Android移动开发-音量调节对话框的实现

Android手机上的需要音量调节有六大类铃音，分别是通话音、系统音、铃音、媒体音、闹钟音和通知音，不过音量键只有加大与减少两个键，当用户按音量增加键时，应用怎么知道用户希望加大那类铃音的音量呢？
要解决这个问题，最好是弹出一个对话框，让用户选择希望调节的铃音类型，并显示拖动条，方便用户把音量一次调整到位，不必连续按增加键或减少键。

• layout/dialog_volume.xml界面布局代码如下：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:background="@color/transparent"    android:gravity="center"    android:orientation="vertical"    android:paddingLeft="40dp"    android:paddingRight="40dp">    <LinearLayout        android:layout_width="match_parent"        android:layout_height="match_parent"        android:background="@color/white"        android:orientation="vertical">        <SeekBar            android:id="@+id/sb_music"            android:layout_width="match_parent"            android:layout_height="wrap_content"            android:layout_margin="15dp"            android:max="100"            android:thumb="@drawable/seekbar_point" />    </LinearLayout></LinearLayout>

• widget.VolumeDialog.java.java逻辑代码如下：

package com.fukaimei.keyevent.widget;import android.app.Dialog;import android.content.Context;import android.media.AudioManager;import android.os.Handler;import android.view.KeyEvent;import android.view.LayoutInflater;import android.view.View;import android.view.View.OnKeyListener;import android.view.ViewGroup.LayoutParams;import android.widget.SeekBar;import android.widget.SeekBar.OnSeekBarChangeListener;import com.fukaimei.keyevent.R;public class VolumeDialog implements OnSeekBarChangeListener, OnKeyListener {    private Dialog dialog;    private View view;    private SeekBar sb_music;    private AudioManager mAudioMgr;    private int MUSIC = AudioManager.STREAM_MUSIC;    private int mMaxVolume;    private int mNowVolume;    public VolumeDialog(Context context) {        mAudioMgr = (AudioManager) context.getSystemService(Context.AUDIO_SERVICE);        mMaxVolume = mAudioMgr.getStreamMaxVolume(MUSIC);        mNowVolume = mAudioMgr.getStreamVolume(MUSIC);        view = LayoutInflater.from(context).inflate(R.layout.dialog_volume, null);        dialog = new Dialog(context, R.style.VolumeDialog);        sb_music = (SeekBar) view.findViewById(R.id.sb_music);        sb_music.setOnSeekBarChangeListener(this);        sb_music.setProgress(sb_music.getMax() * mNowVolume / mMaxVolume);    }    public void show() {        dialog.getWindow().setContentView(view);        dialog.getWindow().setLayout(LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT);        dialog.show();        sb_music.setFocusable(true);        sb_music.setFocusableInTouchMode(true);        sb_music.setOnKeyListener(this);    }    public void dismiss() {        if (dialog != null && dialog.isShowing()) {            dialog.dismiss();        }    }    public boolean isShowing() {        if (dialog != null) {            return dialog.isShowing();        } else {            return false;        }    }    public void adjustVolume(int direction, boolean fromActivity) {        if (direction == AudioManager.ADJUST_RAISE) {            mNowVolume += 1;        } else {            mNowVolume -= 1;        }        sb_music.setProgress(sb_music.getMax() * mNowVolume / mMaxVolume);        mAudioMgr.adjustStreamVolume(MUSIC, direction, AudioManager.FLAG_PLAY_SOUND);        if (mListener != null && fromActivity != true) {            mListener.onVolumeAdjust(mNowVolume);        }        close();    }    private void close() {        mHandler.removeCallbacks(mClose);        mHandler.postDelayed(mClose, 2000);    }    private Handler mHandler = new Handler();    private Runnable mClose = new Runnable() {        @Override        public void run() {            dismiss();        }    };    @Override    public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {    }    @Override    public void onStartTrackingTouch(SeekBar seekBar) {    }    @Override    public void onStopTrackingTouch(SeekBar seekBar) {        mNowVolume = mMaxVolume * seekBar.getProgress() / seekBar.getMax();        mAudioMgr.setStreamVolume(MUSIC, mNowVolume, AudioManager.FLAG_PLAY_SOUND);        if (mListener != null) {            mListener.onVolumeAdjust(mNowVolume);        }        close();    }    @Override    public boolean onKey(View v, int keyCode, KeyEvent event) {        if (keyCode == KeyEvent.KEYCODE_VOLUME_UP && event.getAction() == KeyEvent.ACTION_DOWN) {            adjustVolume(AudioManager.ADJUST_RAISE, false);            return true;        } else if (keyCode == KeyEvent.KEYCODE_VOLUME_DOWN && event.getAction() == KeyEvent.ACTION_DOWN) {            adjustVolume(AudioManager.ADJUST_LOWER, false);            return true;        } else {            return false;        }    }    private VolumeAdjustListener mListener;    public void setVolumeAdjustListener(VolumeAdjustListener listener) {        mListener = listener;    }    public static interface VolumeAdjustListener {        public abstract void onVolumeAdjust(int volume);    }}

• layout/activity_volume_set.xml界面布局代码如下：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:orientation="vertical"    android:padding="5dp">    <TextView        android:id="@+id/tv_volume"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:text="按下加减键调整音乐音量"        android:textColor="@color/black"        android:textSize="17sp" /></LinearLayout>

• VolumeSetActivity.java逻辑代码如下：

package com.fukaimei.keyevent;import android.content.Context;import android.media.AudioManager;import android.os.Bundle;import android.support.v7.app.AppCompatActivity;import android.view.KeyEvent;import android.widget.TextView;import com.fukaimei.keyevent.widget.VolumeDialog;public class VolumeSetActivity extends AppCompatActivity implements VolumeDialog.VolumeAdjustListener {    private TextView tv_volume;    private VolumeDialog dialog;    private AudioManager mAudioMgr;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_volume_set);        tv_volume = (TextView) findViewById(R.id.tv_volume);        mAudioMgr = (AudioManager) getSystemService(Context.AUDIO_SERVICE);    }    @Override    public boolean onKeyDown(int keyCode, KeyEvent event) {        if (keyCode == KeyEvent.KEYCODE_VOLUME_UP && event.getAction() == KeyEvent.ACTION_DOWN) {            showVolumeDialog(AudioManager.ADJUST_RAISE);            return true;        } else if (keyCode == KeyEvent.KEYCODE_VOLUME_DOWN && event.getAction() == KeyEvent.ACTION_DOWN) {            showVolumeDialog(AudioManager.ADJUST_LOWER);            return true;        } else if (keyCode == KeyEvent.KEYCODE_BACK) {            finish();            return false;        } else {            return false;        }    }    private void showVolumeDialog(int direction) {        if (dialog == null || dialog.isShowing() != true) {            dialog = new VolumeDialog(this);            dialog.setVolumeAdjustListener(this);            dialog.show();        }        dialog.adjustVolume(direction, true);        onVolumeAdjust(mAudioMgr.getStreamVolume(AudioManager.STREAM_MUSIC));    }    @Override    public void onVolumeAdjust(int volume) {        tv_volume.setText("调节后的音乐音量大小为：" + volume);    }}

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