Android ontouch를 사용하여 캔버스에 사각형을 그립니다.

Question

캔버스에 ontouch 이벤트의 포인트로 직사각형을 그려야합니다. 직사각형 모양이 작동하지만 다른 사각형을 그릴 때 이전 사각형이 사라집니다. 나는 어떤 배열에 직사각형 점을 저장할 필요가 있다고 생각한다. 나에게 몇 가지 아이디어를 제안 해주세요.

지금까지 제 코드는 다음과 같습니다. 뷰 클래스 ontouch 방법 제

는

private void onTouchEvent(MotionEvent event) { 
    xTouchCoordinate = event.getX(); 
    yTouchCoordinate = event.getY(); 
if (event.getAction() == MotionEvent.ACTION_DOWN) { 
     isActionUp = false; 
     pushState(); 

     startX = event.getX(); 
     startY = event.getY(); 
} 
else if (event.getAction() == MotionEvent.ACTION_UP) { 
isActionUp = true; 
} 
else if (event.getAction() == MotionEvent.ACTION_MOVE){ 
     isActionUp = false; 
if(mTouchMode == TouchModes.RECTANGLE) 
     { 
      updateRectPath(startX,startY , xTouchCoordinate , yTouchCoordinate); 

     } 
} 
} 

과의 onDraw 방법은

protected void onDraw(Canvas canvas) { 
    ImageObject.setInteractiveMode(true); 
    int sc = canvas.save(); 
    canvas.drawColor(Color.BLACK); 
    canvas.scale(mCanvasScale, mCanvasScale); 
    canvas.translate(mCanvasOffset.x, mCanvasOffset.y); 
    canvas.clipRect(mCanvasLimits); 
    canvas.drawColor(Color.WHITE); 

    if (currentState.drawGrid) 
     drawGridLines (canvas); 
    drawImages (canvas, true); 
    drawLines (canvas); 
    drawRectangles(canvas); 
    drawCircles(canvas); 
    drawOvals(canvas); 
    drawImages (canvas, false); 
    } 

DrawRectangles 방법이다

private void drawRectangles(Canvas canvas) { 
    try 
    { 
     if(path!=null) 
     { 
      if(mTouchMode == TouchModes.RECTANGLE) 
      { 

        finishPath(canvas); 
      } 
     } 
    }catch(Exception e) 
    { 

    } 

} 

finishpath 방법

void finishPath(Canvas canvas) { 




    if(mTouchMode == TouchModes.RECTANGLE) 
    { 
     paint = new Paint(); 

     paint.setAntiAlias(true); 
     paint.setDither(true); 
     paint.setStyle(Paint.Style.STROKE); 
     paint.setColor(currentState.currentColor); 
     paint.setFlags(Paint.DITHER_FLAG | Paint.ANTI_ALIAS_FLAG); 
     paint.setStrokeJoin(Paint.Join.ROUND); 
     paint.setStrokeCap(Paint.Cap.ROUND); 
     paint.setStrokeWidth(currentStrokeWidth); 

     canvas.drawPath(path, paint); 

    } 
} 


void updateRectPath(float x1, float y1, float x2, float y2) { 
    path.rewind(); 
    x1 = x1 - mCanvasOffset.x; 
    y1 = y1 - mCanvasOffset.y; 
    x2 = x2 - mCanvasOffset.x; 
    y2 = y2 - mCanvasOffset.y; 
    translate(x1, y1); 
    Log.d ("x1 is "+x1, "y1 is "+y1); 


    if (x1 < x2 && y1 > y2) { 
     path.addRect(x1, y2, x2, y1, Path.Direction.CW); 
    } 
    if (x1 < x2 && y1 < y2) { 
     path.addRect(x1, y1, x2, y2, Path.Direction.CW); 
    } 
    if (x1 > x2 && y1 > y2) { 
     path.addRect(x2, y2, x1, y1, Path.Direction.CW); 
    } 
    if (x1 > x2 && y1 < y2) { 
     path.addRect(x2, y1, x1, y2, Path.Direction.CW); 
    } 



} 

,

Answer 1

Hi if you have the source code of apidemos (or can find on internet), it has a fingerpaint example code. you can refer that: In any case i am pasting the code here.. 

/* 
* Copyright (C) 2007 The Android Open Source Project 
* 
* Licensed under the Apache License, Version 2.0 (the "License"); 
* you may not use this file except in compliance with the License. 
* You may obtain a copy of the License at 
* 
*  http://www.apache.org/licenses/LICENSE-2.0 
* 
* Unless required by applicable law or agreed to in writing, software 
* distributed under the License is distributed on an "AS IS" BASIS, 
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 
* See the License for the specific language governing permissions and 
* limitations under the License. 
*/ 

package com.example.android.apis.graphics; 

import android.content.Context; 
import android.graphics.*; 
import android.os.Bundle; 
import android.view.Menu; 
import android.view.MenuItem; 
import android.view.MotionEvent; 
import android.view.View; 

public class FingerPaint extends GraphicsActivity 
     implements ColorPickerDialog.OnColorChangedListener { 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(new MyView(this)); 

     mPaint = new Paint(); 
     mPaint.setAntiAlias(true); 
     mPaint.setDither(true); 
     mPaint.setColor(0xFFFF0000); 
     mPaint.setStyle(Paint.Style.STROKE); 
     mPaint.setStrokeJoin(Paint.Join.ROUND); 
     mPaint.setStrokeCap(Paint.Cap.ROUND); 
     mPaint.setStrokeWidth(12); 

