Android打开特定文件，例如自动安装APK程序

public static Intent openFile(String filePath){

  File file = new File(filePath);
  if(!file.exists()) return null;
  /* 取得扩展名 */
  String end=file.getName().substring(file.getName().lastIndexOf(".") + 1,file.getName().length()).toLowerCase();
  /* 依扩展名的类型决定MimeType */
  if(end.equals("m4a")||end.equals("mp3")||end.equals("mid")||
    end.equals("xmf")||end.equals("ogg")||end.equals("wav")){
   return getAudioFileIntent(filePath);
  }else if(end.equals("3gp")||end.equals("mp4")){
   return getAudioFileIntent(filePath);
  }else if(end.equals("jpg")||end.equals("gif")||end.equals("png")||
    end.equals("jpeg")||end.equals("bmp")){
   return getImageFileIntent(filePath);
  }else if(end.equals("apk")){
   return getApkFileIntent(filePath);
  }else if(end.equals("ppt")){
   return getPptFileIntent(filePath);
  }else if(end.equals("xls")){
   return getExcelFileIntent(filePath);
  }else if(end.equals("doc")){
   return getWordFileIntent(filePath);
  }else if(end.equals("pdf")){
   return getPdfFileIntent(filePath);
  }else if(end.equals("chm")){
   return getChmFileIntent(filePath);
  }else if(end.equals("txt")){
   return getTextFileIntent(filePath,false);
  }else{
   return getAllIntent(filePath);
  }
}

//Android获取一个用于打开APK文件的intent
public static Intent getAllIntent( String param ) {

  Intent intent = new Intent();
  intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
  intent.setAction(android.content.Intent.ACTION_VIEW);
  Uri uri = Uri.fromFile(new File(param ));
  intent.setDataAndType(uri,"*/*");
  return intent;
}
//Android获取一个用于打开APK文件的intent
public static Intent getApkFileIntent( String param ) {

  Intent intent = new Intent();
  intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
  intent.setAction(android.content.Intent.ACTION_VIEW);
  Uri uri = Uri.fromFile(new File(param ));
  intent.setDataAndType(uri,"application/vnd.android.package-archive");
  return intent;
}

//Android获取一个用于打开VIDEO文件的intent
public static Intent getVideoFileIntent( String param ) {

  Intent intent = new Intent("android.intent.action.VIEW");
  intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
  intent.putExtra("oneshot", 0);
  intent.putExtra("configchange", 0);
  Uri uri = Uri.fromFile(new File(param ));
  intent.setDataAndType(uri, "video/*");
  return intent;
}

//Android获取一个用于打开AUDIO文件的intent
public static Intent getAudioFileIntent( String param ){

//Android获取一个用于打开Html文件的intent
public static Intent getHtmlFileIntent( String param ){

  Uri uri = Uri.parse(param ).buildUpon().encodedAuthority("com.android.htmlfileprovider").scheme("content").encodedPath(param ).build();
  Intent intent = new Intent("android.intent.action.VIEW");
  intent.setDataAndType(uri, "text/html");
  return intent;
}

//Android获取一个用于打开图片文件的intent
public static Intent getImageFileIntent( String param ) {

//Android获取一个用于打开PPT文件的intent
public static Intent getPptFileIntent( String param ){

//Android获取一个用于打开Excel文件的intent
public static Intent getExcelFileIntent( String param ){

//Android获取一个用于打开Word文件的intent
public static Intent getWordFileIntent( String param ){

//Android获取一个用于打开CHM文件的intent
public static Intent getChmFileIntent( String param ){

//Android获取一个用于打开文本文件的intent
public static Intent getTextFileIntent( String param, boolean paramBoolean){

  Intent intent = new Intent("android.intent.action.VIEW");
  intent.addCategory("android.intent.category.DEFAULT");
  intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
  if (paramBoolean){
   Uri uri1 = Uri.parse(param );
   intent.setDataAndType(uri1, "text/plain");
  }else{
   Uri uri2 = Uri.fromFile(new File(param ));
   intent.setDataAndType(uri2, "text/plain");
  }
  return intent;
}
//Android获取一个用于打开PDF文件的intent
public static Intent getPdfFileIntent( String param ){

原文出处：http://blog.csdn.net/weich_java/article/details/7002829