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

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" >

android:id="@ id/iv_drawingBoard"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:src="@drawable/bg"/>

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。