Answers:
您可以使用Google PDF Viewer在线阅读pdf：
WebView webview = (WebView) findViewById(R.id.webview);
webview.getSettings().setJavaScriptEnabled(true);
String pdf = "http://www.adobe.com/devnet/acrobat/pdfs/pdf_open_parameters.pdf";
webview.loadUrl("https://drive.google.com/viewerng/viewer?embedded=true&url=" + pdf);
You've reached the bandwidth limit for viewing or downloading files that aren't in Google Docs format....。因此似乎并不可靠。
就用户体验而言，使用google docs打开pdf是一个坏主意。这真的很慢而且没有反应。
从api 21开始，我们有了PdfRenderer，可帮助将pdf转换为Bitmap。我从未使用过它，但是似乎很容易。
其他解决方案是下载PDF，并将其通过Intent传递到专用的PDF应用程序，该应用程序会显示它。快速而良好的用户体验，尤其是如果该功能不是您应用程序的核心。
使用此代码下载并打开PDF
public class PdfOpenHelper {
public static void openPdfFromUrl(final String pdfUrl, final Activity activity){
Observable.fromCallable(new Callable<File>() {
@Override
public File call() throws Exception {
try{
URL url = new URL(pdfUrl);
URLConnection connection = url.openConnection();
connection.connect();
// download the file
InputStream input = new BufferedInputStream(connection.getInputStream());
File dir = new File(activity.getFilesDir(), "/shared_pdf");
dir.mkdir();
File file = new File(dir, "temp.pdf");
OutputStream output = new FileOutputStream(file);
byte data[] = new byte[1024];
long total = 0;
int count;
while ((count = input.read(data)) != -1) {
total += count;
output.write(data, 0, count);
}
output.flush();
output.close();
input.close();
return file;
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
})
.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.subscribe(new Subscriber<File>() {
@Override
public void onCompleted() {
}
@Override
public void onError(Throwable e) {
}
@Override
public void onNext(File file) {
String authority = activity.getApplicationContext().getPackageName() + ".fileprovider";
Uri uriToFile = FileProvider.getUriForFile(activity, authority, file);
Intent shareIntent = new Intent(Intent.ACTION_VIEW);
shareIntent.setDataAndType(uriToFile, "application/pdf");
shareIntent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
if (shareIntent.resolveActivity(activity.getPackageManager()) != null) {
activity.startActivity(shareIntent);
}
}
});
}
}
为了使Intent发挥作用，您需要创建一个FileProvider来授予接收应用程序打开文件的权限。
实现方法如下：在清单中：
<provider
android:name="android.support.v4.content.FileProvider"
android:authorities="${applicationId}.fileprovider"
android:exported="false"
android:grantUriPermissions="true">
<meta-data
android:name="android.support.FILE_PROVIDER_PATHS"
android:resource="@xml/file_paths" />
</provider>
最后在资源管理器中创建一个file_paths.xml文件
<?xml version="1.0" encoding="utf-8"?>
<paths>
<files-path name="shared_pdf" path="shared_pdf"/>
</paths>
希望这可以帮助=）
使用此代码：
private void pdfOpen(String fileUrl){
webView.getSettings().setJavaScriptEnabled(true);
webView.getSettings().setPluginState(WebSettings.PluginState.ON);
//---you need this to prevent the webview from
// launching another browser when a url
// redirection occurs---
webView.setWebViewClient(new Callback());
webView.loadUrl(
"http://docs.google.com/gview?embedded=true&url=" + fileUrl);
}
private class Callback extends WebViewClient {
@Override
public boolean shouldOverrideUrlLoading(
WebView view, String url) {
return (false);
}
}
在这里加载progressDialog。需要提供WebClient，否则将强制在浏览器中打开：
final ProgressDialog pDialog = new ProgressDialog(context);
pDialog.setTitle(context.getString(R.string.app_name));
pDialog.setMessage("Loading...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(false);
WebView webView = (WebView) rootView.findViewById(R.id.web_view);
webView.getSettings().setJavaScriptEnabled(true);
webView.setWebViewClient(new WebViewClient() {
@Override
public void onPageStarted(WebView view, String url, Bitmap favicon) {
super.onPageStarted(view, url, favicon);
pDialog.show();
}
@Override
public void onPageFinished(WebView view, String url) {
super.onPageFinished(view, url);
pDialog.dismiss();
}
});
String pdf = "http://www.adobe.com/devnet/acrobat/pdfs/pdf_open_parameters.pdf";
webView.loadUrl("https://drive.google.com/viewerng/viewer?embedded=true&url=" + pdf);
实际上，所有解决方案都非常复杂，我找到了一个非常简单的解决方案（我不确定它是否可用于所有sdk版本）。它将在预览窗口中打开pdf文档，用户可以在其中查看和保存/共享该文档：
webView.setDownloadListener(DownloadListener { url, userAgent, contentDisposition, mimetype, contentLength ->
val i = Intent(Intent.ACTION_QUICK_VIEW)
i.data = Uri.parse(url)
if (i.resolveActivity(getPackageManager()) != null) {
startActivity(i)
} else {
val i2 = Intent(Intent.ACTION_VIEW)
i2.data = Uri.parse(url)
startActivity(i2)
}
})（科特琳）
从此处下载源代码（在webview android中打开pdf）
activity_main.xml
<RelativeLayout android:layout_width="match_parent"
android:layout_height="match_parent"
xmlns:android="http://schemas.android.com/apk/res/android">
<WebView
android:layout_width="match_parent"
android:background="#ffffff"
android:layout_height="match_parent"
android:id="@+id/webview"></WebView>
</RelativeLayout>MainActivity.java
package com.pdfwebview;
import android.app.ProgressDialog;
import android.graphics.Bitmap;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.webkit.WebView;
import android.webkit.WebViewClient;
public class MainActivity extends AppCompatActivity {
WebView webview;
ProgressDialog pDialog;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
init();
listener();
}
private void init() {
webview = (WebView) findViewById(R.id.webview);
webview.getSettings().setJavaScriptEnabled(true);
pDialog = new ProgressDialog(MainActivity.this);
pDialog.setTitle("PDF");
pDialog.setMessage("Loading...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(false);
webview.loadUrl("https://drive.google.com/file/d/0B534aayZ5j7Yc3RhcnRlcl9maWxl/view");
}
private void listener() {
webview.setWebViewClient(new WebViewClient() {
@Override
public void onPageStarted(WebView view, String url, Bitmap favicon) {
super.onPageStarted(view, url, favicon);
pDialog.show();
}
@Override
public void onPageFinished(WebView view, String url) {
super.onPageFinished(view, url);
pDialog.dismiss();
}
});
}
}