Android 实现涂鸦笔效果_android paint 蜡笔效果

1、主要可以通过手指绘制各种图案、还可以清除回撤等效果，实现比较简单。

2、主要实现代码，功能实现比较简单。

package com.example.mytestproject;
 
 
import android.content.Context;
import android.graphics.BlurMaskFilter;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.drawable.Drawable;
import android.util.AttributeSet;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;
import androidx.annotation.Nullable;
import java.util.ArrayList;
import java.util.List;
 
public class DrawView extends View {
    public float mCurrentX = 40;
    public float mCurrentY = 50;
    private float mDownX;
    private float mDownY;
    private Paint mPaint;
    private Line mCurrentLine = new Line();
    private ArrayList<Line> lines = new ArrayList<>();
    private float mLastMoveX = 0;
    private float mLastMoveY = 0;
    private int mSpace;
    private Matrix mMatrix;
    private Drawable[] mDrawables = new Drawable[3];
    private List<Line> mCheLines = new ArrayList<>();
    private int mResetPosition = 0;
 
    public DrawView(Context context) {
        this(context, null);
    }
 
    public DrawView(Context context, @Nullable AttributeSet attrs) {
        this(context, attrs, 0);
    }
 
    public DrawView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
 
        // mPaint.setShader(new BitmapShader(mBitmap, Shader.TileMode.CLAMP, Shader.TileMode.MIRROR));
//        BlurMaskFilter maskFilter = new BlurMaskFilter(10, BlurMaskFilter.Blur.NORMAL);
//        mPaint.setMaskFilter(maskFilter);
        //Shader shader0 = new BitmapShader(mBitmap, Shader.TileMode.REPEAT, Shader.TileMode.REPEAT);
//        Shader shader = new LinearGradient(0, 0, 30, 0, new int[]{Color.WHITE, Color.RED, Color.RED}, new float[]{0f, 0.5f, 1f}, Shader.TileMode.REPEAT);
//        Shader shader1 = new RadialGradient(10, 10, 10, new int[]{Color.GREEN, Color.WHITE, Color.GREEN}, new float[]{0, 0.5f, 1}, Shader.TileMode.MIRROR);
//        Shader shader2 = new SweepGradient(15, 15, Color.RED, Color.BLUE);
//        Shader shader3 = new ComposeShader(shader, shader1, PorterDuff.Mode.MULTIPLY);
//        mMatrix = new Matrix();
//        mLinearGradient.setLocalMatrix(mMatrix);
        //  mPaint.setShader(shader);
 
        BlurMaskFilter PaintBGBlur = new BlurMaskFilter(10, BlurMaskFilter.Blur.SOLID);
        mPaint = new Paint();
        mPaint.setStyle(Paint.Style.STROKE);
        mPaint.setStrokeCap(Paint.Cap.ROUND);
        mPaint.setMaskFilter(PaintBGBlur);
        //mPaint.setAntiAlias(true);
        mPaint.setColor(Color.RED);
        mDrawables[0] = getResources().getDrawable(R.mipmap.star_big_off);
        mDrawables[1] = getResources().getDrawable(R.mipmap.star_big_on);
        mDrawables[2] = getResources().getDrawable(R.mipmap.rate_star_med_on_holo_light);
 
        mSpace = mDrawables[0].getIntrinsicWidth();
        mPaint.setStrokeWidth(mDrawables[0].getIntrinsicWidth());
    }
 
 
    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        for (int i = 0; i < lines.size(); i++) {
            drawLine(canvas, lines.get(i));
        }
        drawLine(canvas, mCurrentLine);
    }
 
    private void drawLine(Canvas canvas, Line line) {
        for (int i = 0; i < line.points.size() - 1; i++) {
            float x = line.points.get(i).x;
            float y = line.points.get(i).y;
            int size = mDrawables.length;
            int surplus = i%size;
            for (int j=0;j<size;j++){
                if (surplus==j){
                    mDrawables[j].setBounds((int) x, (int) y, (int) x + mDrawables[j].getIntrinsicWidth(), (int) y + mDrawables[j].getIntrinsicHeight());
                    mDrawables[j].draw(canvas);
                    break;
                }
            }
        }
    }
 
    @Override
    public boolean onTouchEvent(MotionEvent event) {
 
        switch (event.getAction()) {
 
            case MotionEvent.ACTION_DOWN:
                mDownX = event.getX();
                mDownY = event.getY();
                mLastMoveX = mDownX;
                mLastMoveY = mDownY;
                break;
 
            case MotionEvent.ACTION_MOVE:
                mCurrentX = event.getX();
                mCurrentY = event.getY();
                if (Math.abs(mCurrentX - mLastMoveX) > mSpace || Math.abs(mCurrentY - mLastMoveY) > mSpace) {
                    ViewPoint point = new ViewPoint();
                    point.x = mCurrentX;
                    point.y = mCurrentY;
                    mCurrentLine.points.add(point);
                    mLastMoveX = mCurrentX;
                    mLastMoveY = mCurrentY;
                }
 
                break;
 
            case MotionEvent.ACTION_UP:
                lines.add(mCurrentLine);
                mCheLines.add(mCurrentLine);
                mCurrentLine = new Line();
                mResetPosition = mCheLines.size();
                break;
 
        }
        invalidate();
        return true;
    }
 
    public void last() {
        mResetPosition--;
        if (mResetPosition <= 0) {
            mResetPosition = 0;
        }
        lines.clear();
        for (int i = 0; i < mResetPosition; i++) {
            lines.add(mCheLines.get(i));
        }
        invalidate();
    }
 
    public void next() {
        mResetPosition++;
        if (mResetPosition >= mCheLines.size()) {
            mResetPosition = mCheLines.size();
        }
        lines.clear();
 
        for (int i = 0; i < mResetPosition; i++) {
            lines.add(mCheLines.get(i));
        }
        invalidate();
    }
 
 
    public void clear() {
        mCheLines.clear();
        lines.clear();
        mCurrentLine.points.clear();
        invalidate();
    }
}