Mega Code Archive
A custom preference type The preference counts the number of clicks it has received and storesretrieves it from the storage
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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 com.example.android.apis.preference;
import com.example.android.apis.R;
import android.content.Context;
import android.content.res.TypedArray;
import android.os.Parcel;
import android.os.Parcelable;
import android.preference.Preference;
import android.util.AttributeSet;
import android.view.View;
import android.widget.TextView;
/**
* This is an example of a custom preference type. The preference counts the
* number of clicks it has received and stores/retrieves it from the storage.
*/
public class MyPreference extends Preference {
private int mClickCounter;
// This is the constructor called by the inflater
public MyPreference(Context context, AttributeSet attrs) {
super(context, attrs);
setWidgetLayoutResource(R.layout.preference_widget_mypreference);
}
@Override
protected void onBindView(View view) {
super.onBindView(view);
// Set our custom views inside the layout
final TextView myTextView = (TextView) view.findViewById(R.id.mypreference_widget);
if (myTextView != null) {
myTextView.setText(String.valueOf(mClickCounter));
}
}
@Override
protected void onClick() {
int newValue = mClickCounter + 1;
// Give the client a chance to ignore this change if they deem it
// invalid
if (!callChangeListener(newValue)) {
// They don't want the value to be set
return;
}
// Increment counter
mClickCounter = newValue;
// Save to persistent storage (this method will make sure this
// preference should be persistent, along with other useful checks)
persistInt(mClickCounter);
// Data has changed, notify so UI can be refreshed!
notifyChanged();
}
@Override
protected Object onGetDefaultValue(TypedArray a, int index) {
// This preference type's value type is Integer, so we read the default
// value from the attributes as an Integer.
return a.getInteger(index, 0);
}
@Override
protected void onSetInitialValue(boolean restoreValue, Object defaultValue) {
if (restoreValue) {
// Restore state
mClickCounter = getPersistedInt(mClickCounter);
} else {
// Set state
int value = (Integer) defaultValue;
mClickCounter = value;
persistInt(value);
}
}
@Override
protected Parcelable onSaveInstanceState() {
/*
* Suppose a client uses this preference type without persisting. We
* must save the instance state so it is able to, for example, survive
* orientation changes.
*/
final Parcelable superState = super.onSaveInstanceState();
if (isPersistent()) {
// No need to save instance state since it's persistent
return superState;
}
// Save the instance state
final SavedState myState = new SavedState(superState);
myState.clickCounter = mClickCounter;
return myState;
}
@Override
protected void onRestoreInstanceState(Parcelable state) {
if (!state.getClass().equals(SavedState.class)) {
// Didn't save state for us in onSaveInstanceState
super.onRestoreInstanceState(state);
return;
}
// Restore the instance state
SavedState myState = (SavedState) state;
super.onRestoreInstanceState(myState.getSuperState());
mClickCounter = myState.clickCounter;
notifyChanged();
}
/**
* SavedState, a subclass of {@link BaseSavedState}, will store the state
* of MyPreference, a subclass of Preference.
* <p>
* It is important to always call through to super methods.
*/
private static class SavedState extends BaseSavedState {
int clickCounter;
public SavedState(Parcel source) {
super(source);
// Restore the click counter
clickCounter = source.readInt();
}
@Override
public void writeToParcel(Parcel dest, int flags) {
super.writeToParcel(dest, flags);
// Save the click counter
dest.writeInt(clickCounter);
}
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];
}
};
}
}
//layout/preference_widget_mypreference.xml
<?xml version="1.0" encoding="utf-8"?>
<!-- Copyright (C) 2006 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.
-->
<!-- Custom preference type using a text view. -->
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/mypreference_widget"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_vertical"
android:layout_marginRight="6sp"
android:focusable="false"
android:clickable="false" />
]]>