阅读《Android 从入门到精通》（18）——拖动条
拖动条（SeekBar）
android.widget.ProgressBar;
android.widget.AbsSeekBar;
android.widget.SeekBar;
SeekBar 类方法
SeekBar 示例
完整工程：http://download.csdn.net/detail/sweetloveft/9419276
下面演示了 SeekBar 调节音量的功能，因为 SeekBar 继承于 ProgressBar，因此它也有 SetMax 等方法。
1.MainActivity.java
package com.sweetlover.activity;
import com.sweetlover.audiorecord.R;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.media.AudioFormat;
import android.media.AudioManager;
import android.media.AudioRecord;
import android.media.AudioTrack;
import android.media.MediaRecorder;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.SeekBar;
import android.widget.Toast;
public class MainActivity extends Activity {
Button recordButton, stopButton, exitButton;
SeekBar skbVolume;
boolean isRecording = false;
static final int frequency = 44100;
@SuppressWarnings("deprecation")
static final int channelConfiguration = AudioFormat.CHANNEL_CONFIGURATION_MONO;
static final int audioEncoding = AudioFormat.ENCODING_PCM_16BIT;
int recBufSize, playBufSize;
AudioRecord audioRecord;
AudioTrack audioTrack;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// 用getMinBufferSize()方法得到采集数据所需要的最小缓冲区的大小
recBufSize = AudioRecord.getMinBufferSize(frequency,
channelConfiguration, audioEncoding);
playBufSize = AudioTrack.getMinBufferSize(frequency,
channelConfiguration, audioEncoding);
// 实例化AudioRecord(声音来源，采样率，声道设置，采样声音编码，缓存大小）
audioRecord = new AudioRecord(MediaRecorder.AudioSource.MIC, frequency,
channelConfiguration, audioEncoding, recBufSize);
audioTrack = new AudioTrack(AudioManager.STREAM_MUSIC, frequency,
channelConfiguration, audioEncoding, playBufSize,
AudioTrack.MODE_STREAM);
recordButton = (Button) this.findViewById(R.id.recordbutton);
stopButton = (Button) this.findViewById(R.id.stopbutton);
exitButton = (Button) this.findViewById(R.id.exitbutton);
recordButton.setOnClickListener(new ClickEvent());
stopButton.setOnClickListener(new ClickEvent());
exitButton.setOnClickListener(new ClickEvent());
skbVolume = (SeekBar) this.findViewById(R.id.seekBarVolume);
skbVolume.setMax(100);
skbVolume.setProgress(70);
// 设置声音大小
audioTrack.setStereoVolume(0.7f, 0.7f);
skbVolume.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
public void onStopTrackingTouch(SeekBar seekBar) {
float vol = (float) (seekBar.getProgress())
/ (float) (seekBar.getMax());
audioTrack.setStereoVolume(vol, vol);
}
@Override
public void onStartTrackingTouch(SeekBar seekBar) {
// TODO Auto-generated method stub
}
@Override
public void onProgressChanged(SeekBar seekBar,
int progress, boolean fromUser) {
// TODO Auto-generated method stub
}
});
}
protected void onDestroy() {
super.onDestroy();
// 杀死当前进程
android.os.Process.killProcess(android.os.Process.myPid());
}
class ClickEvent implements View.OnClickListener {
public void onClick(View v) {
if (v == recordButton) {
isRecording = true;
new RecordPlayThread().start();
} else if (v == stopButton) {
isRecording = false;
} else if (v == exitButton) {
isRecording = false;
MainActivity.this.finish();
}
}
}
class RecordPlayThread extends Thread {
@SuppressLint("ShowToast")
public void run() {
try {
// byte 文件来存储声音
byte[] buffer = new byte[recBufSize];
// 开始采集声音
audioRecord.startRecording();
// 播放声音
audioTrack.play();
while (isRecording) {
// 从MIC存储到缓存区
int bufferReadResult = audioRecord.read(buffer, 0,
recBufSize);
byte[] tmpBuf = new byte[bufferReadResult];
System.arraycopy(buffer, 0, tmpBuf, 0, bufferReadResult);
// 播放缓存区的数据
audioTrack.write(tmpBuf, 0, tmpBuf.length);
}
audioTrack.stop();
audioRecord.stop();
} catch (Throwable t) {
Toast.makeText(MainActivity.this, t.getMessage(), 1000);
}
}
};
}
2.activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<TextView
android:id="@+id/textViewOper"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/operator"
android:textAppearance="?android:attr/textAppearanceMedium" />
<Button
android:id="@+id/recordbutton"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="@string/action" />
<Button
android:id="@+id/stopbutton"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="@string/stop" />
<Button
android:id="@+id/exitbutton"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="@string/exit" />
<TextView
android:id="@+id/textViewAdjust"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/adjust"
android:textAppearance="?android:attr/textAppearanceMedium" />
<SeekBar
android:id="@+id/seekBarVolume"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</LinearLayout>
3.string.xml
<resources>
<string name="app_name">SeekBarDemo</string>
<string name="operator">录制操作</string>
<string name="action">开始边录边放</string>
<string name="stop">停止</string>
<string name="exit">退出</string>
<string name="adjust">音量调节</string>
</resources>
4.AndroidManifest.xml
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.sweetlover.audiorecord"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="19" />
<uses-permission android:name="android.permission.RECORD_AUDIO"/>
<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity android:name="com.sweetlover.activity.MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN"/>
<category android:name="android.intent.category.LAUNCHER"/>
</intent-filter>
</activity>
</application>
</manifest>