简单封装PagerAdapter以支持多种类型的视图

public abstract class MultifariousPageAdapter extends PagerAdapter {

// log_begin

private static final DetailedLog Log = new DetailedLog();

private static final String LOG_TAG = Common.LOG_TAG;

// log_end

private LayoutInflater inflater = null;

protected abstract LayoutInflater getInflater();

protected abstract int getItemViewType(int position);

protected abstract int getLayoutId(int position, int itemViewType);

protected abstract int[] getViewIds(int position, int layoutId);

protected abstract void handleView(int position, View v, View parent);

private SparseArray<ArrayList<View>> viewCache = new SparseArray<ArrayList<View>>();

/**

重点看这里

**/

@Override

public Object instantiateItem(ViewGroup arg0, int arg1) {

if (inflater == null) {

inflater = getInflater();

}

View convertView = null;

//取到视图类型

int itemViewType = getItemViewType(arg1);

ArrayList<View> convertViews = viewCache.get(itemViewType);

ArrayList<View> views = null;

if (convertViews == null || convertViews.isEmpty()) {

//取到视图布局id

int layoutId = getLayoutId(arg1, itemViewType);

convertView = inflater.inflate(layoutId, null);

if (convertView != null) {

int[] viewIds = getViewIds(arg1, layoutId);

if (viewIds != null && viewIds.length != 0) {

views = new ArrayList<View>();

for (Integer viewId : viewIds) {

View view = convertView.findViewById(viewId);

if (view != null) {

views.add(view);

} else {

throw new NullPointerException("layout(id:"

+ layoutId + ") findViewById(" + viewId

+ ")");

}

}

convertView.setTag(views);

}

} else {

throw new NullPointerException("inflate layout(id:" + layoutId

+ ")");

}

} else {

// 重用视图

convertView = convertViews.remove(convertViews.size() - 1);

views = (ArrayList<View>) convertView.getTag();

}

if (views != null) {

for (View v : views) {

handleView(arg1, v, convertView);

}

}

arg0.addView(convertView);

return convertView;

}

/**重点看这里**/

@Override

public void destroyItem(ViewGroup arg0, int arg1, Object arg2) {

View view = (View) arg2;

arg0.removeView(view);

//缓存视图以重用

int itemViewType = getItemViewType(arg1);

ArrayList<View> convertViews = viewCache.get(itemViewType);

if (convertViews == null) {

convertViews = new ArrayList<View>();

viewCache.put(itemViewType, convertViews);

}

convertViews.add(view);

}

@Override

public boolean isViewFromObject(View arg0, Object arg1) {

return arg0 == arg1;

}

@Override

public void restoreState(Parcelable arg0, ClassLoader arg1) {

}

@Override

public Parcelable saveState() {

return null;

}

@Override

public void startUpdate(View arg0) {

}

@Override

public void finishUpdate(View arg0) {

}

}

用例

public class MainActivity extends Activity {

/**

* The {@link android.support.v4.view.PagerAdapter} that will provide

* fragments for each of the sections. We use a

* {@link android.support.v4.app.FragmentPagerAdapter} derivative, which

* will keep every loaded fragment in memory. If this becomes too memory

* intensive, it may be best to switch to a

* {@link android.support.v4.app.FragmentStatePagerAdapter}.

*/

MultifariousPageAdapter mSectionsPagerAdapter;

//经过缓存重用，这里定义了3000个页面也没问题

int pageCount = 3000;

/**

* The {@link ViewPager} that will host the section contents.

*/

ViewPager mViewPager;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

// Create the adapter that will return a fragment for each of the three

// primary sections of the app.

/**使用方法重点看这里**/

mSectionsPagerAdapter = new MultifariousPageAdapter() {

@Override

public int getCount() {

// TODO 自动生成的方法存根

return pageCount;

}

@Override

protected void handleView(int position, View v, View parent) {

// TODO 自动生成的方法存根

Toast.makeText(

MainActivity.this,

"position=" + position + ",v=" + v + ",parent="

+ parent, Toast.LENGTH_LONG).show();

switch (v.getId()) {

case R.id.page1_label:

// ((TextView) v).setText("这是页面"+ Integer.toString(position

// + 1));

break;

default:

break;

}

}

//提供视图中的view id

@Override

protected int[] getViewIds(int position, int layoutId) {

// TODO 自动生成的方法存根

switch (layoutId) {

case R.layout.page1:

return new int[] { R.id.page1_label };

default:

break;

}

return null;

}

// 根据视图类型提供layout id

@Override

protected int getLayoutId(int position, int itemViewType) {

// TODO 自动生成的方法存根

switch (itemViewType) {

case 0:

return R.layout.page1;

case 1:

return R.layout.page2;

case 2:

return R.layout.page3;

case 3:

return R.layout.page4;

case 4:

return R.layout.page5;

case 5:

return R.layout.page6;

default:

return 0;

}

}

@Override

protected LayoutInflater getInflater() {

// TODO 自动生成的方法存根

return LayoutInflater.from(MainActivity.this);

}

@Override

public CharSequence getPageTitle(int position) {

// TODO 自动生成的方法存根

return Integer.toString(position + 1);

}

// 共有0、1、2、3、4、5 共6种视图类型

@Override

protected int getItemViewType(int position) {

// TODO 自动生成的方法存根

return position % 6;

}

};

// Set up the ViewPager with the sections adapter.

mViewPager = (ViewPager) findViewById(R.id.pager);

mViewPager.setAdapter(mSectionsPagerAdapter);

}

@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;

}

……

}

完整例子：http://download.csdn.net/detail/z13759561330/8660511

APK：http://download.csdn.net/detail/z13759561330/8660549