音乐播放器开发

MediaPlayer 是Android 控制音频和视频文件播放类
1.创建MediaPlayer 对象 的Create方法
2.无can构造方法 -> setDataSorce -> prepare(）加载创造文件
注意访问SDK需要授予权限
当Mediaplay.stop() 资源后需要重新加载资源，使用Mediaplay.setDataSource() 方法进行加载 ，最后还需要释放资源，防止内存泄漏

• 缺点： 1.延迟低长，占有资源多 2. 不支持同时播放多个音频

package com.example.myapplication;import android.media.MediaPlayer;
import android.net.Uri;
import android.os.Build;
import android.os.Bundle;
import android.view.View;
import android.widget.ImageButton;
import android.widget.Toast;import androidx.annotation.RequiresApi;
import androidx.appcompat.app.AppCompatActivity;import java.io.File;
import java.io.IOException;
/*** MediaPlay 实现简易的播放器
*/
public class MainActivity extends AppCompatActivity {private MediaPlayer mediaPlayer;            //定义MediaPlayer对象private boolean isPause = false;        //定义是否暂停private File file;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);final ImageButton btn_play = (ImageButton) findViewById(R.id.btn_play); //获取“播放/暂停”按钮final ImageButton btn_stop = (ImageButton) findViewById(R.id.btn_stop); //获取“停止”按钮;file = new File("/res/raw/bird.ogg");if (file.exists()) {mediaPlayer = MediaPlayer.create(this, Uri.parse(file.getAbsolutePath()));} else {Toast.makeText(MainActivity.this, "要播放的音频文件不存在！", Toast.LENGTH_SHORT).show();return;}// 为MediaPlayer 添加监听事件 完成事件监听器，当media.play.stop 后在重新playmediaPlayer.setOnCompletionListener(new MediaPlayer.OnCompletionListener() {@Overridepublic void onCompletion(MediaPlayer mediaPlayer) {play();}});btn_play.setOnClickListener(new View.OnClickListener(){@RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)@Overridepublic void onClick(View view) {if(mediaPlayer.isPlaying() && !isPause){mediaPlayer.pause();isPause = true; // 暂停播放// 更好播放图标((ImageButton) view).setImageDrawable(getResources().getDrawable(R.drawable.play, null));}else{mediaPlayer.start();                           //继续播放// 更换为暂停图标((ImageButton) view).setImageDrawable(getResources().getDrawable(R.drawable.pause, null));isPause = false;                         //设置为播放状态}}});btn_stop.setOnClickListener(new View.OnClickListener() { //单击停止按钮，实现停止播放音频@RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)@Overridepublic void onClick(View v) {mediaPlayer.stop();                    //停止播放//更换为播放图标btn_play.setImageDrawable(getResources().getDrawable(R.drawable.play, null));}});}private void play(){// 重置MediaPlaymediaPlayer.reset();try {mediaPlayer.setDataSource(file.getAbsolutePath());mediaPlayer.prepare(); // 预加载} catch (IOException e) {e.printStackTrace();}}@Overrideprotected void onDestroy() {if(mediaPlayer.isPlaying()){mediaPlayer.stop();}mediaPlayer.release();super.onDestroy();}
}

SoundPool 播放多个音频

优点： 1. 延迟低 2.占有资源少 3. 支持多个音频播放
缺点： 不能播放大文件音频
应用场景： 小型游戏中多个飞机被击破声音
创建SoundPool 对象，load ， play

