首先自定義一個 ViewGroup: android
- public class MyScrollLayout extends ViewGroup{
-
- private VelocityTracker mVelocityTracker; // 用於判斷甩動手勢
- private static final int SNAP_VELOCITY = 600;
- private Scroller mScroller; // 滑動控制器
- private int mCurScreen;
- private int mDefaultScreen = 0;
- private float mLastMotionX;
- // private int mTouchSlop;
-
- private OnViewChangeListener mOnViewChangeListener;
-
- public MyScrollLayout(Context context) {
- super(context);
- // TODO Auto-generated constructor stub
- init(context);
- }
- public MyScrollLayout(Context context, AttributeSet attrs) {
- super(context, attrs);
- // TODO Auto-generated constructor stub
- init(context);
- }
-
- public MyScrollLayout(Context context, AttributeSet attrs, int defStyle) {
- super(context, attrs, defStyle);
- // TODO Auto-generated constructor stub
- init(context);
- }
-
- private void init(Context context)
- {
- mCurScreen = mDefaultScreen;
- // mTouchSlop = ViewConfiguration.get(getContext()).getScaledTouchSlop();
- mScroller = new Scroller(context);
-
- }
-
- @Override
- protected void onLayout(boolean changed, int l, int t, int r, int b) {
- // TODO Auto-generated method stub
- if (changed) {
- int childLeft = 0;
- final int childCount = getChildCount();
- for (int i=0; i<childCount; i++) {
- final View childView = getChildAt(i);
- if (childView.getVisibility() != View.GONE) {
- final int childWidth = childView.getMeasuredWidth();
- childView.layout(childLeft, 0,
- childLeft+childWidth, childView.getMeasuredHeight());
- childLeft += childWidth;
- }
- }
- }
- }
-
- @Override
- protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
- // TODO Auto-generated method stub
- super.onMeasure(widthMeasureSpec, heightMeasureSpec);
- final int width = MeasureSpec.getSize(widthMeasureSpec);
- final int widthMode = MeasureSpec.getMode(widthMeasureSpec);
-
- final int count = getChildCount();
- for (int i = 0; i < count; i++) {
- getChildAt(i).measure(widthMeasureSpec, heightMeasureSpec);
- }
- scrollTo(mCurScreen * width, 0);
- }
-
- public void snapToDestination() {
- final int screenWidth = getWidth();
- final int destScreen = (getScrollX()+ screenWidth/2)/screenWidth;
- snapToScreen(destScreen);
- }
-
- public void snapToScreen(int whichScreen) {
- // get the valid layout page
- whichScreen = Math.max(0, Math.min(whichScreen, getChildCount()-1));
- if (getScrollX() != (whichScreen*getWidth())) {
- final int delta = whichScreen*getWidth()-getScrollX();
- mScroller.startScroll(getScrollX(), 0,
- delta, 0, Math.abs(delta)*2);
-
- mCurScreen = whichScreen;
- invalidate(); // Redraw the layout
- if (mOnViewChangeListener != null)
- {
- mOnViewChangeListener.OnViewChange(mCurScreen);
- }
- }
- }
-
- @Override
- public void computeScroll() {
- // TODO Auto-generated method stub
- if (mScroller.computeScrollOffset()) {
- scrollTo(mScroller.getCurrX(), mScroller.getCurrY());
- postInvalidate();
- }
- }
-
- @Override
- public boolean onTouchEvent(MotionEvent event) {
- // TODO Auto-generated method stub
- final int action = event.getAction();
- final float x = event.getX();
- final float y = event.getY();
-
- switch (action) {
- case MotionEvent.ACTION_DOWN:
- Log.i("", "onTouchEvent ACTION_DOWN");
- if (mVelocityTracker == null) {
- mVelocityTracker = VelocityTracker.obtain();
- mVelocityTracker.addMovement(event);
- }
- if (!mScroller.isFinished()){
- mScroller.abortAnimation();
- }
- mLastMotionX = x;
- break;
-
- case MotionEvent.ACTION_MOVE:
- int deltaX = (int)(mLastMotionX - x);
- if (IsCanMove(deltaX))
- {
- if (mVelocityTracker != null)
- {
- mVelocityTracker.addMovement(event);
- }
- mLastMotionX = x;
- scrollBy(deltaX, 0);
- }
-
- break;
- case MotionEvent.ACTION_UP:
- int velocityX = 0;
- if (mVelocityTracker != null)
- {
- mVelocityTracker.addMovement(event);
- mVelocityTracker.computeCurrentVelocity(1000);
- velocityX = (int) mVelocityTracker.getXVelocity();
- }
- if (velocityX > SNAP_VELOCITY && mCurScreen > 0) {
- // Fling enough to move left
- snapToScreen(mCurScreen - 1);
- } else if (velocityX < -SNAP_VELOCITY
- && mCurScreen < getChildCount() - 1) {
- // Fling enough to move right
- snapToScreen(mCurScreen + 1);
- } else {
- snapToDestination();
- }
-
- if (mVelocityTracker != null) {
- mVelocityTracker.recycle();
- mVelocityTracker = null;
- }
- // mTouchState = TOUCH_STATE_REST;
- break;
- }
- return true;
- }
-
- private boolean IsCanMove(int deltaX)
- {
- if (getScrollX() <= 0 && deltaX < 0 ){
- return false;
- }
- if (getScrollX() >= (getChildCount() - 1) * getWidth() && deltaX > 0){
- return false;
- }
- return true;
- }
-
- public void SetOnViewChangeListener(OnViewChangeListener listener)
- {
- mOnViewChangeListener = listener;
- }
- }
