Android实现画板、写字板功能（附源码下载）

<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>

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;  } });}