Java tutorial
/* * Copyright (C) 2015 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.support.v7.preference; import android.content.Context; import android.content.res.TypedArray; import android.os.Parcel; import android.os.Parcelable; import android.support.v4.content.res.TypedArrayUtils; import android.text.TextUtils; import android.util.AttributeSet; import android.widget.EditText; /** * A {@link Preference} that allows for string * input. * <p> * It is a subclass of {@link DialogPreference} and shows the {@link EditText} * in a dialog. * <p> * This preference will store a string into the SharedPreferences. */ public class EditTextPreference extends DialogPreference { private String mText; public EditTextPreference(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) { super(context, attrs, defStyleAttr, defStyleRes); } public EditTextPreference(Context context, AttributeSet attrs, int defStyleAttr) { this(context, attrs, defStyleAttr, 0); } public EditTextPreference(Context context, AttributeSet attrs) { this(context, attrs, TypedArrayUtils.getAttr(context, R.attr.editTextPreferenceStyle, AndroidResources.ANDROID_R_EDITTEXT_PREFERENCE_STYLE)); } public EditTextPreference(Context context) { this(context, null); } /** * Saves the text to the {@link android.content.SharedPreferences}. * * @param text The text to save */ public void setText(String text) { final boolean wasBlocking = shouldDisableDependents(); mText = text; persistString(text); final boolean isBlocking = shouldDisableDependents(); if (isBlocking != wasBlocking) { notifyDependencyChange(isBlocking); } } /** * Gets the text from the {@link android.content.SharedPreferences}. * * @return The current preference value. */ public String getText() { return mText; } @Override protected Object onGetDefaultValue(TypedArray a, int index) { return a.getString(index); } @Override protected void onSetInitialValue(boolean restoreValue, Object defaultValue) { setText(restoreValue ? getPersistedString(mText) : (String) defaultValue); } @Override public boolean shouldDisableDependents() { return TextUtils.isEmpty(mText) || super.shouldDisableDependents(); } @Override protected Parcelable onSaveInstanceState() { final Parcelable superState = super.onSaveInstanceState(); if (isPersistent()) { // No need to save instance state since it's persistent return superState; } final SavedState myState = new SavedState(superState); myState.text = getText(); 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()); setText(myState.text); } private static class SavedState extends BaseSavedState { String text; public SavedState(Parcel source) { super(source); text = source.readString(); } @Override public void writeToParcel(Parcel dest, int flags) { super.writeToParcel(dest, flags); dest.writeString(text); } public SavedState(Parcelable superState) { super(superState); } public static final Parcelable.Creator<SavedState> CREATOR = new Parcelable.Creator<SavedState>() { public SavedState createFromParcel(Parcel in) { return new SavedState(in); } public SavedState[] newArray(int size) { return new SavedState[size]; } }; } }