package com.example.myapplication;import android.media.AudioAttributes;
import android.media.SoundPool;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ListView;import androidx.appcompat.app.AppCompatActivity;import java.util.HashMap;public class MainActivity extends AppCompatActivity {@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);ListView listView = findViewById(R.id.listView);// 创建SoundPool 对象设置音频相关特性//1.音频对象AudioAttributes attr = new AudioAttributes.Builder()           //设置音效相关属性.setUsage(AudioAttributes.USAGE_GAME)                 // 设置音效使用场景.setContentType(AudioAttributes.CONTENT_TYPE_MUSIC)  // 设置音效的类型.build();final SoundPool soundpool = new SoundPool.Builder()           // 创建SoundPool对象.setAudioAttributes(attr) // 设置音效池的属性.setMaxStreams(10) // 设置最多可容纳10个音频流，.build();// 要播放音频保存到HashMap中final HashMap<Integer, Integer> soundmap = new HashMap<Integer, Integer>();soundmap.put(0, soundpool.load(this, R.raw.cuckoo, 1));soundmap.put(1, soundpool.load(this, R.raw.chimes, 1));soundmap.put(2, soundpool.load(this, R.raw.notify, 1));soundmap.put(3, soundpool.load(this, R.raw.ringout, 1));soundmap.put(4, soundpool.load(this, R.raw.bird, 1));soundmap.put(5, soundpool.load(this, R.raw.water, 1));soundmap.put(6, soundpool.load(this, R.raw.cock, 1));listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {@Overridepublic void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {soundpool.play(soundmap.get(i),1,1,0,0,1);}});}
}

video View 播放视频

1. 在XML中添加Videoview 组件：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayoutxmlns:android="http://schemas.android.com/apk/res/android"xmlns:tools="http://schemas.android.com/tools"android:layout_width="match_parent"android:layout_height="match_parent"tools:context=".MainActivity"><VideoViewandroid:id="@+id/video"android:layout_width="match_parent"android:layout_height="match_parent" />
</RelativeLayout>

读取SDK上数据 设置Mainifest.xml 设置访问权限，同时在Android 机器上设置权限打开

  <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" /><uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS" />
-----------------------------------------------------------
<?xml version="1.0" encoding="utf-8"?>
<manifest package="com.mingrisoft"xmlns:android="http://schemas.android.com/apk/res/android"><uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" /><uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS" /><applicationandroid:allowBackup="true"android:icon="@mipmap/ic_launcher"android:label="@string/app_name"android:supportsRtl="true"android:theme="@style/AppTheme"><activity android:name=".MainActivity" android:screenOrientation="landscape"><intent-filter><action android:name="android.intent.action.MAIN"/><category android:name="android.intent.category.LAUNCHER"/></intent-filter></activity></application></manifest>

package com.example.myapplication;import android.media.MediaPlayer;
import android.os.Bundle;import com.google.android.material.floatingactionbutton.FloatingActionButton;
import com.google.android.material.snackbar.Snackbar;import androidx.appcompat.app.AppCompatActivity;
import androidx.appcompat.widget.Toolbar;import android.os.Environment;
import android.view.View;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.MediaController;
import android.widget.Toast;
import android.widget.VideoView;import java.io.File;public class MainActivity extends AppCompatActivity {@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);VideoView videoView = findViewById(R.id.video);File file = new File(Environment.getExternalStorageDirectory()+"/video.mp4");if(file.exists()){videoView.setVideoPath(file.getAbsolutePath());}else{return ;}// 控制视频播放MediaController mc = new MediaController(MainActivity.this);videoView.setMediaController(mc);// videoiew 获取焦点videoView.requestFocus();videoView.start();// 完成监听器videoView.setOnCompletionListener(new MediaPlayer.OnCompletionListener() {@Overridepublic void onCompletion(MediaPlayer mediaPlayer) {Toast.makeText(MainActivity.this,"视频播放完成",Toast.LENGTH_SHORT).show();}});}}

