Android中ViewPager中动态生成…

在Android  APP设计中，经常会用到引导菜单，关于引导页面的设计，大家都很熟悉会用ViewPager。看下下面这个例子，今天要说的就是最下面的小圆点。一般的设计思路是：在ViewPager下直接写上小圆点的布局就ok啊。且看下面代码：

<?xml version="1.0" encoding="utf-8"?>  <FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="fill_parent"    android:layout_height="fill_parent"    android:orientation="vertical"     >        <android.support.v4.view.ViewPager        android:id="@+id/welcome"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_gravity="center">    </android.support.v4.view.ViewPager>        <!-- set the layout bottom  little circle -->    <LinearLayout         android:layout_width="match_parent"        android:layout_height="match_parent"        android:orientation="horizontal">        <LinearLayout             android:layout_width="fill_parent"            android:layout_height="wrap_content"            android:layout_gravity="bottom"            android:layout_marginBottom="30dp"            android:gravity="center_horizontal"            >            <ImageView android:id="@+id/imview0"                android:layout_width="wrap_content"                android:layout_height="wrap_content"                android:scaleType="matrix"                android:src="@drawable/page_now"/>             <ImageView android:id="@+id/imview1"                android:layout_width="wrap_content"                android:layout_height="wrap_content"                android:scaleType="matrix"                android:layout_marginLeft="10dp"                android:src="@drawable/page"/>             <ImageView android:id="@+id/imview2"                android:layout_width="wrap_content"                android:layout_height="wrap_content"                android:scaleType="matrix"                android:layout_marginLeft="10dp"                android:src="@drawable/page"/>             <ImageView android:id="@+id/imview3"                android:layout_width="wrap_content"                android:layout_height="wrap_content"                android:scaleType="matrix"                android:layout_marginLeft="10dp"                android:src="@drawable/page"/>             <ImageView android:id="@+id/imview4"                android:layout_width="wrap_content"                android:layout_height="wrap_content"                android:scaleType="matrix"                android:layout_marginLeft="10dp"                android:src="@drawable/page"/>        </LinearLayout>    </LinearLayout></FrameLayout>

 

        但是这样设计有一个缺陷，就是当我们的引导页数目变化时不好操作，需要每次都去更改下xml文件里的圆点数目，这样无疑不利于后期开发。所以我们可以考虑采用动态生成下面的圆点的方法来解决这个问题，这样当上面的引导页数目变化时，不需要去修改xml文件。
   

Bitmap bitmap = BitmapFactory.decodeResource(getResources(),R.drawable.page);             for (int i =0; i < mArrayList.size(); i++) {               Button bt = new Button(this);               bt.setLayoutParams(new ViewGroup.LayoutParams(bitmap.getWidth(),bitmap.getHeight()));               bt.setBackgroundResource(R.drawable.page);               bt.setRight(10);             mLinearLayout.addView(bt);             }  

这里的mViewList就是指上边的引导页，

ArrayList<View> mArrayList = new ArrayList<View>();

完整实现代码：

public class Welcome extends Activity{private ViewPager pager;ArrayList<View> mArrayList = new ArrayList<View>();LayoutInflater mInflater;LinearLayout mLinearLayout;Button mSeletedButton; @Overrideprotected void onCreate(Bundle savedInstanceState) {// TODO Auto-generated method stubsuper.onCreate(savedInstanceState);setContentView(R.layout.welcome);       pager = (ViewPager) findViewById(R.id.welcome);mInflater = getLayoutInflater();View view1 = mInflater.inflate(R.layout.wel1, null);View view2 = mInflater.inflate(R.layout.wel2, null);View view3 = mInflater.inflate(R.layout.wel3, null);View view4 = mInflater.inflate(R.layout.wel5, null);mArrayList.add(view1);mArrayList.add(view2);mArrayList.add(view3);mArrayList.add(view4);mLinearLayout = (LinearLayout) findViewById(R.id.ll_num);PagerAdapter mPagerAdapter = new PagerAdapter() {@Overridepublic boolean isViewFromObject(View arg0, Object arg1) {// TODO Auto-generated method stubreturn arg0 == arg1;}@Overridepublic int getCount() {// TODO Auto-generated method stubreturn mArrayList.size();}@Overridepublic void destroyItem(View container, int position, Object object) {// TODO Auto-generated method stub((ViewPager)container).removeView(mArrayList.get(position));}@Overridepublic Object instantiateItem(View container, int position) {// TODO Auto-generated method stub((ViewPager)container).addView(mArrayList.get(position));return mArrayList.get(position);}};pager.setAdapter(mPagerAdapter);Bitmap bitmap = BitmapFactory.decodeResource(getResources(),R.drawable.page);             for (int i =0; i < mArrayList.size(); i++) {             Button bt = new Button(this);             bt.setLayoutParams(new ViewGroup.LayoutParams(bitmap.getWidth(),bitmap.getHeight()));             bt.setBackgroundResource(R.drawable.page);             bt.setRight(10);           mLinearLayout.addView(bt);         }                 pager.setOnPageChangeListener(new OnPageChangeListener() {@Overridepublic void onPageSelected(int position) {// TODO Auto-generated method stubif (mSeletedButton != null) {mSeletedButton.setBackgroundResource(R.drawable.page);}Button currentButton = (Button) mLinearLayout.getChildAt(position);currentButton.setBackgroundResource(R.drawable.page_now);mSeletedButton = currentButton;Log.i("lyc", "current item:"+position);}@Overridepublic void onPageScrolled(int arg0, float arg1, int arg2) {// TODO Auto-generated method stub}@Overridepublic void onPageScrollStateChanged(int arg0) {// TODO Auto-generated method stub}});}}