在上一篇基础知识上实现的简单的画板工具:
Android 移动开发 | 图形与图像处理–剖析三个绘图工具类–实现Android 机器人绘制案例
一. 效果预览：
二. 实现代码：
1. MyPaintToolsActivity：
自定义一个空的Activity为MyPaintToolsActivity，写入下面代码：
package com.example.draw;
import androidx.appcompat.app.AppCompatActivity;
import android.annotation.SuppressLint;
import android.content.Intent;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.Point;
import android.graphics.PorterDuff;
import android.graphics.PorterDuffXfermode;
import android.net.Uri;
import android.os.Bundle;
import android.os.Environment;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;
import android.widget.Button;
import android.widget.CompoundButton;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import android.widget.SeekBar;
import android.widget.TextView;
import android.widget.Toast;
import java.io.File;
import java.io.FileOutputStream;
import java.io.OutputStream;
public class MyPaintToolsActivity extends AppCompatActivity{
Paint paint;
Canvas canvas;
ImageView imageview;
Bitmap bitmap,newbitmap;
TextView tv_stroke;
int startX, startY, endX, endY;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_my_paint_tools);
tv_stroke = findViewById(R.id.tv_stroke);
LinearLayout ll_layout = findViewById(R.id.ll_layout);
RadioGroup rg_color = findViewById(R.id.rg_color);
// 原始Bitmap
// originalBitmap = BitmapFactory.decodeResource(getResources(),R.drawable.j).copy(Bitmap.Config.ARGB_8888,true);
// 循环遍历单选按钮
for (int i = 0;i<rg_color.getChildCount();i++){
RadioButton rb = (RadioButton) rg_color.getChildAt(i);
rb.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
// 为单选按钮注册选中响应事件
@Override
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
if (buttonView.isChecked()){
paint.setColor(buttonView.getTextColors().getDefaultColor()); // 获取单选按钮颜色并将颜色设置
}
}
});
}
imageview = findViewById(R.id.imageview);
Log.i("MyPaintToolsActivity",imageview.getWidth()+" "+imageview.getHeight());
Point point = new Point();
getWindowManager().getDefaultDisplay().getSize(point);
Log.i("MyPaintToolsActivity",point.x+" "+point.y);
bitmap = Bitmap.createBitmap(800,1000,Bitmap.Config.ARGB_8888); // 创建一张空白图片
canvas = new Canvas(bitmap); // 创建一张画布,并图片放在画布上面
canvas.drawColor(Color.argb(100,250,250,250)); // 设置画布背景颜色为白色
paint = new Paint();
paint.setStrokeWidth(5);
paint.setAntiAlias(true);
paint.setColor(Color.RED);
canvas.drawBitmap(bitmap,new Matrix(),paint); //把灰色背景画在画布上
imageview.setImageBitmap(bitmap); // 把图片加载到ImageView上
// 注册触摸监听事件
imageview.setOnTouchListener(new View.OnTouchListener() {
@Override
public boolean onTouch(View v, MotionEvent event) {
switch(event.getAction()){
case MotionEvent.ACTION_DOWN:
Log.i("MyPaintToolsActivity","ACTION_DOWN");
// 获取鼠标按下时的坐标
startX = (int) (event.getX()/1.4);
startY = (int) (event.getY()/1.4);
break;
case MotionEvent.ACTION_MOVE:
Log.i("MyPaintToolsActivity","ACTION_MOVE");
// 获取鼠标移动后的坐标
endX = (int) (event.getX()/1.4);
endY = (int) (event.getY()/1.4);
//在开始和结束之间画一条直线
canvas.drawLine(startX,startY,endX,endY,paint);
// 实时更新开始坐标
startX = (int) (event.getX()/1.4);
startY = (int) (event.getY()/1.4);
// 更新ImageView上的画布图片
imageview.setImageBitmap(bitmap);
break;
case MotionEvent.ACTION_UP:
Log.i("MyPaintToolsActivity","ACTION_UP");
break;
}
imageview.invalidate();
return true;
}
});
// 清除
Button btn_clear = findViewById(R.id.btn_clear);
btn_clear.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// 清空画布的方法：
// 方法一：
// canvas.drawColor(0,PorterDuff.Mode.CLEAR);
// 方法二：
// canvas.drawColor(Color.TRANSPARENT,PorterDuff.Mode.CLEAR);
// 方法三：
Paint paint =new Paint();
paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.CLEAR));
canvas.drawPaint(paint);
paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC));
imageview.invalidate(); //显示到布局文件中的ImageView控件上
}
});
// 保存
Button btn_save = findViewById(R.id.btn_save);
btn_save.setOnClickListener(new View.OnClickListener() {
