我對Android中的ViewPager和適配器世界很新穎。我看過這個問題很多次,但不太明白,所以希望得到一個簡單的答案:)。在viewpager中不更新的片段
我有一個ViewPager有3個選項卡,每個選項卡都有一個片段。默認情況下,用戶首先看到tab2,在那裏他提供了一些輸入來生成一個字符串。這個字符串需要在tab3中生成一個qr代碼。
來自標籤2的字符串更新爲類,並且tab3從那裏接收字符串。
我的問題是,當我從tab2-> tab3移動qr代碼不會生成。但是當我去tab2-> tab1-> tab3它被生成。我猜測它保留了我的舊片段。
以下是我的班級代碼。請讓我知道爲什麼這個viewpager行爲如此。
我FragementActivity類:
public class ConfigExchangeMain extends FragmentActivity {
FragmentPagerAdapter adapterViewPager;
SampleFragementPagerAdapterExchange adapter;
String sent;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.config_exchange_main);
final ViewPager viewPager = (ViewPager) findViewById(R.id.viewpager);
adapter=new SampleFragementPagerAdapterExchange(getSupportFragmentManager());
viewPager.setAdapter(adapter);
viewPager.setCurrentItem(1);
// Give the TabLayout the ViewPager
TabLayout tabLayout = (TabLayout) findViewById(R.id.sliding_tabs);
tabLayout.setTabGravity(TabLayout.GRAVITY_FILL);
tabLayout.setupWithViewPager(viewPager);
}
}
我的傳呼機適配器看起來像
public class SampleFragementPagerAdapterExchange extends FragmentStatePagerAdapter {
final int PAGE_COUNT = 3;
private String tabTitles[] = new String[]{"CONTACTS", "HOME", "QR+SCAN"};
private ConfigDetail context;
public SampleFragementPagerAdapterExchange(FragmentManager fm) {
super(fm);
//this.context = context;
}
@Override
public Fragment getItem(int position) {
switch (position) {
case 1:
return new ConfigExchangeNFR();
case 0:
return new ConfigExchangeHome();
case 2:
return new ConfigExchangeQR();
default:
return new ConfigExchangeQR();
}
}
@Override
public int getCount() {
return PAGE_COUNT;
}
public CharSequence getPageTitle(int position) {
// Generate title based on item position
return tabTitles[position];
}
@Override
public int getItemPosition(Object object) {
return POSITION_NONE;
}
}
和我TAB3片段未更新:
public class ConfigExchangeQR extends Fragment {
ImageView iQRCode ;
int iQRDimension;
Button bScan;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
FacebookSdk.sdkInitialize(getActivity().getApplicationContext());
View view1 = inflater.inflate(R.layout.config_exchange_qr, container, false);
iQRCode = (ImageView)view1.findViewById(R.id.qrCode);
iQRDimension = 900;
String FinalQRCode = KeyValueDb.getPrefFinalVCard(getActivity());
QRCodeEncoder qrCodeEncoder = new QRCodeEncoder(FinalQRCode, null,
contents.Type.TEXT, BarcodeFormat.QR_CODE.toString(), iQRDimension);
try {
Bitmap bitmap = qrCodeEncoder.encodeAsBitmap();
iQRCode.setImageBitmap(bitmap);
} catch (WriterException e) {
e.printStackTrace();
}
bScan = (Button)view1.findViewById(R.id.scan_qr);
bScan.setOnClickListener(new View.OnClickListener() {
public void onClick(View paramAnonymousView) {
Intent intent = new Intent("android.media.action.IMAGE_CAPTURE");
startActivityForResult(intent, 0);
}
});
return view1;
}
}
感謝@Adam,它的工作,必須與keyvalue thingi一起玩,因爲這是我的共享首選項,但是,是的,您選擇選項卡時調用更新的解決方案確實完美地工作。也接受了你的回答,再次感謝 –