画画板

public class MainActivity extends Activity {private ImageView iv;int startX;int startY;private Canvas canvas;private Paint paint;private Bitmap bmCopy;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);//加载画画板的背景图Bitmap bmSrc = BitmapFactory.decodeResource(getResources(), R.drawable.bg);bmCopy = Bitmap.createBitmap(bmSrc.getWidth(), bmSrc.getHeight(), bmSrc.getConfig());paint = new Paint();canvas = new Canvas(bmCopy);//绘制canvas.drawBitmap(bmSrc, new Matrix(), paint);iv = (ImageView) findViewById(R.id.iv);iv.setImageBitmap(bmCopy);//设置触摸侦听iv.setOnTouchListener(new OnTouchListener() {//触摸屏幕时，触摸事件产生时，此方法调用@Overridepublic boolean onTouch(View v, MotionEvent event) {int action = event.getAction();switch (action) {//用户手指摸到屏幕case MotionEvent.ACTION_DOWN:startX = (int) event.getX();startY = (int) event.getY();break;//用户手指正在滑动case MotionEvent.ACTION_MOVE:int x = (int) event.getX();int y = (int) event.getY();canvas.drawLine(startX, startY, x, y, paint);//每次绘制完毕之后，本次绘制的结束坐标变成下一次绘制的初始坐标startX = x;startY = y;iv.setImageBitmap(bmCopy);break;//用户手指离开屏幕case MotionEvent.ACTION_UP:break;}//true：告诉系统，这个触摸事件由我来处理//false：告诉系统，这个触摸事件我不处理，这时系统会把触摸事件传递给imageview的父节点return true;}});}public void red(View v){paint.setColor(Color.RED);}public void green(View v){paint.setColor(Color.GREEN);}public void brush(View v){paint.setStrokeWidth(7);}public void save(View v){File file = new File("sdcard/dazuo.png");FileOutputStream fos = null;try {fos = new FileOutputStream(file);} catch (FileNotFoundException e) {// TODO Auto-generated catch blocke.printStackTrace();}bmCopy.compress(CompressFormat.PNG, 100, fos);//发送sd卡就绪广播Intent intent = new Intent();intent.setAction(Intent.ACTION_MEDIA_MOUNTED);intent.setData(Uri.fromFile(Environment.getExternalStorageDirectory()));sendBroadcast(intent);}}