android 拖动条 SeekBar

拖动条（SeekBar）组件与ProgressBar水平形式显示的进度条比较相似，不过其最大的区别在于，

拖动条可以由用户组件进行手工调节，例如：调整播放音量和播放进度时会用到拖动条。

在main.xml中

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

android:layout_width="fill_parent"

android:layout_height="fill_parent"

android:orientation="vertical" >

<SeekBar

android:id="@+id/seekbar"

android:layout_width="fill_parent"

android:layout_height="wrap_content"/>

<TextView

android:id="@+id/text"

android:layout_width="fill_parent"

android:layout_height="wrap_content"/>

</LinearLayout>

在MySeekBarDemo.java程序中

package com.tarena.seekbar;

import android.app.Activity;

import android.os.Bundle;

import android.text.method.ScrollingMovementMethod;

import android.widget.SeekBar;

import android.widget.SeekBar.OnSeekBarChangeListener;

import android.widget.TextView;

public class MySeekBarDemo extends Activity {

private SeekBar seekbar = null;

private TextView text = null;

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

super.setContentView(R.layout.main);

this.seekbar = (SeekBar) super.findViewById(R.id.seekbar); //取得组件

this.text = (TextView) super.findViewById(R.id.text); //取得组件

this.seekbar.setOnSeekBarChangeListener(new OnSeekBarChangeListenerImpl());

this.text.setMovementMethod(ScrollingMovementMethod.getInstance()); //设置文本组件可以滚动

}

private class OnSeekBarChangeListenerImpl implements OnSeekBarChangeListener{

public void onProgressChanged(SeekBar seekBar, int progress,

boolean fromUser) {

MySeekBarDemo.this.text.append("***开始拖动，当前值为:"

+ seekBar.getProgress() + "\n");

}

public void onStartTrackingTouch(SeekBar seekBar) {

MySeekBarDemo.this.text.append("***正在拖动，当前值为:"

+ seekBar.getProgress() + "\n");

}

public void onStopTrackingTouch(SeekBar seekBar) {

MySeekBarDemo.this.text.append("***停止拖动，当前值为:"

+ seekBar.getProgress() + "\n");

}

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