加載pdf文件時顯示進度欄

Question

iam對於android開發來說還是相當新的東西，所以iam試圖制作的應用程序可以顯示url中的pdf，

我要在從Web加載pdf文件時顯示進度欄（某些pdf文件超過15mb大）我該怎么做？

iam使用com.github.barteksc.pdfviewer.PDFView來顯示來自Web的pdf

這是我的pdf表演活動

private PDFView mPDFview;

private String mStoreId;

private FirebaseDatabase mFirebaseDatabase;
private DatabaseReference mReference;



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


    mFirebaseDatabase = FirebaseDatabase.getInstance();
    mReference = mFirebaseDatabase.getReference("Store");

    if (getIntent()!=null)
    {
        mStoreId = getIntent().getStringExtra("StoreId");
    }

    if (!mStoreId.isEmpty())
    {
        getUrlStoreFlyer(mStoreId);
    }

}

private void getUrlStoreFlyer(String storeId) {
    mReference.child(storeId).addValueEventListener(new ValueEventListener() 
{
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {
            Store storeChain = dataSnapshot.getValue(Store.class);
            String pdfUrl = storeChain.getFlyerPDF().toString();
            mPDFview = findViewById(R.id.flyer_pdfView);
            new RetrievePDFStream().execute(pdfUrl);
        }

        @Override
        public void onCancelled(DatabaseError databaseError) {
        }
    });
}

class RetrievePDFStream extends AsyncTask<String, Void, InputStream>
{
    @Override
    protected InputStream doInBackground(String... strings)
    {
        InputStream inputStream = null;
        try{
            URL url = new URL(strings[0]);
            HttpURLConnection urlConnection = (HttpURLConnection)url.openConnection();

            if (urlConnection.getResponseCode()==200)
            {
                inputStream = new BufferedInputStream(urlConnection.getInputStream());
            }
        }
        catch (IOException e)
        {
            return null;
        }

        return inputStream;
    }

    @Override
    protected void onPostExecute(InputStream inputStream) {
        mPDFview.fromStream(inputStream).load();
    }
}

@Override
public void onBackPressed() {
    finish();
    overridePendingTransition(0, 0);
}
}

這是我的xml

    <?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"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.test.FlyerActivity">


    <ProgressBar

        android:layout_width="50dp"
        android:layout_height="50dp"
        android:layout_alignParentBottom="true"
        android:layout_centerHorizontal="true"
        android:layout_marginBottom="150dp"
        android:id="@+id/progressBar2" />



    <com.github.barteksc.pdfviewer.PDFView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:id="@+id/flyer_pdfView"/>
    enter code here

</RelativeLayout>

Answer 1

這是我使用並完美工作的內容：

   @Override
    protected void onPostExecute(InputStream inputStream) {

        mPDFview.fromStream(inputStream).onLoad(new OnLoadCompleteListener() {
            @Override
            public void loadComplete(int nbPages) {
                ProgressBar progressBar = (ProgressBar) findViewById(R.id.progressBar2);
                progressBar.setVisibility(View.GONE);
            }
        }).load();

    }

Answer 2

  private PDFView mPDFview;

  private String mStoreId;
  //add progressbar
  private ProgressBar progressBar;

  private FirebaseDatabase mFirebaseDatabase;
  private DatabaseReference mReference;



@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_flyer);
//initialize
progressBar = (ProgressBar) findViewById(R.id.progressBar);

mFirebaseDatabase = FirebaseDatabase.getInstance();
mReference = mFirebaseDatabase.getReference("Store");

if (getIntent()!=null)
{
    mStoreId = getIntent().getStringExtra("StoreId");
}

if (!mStoreId.isEmpty())
{
    getUrlStoreFlyer(mStoreId);
}

}

private void getUrlStoreFlyer(String storeId) {
    mReference.child(storeId).addValueEventListener(new ValueEventListener() 
{
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {
            Store storeChain = dataSnapshot.getValue(Store.class);
            String pdfUrl = storeChain.getFlyerPDF().toString();
            mPDFview = findViewById(R.id.flyer_pdfView);
            new RetrievePDFStream().execute(pdfUrl);
        }

        @Override
        public void onCancelled(DatabaseError databaseError) {
        }
    });
}

class RetrievePDFStream extends AsyncTask<String, Void, InputStream>
{

   @Override
    protected void onPExecute(InputStream inputStream) {
        progressBar.setVisibility(View.VISIBLE);
    }

    @Override
    protected InputStream doInBackground(String... strings)
    {
        InputStream inputStream = null;
        try{
            URL url = new URL(strings[0]);
            HttpURLConnection urlConnection = (HttpURLConnection)url.openConnection();

            if (urlConnection.getResponseCode()==200)
            {
                inputStream = new BufferedInputStream(urlConnection.getInputStream());
            }
        }
        catch (IOException e)
        {
            return null;
        }

        return inputStream;
    }

    @Override
    protected void onPostExecute(InputStream inputStream) {
        mPDFview.fromStream(inputStream).load();
        progressBar.setVisibility(View.GONE);

    }
}

@Override
public void onBackPressed() {
    finish();
    overridePendingTransition(0, 0);
    progressBar.setVisibility(View.GONE);

}
}

Answer 3

由於您正在使用庫從輸入流中加載PDF，因此可以執行以下操作。

1. 在執行異步任務之前，使進度條可見，而PDFView不可見。

   progressBar = findViewById(R.id.progressBar2); mPDFview = findViewById(R.id.flyer_pdfView); progressBar.setVisibility(View.VISIBLE); mPDFview.setVisibility(View.INVISIBLE); new RetrievePDFStream().execute(pdfUrl);

2. 在網絡調用完成之后，您可以在AsyncTask的onPostExecute()中執行UI操作。 因此，在這里，您將必須使PDFView可見，而progressBar不可見，而且由於要進行網絡操作，然后將其流式傳輸到PDFView，PDFView也將花費時間來流式傳輸內容。 我查看了正在使用的庫，並相信它具有一個名為onLoad(onLoadCompleteListener)的函數，您可以將該函數與fromStream()一起使用，以使進度條不可見，而pdfView可見。

   @Override protected void onPostExecute(InputStream inputStream) { mPDFview.fromStream(inputStream).onLoad(this).load(); }

   @Override public void loadComplete(int nbPages) { progressBar.setVisibilitiy(INVISIBLE); mPDFView.setVisibility(VISIBLE); }

另外，由於使用的庫實際上可以從URI加載PDF，因此根本不需要使用“異步任務”。 只需調用PDFView.fromUri(uri).onLoad(this).load();