QbSdk.initX5Environment(this,null);

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="@+id/rl_root"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
    android:id="@+id/tv_wangsu"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:text="当前网速:0KB/s"
    android:layout_marginTop="10dp"
    android:layout_centerInParent="true"
    android:gravity="center"
    android:textSize="10sp"
    android:textColor="@color/colorAccent"
    />
<com.wang.avi.AVLoadingIndicatorView
    android:id="@+id/avi"
    style="@style/AVLoadingIndicatorView.Large"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:visibility="visible"
    app:indicatorColor="@color/colorAccent"
    android:layout_centerInParent="true"
    android:layout_below="@+id/tv_wangsu"
    app:indicatorName="BallClipRotateMultipleIndicator" />

<TextView
    android:id="@+id/tv_proess"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:text="当前进度:0%"
    android:layout_marginTop="10dp"
    android:layout_below="@+id/avi"
    android:gravity="center"
    android:textSize="10sp"
    android:textColor="@color/colorAccent"
    />


</RelativeLayout>

import android.Manifest;
import android.content.pm.PackageManager;
import android.os.Bundle;
import android.os.Environment;
import android.support.annotation.NonNull;
import android.support.v4.app.ActivityCompat;
import android.support.v7.app.AppCompatActivity;
import android.text.TextUtils;
import android.util.Log;
import android.view.View;
import android.view.ViewGroup.LayoutParams;
import android.widget.RelativeLayout;
import android.widget.TextView;
import android.widget.Toast;

import com.example.huanhang.henanapp.R;
import com.example.huanhang.henanapp.util.FileUtils;
import com.lzy.okgo.OkGo;
import com.lzy.okgo.callback.FileCallback;
import com.lzy.okgo.model.Progress;
import com.lzy.okgo.model.Response;
import com.tencent.smtt.sdk.TbsReaderView;
import com.wang.avi.AVLoadingIndicatorView;

import java.io.File;
import java.text.DecimalFormat;


/**
 * @author lei
 * @desc 使用腾讯TBS阅览
 * @date 2018/10/31 0031 -- 上午 8:54.
 */
public class ShowPdf2Activity extends AppCompatActivity implements TbsReaderView.ReaderCallback {

AVLoadingIndicatorView avi;
TextView pro;
TextView wangSu;
private TbsReaderView mTbsReaderView;
private String mFileName;
private String mUrl;
private RelativeLayout mRlRoot;
private String path = Environment.getExternalStorageDirectory() + "/tbsTest/" + "/File/";

public static String getDataSize(long size) {
    if (size < 0) {
        size = 0;
    }
    DecimalFormat formater = new DecimalFormat("####.00");
    if (size < 1024) {
        return size + "b";
    } else if (size < 1024 * 1024) {
        float kbsize = size / 1024f;
        return formater.format(kbsize) + "k";
    } else if (size < 1024 * 1024 * 1024) {
        float mbsize = size / 1024f / 1024f;
        return formater.format(mbsize) + "M";
    } else if (size < 1024 * 1024 * 1024 * 1024) {
        float gbsize = size / 1024f / 1024f / 1024f;
        return formater.format(gbsize) + "G";
    } else {
        return String.valueOf(size);
    }

}

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_show_pdf2);
    initView();
    String pdfPath = getIntent().getStringExtra("pdfPath");
    mUrl = FILE_BASE_URL + pdfPath;
//预览文件相关类
    mTbsReaderView = new TbsReaderView(ShowPdf2Activity.this, this);
    mRlRoot.addView(mTbsReaderView, new RelativeLayout.LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT));
    mFileName = parseName(mUrl);
    checkSDCardPermission();
    boolean existsDir = FileUtils.createOrExistsDir(path);
//首先判断本地是否有该文件,有就直接打开,否则就先下载
    if (existsDir) {
        if (isLocalExist()) {
            displayFile();
        } else {
            downLoad(mUrl, path, mFileName);

        }
    }
}

private String parseName(String url) {
    String fileName = null;
    try {
        fileName = url.substring(url.lastIndexOf("/") + 1);
    } finally {
        if (TextUtils.isEmpty(fileName)) {
            fileName = String.valueOf(System.currentTimeMillis());
        }
    }
    return fileName;
}

@Override
protected void onDestroy() {
    super.onDestroy();
    mTbsReaderView.onStop();
    FileUtils.deleteFile(getLocalFile());
}

private void displayFile() {
//解决部分手机无法预览问题
    String bsReaderTemp = "/storage/emulated/0/TbsReaderTemp";
    File file = new File(bsReaderTemp);
    if (!file.exists()) {
        boolean mkdirs = file.mkdirs();
        if (!mkdirs) {
            Toast.makeText(this, "创建/storage/emulated/0/TbsReaderTemp失败！", Toast.LENGTH_SHORT).show();
        }
    }
    Bundle bundle = new Bundle();
    bundle.putString("filePath", getLocalFile().getPath());
    bundle.putString("tempPath", Environment.getExternalStorageDirectory()+ "/" + "TbsReaderTemp");

    boolean result = mTbsReaderView.preOpen(parseFormat(mFileName), false);
    if (result) {
        mTbsReaderView.openFile(bundle);
    }
}

private File getLocalFile() {
    return new File(path, mFileName);
}

private String parseFormat(String fileName) {
    return fileName.substring(fileName.lastIndexOf(".") + 1);
}

private void initView() {
    mRlRoot = (RelativeLayout) findViewById(R.id.rl_root);
    pro = (TextView) findViewById(R.id.tv_proess);
    avi = (AVLoadingIndicatorView) findViewById(R.id.avi);
    wangSu = (TextView) findViewById(R.id.tv_wangsu);
}

private void downLoad(String url, String destFileDir, String destFileName) {
    OkGo.<File>get(url).headers("user", mFileName)
            .execute(new FileCallback(destFileDir, destFileName) {
                @Override
                public void downloadProgress(Progress progress) {
                    super.downloadProgress(progress);
                    pro.setText("当前进度:" + Math.round(progress.fraction * 100) + "%");
                    wangSu.setText("当前网速:" + getDataSize(progress.speed) + "/s");
                }

                @Override
                public void onSuccess(Response<File> response) {
                    Log.d("EasyHttpActivity", "下载完成");
                    avi.setVisibility(View.GONE);
                    pro.setText("下载完成,正在加载...");
                    wangSu.setVisibility(View.GONE);
                    displayFile();
                }
            });
}

@Override
public void onCallBackAction(Integer integer, Object o, Object o1) {

}

private void checkSDCardPermission() {
    if (ActivityCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {
        ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}, 0x01);
    }
}

@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
    super.onRequestPermissionsResult(requestCode, permissions, grantResults);
    if (requestCode == 0x01) {
        if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
            //获取权限
            downLoad(mUrl, path, mFileName);
        } else {
            Toast.makeText(this, "权限被禁止，无法下载文件！", Toast.LENGTH_SHORT).show();
        }
    }
}

private boolean isLocalExist() {
    return getLocalFile().exists();
}
}