     mEmboss = new EmbossMaskFilter(new float[] { 1, 1, 1 }, 
             0.4f, 6, 3.5f); 

     mBlur = new BlurMaskFilter(8, BlurMaskFilter.Blur.NORMAL); 
    } 

    private Paint  mPaint; 
    private MaskFilter mEmboss; 
    private MaskFilter mBlur; 

    public void colorChanged(int color) { 
     mPaint.setColor(color); 
    } 

    public class MyView extends View { 

     private static final float MINP = 0.25f; 
     private static final float MAXP = 0.75f; 

     private Bitmap mBitmap; 
     private Canvas mCanvas; 
     private Path mPath; 
     private Paint mBitmapPaint; 

     public MyView(Context c) { 
      super(c); 

      mPath = new Path(); 
      mBitmapPaint = new Paint(Paint.DITHER_FLAG); 
     } 

     @Override 
     protected void onSizeChanged(int w, int h, int oldw, int oldh) { 
      super.onSizeChanged(w, h, oldw, oldh); 
      mBitmap = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_8888); 
      mCanvas = new Canvas(mBitmap); 
     } 

     @Override 
     protected void onDraw(Canvas canvas) { 
      canvas.drawColor(0xFFAAAAAA); 

      canvas.drawBitmap(mBitmap, 0, 0, mBitmapPaint); 

      canvas.drawPath(mPath, mPaint); 
     } 

     private float mX, mY; 
     private static final float TOUCH_TOLERANCE = 4; 

     private void touch_start(float x, float y) { 
      mPath.reset(); 
      mPath.moveTo(x, y); 
      mX = x; 
      mY = y; 
     } 
     private void touch_move(float x, float y) { 
      float dx = Math.abs(x - mX); 
      float dy = Math.abs(y - mY); 
      if (dx >= TOUCH_TOLERANCE || dy >= TOUCH_TOLERANCE) { 
       mPath.quadTo(mX, mY, (x + mX)/2, (y + mY)/2); 
       mX = x; 
       mY = y; 
      } 
     } 
     private void touch_up() { 
      mPath.lineTo(mX, mY); 
      // commit the path to our offscreen 
      mCanvas.drawPath(mPath, mPaint); 
      // kill this so we don't double draw 
      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: 
        touch_move(x, y); 
        invalidate(); 
        break; 
       case MotionEvent.ACTION_UP: 
        touch_up(); 
        invalidate(); 
        break; 
      } 
      return true; 
     } 
    } 

    private static final int COLOR_MENU_ID = Menu.FIRST; 
    private static final int EMBOSS_MENU_ID = Menu.FIRST + 1; 
    private static final int BLUR_MENU_ID = Menu.FIRST + 2; 
    private static final int ERASE_MENU_ID = Menu.FIRST + 3; 
    private static final int SRCATOP_MENU_ID = Menu.FIRST + 4; 

    @Override 
    public boolean onCreateOptionsMenu(Menu menu) { 
     super.onCreateOptionsMenu(menu); 

     menu.add(0, COLOR_MENU_ID, 0, "Color").setShortcut('3', 'c'); 
     menu.add(0, EMBOSS_MENU_ID, 0, "Emboss").setShortcut('4', 's'); 
     menu.add(0, BLUR_MENU_ID, 0, "Blur").setShortcut('5', 'z'); 
     menu.add(0, ERASE_MENU_ID, 0, "Erase").setShortcut('5', 'z'); 
     menu.add(0, SRCATOP_MENU_ID, 0, "SrcATop").setShortcut('5', 'z'); 

     /**** Is this the mechanism to extend with filter effects? 
     Intent intent = new Intent(null, getIntent().getData()); 
     intent.addCategory(Intent.CATEGORY_ALTERNATIVE); 
     menu.addIntentOptions(
           Menu.ALTERNATIVE, 0, 
           new ComponentName(this, NotesList.class), 
           null, intent, 0, null); 
     *****/ 
     return true; 
    } 

    @Override 
    public boolean onPrepareOptionsMenu(Menu menu) { 
     super.onPrepareOptionsMenu(menu); 
     return true; 
    } 

    @Override 
    public boolean onOptionsItemSelected(MenuItem item) { 
     mPaint.setXfermode(null); 
     mPaint.setAlpha(0xFF); 

     switch (item.getItemId()) { 
      case COLOR_MENU_ID: 
       new ColorPickerDialog(this, this, mPaint.getColor()).show(); 
       return true; 
      case EMBOSS_MENU_ID: 
       if (mPaint.getMaskFilter() != mEmboss) { 
        mPaint.setMaskFilter(mEmboss); 
       } else { 
        mPaint.setMaskFilter(null); 
       } 
       return true; 
      case BLUR_MENU_ID: 
       if (mPaint.getMaskFilter() != mBlur) { 
        mPaint.setMaskFilter(mBlur); 
       } else { 
        mPaint.setMaskFilter(null); 
       } 
       return true; 
      case ERASE_MENU_ID: 
       mPaint.setXfermode(new PorterDuffXfermode(
                 PorterDuff.Mode.CLEAR)); 
       return true; 
      case SRCATOP_MENU_ID: 
       mPaint.setXfermode(new PorterDuffXfermode(
                PorterDuff.Mode.SRC_ATOP)); 
       mPaint.setAlpha(0x80); 
       return true; 
     } 
     return super.onOptionsItemSelected(item); 
    } 
}