Android之Mediaplayer音乐播放器

Main3Acticity.java

package csdn.example.com.notification.PlayerAudioTest;

import android.Manifest;
import android.content.pm.PackageManager;
import android.media.MediaPlayer;
import android.os.Environment;
import android.support.annotation.NonNull;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.ContextCompat;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;

import java.io.File;
import java.io.IOException;

import csdn.example.com.notification.R;

public class Main3Activity extends AppCompatActivity implements View.OnClickListener {

private MediaPlayer mediaPlayer = new MediaPlayer();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main3);
        Button play = (Button) findViewById(R.id.play);
        Button pause = (Button) findViewById(R.id.Pause);
        Button stop = (Button) findViewById(R.id.stop);
        play.setOnClickListener(this);
        pause.setOnClickListener(this);
        stop.setOnClickListener(this);
        if (ContextCompat.checkSelfPermission(Main3Activity.this, Manifest.permission.
                WRITE_EXTERNAL_STORAGE)!= PackageManager.PERMISSION_GRANTED){
            ActivityCompat.requestPermissions(Main3Activity.this,new String[]{
                    Manifest.permission.WRITE_EXTERNAL_STORAGE
            },1);
        }else {
            initMediaPlayer(); //初始化MediaPlayer
        }
    }

    private void initMediaPlayer() {
        Log.d("123","到了吗");
        File file = new File(Environment.getExternalStorageDirectory(),
                "music.mp3");
        try {
            mediaPlayer.setDataSource(file.getPath()); //指定音频文件的路径
            mediaPlayer.prepare(); //让MediaPlayer 进入到准备状态
        } catch (IOException e) {
            e.printStackTrace();
        }

    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        switch (requestCode){
            case 1:
                if(grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED){
                    initMediaPlayer();
                }else {
                    Toast.makeText(this,"拒绝权限将无法使用程序",Toast.LENGTH_SHORT).show();
                    finish();
                }
                break;
            default:
        }
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
    }

    @Override
    public void onClick(View v) {
        switch (v.getId()){
            case R.id.play:
                if(!mediaPlayer.isPlaying()){
                    mediaPlayer.start(); //开始播放
                    Toast.makeText(this,"该音频时长为"+mediaPlayer.getDuration()+"毫秒",Toast.LENGTH_SHORT).show();
                }
                break;
            case R.id.Pause:
                if(mediaPlayer.isPlaying()){
                    //将MediaPlayer对象重置到刚刚创建的状态
                    mediaPlayer.pause(); //暂停播放
                }
                break;
            case R.id.stop:
                if(mediaPlayer.isPlaying()){
                    mediaPlayer.reset(); //停止播放
                    initMediaPlayer();
                }
                break;
            default:
                break;
        }
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        if(mediaPlayer != null){
            mediaPlayer.stop();
            mediaPlayer.release();
        }
    }
}

运行截图如图所示

activity_main3

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout android:orientation="vertical"
    android:layout_height="match_parent"
    android:layout_width="match_parent"
    xmlns:android="http://schemas.android.com/apk/res/android">
    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/play"
        android:text="Play"
        />
    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/Pause"
        android:text="Pause"
        />
    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/stop"
        android:text="Stop"
        />

</LinearLayout>