我正在我的应用程序中实现可刷卡标签。我已经实现了一个演示。下面是我的代码，
活动\主.xml
<?xml version="1.0" encoding="utf-8"?>
<TabHost xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@android:id/tabhost"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical" >
<TabWidget
android:id="@android:id/tabs"
android:layout_width="fill_parent"
android:layout_height="wrap_content" />
<FrameLayout
android:id="@android:id/tabcontent"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<FrameLayout
android:id="@+id/tab1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:visibility="gone" />
<FrameLayout
android:id="@+id/tab2"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:visibility="gone" />
<FrameLayout
android:id="@+id/tab3"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:visibility="gone" />
<FrameLayout
android:id="@+id/tab4"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:visibility="gone" />
</FrameLayout>
<android.support.v4.view.ViewPager
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/pager"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</LinearLayout>
</TabHost>
main活动.java
public class MainActivity extends Activity implements OnTabChangeListener, OnPageChangeListener{
private TabHost host;
private ViewPager pager;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
host = (TabHost)findViewById(android.R.id.tabhost);
pager = (ViewPager) findViewById(R.id.pager);
host.setup();
TabSpec spec = host.newTabSpec("tab1");
spec.setContent(R.id.tab1);
spec.setIndicator("Check In");
host.addTab(spec);
spec = host.newTabSpec("tab2");
spec.setContent(R.id.tab2);
spec.setIndicator("Buddies");
host.addTab(spec);
spec = host.newTabSpec("tab3");
spec.setContent(R.id.tab3);
spec.setIndicator("Recommendation");
host.addTab(spec);
spec = host.newTabSpec("tab4");
spec.setContent(R.id.tab4);
spec.setIndicator("Feed");
host.addTab(spec);
pager.setAdapter(new MyPagerAdapter(this));
pager.setOnPageChangeListener(this);
host.setOnTabChangedListener(this);
}
@Override
public void onTabChanged(String tabId){
int pageNumber = 0;
if(tabId.equals("tab1"))
{
pageNumber = 0;
}
else if(tabId.equals("tab2"))
{
pageNumber = 1;
}
else if(tabId.equals("tab3"))
{
pageNumber = 2;
}
else
{
pageNumber = 3;
}
pager.setCurrentItem(pageNumber);
}
@Override
public void onPageSelected(int pageNumber) {
host.setCurrentTab(pageNumber);
}
@Override
public void onPageScrollStateChanged(int arg0) {
// TODO Auto-generated method stub
}
@Override
public void onPageScrolled(int arg0, float arg1, int arg2) {
// TODO Auto-generated method stub
}
}
mypageradapter.java网站
public class MyPagerAdapter extends PagerAdapter {
private Context ctx;
public MyPagerAdapter(Context ctx){
this.ctx = ctx;
}
@Override
public Object instantiateItem(ViewGroup container, int position) {
TextView tView = new TextView(ctx);
position++;
tView.setText("Page number: " + position);
tView.setTextColor(Color.RED);
tView.setTextSize(20);
container.addView(tView);
return tView;
}
@Override
public int getCount() {
return 3;
}
@Override
public boolean isViewFromObject(View view, Object object) {
return (view == object);
}
}
但是当我刷卡的时候我发现了以下的异常情况，
10-15 05:31:43.146: E/AndroidRuntime(1789): java.lang.UnsupportedOperationException: Required method destroyItem was not overridden
10-15 05:31:43.146: E/AndroidRuntime(1789): at android.support.v4.view.PagerAdapter.destroyItem(PagerAdapter.java:192)
10-15 05:31:43.146: E/AndroidRuntime(1789): at android.support.v4.view.PagerAdapter.destroyItem(PagerAdapter.java:124)
10-15 05:31:43.146: E/AndroidRuntime(1789): at android.support.v4.view.ViewPager.populate(ViewPager.java:1002)
10-15 05:31:43.146: E/AndroidRuntime(1789): at android.support.v4.view.ViewPager.populate(ViewPager.java:914)
10-15 05:31:43.146: E/AndroidRuntime(1789): at android.support.v4.view.ViewPager$3.run(ViewPager.java:244)
10-15 05:31:43.146: E/AndroidRuntime(1789): at android.view.Choreographer$CallbackRecord.run(Choreographer.java:749)
10-15 05:31:43.146: E/AndroidRuntime(1789): at android.view.Choreographer.doCallbacks(Choreographer.java:562)
10-15 05:31:43.146: E/AndroidRuntime(1789): at android.view.Choreographer.doFrame(Choreographer.java:531)
10-15 05:31:43.146: E/AndroidRuntime(1789): at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:735)
10-15 05:31:43.146: E/AndroidRuntime(1789): at android.os.Handler.handleCallback(Handler.java:725)
10-15 05:31:43.146: E/AndroidRuntime(1789): at android.os.Handler.dispatchMessage(Handler.java:92)
10-15 05:31:43.146: E/AndroidRuntime(1789): at android.os.Looper.loop(Looper.java:137)
10-15 05:31:43.146: E/AndroidRuntime(1789): at android.app.ActivityThread.main(ActivityThread.java:5041)
10-15 05:31:43.146: E/AndroidRuntime(1789): at java.lang.reflect.Method.invokeNative(Native Method)
10-15 05:31:43.146: E/AndroidRuntime(1789): at java.lang.reflect.Method.invoke(Method.java:511)
10-15 05:31:43.146: E/AndroidRuntime(1789): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
10-15 05:31:43.146: E/AndroidRuntime(1789): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
10-15 05:31:43.146: E/AndroidRuntime(1789): at dalvik.system.NativeStart.main(Native Method)
需要做什么？
最佳答案
覆盖destroyItem
@Override
public void destroyItem(View container, int position, Object object) {
((ViewPager) container).removeView((View) object);
}
引用文件
实现PageRadapter时，必须至少重写以下方法：
instantiateItem(ViewGroup, int)
destroyItem(ViewGroup, int, Object)
getCount()
isViewFromObject(View, Object)
http://developer.android.com/reference/android/support/v4/view/PagerAdapter.html
public void destroyItem (ViewGroup container, int position, Object object)
Remove a page for the given position. The adapter is responsible for removing the view from its container, although it only must ensure this is done by the time it returns from finishUpdate(ViewGroup).
Parameters
container The containing View from which the page will be removed.
position The page position to be removed.
object The same object that was returned by instantiateItem(View, int).