Question

当我打开应用程序或进行其他活动时，我正在尝试保存复选框的选择，这是一个简单的程序，显示可以设置为收藏夹的国家和标志的列表，我只是看不到哪里我在这里错了：

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;
}




}

它似乎是我目前最苦恼的if(isChecked)部分，我知道我需要保存实例状态，并且尝试使用SharedPreferences保存但不是完全保存确定如何使用它，并希望在此方面有所帮助，以帮助更多地了解它。

Answer 1

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();
    final 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) {
        SharedPreferences.Editor preferencesEditor = sp.edit();
        preferencesEditor.putBoolean("FreshStart", isChecked);
        preferencesEditor.apply();

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

    }
});

return convertView;
}

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




}

Answer 2

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。

Answer 3

mViewHolder.mCheckBox.setChecked(getSharedBoolean(context,"my_switch_key",false));
mViewHolder.mCheckBox.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
    public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) { 
         // buttonView.setSelected(true); // No need to setSelected as callback fired after button check status already change.
         storeSharedItem(context,"storeSharedItem",isChecked);
        }
    }
});

/*
 * RCHIVED_SHARED_PREF "String" the Desired preferences file. If a preferences file by this name
 * does not exist, it will be created when you retrieve an editor 
 */
private final static ARCHIVED_SHARED_PREF = "shared_pref"; // use any String to define SharedPreference storage.

public static boolean getSharedBoolean(Context ctx, String key,boolean def) {
    return ctx.getSharedPreferences(ARCHIVED_SHARED_PREF, 0).getBoolean(key, def);
}

public static void storeSharedItem(Context ctx, String key, boolean value) {
    SharedPreferences sharedPref = ctx.getSharedPreferences(ARCHIVED_SHARED_PREF, 0);
    SharedPreferences.Editor editor = sharedPref.edit();
    editor.putBoolean(key, value);
    editor.apply();
}

保存复选框的选择

3 个答案: