android.preference.PreferenceScreen Maven / Gradle / Ivy
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/*
* Copyright (C) 2007 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package android.preference;
import android.app.Dialog;
import android.content.Context;
import android.content.DialogInterface;
import android.os.Bundle;
import android.os.Parcel;
import android.os.Parcelable;
import android.text.TextUtils;
import android.util.AttributeSet;
import android.view.LayoutInflater;
import android.view.View;
import android.view.Window;
import android.widget.Adapter;
import android.widget.AdapterView;
import android.widget.ListAdapter;
import android.widget.ListView;
/**
* Represents a top-level {@link Preference} that
* is the root of a Preference hierarchy. A {@link PreferenceActivity}
* points to an instance of this class to show the preferences. To instantiate
* this class, use {@link PreferenceManager#createPreferenceScreen(Context)}.
*
* This class can appear in two places:
* - When a {@link PreferenceActivity} points to this, it is used as the root
* and is not shown (only the contained preferences are shown).
*
- When it appears inside another preference hierarchy, it is shown and
* serves as the gateway to another screen of preferences (either by showing
* another screen of preferences as a {@link Dialog} or via a
* {@link Context#startActivity(android.content.Intent)} from the
* {@link Preference#getIntent()}). The children of this {@link PreferenceScreen}
* are NOT shown in the screen that this {@link PreferenceScreen} is shown in.
* Instead, a separate screen will be shown when this preference is clicked.
*
* Here's an example XML layout of a PreferenceScreen:
*
<PreferenceScreen
xmlns:android="http://schemas.android.com/apk/res/android"
android:key="first_preferencescreen">
<CheckBoxPreference
android:key="wifi enabled"
android:title="WiFi" />
<PreferenceScreen
android:key="second_preferencescreen"
android:title="WiFi settings">
<CheckBoxPreference
android:key="prefer wifi"
android:title="Prefer WiFi" />
... other preferences here ...
</PreferenceScreen>
</PreferenceScreen>
*
* In this example, the "first_preferencescreen" will be used as the root of the
* hierarchy and given to a {@link PreferenceActivity}. The first screen will
* show preferences "WiFi" (which can be used to quickly enable/disable WiFi)
* and "WiFi settings". The "WiFi settings" is the "second_preferencescreen" and when
* clicked will show another screen of preferences such as "Prefer WiFi" (and
* the other preferences that are children of the "second_preferencescreen" tag).
*
*
* Developer Guides
* For information about building a settings UI with Preferences,
* read the Settings
* guide.
*
*
* @see PreferenceCategory
*/
public final class PreferenceScreen extends PreferenceGroup implements AdapterView.OnItemClickListener,
DialogInterface.OnDismissListener {
private ListAdapter mRootAdapter;
private Dialog mDialog;
private ListView mListView;
/**
* Do NOT use this constructor, use {@link PreferenceManager#createPreferenceScreen(Context)}.
* @hide-
*/
public PreferenceScreen(Context context, AttributeSet attrs) {
super(context, attrs, com.android.internal.R.attr.preferenceScreenStyle);
}
/**
* Returns an adapter that can be attached to a {@link PreferenceActivity}
* or {@link PreferenceFragment} to show the preferences contained in this
* {@link PreferenceScreen}.
*
* This {@link PreferenceScreen} will NOT appear in the returned adapter, instead
* it appears in the hierarchy above this {@link PreferenceScreen}.
*
* This adapter's {@link Adapter#getItem(int)} should always return a
* subclass of {@link Preference}.
*
* @return An adapter that provides the {@link Preference} contained in this
* {@link PreferenceScreen}.
*/
public ListAdapter getRootAdapter() {
if (mRootAdapter == null) {
mRootAdapter = onCreateRootAdapter();
}
return mRootAdapter;
}
/**
* Creates the root adapter.
*
* @return An adapter that contains the preferences contained in this {@link PreferenceScreen}.
* @see #getRootAdapter()
*/
protected ListAdapter onCreateRootAdapter() {
return new PreferenceGroupAdapter(this);
}
/**
* Binds a {@link ListView} to the preferences contained in this {@link PreferenceScreen} via
* {@link #getRootAdapter()}. It also handles passing list item clicks to the corresponding
* {@link Preference} contained by this {@link PreferenceScreen}.
*
* @param listView The list view to attach to.
*/
public void bind(ListView listView) {
listView.setOnItemClickListener(this);
listView.setAdapter(getRootAdapter());
onAttachedToActivity();
}
@Override
protected void onClick() {
if (getIntent() != null || getFragment() != null || getPreferenceCount() == 0) {
return;
}
showDialog(null);
}
private void showDialog(Bundle state) {
Context context = getContext();
if (mListView != null) {
mListView.setAdapter(null);
}
LayoutInflater inflater = (LayoutInflater)
context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View childPrefScreen = inflater.inflate(
com.android.internal.R.layout.preference_list_fragment, null);
mListView = (ListView) childPrefScreen.findViewById(android.R.id.list);
bind(mListView);
// Set the title bar if title is available, else no title bar
final CharSequence title = getTitle();
Dialog dialog = mDialog = new Dialog(context, context.getThemeResId());
if (TextUtils.isEmpty(title)) {
dialog.getWindow().requestFeature(Window.FEATURE_NO_TITLE);
} else {
dialog.setTitle(title);
}
dialog.setContentView(childPrefScreen);
dialog.setOnDismissListener(this);
if (state != null) {
dialog.onRestoreInstanceState(state);
}
// Add the screen to the list of preferences screens opened as dialogs
getPreferenceManager().addPreferencesScreen(dialog);
dialog.show();
}
public void onDismiss(DialogInterface dialog) {
mDialog = null;
getPreferenceManager().removePreferencesScreen(dialog);
}
/**
* Used to get a handle to the dialog.
* This is useful for cases where we want to manipulate the dialog
* as we would with any other activity or view.
*/
public Dialog getDialog() {
return mDialog;
}
public void onItemClick(AdapterView parent, View view, int position, long id) {
// If the list has headers, subtract them from the index.
if (parent instanceof ListView) {
position -= ((ListView) parent).getHeaderViewsCount();
}
Object item = getRootAdapter().getItem(position);
if (!(item instanceof Preference)) return;
final Preference preference = (Preference) item;
preference.performClick(this);
}
@Override
protected boolean isOnSameScreenAsChildren() {
return false;
}
@Override
protected Parcelable onSaveInstanceState() {
final Parcelable superState = super.onSaveInstanceState();
final Dialog dialog = mDialog;
if (dialog == null || !dialog.isShowing()) {
return superState;
}
final SavedState myState = new SavedState(superState);
myState.isDialogShowing = true;
myState.dialogBundle = dialog.onSaveInstanceState();
return myState;
}
@Override
protected void onRestoreInstanceState(Parcelable state) {
if (state == null || !state.getClass().equals(SavedState.class)) {
// Didn't save state for us in onSaveInstanceState
super.onRestoreInstanceState(state);
return;
}
SavedState myState = (SavedState) state;
super.onRestoreInstanceState(myState.getSuperState());
if (myState.isDialogShowing) {
showDialog(myState.dialogBundle);
}
}
private static class SavedState extends BaseSavedState {
boolean isDialogShowing;
Bundle dialogBundle;
public SavedState(Parcel source) {
super(source);
isDialogShowing = source.readInt() == 1;
dialogBundle = source.readBundle();
}
@Override
public void writeToParcel(Parcel dest, int flags) {
super.writeToParcel(dest, flags);
dest.writeInt(isDialogShowing ? 1 : 0);
dest.writeBundle(dialogBundle);
}
public SavedState(Parcelable superState) {
super(superState);
}
public static final Parcelable.Creator CREATOR =
new Parcelable.Creator() {
public SavedState createFromParcel(Parcel in) {
return new SavedState(in);
}
public SavedState[] newArray(int size) {
return new SavedState[size];
}
};
}
}