- public class SwitchViewDemoActivity extends Activity implements OnViewChangeListener, OnClickListener{
- /** Called when the activity is first created. */
-
- private MyScrollLayout mScrollLayout;
- private ImageView[] mImageViews;
- private int mViewCount;
- private int mCurSel;
-
- @Override
- public void onCreate(Bundle savedInstanceState) {
- super.onCreate(savedInstanceState);
- setContentView(R.layout.main);
- init();
-
- }
-
- private void init()
- {
- mScrollLayout = (MyScrollLayout) findViewById(R.id.ScrollLayout);
- LinearLayout linearLayout = (LinearLayout) findViewById(R.id.llayout);
- //動態添加一個layout控件
- LinearLayout layout=new LinearLayout(this);
- layout.setLayoutParams(new LayoutParams(LayoutParams.FILL_PARENT,LayoutParams.FILL_PARENT));
- layout.setBackgroundResource(R.drawable.guide01);
- mScrollLayout.addView(layout);
- //動態添加一個imageView控件
- ImageView imageView=new ImageView(this);
- imageView.setLayoutParams(new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
- imageView.setPadding(15, 15, 15, 15);
- imageView.setImageResource(R.drawable.guide_round);
- linearLayout.addView(imageView);
-
- mViewCount = mScrollLayout.getChildCount();
- mImageViews = new ImageView[mViewCount];
- for(int i = 0; i < mViewCount; i++) {
- mImageViews[i] = (ImageView) linearLayout.getChildAt(i);
- mImageViews[i].setEnabled(true);
- mImageViews[i].setOnClickListener(this);
- mImageViews[i].setTag(i);
- }
- mCurSel = 0;
- mImageViews[mCurSel].setEnabled(false);
- mScrollLayout.SetOnViewChangeListener(this);
-
- }
-
- private void setCurPoint(int index)
- {
- if (index < 0 || index > mViewCount - 1 || mCurSel == index) {
- return ;
- }
- mImageViews[mCurSel].setEnabled(true);
- mImageViews[index].setEnabled(false);
- mCurSel = index;
- }
-
- @Override
- public void OnViewChange(int view) {
- // TODO Auto-generated method stub
- setCurPoint(view);
- }
-
- @Override
- public void onClick(View v) {
- // TODO Auto-generated method stub
- int pos = (Integer)(v.getTag());
- setCurPoint(pos);
- mScrollLayout.snapToScreen(pos);
- }
- }
最後是佈局文件 :
- <?xml version="1.0" encoding="utf-8"?>
- <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
- android:layout_width="fill_parent"
- android:layout_height="fill_parent" >
-
- <cn.com.karl.scroll.MyScrollLayout
- xmlns:android="http://schemas.android.com/apk/res/android"
- android:id="@+id/ScrollLayout"
- android:layout_width="fill_parent"
- android:layout_height="fill_parent" >
-
- <LinearLayout
- android:layout_width="fill_parent"
- android:layout_height="fill_parent"
- android:background="@drawable/guide01" >
- </LinearLayout>
-
- <LinearLayout
- android:layout_width="fill_parent"
- android:layout_height="fill_parent"
- android:background="@drawable/guide02" >
- </LinearLayout>
-
- <LinearLayout
- android:layout_width="fill_parent"
- android:layout_height="fill_parent"
- android:background="@drawable/guide03" >
- </LinearLayout>
-
- <LinearLayout
- android:layout_width="fill_parent"
- android:layout_height="fill_parent"
- android:background="@drawable/guide04" >
- </LinearLayout>
-
- <LinearLayout
- android:layout_width="fill_parent"
- android:layout_height="fill_parent"
- android:background="@drawable/guide05" >
- </LinearLayout>
- </cn.com.karl.scroll.MyScrollLayout>
-
- <LinearLayout
- android:id="@+id/llayout"
- android:layout_width="wrap_content"
- android:layout_height="wrap_content"
- android:layout_alignParentBottom="true"
- android:layout_centerHorizontal="true"
- android:layout_marginBottom="24.0dip"
- android:orientation="horizontal" >
-
- <ImageView
- android:layout_width="wrap_content"
- android:layout_height="wrap_content"
- android:layout_gravity="center_vertical"
- android:clickable="true"
- android:padding="15.0dip"
- android:src="@drawable/guide_round" />
-
- <ImageView
- android:layout_width="wrap_content"
- android:layout_height="wrap_content"
- android:layout_gravity="center_vertical"
- android:clickable="true"
- android:padding="15.0dip"
- android:src="@drawable/guide_round" />
-
- <ImageView
- android:layout_width="wrap_content"
- android:layout_height="wrap_content"
- android:layout_gravity="center_vertical"
- android:clickable="true"
- android:padding="15.0dip"
- android:src="@drawable/guide_round" />
-
- <ImageView
- android:layout_width="wrap_content"
- android:layout_height="wrap_content"
- android:layout_gravity="center_vertical"
- android:clickable="true"
- android:padding="15.0dip"
- android:src="@drawable/guide_round" />
-
- <ImageView
- android:layout_width="wrap_content"
- android:layout_height="wrap_content"
- android:layout_gravity="center_vertical"
- android:clickable="true"
- android:padding="15.0dip"
- android:src="@drawable/guide_round" />
- </LinearLayout>
-
- </RelativeLayout>
看看運行後的效果到底怎麼樣吧!