如何保存复选框值与共享偏好？ [英] how save checkbox value with shared preferences?
本文介绍了如何保存复选框值与共享偏好？的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
hy everybody，我不知道为什么我的代码不保存复选框的值;如果我选中复选框，然后我点击另一个选项卡，回到上一个选项卡，复选框未选中...我希望你在我的代码中找到错误！
hy everybody, i don't know why my code not save checkbox checked value; if i check checkbox and after i click on another tab and comeback to previous tab, checkbox is not selected...i hope that you find the error in my code!
IDE说我：FATAL EXCEPTION：main java.lang.NullPointerException at line.onCreateView（holder.chkBox.setChecked（true）;
IDE say me: FATAL EXCEPTION: main java.lang.NullPointerException at line ".onCreateView(holder.chkBox.setChecked(true);"
为什么？
提前感谢！
ADAPTOR CLASS：
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; }
}
推荐答案
使用此库，以减少您的共享偏好相关代码的复杂性。如果您的共享首选项确定正在显示的视图的状态，请确保您对onCreate方法中存储的值执行相关检查。
Try using this library to reduce complexity with your shared preferences related code. And if your shared preferences determine the state of views being displayed make sure you do relevant checks for stored values in the onCreate methods.
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