java - 保存复选框的选择

Question

当我打开应用程序或转到其他 Activity 时，我试图保存复选框的选择，这是一个简单的程序，显示您可以设置为 Collection 夹的国家和国旗列表，我只是看不到在哪里我这里出错了:

public class MyAdapter extends ArrayAdapter<String> {

String[] names;
int[] flags;
Context mContext;

public MyAdapter(Context context, String[] countryNames, int[] countryFlags, String[] countryDetails) {
    super(context, R.layout.listview_item);
    this.names = countryNames;
    this.flags = countryFlags;
    this.mContext = context;
}

@Override
public int getCount() {
    return names.length;
}

@NonNull
@Override
public View getView(int position, View convertView, ViewGroup parent) {
    ViewHolder mViewHolder = new ViewHolder();
    SharedPreferences sp = mContext.getSharedPreferences("FreshStart", 0);
    boolean shouldBeChecked = sp.getBoolean(names[position], false);

    if (convertView == null) {
        LayoutInflater mInflater = (LayoutInflater) mContext.
                getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        convertView = mInflater.inflate(R.layout.listview_item, parent, false);
        mViewHolder.mFlag = (ImageView) convertView.findViewById(R.id.imageView);
        mViewHolder.mName = (TextView) convertView.findViewById(R.id.textView);
        mViewHolder.mCheckBox = convertView.findViewById(R.id.check_Box);

    } else {
        mViewHolder = (ViewHolder) convertView.getTag();
    }
    mContext.getSharedPreferences("FreshStart",0);
    mViewHolder.mFlag.setImageResource(flags[position]);
    mViewHolder.mName.setText(names[position]);

    mViewHolder.mCheckBox.setTag(names[position]);
    convertView.setTag(mViewHolder);
    mViewHolder.mCheckBox.setChecked(shouldBeChecked);


    mViewHolder.mCheckBox.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
        public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {

            if (isChecked) {
                buttonView.setSelected(true);
                Toast.makeText(mContext, "Saved as Favorite", Toast.LENGTH_SHORT).show();
            }
            else{
                buttonView.setSelected(false);
                Toast.makeText(mContext, "No Longer set as Favorite", Toast.LENGTH_SHORT).show();
            }

        }
    });

    return convertView;
}

static class ViewHolder {
    ImageView mFlag;
    TextView mName;
    CheckBox mCheckBox;
}




}

它是if(isChecked)我现在似乎最困难的部分，我知道我需要保存实例状态，并且我尝试使用 SharedPreferences保存但不完全确定如何使用它，并希望获得一些帮助以帮助更多地理解它

Answer 1

这样做:

public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
                    final SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(mContext); //mContext is your context
                    final SharedPreferences.Editor editor = prefs.edit();
                    buttonView.setSelected(true);
                    if (isChecked){
                        Toast.makeText(mContext, "Saved as Favorite", Toast.LENGTH_SHORT).show();
                        editor.putBoolean("some_name",true); //
                        editor.apply();
                    }
                    else{
                        Toast.makeText(mContext, "No Longer set as Favorite", Toast.LENGTH_SHORT).show();
                        editor. editor.putBoolean("some_name",false);
                        editor.apply();
                    }

                }

希望有帮助。