一.Assets文件:
Android 中资源分为两种,一种是res下可编译的资源文件, 这种资源文件系统会在R.Java里面自动生成该资源文件的ID,访问也很简单,只需要调用R.XXX.id即可;第二种就是放在assets文件夹下面的原生资源文件,放在这个文件夹下面的文件不会被R文件编译,所以不能像第一种那样直接使用.Android提供了一个工具类,方便我们操作获取assets文件下的文件:AssetManager
AssetManager提供了如下方法用于处理assets
String[] list(String path);//列出该目录下的下级文件和文件夹名称
InputStream open(String fileName);//以顺序读取模式打开文件,默认模式为ACCESS_STREAMING
InputStream open(String fileName, int accessMode);//以指定模式打开文件。读取模式有以下几种:
//ACCESS_UNKNOWN : 未指定具体的读取模式
//ACCESS_RANDOM : 随机读取
//ACCESS_STREAMING : 顺序读取
//ACCESS_BUFFER : 缓存读取
void close()//关闭AssetManager实例
使用
assets目录下主要存放四种文件:文本文件、图像文件、网页文件(包括html中引用的js/ccs/jpg等资源)、音频视频文件,下面通过具体的案例分别来说下怎么获取
加载assets目录下的网页
webView.loadUrl("file:///android_asset/html/index.htmll");
说明:这种方式可以加载assets目录下的网页,并且与网页有关的css,js,图片等文件也会的加载。
加载assets目录下的图片资源
InputStream is = null;
try {
is = getAssets().open("test.png");
Bitmap bitmap = BitmapFactory.decodeStream(is);
iv.setImageBitmap(bitmap);
} catch (IOException e) {
e.printStackTrace();
}
加载assets目录下的文本文件
try {
is = getAssets().open("txt/test.txt");
int lenght = 0;
lenght = is.available();
byte[] buffer = new byte[lenght];
is.read(buffer);
String result = new String(buffer, "gbk");
tv.setText(result);
} catch (IOException e) {
e.printStackTrace();
}
加载assets目录下音乐
//MediaPlayer的情况下
try {
MediaPlayer mPlayer=new MediaPlayer()
// 打开指定音乐文件,获取assets目录下指定文件的AssetFileDescriptor对象
AssetFileDescriptor afd = getAssets().openFd("music/test.mp3");
mPlayer.reset();
// 使用MediaPlayer加载指定的声音文件。
mPlayer.setDataSource(afd.getFileDescriptor(),
afd.getStartOffset(), afd.getLength());
// 准备声音
mPlayer.prepare();
// 播放
mPlayer.start();
} catch (IOException e) {
e.printStackTrace();
}
//IJK
//实例化播放内核
tv.danmaku.ijk.media.player.IjkMediaPlayer ijkPlayer = new tv.danmaku.ijk.media.player.IjkMediaPlayer();
//获得播放源访问入口
AssetManager am = getAssets();
try {
AssetFileDescriptor afd = am.openFd("assets_video.mp4");// 注意这里的区别
//构建IjkPlayer能识别的IMediaDataSource,下面的RawDataSourceProvider实现了IMediaDataSource接口
RawDataSourceProvider sourceProvider = new RawDataSourceProvider(fd);
//给IjkPlayer设置播放源
ijkPlayer.setDataSource(sourceProvider);
} catch (IOException e) {
e.printStackTrace();
}
//设置准备就绪状态监听
ijkPlayer .setOnPreparedListener(new MediaPlayer.OnPreparedListener() {
@Override
public void onPrepared(MediaPlayer mp) {
// 开始播放
ijkPlayer.start();
}
});
//准备播放
ijkPlayer.prepareAsync();
//ExoPlayer
//实例化播放内核
TrackSelection.Factory videoTrackSelectionFactory =
new AdaptiveTrackSelection.Factory(new DefaultBandwidthMeter());
DefaultTrackSelector mTrackSelector = new DefaultTrackSelector(videoTrackSelectionFactory);
boolean preferExtensionDecoders = true;
boolean useExtensionRenderers = true;//是否开启扩展
@DefaultRenderersFactory.ExtensionRendererMode int extensionRendererMode = useExtensionRenderers
? (preferExtensionDecoders ? DefaultRenderersFactory.EXTENSION_RENDERER_MODE_PREFER
: DefaultRenderersFactory.EXTENSION_RENDERER_MODE_ON)
: DefaultRenderersFactory.EXTENSION_RENDERER_MODE_OFF;
DefaultRenderersFactory rendererFactory = new DefaultRenderersFactory(mAppContext, extensionRendererMode);
DefaultLoadControl loadControl = new DefaultLoadControl();
//工厂方法获得播放器实例
