资产文件夹中的pdf阅读器

Question

我想用android studio创建一个pdf阅读器。我在资源文件夹中添加了一个pdf文件。我用了seekbar。但代码没有显示任何内容。怎么了？

我分享所有前卫

Mainactivity.java

package enespolat.polat.com.kuranahmethusrev;

import android.content.res.Configuration;
import android.graphics.Bitmap;
import android.graphics.Matrix;
import android.graphics.Rect;
import android.graphics.pdf.PdfRenderer;
import android.os.Environment;
import android.os.ParcelFileDescriptor;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.SeekBar;
import android.widget.TextView;

import java.io.File;

import uk.co.senab.photoview.PhotoViewAttacher;

public class MainActivity extends AppCompatActivity {
    LinearLayout pagerSection;
    SeekBar pageSeekbar;
    ImageView pageView;
    TextView tvCounter;
    PdfRenderer.Page sayfa;

    PhotoViewAttacher pva;

    int pageCount=0;
    int currPage=0;

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


        pageSeekbar=(SeekBar)findViewById(R.id.sbPager);
        pagerSection=(LinearLayout)findViewById(R.id.llPageCounter);
        pageView=(ImageView)findViewById(R.id.iv);
        tvCounter=(TextView)findViewById(R.id.tvCounter);

        render();

        pva = new PhotoViewAttacher(pageView);
        pva.setMaximumScale(10.0f);

        pageSeekbar.setMax(605);
        pageSeekbar.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
            @Override
            public void onProgressChanged(SeekBar seekBar, int i, boolean b)
            {
                currPage=i;
                showCurrentPageIndicator();

            }

            @Override
            public void onStartTrackingTouch(SeekBar seekBar)
            {

            }

            @Override
            public void onStopTrackingTouch(SeekBar seekBar)
            {
                currPage=seekBar.getProgress();
                render();


            }
        });




    }

    public void onConfigurationChanged(Configuration newConfig) {
        super.onConfigurationChanged(newConfig);
        if (pageView != null)
            pageView.invalidate();

    }

    void showCurrentPageIndicator()
    {

        tvCounter.setText(""+(currPage+1));
        pagerSection.setVisibility(View.VISIBLE);
        pagerSection.postDelayed(new Runnable() {
            @Override
            public void run() {
                pagerSection.setVisibility(View.GONE);
            }
        },700);
    }

    private void render()
    {
        try {
            File dlFolder = new File(Environment.getExternalStorageDirectory(), "Download");
            File pdfFile = new File(dlFolder, "kuran.pdf");
            PdfRenderer renderer = new PdfRenderer(ParcelFileDescriptor.open(pdfFile,ParcelFileDescriptor.MODE_READ_ONLY));




            sayfa =  renderer.openPage(currPage);

            Bitmap bitmap=Bitmap.createBitmap(sayfa.getWidth(),sayfa.getHeight(), Bitmap.Config.ARGB_8888);


            Matrix m=pageView.getImageMatrix();
            m.setScale(1.0f, 1.0f);
            Rect rect=new Rect(0,0,sayfa.getWidth(),sayfa.getHeight());


            sayfa.render(bitmap,rect,m,PdfRenderer.Page.RENDER_MODE_FOR_DISPLAY);
            //img.setImageMatrix(m);
            pageView.setImageBitmap(bitmap);
            pageView.invalidate();

            /**/


            sayfa.close();


        } catch (Exception e) {
            e.printStackTrace();

        }
    }
}

布局文件夹

  <?xml version="1.0" encoding="utf-8" ?> 
- <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:id="@+id/activity_main" android:layout_width="match_parent" android:background="#FFFFFF" android:layout_height="match_parent">
  <ImageView android:id="@+id/iv" android:layout_width="match_parent" android:layout_height="match_parent" android:layout_above="@+id/ly" /> 
- <LinearLayout android:background="#88333333" android:layout_width="match_parent" android:paddingRight="5dp" android:paddingLeft="5dp" android:id="@+id/ly" android:paddingBottom="12dp" android:paddingTop="12dp" android:layout_height="wrap_content" android:layout_alignParentBottom="true" android:layout_alignParentLeft="true" android:layout_alignParentStart="true">
  <SeekBar android:id="@+id/sbPager" android:layout_width="match_parent" android:layout_height="wrap_content" /> 
  </LinearLayout>
- <LinearLayout android:visibility="gone" android:orientation="vertical" android:layout_width="wrap_content" android:layout_height="wrap_content" android:padding="40dp" android:background="#88333333" android:id="@+id/llPageCounter" android:layout_centerVertical="true" android:layout_centerHorizontal="true">
  <TextView android:layout_width="match_parent" android:layout_height="match_parent" android:textColor="#FFFFFF" android:textStyle="bold" android:id="@+id/tvCounter" android:text="355" android:textSize="40sp" android:gravity="center" /> 
  </LinearLayout>
  </RelativeLayout>

清单

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