Android 播放音频/视频（基础用法）

运行环境：miui 10.3.3
运行截图（播放视频）：
下面分别贴上的是播放音频的MainActivity.java和播放视频的MainActivity.java

package com.example.playaudiotest;

import androidx.appcompat.app.AppCompatActivity;
import androidx.core.app.ActivityCompat;
import androidx.core.content.ContextCompat;

import android.Manifest;
import android.content.pm.PackageManager;
import android.media.MediaPlayer;
import android.os.Bundle;
import android.os.Environment;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;

import java.io.File;

public class MainActivity extends AppCompatActivity implements View.OnClickListener{

    private MediaPlayer mediaPlayer=new MediaPlayer();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        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(MainActivity.this, Manifest.permission.WRITE_EXTERNAL_STORAGE)
        != PackageManager.PERMISSION_GRANTED){
            ActivityCompat.requestPermissions(MainActivity.this,new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE},1);
        }else{
            initMediaPlayer();
        }
    }

    private void initMediaPlayer(){
        try{
            File file=new File(Environment.getExternalStorageDirectory(),"music.mp3");
            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(Exception e){
            e.printStackTrace();
        }
    }

    @Override
    public void onRequestPermissionsResult(int requestCode,String[] permissions,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_LONG).show();
                    finish();
                }
                break;
                default:
                    break;
        }
    }
    @Override
    public void onClick(View v){
        switch (v.getId()){
            case R.id.play:
                if(!mediaPlayer.isPlaying()){
                    mediaPlayer.start();//开始播放
                }
                break;
            case R.id.pause:
                if(mediaPlayer.isPlaying()){
                    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();
        }
    }
}

package com.example.playvideotest;

import androidx.appcompat.app.AppCompatActivity;
import androidx.core.app.ActivityCompat;
import androidx.core.content.ContextCompat;

import android.Manifest;
import android.content.pm.PackageManager;
import android.os.Bundle;
import android.os.Environment;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;
import android.widget.VideoView;

import java.io.File;

public class MainActivity extends AppCompatActivity implements View.OnClickListener{
    private VideoView videoView;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        videoView=(VideoView)findViewById(R.id.video_view);
        Button play=(Button)findViewById(R.id.play);
        Button pause=(Button)findViewById(R.id.pause);
        Button replay=(Button)findViewById(R.id.replay);
        play.setOnClickListener(this);
        pause.setOnClickListener(this);
        replay.setOnClickListener(this);
        if(ContextCompat.checkSelfPermission(MainActivity.this, Manifest.permission.WRITE_EXTERNAL_STORAGE)!= PackageManager.PERMISSION_GRANTED){
            ActivityCompat.requestPermissions(MainActivity.this,new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE},1);
        }else{
            initVideoPath();
        }
    }
    private void initVideoPath(){
        //getExternalStorageDirectory()方法获得的是sd卡的路径
        File file=new File(Environment.getExternalStorageDirectory(),"movie.mp4");
        videoView.setVideoPath(file.getPath());
    }

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

    @Override
    public void onClick(View v){
        switch (v.getId()){
            case R.id.play:
                if(!videoView.isPlaying()){
                    videoView.start();
                }
                break;
            case R.id.pause:
                if(videoView.isPlaying()){
                    videoView.pause();
                }
                break;
            case R.id.replay:
                if(videoView.isPlaying()){
                    videoView.resume();//重新播放

                }
                break;
        }
    }
    @Override
    public void onDestroy(){
        super.onDestroy();
        if(videoView!=null){
            videoView.suspend();
        }
    }
}

两份代码的思路基本相同。

首先在onCreate()方法中

1、获取几个按钮的实例并给他们设置点击事件
2、申请访问文件的权限，并重写onRequestPermissionsResult()方法，如果拒绝权限则finish()

然后编写初始化MediaPlayer/VideoView的方法

以VideoView为例
1、File file=new File(Environment.getExternalStorageDirectory(),"movie.mp4");
2、videoView.setVideoPath(file.getPath());
通过以上两个步骤指定视频文件的路径。

在onDestroy()方法中记得将MediaPlayer/VideoView的相关资源释放掉

最后记得在AndroidManifest.xml文件中声明所用的权限，