@SuppressLint("WrongConstant")
@Override
public void onClick(View v) {
try {
File file = new File(Environment.getExternalStorageDirectory(), System.currentTimeMillis() + ".jpg");
OutputStream stream = new FileOutputStream(file);
bitmap.compress(Bitmap.CompressFormat.JPEG, 100, stream);
stream.close();
Intent intent = new Intent();
intent.setAction(Intent.ACTION_MEDIA_MOUNTED);
intent.setData(Uri.fromFile(Environment.getExternalStorageDirectory()));
sendBroadcast(intent);
Toast.makeText(getApplicationContext(), "保存图片成功", 0).show();
} catch (Exception e) {
Toast.makeText(getApplicationContext(), "保存图片失败", 0).show();
e.printStackTrace();
}
}
});
// 擦除
Button btn_eraser = findViewById(R.id.btn_eraser);
btn_eraser.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
paint.setColor(Color.rgb(250,250,250));
paint.setStrokeWidth(30);
}
});
// Progress进度条 ，调节画笔粗细
SeekBar sb_stroke = findViewById(R.id.sb_stroke);
sb_stroke.setProgress(5); //进度条初始大小值为5
sb_stroke.setMax(30);
sb_stroke.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener(){
@Override
public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
paint.setStrokeWidth(progress);
tv_stroke.setText("画笔粗度为:"+progress);
}
@Override
public void onStartTrackingTouch(SeekBar seekBar) {
}
@Override
public void onStopTrackingTouch(SeekBar seekBar) {
}
});
}
}
2.页面布局activity_my_paint_tools.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"
android:orientation="vertical"
android:id="@+id/ll_layout"
tools:context=".MyPaintToolsActivity">
<ImageView
android:id="@+id/imageview"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="1"/>
<RadioGroup
android:layout_width="match_parent"
android:orientation="horizontal"
android:id="@+id/rg_color"
android:layout_height="wrap_content">
<RadioButton
android:id="@+id/rb_red"
android:layout_width="wrap_content"
android:layout_height="30dp"
android:layout_weight="1"
android:text="红色"
android:textColor="#FF1400"/>
<RadioButton
android:id="@+id/rb_green"
android:layout_width="wrap_content"
android:layout_height="30dp"
android:layout_weight="1"
android:text="绿色"
android:textColor="#02FD07"/>
<RadioButton
android:id="@+id/rb_blue"
android:layout_width="wrap_content"
android:layout_height="30dp"
android:layout_weight="1"
android:text="蓝色"
android:textColor="#0454F8"/>
<RadioButton
android:id="@+id/rb_yellow"
android:layout_width="wrap_content"
android:layout_height="30dp"
android:layout_weight="1"
android:text="黄色"
android:textColor="#F8F004"/>
<RadioButton
android:id="@+id/rb_purple"
android:layout_width="wrap_content"
android:layout_height="30dp"
android:layout_weight="1"
android:text="紫色"
android:textColor="#F803E8"/>
</RadioGroup>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center"
android:layout_marginTop="15dp"
android:orientation="horizontal">
<Button
android:id="@+id/btn_clear"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="#047EFD"
android:textColor="#FFFFFF"
android:textSize="18sp"
android:layout_marginRight="10dp"
android:text="清除"/>
<Button
android:id="@+id/btn_eraser"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textColor="#FFFFFF"
android:textSize="18sp"
android:layout_marginRight="10dp"
android:background="#047EFD"
android:text="擦除"/>
<Button
android:id="@+id/btn_save"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textColor="#FFFFFF"
android:textSize="18sp"
android:layout_marginRight="10dp"
android:background="#047EFD"
android:text="保存"/>
</LinearLayout>
<SeekBar
android:layout_marginTop="10dp"
android:id="@+id/sb_stroke"
android:layout_width="match_parent"
android:layout_height="30dp"
android:progress="5"
android:min="1"
android:max="30"/>
<TextView
android:id="@+id/tv_stroke"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="画笔粗细"
android:layout_marginBottom="30dp"
android:gravity="center"/>
</LinearLayout>