前言

本文给大家分享一个使用Android开发写字板功能Dem、简单操作内存中的图像、对图像进行简单的处理、绘制直线、以达到写字板的效果

效果图如下

XML布局代码

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" android:paddingBottom="@dimen/activity_vertical_margin" android:paddingLeft="@dimen/activity_horizontal_margin" android:paddingRight="@dimen/activity_horizontal_margin" android:paddingTop="@dimen/activity_vertical_margin" tools:context="com.tomes.paint.MainActivity" > <ImageView android:id="@ id/iv_drawingBoard" android:layout_width="wrap_content" android:layout_height="wrap_content" android:src="@drawable/bg"/></RelativeLayout>

Java代码

public void init() { Bitmap bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.bg); copyBitmap = Bitmap.createBitmap(bitmap.getWidth(), bitmap.getHeight(), bitmap.getConfig()); paint = new Paint(); canvas = new Canvas(copyBitmap); Matrix matrix=new Matrix(); canvas.drawBitmap(bitmap, matrix, paint); imageView = (ImageView) findViewById(R.id.iv_drawingBoard); imageView.setImageBitmap(copyBitmap); imageView.setOnTouchListener(new OnTouchListener() { @SuppressLint("ClickableViewAccessibility") @Override public boolean onTouch(View v, MotionEvent event) { int action = event.getAction(); switch (action) { case MotionEvent.ACTION_DOWN: startX=event.getX(); startY=event.getY(); break; case MotionEvent.ACTION_MOVE: float currentX=event.getX(); float currentY=event.getY(); canvas.drawLine(startX, startY, currentX, currentY, paint); imageView.setImageBitmap(copyBitmap); startX=currentX; startY=currentY; break; case MotionEvent.ACTION_UP: break; } return true; } });}

源码下载：点击这里

总结

以上就是这篇文章的全部内容了，希望本文的内容对各位Android开发者们能带来一定的帮助，如果有疑问大家可以留言交流。