//视频缓存
    implementation ‘com.danikula:videocache:2.7.1‘

public class MainActivity extends AppCompatActivity {

    private static final int MY_PERMISSIONS_WRITE_EXTERNAL_STORAGE = 1;

    String url = "http://clips.vorwaerts-gmbh.de/big_buck_bunny.mp4";
    VideoView videoView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        videoView = findViewById(R.id.videoView);

        //检查版本是否大于M
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
            if (ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {
                ActivityCompat.requestPermissions(this,
                        new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE},
                        MY_PERMISSIONS_WRITE_EXTERNAL_STORAGE);
            } else {
                Log.i("aaa", "权限已申请");
                initVideo();
            }
        }
    }

    private void initVideo() {
        HttpProxyCacheServer proxy = VideoApplication.getProxy(this);
        //1.我们会将原始url注册进去
        // proxy.registerCacheListener(, bean.getVideo_url());
        //2.我们播放视频的时候会调用以下代码生成proxyUrl
        String proxyUrl = proxy.getProxyUrl(url);
        if (proxy.isCached(url)) {
            Log.i("aaaa", "已缓存");
        } else {
            Log.i("aaaa", "未缓存");
        }
        Log.i("aaaapath", proxyUrl);
        videoView.setVideoPath(proxyUrl);
        videoView.start();
        videoView.findFocus();
    }


    @Override
    public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {

        if (requestCode == MY_PERMISSIONS_WRITE_EXTERNAL_STORAGE) {
            if (grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                initVideo();
            } else {
                //"权限已拒绝";
            }
        }
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
    }

}

public class VideoApplication extends Application {


    @Override
    public void onCreate() {
        super.onCreate();
    }

    private HttpProxyCacheServer proxy;

    public static HttpProxyCacheServer getProxy(Context context) {
        VideoApplication app = (VideoApplication) context.getApplicationContext();
        return app.proxy == null ? (app.proxy = app.newProxy()) : app.proxy;
    }

    private HttpProxyCacheServer newProxy() {
        return new HttpProxyCacheServer.Builder(this)
                .maxCacheSize(1024 * 1024 * 1024)       // 1 Gb for cache
                .fileNameGenerator(new MyFileNameGenerator())
                .build();
    }
}

  <uses-permission android:name="android.permission.INTERNET" />
    <!--用于写入缓存数据到扩展存储卡-->
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.VIBRATE" />