Android实现画板工具 (实现涂写、清除、擦除、保存功能) |
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Android实现画板工具 (实现涂写、清除、擦除、保存功能)
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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：
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 // 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：
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