将Pdf页面转换为Android Java中的Bitmap
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内容图文
我需要将PDF文件(PDF页面)转换为Android中的位图(或图像文件).
1.使用Apache的Pdfbox jar.但是它使用了android中不支持的一些java类.
2.尝试将图像转换为pdf的Itext jar(我需要反向操作)
就像我尝试了很多罐子一样.但没有积极的结果.
byte[] bytes;
try {
File file = new File(this.getFilesDir().getAbsolutePath()+"/2010Q2_SDK_Overview.pdf");
FileInputStream is = new FileInputStream(file);
// Get the size of the file
long length = file.length();
bytes = new byte[(int) length];
int offset = 0;
int numRead = 0;
while (offset < bytes.length && (numRead=is.read(bytes, offset, bytes.length-offset)) >= 0) {
offset += numRead;
}
ByteBuffer buffer = ByteBuffer.NEW(bytes);
String data = Base64.encodeToString(bytes, Base64.DEFAULT);
PDFFile pdf_file = new PDFFile(buffer);
PDFPage page = pdf_file.getPage(2);
RectF rect = new RectF(0, 0, (int) page.getBBox().width(),
(int) page.getBBox().height());
// Bitmap bufferedImage = Bitmap.createBitmap((int)rect.width(), (int)rect.height(),
// Bitmap.Config.ARGB_8888);
Bitmap image = page.getImage((int)rect.width(), (int)rect.height(), rect);
FileOutputStream os = new FileOutputStream(this.getFilesDir().getAbsolutePath()+"/pdf.jpg");
image.compress(Bitmap.CompressFormat.JPEG, 80, os);
// ((ImageView) findViewById(R.id.testView)).setImageBitmap(image);
我正在获取图像文件,
代替,
package com.test123;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import com.sun.pdfview.PDFFile;
import com.sun.pdfview.PDFPage;
import net.sf.andpdf.nio.ByteBuffer;
import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.RectF;
import android.os.Bundle;
import android.util.Base64;
public class Test123Activity extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
byte[] bytes;
try {
File file = new File(this.getFilesDir().getAbsolutePath()+"/2010Q2_SDK_Overview.pdf");
FileInputStream is = new FileInputStream(file);
// Get the size of the file
long length = file.length();
bytes = new byte[(int) length];
int offset = 0;
int numRead = 0;
while (offset < bytes.length && (numRead=is.read(bytes, offset, bytes.length-offset)) >= 0) {
offset += numRead;
}
ByteBuffer buffer = ByteBuffer.NEW(bytes);
String data = Base64.encodeToString(bytes, Base64.DEFAULT);
PDFFile pdf_file = new PDFFile(buffer);
PDFPage page = pdf_file.getPage(2);
RectF rect = new RectF(0, 0, (int) page.getBBox().width(),
(int) page.getBBox().height());
// Bitmap bufferedImage = Bitmap.createBitmap((int)rect.width(), (int)rect.height(),
// Bitmap.Config.ARGB_8888);
Bitmap image = page.getImage((int)rect.width(), (int)rect.height(), rect);
FileOutputStream os = new FileOutputStream(this.getFilesDir().getAbsolutePath()+"/pdf.jpg");
image.compress(Bitmap.CompressFormat.JPEG, 80, os);
//((ImageView) findViewById(R.id.testView)).setImageBitmap(image);
} catch (Exception e) {
e.printStackTrace();
}
}
}
否则,使用内置在应用程序中的函数在android中显示pdf文件的任何其他方式？
解决方法:
我解决了这个问题.它就像让设备有时间渲染每个页面一样简单.
要解决这个问题,你所要做的就是改变
PDFPage page = pdf_file.getPage(2);
至
PDFPage page = pdf_file.getPage(2, true);
首先,要在Android中查看PDF,您必须将PDF转换为图像,然后将其显示给用户. (我将使用webview)
所以要做到这一点,我们需要这个library.这是我编辑的git版本.
将库导入项目后,需要创建活动.
