Android小应用-画画夹

public class MainActivity extends Activity {	private ImageView iv;	float startX = 0;	float startY = 0;	//获得一个可以被bitmap	Bitmap bitmap = Bitmap.createBitmap(400, 400,Bitmap.Config.ARGB_8888);	//创建画布	Canvas canvas = new Canvas(bitmap);	//创建画笔	Paint paint = new Paint();		@Override	protected void onCreate(Bundle savedInstanceState) {		super.onCreate(savedInstanceState);		setContentView(R.layout.activity_main);		iv = (ImageView) this.findViewById(R.id.iv);				paint.setColor(Color.BLACK);		paint.setStrokeWidth(1);//设置像素				iv.setOnTouchListener(new OnTouchListener() {			@Override			public boolean onTouch(View v, MotionEvent event) {				switch (event.getAction()) {					case MotionEvent.ACTION_DOWN:						startX = event.getX();						startY = event.getY();						break;					case MotionEvent.ACTION_MOVE:						float newX = event.getX();						float newY = event.getY();						canvas.drawLine(startX, startY, newX, newY, paint);						iv.setImageBitmap(bitmap);						break;					case MotionEvent.ACTION_UP:						break;					default:						break;				}				return true;			}		});	}			@Override	public boolean onCreateOptionsMenu(Menu menu) {		// Inflate the menu; this adds items to the action bar if it is present.		getMenuInflater().inflate(R.menu.main, menu);		return true;	}}