How to set icon in ListPreference's item in an

I want to set the icon in ListPreference items in android.

What to write in ListPreference or where to write to set the list items icon?

回答1:

You need to use a custom layout for your ListPreference.

eg:

<android.preference.ListPreference
                android:layout="@layout/your_custom_layout"
                 ....
/>

And add what you want to your custom layout.

eg:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:minHeight="?android:attr/listPreferredItemHeight"
    android:gravity="center_vertical"
    android:paddingRight="?android:attr/scrollbarSize">

    <RelativeLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:layout_margin="@dimen/preferences_layout_margin">

        <ImageView android:id="@+id/yourIconId"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_centerVertical="true" /> <!-- here i've added an ImageView for icon -->

        <TextView android:id="@android:id/title"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:singleLine="true"
            android:textAppearance="?android:attr/textAppearanceMedium"
            android:ellipsize="marquee"
            android:fadingEdge="horizontal"
            android:layout_toRightOf="@+id/iconImageView"
            android:layout_marginLeft="@dimen/preferences_icon_margin" />

        <TextView android:id="@android:id/summary"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_below="@android:id/title"
            android:layout_alignLeft="@android:id/title"
            android:textAppearance="?android:attr/textAppearanceSmall"
            android:maxLines="2" />

    </RelativeLayout>
    <!-- Preference should place its actual preference widget here. -->
    <LinearLayout android:id="@android:id/widget_frame"
        android:layout_width="wrap_content"
        android:layout_height="fill_parent"
        android:gravity="center_vertical"
        android:orientation="vertical" />

</LinearLayout>

回答2:

When you need multiple uses of a list preference with texts/icons, then you can use this solution.

This version is heavily based on the nice version of LucaZanini. I made some minor changes to the version so it is only dependant on the own preference attributes. In this way you can use them multiple times. Please refer to his tutorial.

@Luca - thank you very much!

The minor changes are only:

IconPickerPreference.java, see below.
You don't need a reference to the strings.xml file. The default value, set at the start is just "0".
You could improve this version by using an integer for the currentIndex and not a string.

IconPickerPreference:

// @Based on the nice version of LucaZanini. Thank you!
public class IconPickerPreference extends ListPreference {
    private int currentIndex = 0;

    private class CustomListPreferenceAdapter extends ArrayAdapter<IconItem> {
        private Context context;
        private List<IconItem> icons;
        private int resource;

        public CustomListPreferenceAdapter(Context context, int resource, List<IconItem> objects) {
            super(context, resource, objects);
            this.context = context;
            this.resource = resource;
            this.icons = objects;
        }

        @Override
        public View getView(final int position, View convertView, ViewGroup parent) {

            ViewHolder holder;
            if (convertView == null) {
                LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
                convertView = inflater.inflate(resource, parent, false);

                holder = new ViewHolder();
                holder.iconName = (TextView) convertView.findViewById(R.id.iconName);
                holder.iconImage = (ImageView) convertView.findViewById(R.id.iconImage);
                holder.radioButton = (RadioButton) convertView.findViewById(R.id.iconRadio);
                convertView.setTag(holder);
            } else {
                holder = (ViewHolder) convertView.getTag();
            }

            holder.iconName.setText(icons.get(position).name);

            int identifier = context.getResources().getIdentifier( icons.get(position).file, "drawable", context.getPackageName());
            holder.iconImage.setImageResource(identifier);
            holder.radioButton.setChecked(icons.get(position).isChecked);
            convertView.setOnClickListener(new OnClickListener() {
                @Override
                public void onClick(View v) {
                    ViewHolder holder = (ViewHolder) v.getTag();
                    for (int i = 0; i < icons.size(); i++) {
                        if (i == position) {
                            icons.get(i).isChecked = true;
                        } else {
                            icons.get(i).isChecked = false;
                        }
                    }
                    getDialog().dismiss();
                }
            });
            return convertView;
        }
    }

    private class IconItem {
        private String  file;
        private boolean isChecked;
        private String  name;

        public IconItem(CharSequence name, CharSequence file, boolean isChecked) {
            this(name.toString(), file.toString(), isChecked);
        }

        public IconItem(String name, String file, boolean isChecked) {
            this.name = name;
            this.file = file;
            this.isChecked = isChecked;
        }

    }

    private class ViewHolder {
        protected ImageView     iconImage;
        protected TextView      iconName;
        protected RadioButton   radioButton;
    }

    private Context context;
    private ImageView icon;

    private CharSequence[] iconFile;
    private CharSequence[] iconName;
    private List<IconItem> icons;
    private SharedPreferences preferences;
    private Resources resources;
    private String selectedIconFile, defaultIconFile;
    private TextView summary;

    public IconPickerPreference(Context context, AttributeSet attrs) {
        super(context, attrs);
        this.context = context;
        resources = context.getResources();
        preferences = PreferenceManager.getDefaultSharedPreferences(context);

        TypedArray a = context.getTheme().obtainStyledAttributes( attrs, R.styleable.attrs_icon, 0, 0);
        try {
            defaultIconFile = a.getString(R.styleable.attrs_icon_iconFile);
        } finally {
            a.recycle();
        }
    }

    @Override
    protected void onBindView(View view) {
        super.onBindView(view);

        CharSequence[] entries = getEntries();
        CharSequence[] values = getEntryValues();
        selectedIconFile = values[ currentIndex].toString();
        icon = (ImageView) view.findViewById(R.id.iconSelected);
        updateIcon();
        summary = (TextView) view.findViewById( R.id.preference_summary);
        summary.setText( entries[ currentIndex]);
    }

    @Override
    protected void onDialogClosed(boolean positiveResult) {
        super.onDialogClosed(positiveResult);
        if (icons != null) {
            for (int i = 0; i < iconName.length; i++) {
                IconItem item = icons.get(i);
                if (item.isChecked) {
                    persistString( "" + i);
                    currentIndex = i;
                    selectedIconFile = item.file;
                    updateIcon();
                    summary.setText(item.name);
                    break;
                }
            }
        }
    }

    @Override
    protected void onSetInitialValue(boolean restorePersistedValue, Object defaultValue) {
        String number = "0";
        if (restorePersistedValue) {
            // Restore existing state
            number = this.getPersistedString( "0");
        } else {
            persistString( number);
        }
        try {
            currentIndex = Integer.parseInt(number);
        } catch( Exception e) {
            ; // skip any error, it will be corrected to 0
        }
    }

    @Override
    protected void onPrepareDialogBuilder(Builder builder) {   
        builder.setNegativeButton("Cancel", null);
        builder.setPositiveButton(null, null);
        iconName = getEntries();
        iconFile = getEntryValues();

        if (iconName == null || iconFile == null || iconName.length != iconFile.length) {
            throw new IllegalStateException(
                    "IconPickerPreference requires an entries array and an entryValues array which are both the same length");
        }

        icons = new ArrayList<IconItem>();
        for (int i = 0; i < iconName.length; i++) {
            IconItem item = new IconItem(iconName[i], iconFile[i], ( i == currentIndex));
            icons.add(item);
        }
        CustomListPreferenceAdapter customListPreferenceAdapter = new CustomListPreferenceAdapter(
                context, R.layout.preference_list_icon_picker, icons);
        builder.setAdapter(customListPreferenceAdapter, null);
    }
    private void updateIcon() {
        int identifier = resources.getIdentifier( selectedIconFile, "drawable", context.getPackageName());
        icon.setImageResource(identifier);
        icon.setTag(selectedIconFile);
    }
}