学步园

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"
/>