Android学习之SeekBar(控制wav音频的声音)

使用SeekBar调节声音

SeekBar控件其实就是一个高级点的进度条，就像我们在听歌，看电影用的播放器上的进度条一样，是可以拖动的，可以改变进度的一个进度条控件！

SeekBar常用属性：

android:max[integer]//设置拖动条的最大值

android:progress[integer]//设置当前的进度值

android:secondaryProgress[integer]//设置第二进度，通常用做显示视频等的缓冲效果

android:thumb[drawable]//设置滑块的图样

android:progressDrawable[drawable]//设置进度条的图样

1.XML代码：

 <?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" >

     <TextView
         android:layout_width="fill_parent"
         android:layout_height="wrap_content"
         android:text="SeekBar声音控制" />

     <SeekBar
         android:id="@+id/seekbar"
         android:layout_width="620px"
         android:layout_height="wrap_content"
         android:max="100"
         android:progress="20"
         android:progressDrawable="@drawable/soundbar"
         android:thumb="@drawable/soundbutton" />

     <TextView
         android:id="@+id/txtProgress"
         android:layout_width="fill_parent"
         android:layout_height="wrap_content" />

     <Button
         android:id="@+id/btnStart"
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
         android:text="播放" >
     </Button>

 </LinearLayout>

2.java代码：

 package com.example.seekbar;

 import java.io.File;
 import java.io.IOException;
 import android.app.Activity;
 import android.content.Context;
 import android.media.AudioManager;
 import android.media.MediaPlayer;
 import android.os.Bundle;
 import android.os.Environment;
 import android.util.Log;
 import android.view.KeyEvent;
 import android.view.View;
 import android.view.View.OnClickListener;
 import android.widget.Button;
 import android.widget.SeekBar;
 import android.widget.SeekBar.OnSeekBarChangeListener;
 import android.widget.TextView;

 public class MainActivity extends Activity implements OnClickListener,
         OnSeekBarChangeListener {
     // 定义一个SeekBar和一个TextView
     private SeekBar seekBar;
     private TextView textView;
     private Button btn;
     private MediaPlayer mMediaPlayer;

     @Override
     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);

         /** 创建MediaPlayer对象 **/
         mMediaPlayer = new MediaPlayer();
         initView();
     }

     // 初始化
     private void initView() {
         textView = (TextView) findViewById(R.id.txtProgress);
         seekBar = (SeekBar) findViewById(R.id.seekbar);
         btn = (Button) findViewById(R.id.btnStart);
         seekBar.setMax(100);
         seekBar.setOnSeekBarChangeListener(this);
         btn.setOnClickListener(this);
     }

     private void play() throws IOException {
         // 获取文件路径 ,放在SD卡下
         File audioFile = new File(Environment.getExternalStorageDirectory(),
                 "welcome.wav");
         Log.i("PATH", audioFile.getAbsolutePath());
         mMediaPlayer.reset();
         mMediaPlayer.setDataSource(audioFile.getAbsolutePath());
         mMediaPlayer.prepare();
         mMediaPlayer.start();
         mMediaPlayer.setVolume(1f, 2f);
     }

     @Override
     public boolean onKeyDown(int keyCode, KeyEvent event) {
         if (keyCode == KeyEvent.KEYCODE_VOLUME_DOWN
                 || keyCode == KeyEvent.KEYCODE_1) {
             AudioManager audioMa = (AudioManager) MainActivity.this
                     .getSystemService(Context.AUDIO_SERVICE);
             audioMa.adjustStreamVolume(AudioManager.STREAM_MUSIC,
                     AudioManager.ADJUST_LOWER,
                     AudioManager.FX_FOCUS_NAVIGATION_UP);
         } else if (keyCode == KeyEvent.KEYCODE_VOLUME_UP
                 || keyCode == KeyEvent.KEYCODE_2) {
             AudioManager audioMa = (AudioManager) MainActivity.this
                     .getSystemService(Context.AUDIO_SERVICE);
             audioMa.adjustStreamVolume(AudioManager.STREAM_MUSIC,
                     AudioManager.ADJUST_RAISE,
                     AudioManager.FX_FOCUS_NAVIGATION_UP);
         }
         return true;
     }

     @Override
     public void onProgressChanged(SeekBar arg0, int arg1, boolean arg2) {
         int i = seekBar.getProgress();
         textView.setText("" + i);

     }

     @Override
     public void onStartTrackingTouch(SeekBar arg0) {
         // TODO Auto-generated method stub

     }

     @Override
     public void onStopTrackingTouch(SeekBar arg0) {
         int i = seekBar.getProgress();
         mMediaPlayer.setVolume(i / 100f, i / 100f);

     }

     @Override
     public void onClick(View v) {
         if (v.getId() == R.id.btnStart) {
             try {
                 mMediaPlayer.prepare();
             } catch (Exception e) {
                 e.printStackTrace();
             }
             try {
                 // 播放音效
                 if (!mMediaPlayer.isPlaying()) {
                     play();
                 } else {
                     mMediaPlayer.stop();
                 }
             } catch (Exception e) {
                 e.printStackTrace();
             }
         }
     }
 }