IDE说我：FATAL EXCEPTION：主要的java.lang.NullPointerException行＃34; .onCreateView（holder.chkBox.setChecked（true）;＆＃34;
为什么？
提前感谢！
ADAPTER CLASS：
public abstract class PlanetAdapter extends ArrayAdapter<Planet> implements CompoundButton.OnCheckedChangeListener
{
private List<Planet> planetList;
private Context context;
ArrayList<Birra> objects;
public PlanetAdapter(List<Planet> planetList, Context context) {
super(context, R.layout.single_listview_item, planetList);
this.planetList = planetList;
this.context = context;
}
public class PlanetHolder {
public TextView planetName;
public TextView distView;
public TextView valuta;
public CheckBox chkBox;
public EditText edit;
public String quantità;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View row = convertView;
PlanetHolder holder = null;
if (row == null) {
LayoutInflater inflater = ((Activity) context).getLayoutInflater();
row = inflater.inflate(R.layout.single_listview_item, parent, false);
holder = new PlanetHolder();
holder.planetName = (TextView) row.findViewById(R.id.name);
holder.distView = (TextView) row.findViewById(R.id.dist);
holder.valuta = (TextView) row.findViewById(R.id.valuta);
holder.chkBox = (CheckBox) row.findViewById(R.id.chk_box);
holder.edit = (EditText) row.findViewById(R.id.editText);
holder.edit.setVisibility(View.GONE);
holder.edit.setEnabled(false);
row.setTag(holder);
} else {
holder = (PlanetHolder) row.getTag();
}
final Planet p = planetList.get(position);
final PlanetHolder finalHolder = holder;
if(p.isCheckBoxchecked ())
{
finalHolder.chkBox.setChecked(true);
}
/*SharedPreferences preferences = getContext().getSharedPreferences("MaterialTabs", android.content.Context.MODE_PRIVATE);
boolean mCheckBoxValue = preferences .getBoolean("CheckBox_Value", false);
if (mCheckBoxValue) {
holder.chkBox.setChecked(true);
} else {
holder.chkBox.setChecked(false);
}*/
holder.chkBox.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (finalHolder.chkBox.isChecked()) {
finalHolder.edit.setVisibility(View.VISIBLE);
finalHolder.edit.setEnabled(true);
SharedPreferences preferences = getContext().getSharedPreferences("MaterialTabs", android.content.Context.MODE_PRIVATE);
/* SharedPreferences.Editor editor = preferences.edit();
editor.putBoolean("showActivity", finalHolder.chkBox.isChecked());
editor.commit();*/
// boolean value= true;
SharedPreferences.Editor mEditor = preferences .edit();
mEditor.putBoolean("CheckBox_Value", finalHolder.chkBox.isChecked());
mEditor.commit();
finalHolder.edit.addTextChangedListener(new TextWatcher() {
@Override
public void beforeTextChanged(CharSequence s, int start, int count, int after) {
}
@Override
public void onTextChanged(CharSequence s, int start, int before, int count) {
}
@Override
public void afterTextChanged(Editable s) {
p.setQuantità(finalHolder.edit.getText().toString().trim());
SharedPreferences preferences = getContext().getSharedPreferences("PROJECT_NAME", android.content.Context.MODE_PRIVATE);
SharedPreferences.Editor editor = preferences.edit();
editor.putString("KEY", finalHolder.edit.getText().toString().trim());
editor.commit();
}
});
} else {
finalHolder.edit.setVisibility(View.GONE);
finalHolder.edit.setEnabled(false);
finalHolder.edit.setText(null);
}
}
});
holder.planetName.setText(p.getName());
holder.distView.setText("" + p.getDistance());
holder.valuta.setText(""+p.getValuta());
holder.chkBox.setChecked(p.isSelected());
holder.chkBox.setTag(p);
holder.edit.setEnabled(false);
return row;
}
ArrayList<Planet> getBox() {
ArrayList<Planet> box = new ArrayList<Planet>();
for (Planet p : planetList) {
if (p.selected)
box.add(p);
}
return box;
}
}
FRAGMENT：
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
ViewGroup rootView = (ViewGroup) inflater.inflate(R.layout.fragment_list2, container, false);
SharedPreferences preferences = getContext().getSharedPreferences("MaterialTabs", android.content.Context.MODE_PRIVATE);
// preferences.getBoolean("showActivity", false);
//preferences.getString("KEY", null);
boolean mCheckBoxValue = preferences .getBoolean("CheckBox_Value", false);
if (mCheckBoxValue) {
holder.chkBox.setChecked(true);
} else {
holder.chkBox.setChecked(false);
}
Button mButton = (Button) rootView.findViewById(R.id.button);
mButton.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
showResult(v);
}
});
//return inflater.inflate(R.layout.fragment_list2, container, false);
return rootView;
}
PLANET：
class Planet {
String name;
int distance;
String quantità;
String valuta;
boolean selected = false;
boolean mCheckBoxState;
public Planet(String name, int distance, String valuta) {
super();
this.name = name;
this.distance = distance;
this.valuta = valuta;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getDistance() {
return distance;
}
public void setDistance(int distance) {
this.distance = distance;
}
public boolean isSelected() {
return selected;
}
public void setSelected(boolean selected) {
this.selected = selected;
}
public String getQuantità() {
return quantità;
}
public void setQuantità(String quantità) {
this.quantità = quantità;
}
public String getValuta() {
return valuta;
}
public void setValuta(String valuta) {
this.valuta = valuta;
}
public boolean isCheckBoxchecked () { return mCheckBoxState; }
private void setCheckBoxCheck(boolean state){ mCheckBoxState = state; }
}
答案 0 :(得分：0)
每次都会刷新片段视图，因此更好的选项将不是将其存储在首选项中，而是使用用于创建值的项目（对象） 对于适配器中的Ex执行此操作 final Planet p = planetList.get（position）;
Fragment答案 1 :(得分：0)
尝试使用this library来降低与共享首选项相关的代码的复杂性。如果您的共享首选项确定要显示的视图状态，请确保对onCreate方法中的存储值进行相关检查。