我只是在创建片段时尝试设置一些 TextView，只需首先检查以确保我的 sharedPrefrences 已设置或未设置。
我的片段代码如下所示：
@SuppressLint("ValidFragment")
public class CardBackFragment extends Fragment {
public CardBackFragment() {
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
backView = inflater.inflate(R.layout.postcardback, container, false);
TextView to = (TextView) findViewById(R.id.backToLabel);
TextView address = (TextView) findViewById(R.id.backAddressLabel);
TextView city = (TextView) findViewById(R.id.cityLabel);
TextView state = (TextView) findViewById(R.id.stateLabel);
TextView zip = (TextView) findViewById(R.id.zipLabel);
TextView country = (TextView) findViewById(R.id.countryLabel);
postcard = getApplicationContext().getSharedPreferences(postcardconst, 0);
if(savedInstanceState != null){
if(!getFreshValueForBackView()){
postcard = getApplicationContext().getSharedPreferences(postcardconst, 0);
toString = (postcard.getString(toConst, null));
addressString = (postcard.getString(address1Const, null));
cityString = (postcard.getString(cityConst, null));
stateString = (postcard.getString(stateConst, null));
zipString = (postcard.getString(zipcodeConst, null));
countryString = (postcard.getString(countryConst, null));
//setText
to.setText(toString);
address.setText(addressString);
city.setText(cityString);
state.setText(stateString);
zip.setText(zipString);
country.setText(countryString);
}else{
toString = ("add recipiants address");
addressString = ("");
cityString = ("");
stateString = ("");
zipString = ("");
countryString = ("");
//setText
to.setText(toString);
address.setText(addressString);
city.setText(cityString);
state.setText(stateString);
zip.setText(zipString);
country.setText(countryString);
}
}else if(!getFreshValueForBackView()){
postcard = getApplicationContext().getSharedPreferences(postcardconst, 0);
toString = (postcard.getString(toConst, null));
addressString = (postcard.getString(address1Const, null));
cityString = (postcard.getString(cityConst, null));
stateString = (postcard.getString(stateConst, null));
zipString = (postcard.getString(zipcodeConst, null));
countryString = (postcard.getString(countryConst, null));
//setText
to.setText(toString);
address.setText(addressString);
city.setText(cityString);
state.setText(stateString);
zip.setText(zipString);
country.setText(countryString);
}else{
toString = ("add recipiants address");
addressString = ("");
cityString = ("");
stateString = ("");
zipString = ("");
countryString = ("");
}
return backView;
}
}
这一直给我一个 NPE（空指针异常），无论我在哪里尝试和 setText（）。
为什么这不起作用，我该如何解决？我在另一个片段上复制了一些非常相似的东西，以获取 Bitmap 并将其保存到 ImageView。