//
// check if we have a PDF viewer,else bad things happen
//
Intent intent = new Intent(Intent.ACTION_VIEW);
intent.setType("application/pdf");

List<ResolveInfo> intents = getPackageManager().queryIntentActivities(intent,PackageManager.MATCH_DEFAULT_ONLY);

if (intents == null || intents.size() == 0) {
       // display message then...
       finish();
}

在我的HTC Desire上,即使我有Adobe的PDF查看器,也不会返回匹配项.这个问题的答案android: open a pdf from my app using the built in pdf viewer提到Adobe可能没有任何公共意图,因此上述检查显然不会返回任何内容.

任何人都可以验证您是否应该从意图启动Acrobat,或者是否有其他方法或PDF查看器可供使用.

实际用例是下载发票副本并使用以下代码将其存储在本地存储中：

URL url = new URL(data);
 InputStream myInput = url.openConnection().getInputStream();

 FileOutputStream fos = openFileOutput(fname,Context.MODE_WORLD_READABLE);

 // transfer bytes from the input file to the output file
 byte[] buffer = new byte[8192];
 int length;
 while ((length = myInput.read(buffer)) > 0) {
    fos.write(buffer,length);
    progressDialog.setProgress(i++);
 }
 fos.close();

然后展示

// read from disk,and call intent
openFileInput(fname);   // will throw FileNotFoundException

File dir = getFilesDir();       // where files are stored
File file = new File(dir,fname);   // new file with our name

Intent intent = new Intent(Intent.ACTION_VIEW,Uri.fromFile(file));
intent.setType("application/pdf");

startActivity(intent);