5、裁剪的一个小用处

[java] view plain

Activity {

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

}

private Bitmap mBitmap;

private int limitLength = 0;

private boolean status = HIDE;//显示还是隐藏的状态，最开始为HIDE

public SampleView(Context context) {

super(context);

mBitmap = BitmapFactory.decodeResource(getResources(), R.drawable.image1);

protected void onDraw(Canvas canvas) {

while (i * CLIP_HEIGHT <= heigth) {//计算clip的区域

, i * CLIP_HEIGHT, limitLength, (i + 1) * CLIP_HEIGHT));

region.union(new Rect(width - limitLength, i * CLIP_HEIGHT, width, (i + 1)

if (status == HIDE) {//如果此时是隐藏

status=SHOW;

if(limitLength>=width)

public class ClippingRegion extends Activity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(new SampleView(this)); } private class SampleView extends View { private Bitmap mBitmap; private int limitLength = 0; private int width; private int heigth; private static final int CLIP_HEIGHT = 30; private boolean status = HIDE;//显示还是隐藏的状态，最开始为HIDE private static final boolean SHOW = true;//显示图片 private static final boolean HIDE = false;//隐藏图片 public SampleView(Context context) { super(context); mBitmap = BitmapFactory.decodeResource(getResources(), R.drawable.image1); limitLength = width = mBitmap.getWidth(); heigth = mBitmap.getHeight(); } @Override protected void onDraw(Canvas canvas) { Region region = new Region(); int i = 0; while (i * CLIP_HEIGHT <= heigth) {//计算clip的区域 if (i % 2 == 0) { region.union(new Rect(0, i * CLIP_HEIGHT, limitLength, (i + 1) * CLIP_HEIGHT)); } else { region.union(new Rect(width - limitLength, i * CLIP_HEIGHT, width, (i + 1) * CLIP_HEIGHT)); } i++; } canvas.clipRegion(region); canvas.drawBitmap(mBitmap, 0, 0, new Paint()); if (status == HIDE) {//如果此时是隐藏 limitLength -= 5; if(limitLength<=0) status=SHOW; } else {//如果此时是显示 limitLength += 5; if(limitLength>=width) status=HIDE; } invalidate(); } } }
效果就是一直这样交叉的隐藏和显示图片

转自