om.google.android.exoplayer2.SimpleExoPlayer exoPlayer =
ExoPlayerFactory.newSimpleInstance(rendererFactory, mTrackSelector, loadControl, null);
//构建ExoPlayer能识别的播放源--MediaSource
String url = "file:///android_asset/" + "assets_video.mp4";
MediaSource mediaSource = ExoSourceManager.newInstance(mAppContext, getHeaders()).getMediaSource(
url, false, false, MediaPlayerManager.instance().isLooping(), null
);
//给ExoPlayer设置播放源,并准备播放
exoPlayer.prepare(mediaSource);
//让ExoPlayer准备好后就开始播放
exoPlayer.setPlayWhenReady(true);
将assets下的文件复制到SD卡中
/**
* 从assets目录中复制整个文件夹内容
* @param context Context 使用CopyFiles类的Activity
* @param oldPath String 原文件路径 如:/aa
* @param newPath String 复制后路径 如:xx:/bb/cc
*/
public void copyFilesFassets(Context context,String oldPath,String newPath) {
try {
String fileNames[] = context.getAssets().list(oldPath);//获取assets目录下的所有文件及目录名
if (fileNames.length > 0) {//如果是目录
File file = new File(newPath);
file.mkdirs();//如果文件夹不存在,则递归
for (String fileName : fileNames) {
copyFilesFassets(context,oldPath + "/" + fileName,newPath+"/"+fileName);
}
} else {//如果是文件
InputStream is = context.getAssets().open(oldPath);
FileOutputStream fos = new FileOutputStream(new File(newPath));
byte[] buffer = new byte[1024];
int byteCount=0;
while((byteCount=is.read(buffer))!=-1) {//循环从输入流读取 buffer字节
fos.write(buffer, 0, byteCount);//将读取的输入流写入到输出流
}
fos.flush();//刷新缓冲区
is.close();
fos.close();
}
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
//如果捕捉到错误则通知UI线程
MainActivity.handler.sendEmptyMessage(COPY_FALSE);
}
}
Android studio下添加asset
然后点击finish就好了
然后还有个就是assets单个存储文件不能超过1MB,超过的话会报
This file can not be opened as a file descriptor; it is probably compressed
二.raw文件
其实音视频那用raw的方式实现也行,反正2个最后打包生成的apk后没有被转成二进制
Raw文件访问方式
Raw
文件位于res/raw目录下,Raw文件会被映射到R.java文件中,所以访问的时候直接使用资源ID即可,如
R.raw.test
或者获得该文件的AssetFileDescriptor:
AssetFileDescriptor afd = getResources().openRawResourceFd(R.raw.raw_video);
使用:
//MediaPlayer
//实例化播放内核
android.media.MediaPlayer mediaPlayer = new android.media.MediaPlayer();
//获得播放源访问入口
AssetFileDescriptor afd = getResources().openRawResourceFd(R.raw.test); // 注意这里的区别
//给MediaPlayer设置播放源
mediaPlayer.setDataSource(afd.getFileDescriptor(), afd.getStartOffset(), afd.getLength());
//设置准备就绪状态监听
mediaPlayer.setOnPreparedListener(new MediaPlayer.OnPreparedListener() {
@Override
public void onPrepared(MediaPlayer mp) {
// 开始播放
mediaPlayer.start();
}
});
//准备播放
mediaPlayer.prepareAsync();
//IJK
//实例化播放内核
tv.danmaku.ijk.media.player.IjkMediaPlayer ijkPlayer = new tv.danmaku.ijk.media.player.IjkMediaPlayer();
//获得播放源访问入口
AssetFileDescriptor afd = getResources().openRawResourceFd(R.raw.test); // 注意这里的区别
//构建IjkPlayer能识别的IMediaDataSource,下面的RawDataSourceProvider实现了IMediaDataSource接口
RawDataSourceProvider sourceProvider = new RawDataSourceProvider(fd);
//给IjkPlayer设置播放源
ijkPlayer.setDataSource(sourceProvider);
//设置准备就绪状态监听
ijkPlayer .setOnPreparedListener(new MediaPlayer.OnPreparedListener() {
@Override
public void onPrepared(MediaPlayer mp) {
// 开始播放
ijkPlayer.start();
}
});
//准备播放
ijkPlayer.prepareAsync();
//补充下,其中的RawDataSourceProvider实现了IMediaDataSource 接口,IMediaDataSource是IjkPlayer包中的接口,实现了IMediaDataSource接口的类可以设置给IjkPlayer作为播放源。就像下面这样:
import tv.danmaku.ijk.media.player.misc.IMediaDataSource;
public class RawDataSourceProvider implements IMediaDataSource {
private AssetFileDescriptor mDescriptor;
private byte[] mMediaBytes;
public RawDataSourceProvider(AssetFileDescriptor descriptor) {
this.mDescriptor = descriptor;
}
@Override
public int readAt(long position, byte[] buffer, int offset, int size) {
if (position + 1 >= mMediaBytes.length) {
return -1;
}
int length;
if (position + size < mMediaBytes.length) {
length = size;
} else {
length = (int) (mMediaBytes.length - position);
if (length > buffer.length)
length = buffer.length;
length--;
}
// 把文件内容copy到buffer中;
System.arraycopy(mMediaBytes, (int) position, buffer, offset, length);
return length;
}
@Override
public long getSize() throws IOException {
long length = mDescriptor.getLength();
if (mMediaBytes == null) {
InputStream inputStream = mDescriptor.createInputStream();
mMediaBytes = readBytes(inputStream);
}
return length;
}
@Override
public void close() throws IOException {
if (mDescriptor != null)
mDescriptor.close();
mDescriptor = null;
mMediaBytes = null;
}
//读取文件内容
private byte[] readBytes(InputStream inputStream) throws IOException {
ByteArrayOutputStream byteBuffer = new ByteArrayOutputStream();
int bufferSize = 1024;
byte[] buffer = new byte[bufferSize];
int len;
while ((len = inputStream.read(buffer)) != -1) {
byteBuffer.write(buffer, 0, len);
}
return byteBuffer.toByteArray();
}
}
我们首先获取到Raw/Assets文件的AssetFileDescriptor,然后用它去构建一个IMediaDataSource,最后设置给IjkPlayer。
//ExoPlayer
//实例化播放内核
TrackSelection.Factory videoTrackSelectionFactory =
new AdaptiveTrackSelection.Factory(new DefaultBandwidthMeter());
DefaultTrackSelector mTrackSelector = new DefaultTrackSelector(videoTrackSelectionFactory);
boolean preferExtensionDecoders = true;
boolean useExtensionRenderers = true;//是否开启扩展
@DefaultRenderersFactory.ExtensionRendererMode int extensionRendererMode = useExtensionRenderers
? (preferExtensionDecoders ? DefaultRenderersFactory.EXTENSION_RENDERER_MODE_PREFER
: DefaultRenderersFactory.EXTENSION_RENDERER_MODE_ON)
: DefaultRenderersFactory.EXTENSION_RENDERER_MODE_OFF;
DefaultRenderersFactory rendererFactory = new DefaultRenderersFactory(mAppContext, extensionRendererMode);
DefaultLoadControl loadControl = new DefaultLoadControl();
//工厂方法获得播放器实例
om.google.android.exoplayer2.SimpleExoPlayer exoPlayer =
ExoPlayerFactory.newSimpleInstance(rendererFactory, mTrackSelector, loadControl, null);
//构建Raw文件播放源--RawResourceDataSource
DataSpec dataSpec = new DataSpec(RawResourceDataSource.buildRawResourceUri(R.raw.raw_video));
RawResourceDataSource rawResourceDataSource = new RawResourceDataSource(this);
try {
rawResourceDataSource.open(dataSpec);
} catch (RawResourceDataSource.RawResourceDataSourceException e) {
e.printStackTrace();
}
//构建ExoPlayer能识别的播放源--MediaSource
String url = rawDataSource.getUri().toString();
MediaSource mediaSource = ExoSourceManager.newInstance(mAppContext, getHeaders()).getMediaSource(
url, false, false, MediaPlayerManager.instance().isLooping(), null
);
//给ExoPlayer设置播放源,并准备播放
exoPlayer.prepare(mediaSource);
//让ExoPlayer准备好后就开始播放
exoPlayer.setPlayWhenReady(true);