XML：
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<WebView
android:id="@+id/webView1"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
</LinearLayout>
java：
//Imports:
import android.app.Activity;
import android.app.ProgressDialog;
import android.content.Intent;
import android.graphics.Bitmap;
import android.os.AsyncTask;
import android.os.Bundle;
import android.os.Environment;
import android.util.Base64;
import android.util.Log;
import android.view.View;
import android.view.ViewTreeObserver;
import android.webkit.WebView;
import com.sun.pdfview.PDFFile;
import com.sun.pdfview.PDFImage;
import com.sun.pdfview.PDFPage;
import com.sun.pdfview.PDFPaint;
import net.sf.andpdf.nio.ByteBuffer;
import net.sf.andpdf.refs.HardReference;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.RandomAccessFile;
import java.nio.channels.FileChannel;
//Globals:
private WebView wv;
private int ViewSize = 0;
//OnCreate Method:
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//Settings
PDFImage.sShowImages = true; // show images
PDFPaint.s_doAntiAlias = true; // make text smooth
HardReference.sKeepCaches = true; // save images in cache
//Setup webview
wv = (WebView)findViewById(R.id.webView1);
wv.getSettings().setBuiltInZoomControls(true);//show zoom buttons
wv.getSettings().setSupportZoom(true);//allow zoom
//get the width of the webview
wv.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener()
{
@Override
public void onGlobalLayout()
{
ViewSize = wv.getWidth();
wv.getViewTreeObserver().removeGlobalOnLayoutListener(this);
}
});
try
{
File file = new File(Environment.getExternalStorageDirectory().getPath() + "/randompdf.pdf");
RandomAccessFile f = new RandomAccessFile(file, "r");
byte[] data = new byte[(int)f.length()];
f.readFully(data);
pdfLoadImages(data);
}
catch(Exception ignored)
{
}
}
//Load Images:
private void pdfLoadImages(final byte[] data)
{
try
{
// run async
new AsyncTask<Void, Void, String>()
{
// create and show a progress dialog
ProgressDialog progressDialog = ProgressDialog.show(MainActivity.this, "", "Opening...");
@Override
protected void onPostExecute(String html)
{
//after async close progress dialog
progressDialog.dismiss();
//load the html in the webview
wv.loadDataWithBaseURL("", html, "text/html","UTF-8", "");
}
@Override
protected String doInBackground(Void... params)
{
try
{
//create pdf document object from bytes
ByteBuffer bb = ByteBuffer.NEW(data);
PDFFile pdf = new PDFFile(bb);
//Get the first page from the pdf doc
PDFPage PDFpage = pdf.getPage(1, true);
//create a scaling value according to the WebView Width
final float scale = ViewSize / PDFpage.getWidth() * 0.95f;
//convert the page into a bitmap with a scaling value
Bitmap page = PDFpage.getImage((int)(PDFpage.getWidth() * scale), (int)(PDFpage.getHeight() * scale), null, true, true);
//save the bitmap to a byte array
ByteArrayOutputStream stream = new ByteArrayOutputStream();
page.compress(Bitmap.CompressFormat.PNG, 100, stream);
byte[] byteArray = stream.toByteArray();
stream.reset();
//convert the byte array to a base64 string
String base64 = Base64.encodeToString(byteArray, Base64.NO_WRAP);
//create the html + add the first image to the html
String html = "<!DOCTYPE html><html><body bgcolor=\"#b4b4b4\"><img src=\"data:image/png;base64,"+base64+"\" hspace=10 vspace=10><br>";
//loop though the rest of the pages and repeat the above
for(int i = 2; i <= pdf.getNumPages(); i++)
{
PDFpage = pdf.getPage(i, true);
page = PDFpage.getImage((int)(PDFpage.getWidth() * scale), (int)(PDFpage.getHeight() * scale), null, true, true);
page.compress(Bitmap.CompressFormat.PNG, 100, stream);
byteArray = stream.toByteArray();
stream.reset();
base64 = Base64.encodeToString(byteArray, Base64.NO_WRAP);
html += "<img src=\"data:image/png;base64,"+base64+"\" hspace=10 vspace=10><br>";
}
stream.close();
html += "</body></html>";
return html;
}
catch (Exception e)
{
Log.d("error", e.toString());
}
return null;
}
}.execute();
System.gc();// run GC
}
catch (Exception e)
{
Log.d("error", e.toString());
}
}
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