AndroidStudio：设计一个能在图片上涂鸦的程序

浅浅的花香味﹌ 2022-02-23 10:48 341阅读 0赞

一内容：设计一个能在图片上涂鸦的程序

二实现

①布局文件activity\_main.xml

<?xml version="1.0" encoding="utf-8"?>
    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:app="http://schemas.android.com/apk/res-auto"
        xmlns:tools="http://schemas.android.com/tools"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:context=".MainActivity"
        android:orientation="vertical">
    
        <com.example.asus.test442.HandWrite
            android:layout_width="match_parent"
            android:layout_height="550dp"
            android:id="@+id/hw"/>
    
        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="vertical">
            <Button
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:text="clear"
                android:id="@+id/btn"/>
    
        </LinearLayout>
    
    
    </LinearLayout>

②主控文件MainActivity.java

package com.example.asus.test442;
    
    import android.support.v7.app.AppCompatActivity;
    import android.os.Bundle;
    import android.view.View;
    import android.widget.Button;
    
    public class MainActivity extends AppCompatActivity {
        private HandWrite handWrite = null;
        Button clear = null;
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
            handWrite = (HandWrite)findViewById(R.id.hw); //关联view组件
            clear = (Button)findViewById(R.id.btn);
            clear.setOnClickListener(new click());
        }
    
        private class click implements View.OnClickListener {
            @Override
            public void onClick(View view) {
                handWrite.clear();
            }
        }
    }

3记录在屏幕上滑动的轨迹，实现在图片上涂鸦的功能 HandWrite.java

package com.example.asus.test442;
    
    import android.content.Context;
    import android.graphics.Bitmap;
    import android.graphics.BitmapFactory;
    import android.graphics.Canvas;
    import android.graphics.Color;
    import android.graphics.Paint;
    import android.util.AttributeSet;
    import android.view.MotionEvent;
    import android.view.View;
    
    public class HandWrite extends View {
        Paint paint = null;  //定义画笔
        Bitmap origBit = null;  //存放原始图像
        Bitmap new_1Bit = null;   //存放从原始图像复制的位图图像
        Bitmap new_2Bit = null;      //存放处理后的图像
        float startX = 0,startY = 0;   //画线的起点坐标
        float clickX = 0, clickY = 0;   //画线的终点坐标
        boolean isMove = true;   //设置是否画线的标记
        boolean isClear = false;    //设置是否清除涂鸦的标记
        int color = Color.BLUE;    //设置画笔的颜色
        float strokeWidth = 2.0f;    //设置画笔的宽度
        public HandWrite(Context context, AttributeSet attrs) {
            super(context, attrs);
            // 从资源中获取原始图像
            origBit = BitmapFactory.decodeResource(getResources(),R.drawable.p1).copy(Bitmap.Config.ARGB_8888,true);
            // 建立原始图像的位图
            new_1Bit = Bitmap.createBitmap(origBit);
        }
    
        // 清除涂鸦
        public void clear() {
            isClear = true;
            new_2Bit = Bitmap.createBitmap(origBit);
            invalidate();
        }
    
        public void setSyle(float strokeWidth) {
            this.strokeWidth = strokeWidth;
        }
    
        @Override
        protected void onDraw(Canvas canvas) {
            super.onDraw(canvas);
            canvas.drawBitmap(HandWriting(new_1Bit),0,0,null);
        }
    
        private Bitmap HandWriting(Bitmap newBit) {  //记录绘制图形
            Canvas canvas = null;  // 定义画布
            if (isClear) {  // 创建绘制新图形的画布
                canvas = new Canvas(new_2Bit);
            }
            else {
                canvas = new Canvas(newBit);  //创建绘制原图形的画布
            }
    
            paint = new Paint();
            paint.setStyle(Paint.Style.STROKE);
            paint.setAntiAlias(true);
            paint.setColor(color);
            paint.setStrokeWidth(strokeWidth);
    
            if (isMove){
                canvas.drawLine(startX,startY,clickX,clickY,paint);  // 在画布上画线条
            }
            startX = clickX;
            startY = clickY;
    
            if (isClear){
                return new_2Bit;  // 返回新绘制的图像
            }
            return newBit;  // 若清屏，则返回原图像
        }
    
        // 定义触摸屏事件
        @Override
        public boolean onTouchEvent(MotionEvent event) {
            clickX = event.getX();  // 获取触摸坐标位置
            clickY = event.getY();
            if (event.getAction() == MotionEvent.ACTION_DOWN) {  // 按下屏幕时无绘图
                isMove = false;
                invalidate();
                return true;
            } else if (event.getAction() == MotionEvent.ACTION_MOVE) {  // 记录在屏幕上划动的轨迹
                isMove = true;
                invalidate();
                return true;
            }
            return super.onTouchEvent(event);
        }
    }

三效果

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MDE0MTQ3Mw_size_16_color_FFFFFF_t_70][]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MDE0MTQ3Mw_size_16_color_FFFFFF_t_70]: /images/20220223/225969dcc54841d199e979a42e49579d.png