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();
            }
        }
    }
}