android UI效果三: 滚动切换屏幕

效果如下:

主要有3个类1个layout:

Activity: ScrollViewTestActivity, 两个自定义View, 1个 ScrollView用来控制滑动效果, 1个PageControlView,用来控制下方显示的处在第几屏.

1个mian.xml

Activity:

import android.app.Activity; import android.os.Bundle; import android.view.View; import android.widget.ImageView; public class ScrollViewTestActivity extends Activity { /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super .onCreate(savedInstanceState); setContentView(R.layout.main); ScrollView sv = (ScrollView)findViewById(R.id.scroll); ImageView iv = new ImageView( this ); iv.setImageDrawable( this .getResources().getDrawable(R.drawable.a1)); sv.addView(iv); sv.addView(View.inflate( this , R.layout.layout_0, null )); ImageView iv2 = new ImageView( this ); iv2.setImageDrawable(getResources().getDrawable(R.drawable.a2)); sv.addView(iv2); PageControlView pageControl = (PageControlView)findViewById(R.id.pageControl); sv.setOnScreenChangeListener(pageControl); sv.initPageControlView(); } }

　ScrollView:

import android.content.Context; import android.util.AttributeSet; import android.view.GestureDetector; import android.view.GestureDetector.SimpleOnGestureListener; import android.view.MotionEvent; import android.view.View; import android.view.ViewConfiguration; import android.view.ViewGroup; import android.widget.Scroller; public class ScrollView extends ViewGroup{ private GestureDetector gesture; private Context context; private boolean fling; private Scroller scroller; private OnScreenChangeListener onScreenChangeListener; public ScrollView(Context context) { super (context); this .context = context; gesture = new GestureDetector(context, new GestureListener()); scroller = new Scroller(context); } public ScrollView(Context context,AttributeSet att){ super (context,att); this .context = context; gesture = new GestureDetector(context, new GestureListener()); scroller = new Scroller(context); } @Override protected void onLayout( boolean changed, int l, int t, int r, int b) { for ( int i= 0 ;i<getChildCount();i++){ View child = (View)getChildAt(i); child.measure(r-l, b-t); child.layout(getWidth()*i, 0 , getWidth()*(i+ 1 ), getHeight()); } } @Override public boolean onTouchEvent(MotionEvent ev){ gesture.onTouchEvent(ev); switch (ev.getAction()){ case MotionEvent.ACTION_MOVE: break ; case MotionEvent.ACTION_UP: System.out.println( "action_up..." ); if (!fling){ scrollToScreen(); } fling = false ; break ; } return true ; } /** * 用来计算拖动一段距离后，要显示哪个界面 */ private void scrollToScreen(){ int leftWidth = getScrollX(); int tabs = leftWidth/getWidth(); int len = leftWidth - tabs*getWidth(); if (len<getWidth()/ 2 ){ // scrollTo(tabs*getWidth(),0); scroller.startScroll(leftWidth, 0 , -len, 0 , len* 2 ); } else { // scrollTo((tabs+1)*getWidth(),0); scroller.startScroll(leftWidth, 0 , getWidth()-len, 0 , len* 2 ); tabs = tabs + 1 ; } if (onScreenChangeListener!= null ){ onScreenChangeListener.screenChange(tabs, getChildCount()); } invalidate(); } @Override public void computeScroll() { if (scroller.computeScrollOffset()) { scrollTo(scroller.getCurrX(), 0 ); postInvalidate(); } } class GestureListener extends SimpleOnGestureListener{ @Override public boolean onDoubleTap(MotionEvent e){ return super .onDoubleTap(e); } @Override public boolean onDown(MotionEvent e){ return super .onDown(e); } @Override public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY){ if (Math.abs(velocityX)>ViewConfiguration.get(context).getScaledMinimumFlingVelocity()){ scrollToScreen(); fling = true ; } return true ; } @Override public void onShowPress(MotionEvent e){ super .onShowPress(e); } @Override public void onLongPress(MotionEvent e){ super .onLongPress(e); } @Override public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY){ if (distanceX> 0 &&getScrollX()<(getChildCount()- 1 )*getWidth()|| distanceX< 0 &&getScrollX()> 0 ){ scrollBy(( int )distanceX, 0 ); } return true ; } @Override public boolean onSingleTapUp(MotionEvent e){ return super .onSingleTapUp(e); } } public interface OnScreenChangeListener { void screenChange( int currentTab, int totalTab); } public void setOnScreenChangeListener(OnScreenChangeListener onScreenChangeListener){ this .onScreenChangeListener = onScreenChangeListener; } public void initPageControlView(){ if (onScreenChangeListener!= null ){ onScreenChangeListener.screenChange( 0 , getChildCount()); } } }

　　PageControlView:

import com.yang.testscroll.ScrollView.OnScreenChangeListener; import android.content.Context; import android.util.AttributeSet; import android.widget.ImageView; import android.widget.LinearLayout; public class PageControlView extends LinearLayout implements OnScreenChangeListener{ private Context context; public PageControlView(Context context) { super (context); this .context = context; } public PageControlView(Context context,AttributeSet attr){ super (context,attr); this .context = context; } @Override public void screenChange( int currentTab, int totalTab) { this .removeAllViews(); for ( int i= 0 ;i<totalTab;i++){ ImageView iv = new ImageView(context); if (i==currentTab){ iv.setImageResource(R.drawable.page_indicator_focused); } else { iv.setImageResource(R.drawable.page_indicator); } this .addView(iv); } } }

main.xml:

<?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"    android:orientation="vertical" >    <com.yang.testscroll.ScrollView        android:id="@+id/scroll"        android:layout_width="fill_parent"        android:layout_height="fill_parent" />        <com.yang.testscroll.PageControlView        android:id="@+id/pageControl"        android:layout_width="fill_parent"        android:layout_height="40dp"        android:layout_alignParentBottom="true"        android:background="#8f00000f"         android:gravity="center"/>    </RelativeLayout>

复制代码

http://www.cnblogs.com/yyyyy5101/archive/2012/01/12/2320587.html

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