvent(MotionEvent event) {
float x = event.getX();
float y = event.getY();
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
touch_start(x, y);
invalidate();
break;
case MotionEvent.ACTION_MOVE:
eraseAll();
touch_upline(x, y);
invalidate();
break;
case MotionEvent.ACTION_UP:
touch_upline(x,y);
invalidate();
break;
}
return true;
}
public void eraseAll()
{
mBitmap.eraseColor(android.graphics.Color.TRANSPARENT);
mCanvas = new Canvas(mBitmap);
}
public class MainActivity extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
RelativeLayout relativeLayout= (RelativeLayout) (findViewById(R.id.mainLayout));
relativeLayout.addView(new Drawing(this));
}
}
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