控制摄像头摄像

 <!-- 授予程序可以向SD卡中保存文件的权限 --><uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS"/><uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/><!-- 授予程序使用摄像头的权限 --><uses-permission android:name="android.permission.CAMERA"/><uses-feature android:name="android.hardware.camera.autofocus"/><uses-feature android:name="android.hardware.camera"/>

package com.example.myapplication;import android.content.Intent;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.PixelFormat;
import android.hardware.Camera;
import android.net.Uri;
import android.os.Bundle;
import android.os.Environment;
import android.provider.MediaStore;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;
import android.view.WindowManager;
import android.widget.ImageButton;
import android.widget.Toast;import androidx.appcompat.app.AppCompatActivity;import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;public class MainActivity extends AppCompatActivity {private Camera camera;private boolean isPreview = false; // 设置是否是预览状态@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);//设置全屏显示getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,WindowManager.LayoutParams.FLAG_FULLSCREEN);if (!android.os.Environment.getExternalStorageState().equals(  //判断手机是否安装SD卡android.os.Environment.MEDIA_MOUNTED)) {Toast.makeText(this, "请安装SD卡！", Toast.LENGTH_SHORT).show(); // 提示安装SD卡}// 设置预览final SurfaceView surfaceView = findViewById(R.id.surfaceView);final SurfaceHolder surfaceHolder = surfaceView.getHolder();// 设置自己维护缓存surfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);ImageButton preview = (ImageButton) findViewById(R.id.preview);        //获取“预览”按钮ImageButton takePicture = (ImageButton) findViewById(R.id.takephoto);  //获取“拍照”按钮preview.setOnClickListener(new View.OnClickListener() {@Overridepublic void onClick(View view) {if (!isPreview) {camera = Camera.open();isPreview = true;}try {camera.setPreviewDisplay(surfaceHolder);                   // 设置用于显示预览的SurfaceViewCamera.Parameters parameters = camera.getParameters();    //获取相机参数parameters.setPictureFormat(PixelFormat.JPEG);    //指定图片为JPEG图片parameters.set("jpeg-quality", 80);            //设置图片的质量camera.setParameters(parameters);                //重新设置相机参数camera.startPreview();                            //开始预览camera.autoFocus(null);                        //设置自动对焦} catch (IOException e) {                           //输出异常信息e.printStackTrace();}}});// 保存拍照//实现相机拍照功能takePicture.setOnClickListener(new View.OnClickListener() {@Overridepublic void onClick(View v) {if (camera != null) {                                     //相机不为空camera.takePicture(null, null, jpeg);                //进行拍照}}});}final   Camera.PictureCallback jpeg = new Camera.PictureCallback() {@Overridepublic void onPictureTaken(byte[] data, Camera camera) {// 根据拍照所得的数据创建位图final Bitmap bm = BitmapFactory.decodeByteArray(data, 0,data.length);camera.stopPreview();        //停止预览isPreview = false;         //设置为非预览状态//获取sd卡根目录File appDir = new File(Environment.getExternalStorageDirectory(), "/DCIM/Camera/");if (!appDir.exists()) {      //如果该目录不存在appDir.mkdir();          //就创建该目录}String fileName = System.currentTimeMillis() + ".jpg"; //将获取当前系统时间设置为照片名称File file = new File(appDir, fileName);  //创建文件对象try {  //保存拍到的图片FileOutputStream fos = new FileOutputStream(file);  //创建一个文件输出流对象bm.compress(Bitmap.CompressFormat.JPEG, 100, fos);  //将图片内容压缩为JPEG格式输出到输出流对象中fos.flush();                                        //将缓冲区中的数据全部写出到输出流中fos.close();                                        //关闭文件输出流对象} catch (FileNotFoundException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();}// 将照片插入到图库当中try {MediaStore.Images.Media.insertImage(MainActivity.this.getContentResolver(),file.getAbsolutePath(),fileName,null);} catch (FileNotFoundException e) {e.printStackTrace();}// 更新通知图库MainActivity.this.sendBroadcast(new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE, Uri.parse("file://" + "")));restCamera();}};private void restCamera(){if(!isPreview){camera.startPreview();isPreview = true;}}@Overrideprotected void onPause() {  //当暂停Activity时，停止预览并释放资源if (camera != null) {        //如果相机不为空camera.stopPreview();    //停止预览camera.release();        //释放资源}super.onPause();}
}