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");

     }

   

    }

   

}