自定义SeekBarPreference控件（老外出品,直接在preferences文件中使用，无需其他代码）

下面介绍SeekBarPreference控件，保存的Value为数字值，直接可以在preferences.xml文件中使用无需其他代码。

下面是控件使用到得标准Android属性

android:dialogMessage 显示对话框中的文本信息
android:text 在选择进度条后，显示的文本信息
android:max SeekBar的最大值

/* The following code was written by Matthew Wiggins
* and is released under the APACHE 2.0 license
*
* http://www.apache.org/licenses/LICENSE-2.0 */
package com.hlidskialf.android.preference;

import android.content.Context;
import android.util.AttributeSet;
import android.view.Gravity;
import android.view.View;
import android.view.ViewGroup;
import android.preference.DialogPreference;
import android.widget.SeekBar;
import android.widget.TextView;
import android.widget.LinearLayout;

public class SeekBarPreference extends DialogPreference implements SeekBar.OnSeekBarChangeListener
{
private static final String androidns="http://schemas.android.com/apk/res/android";

private SeekBar mSeekBar;
private TextView mSplashText,mValueText;
private Context mContext;

private String mDialogMessage, mSuffix;
private int mDefault, mMax, mValue = 0;

public SeekBarPreference(Context context, AttributeSet attrs) {
super(context,attrs);
mContext = context;

mDialogMessage = attrs.getAttributeValue(androidns,"dialogMessage");
mSuffix = attrs.getAttributeValue(androidns,"text");
mDefault = attrs.getAttributeIntValue(androidns,"defaultValue", 0);
mMax = attrs.getAttributeIntValue(androidns,"max", 100);

}
@Override
protected View onCreateDialogView() {
LinearLayout.LayoutParams params;
LinearLayout layout = new LinearLayout(mContext);
layout.setOrientation(LinearLayout.VERTICAL);
layout.setPadding(6,6,6,6);

mSplashText = new TextView(mContext);
if (mDialogMessage != null)
mSplashText.setText(mDialogMessage);
layout.addView(mSplashText);

mValueText = new TextView(mContext);
mValueText.setGravity(Gravity.CENTER_HORIZONTAL);
mValueText.setTextSize(32);
params = new LinearLayout.LayoutParams(
LinearLayout.LayoutParams.FILL_PARENT,
LinearLayout.LayoutParams.WRAP_CONTENT);
layout.addView(mValueText, params);

mSeekBar = new SeekBar(mContext);
mSeekBar.setOnSeekBarChangeListener(this);
layout.addView(mSeekBar, new LinearLayout.LayoutParams(LinearLayout.LayoutParams.FILL_PARENT, LinearLayout.LayoutParams.WRAP_CONTENT));

if (shouldPersist())
mValue = getPersistedInt(mDefault);

mSeekBar.setMax(mMax);
mSeekBar.setProgress(mValue);
return layout;
}
@Override
protected void onBindDialogView(View v) {
super.onBindDialogView(v);
mSeekBar.setMax(mMax);
mSeekBar.setProgress(mValue);
}
@Override
protected void onSetInitialValue(boolean restore, Object defaultValue)
{
super.onSetInitialValue(restore, defaultValue);
if (restore)
mValue = shouldPersist() ? getPersistedInt(mDefault) : 0;
else
mValue = (Integer)defaultValue;
}

public void onProgressChanged(SeekBar seek, int value, boolean fromTouch)
{
String t = String.valueOf(value);
mValueText.setText(mSuffix == null ? t : t.concat(mSuffix));
if (shouldPersist())
persistInt(value);
callChangeListener(new Integer(value));
}
public void onStartTrackingTouch(SeekBar seek) {}
public void onStopTrackingTouch(SeekBar seek) {}

public void setMax(int max) { mMax = max; }
public int getMax() { return mMax; }

public void setProgress(int progress) {
mValue = progress;
if (mSeekBar != null)
mSeekBar.setProgress(progress);
}
public int getProgress() { return mValue; }
}

下面是在XML layout的例子

<com.hlidskialf.android.preference.SeekBarPreference android:key="duration"
android:title="Duration of something"
android:summary="How long something will last"
android:dialogMessage="Something duration"
android:defaultValue="5"
android:text=" minutes"
android:max="60"
/>