Android从本地选择文件并判断文件类型并获取选到文件大小的方法

最近有一个android选择本地文件的并判断文件类型的需求

首先要选择文件通过点击事件进入到文件列表 这里是浏览所有的文件。用到的是startActivityForResult

Intent intent = new Intent(Intent.ACTION_GET_CONTENT);
intent.setType("*/*");
intent.addCategory(Intent.CATEGORY_OPENABLE);
startActivityForResult(Intent.createChooser(intent, "Select a File to Upload"), 1);

然后在这个页面重写onActivytResult这个方法

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (resultCode == Activity.RESULT_OK) {
if (data != null) {
final Uri uri = data.getData();
String path = getPath(this, uri);
/*这里要调用这个getPath方法来能过uri获取路径不能直接使用uri.getPath。
因为如果选的图片的话直接使用得到的path不是图片的本身路径*/
File file = new File(path);
/* 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 这里只用了pdf word 图片更类型可查http://www.cnblogs.com/hibr		aincol/archive/2010/09/16/1828502.html*/
if (end.equals("jpg") || end.equals("gif") || end.equals("png") ||
end.equals("jpeg") || end.equals("bmp")) {
try {//图片
String daxiao = FormentFileSize(getFileSizes(file));//获取文件大小的方法
fileDatas.add(new FilesParam(daxiao, path, file.getName()));
Hadapter.notifyDataSetChanged();//更新listview显示本图片
} catch (Exception e) {
e.printStackTrace();
}
} else if (end.equals("doc")) {
try {//word
String daxiao = FormentFileSize(getFileSizes(file));
fileDatas.add(new FilesParam(daxiao, "DOC", file.getName()));
Hadapter.notifyDataSetChanged();
} catch (Exception e) {
e.printStackTrace();
}
} else if (end.equals("pdf")) {
try {//pdf
String daxiao = FormentFileSize(getFileSizes(file));
fileDatas.add(new FilesParam(daxiao, "PDF", file.getName()));
Hadapter.notifyDataSetChanged();
} catch (Exception e) {
e.printStackTrace();
}
} else if (end.equals("txt")) {
try {//text
String daxiao = FormentFileSize(getFileSizes(file));
fileDatas.add(new FilesParam(daxiao, "DOC", file.getName()));
Hadapter.notifyDataSetChanged();
} catch (Exception e) {
e.printStackTrace();
}
} else {
Toast.makeText(this, "只能选择图片、文档、PDF三种格式", Toast.LENGTH_SHORT).show();
}
}

}

}

下面是上面中提到的获取文件路径和文件大小的方法。值得注意的是在Android4.4以前可以通过data.getpath()来直接得到文件路径，但是4.4以后通过这个方法得到是路径不是正确路径（这里说的是图片）所以我们用下面getPath（）方法来解决这个问题。别外在6.0版本以后读写文件要有运行时权限

//得到正确路径
public static String getPath(Context context, Uri uri) {

final boolean isKitKat = Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT;//sdk版本是否大于4.4

// DocumentProvider
if (isKitKat && DocumentsContract.isDocumentUri(context, uri)) {
// ExternalStorageProvider
if (isExternalStorageDocument(uri)) {
final String docId = DocumentsContract.getDocumentId(uri);
final String[] split = docId.split(":");
final String type = split[0];

if ("primary".equalsIgnoreCase(type)) {
return Environment.getExternalStorageDirectory() + "/" + split[1];
}

// TODO handle non-primary volumes
}else if (isDownloadsDocument(uri)) {

final String id = DocumentsContract.getDocumentId(uri);
final Uri contentUri = ContentUris.withAppendedId(
Uri.parse("content://downloads/public_downloads"), Long.valueOf(id));

return getDataColumn(context, contentUri, null, null);
}
// MediaProvider
else if (isMediaDocument(uri)) {
final String docId = DocumentsContract.getDocumentId(uri);
final String[] split = docId.split(":");
final String type = split[0];

Uri contentUri = null;
if ("image".equals(type)) {
contentUri = MediaStore.Images.Media.EXTERNAL_CONTENT_URI;
} else if ("video".equals(type)) {
contentUri = MediaStore.Video.Media.EXTERNAL_CONTENT_URI;
} else if ("audio".equals(type)) {
contentUri = MediaStore.Audio.Media.EXTERNAL_CONTENT_URI;
}

final String selection = "_id=?";
final String[] selectionArgs = new String[]{
split[1]
};

return getDataColumn(context, contentUri, selection, selectionArgs);
}
}
// MediaStore (and general)
else if ("content".equalsIgnoreCase(uri.getScheme())) {

// Return the remote address
if (isGooglePhotosUri(uri))
return uri.getLastPathSegment();

return getDataColumn(context, uri, null, null);
}
// File
else if ("file".equalsIgnoreCase(uri.getScheme())) {
return uri.getPath();
}
return null;

}
下面这些是getPath中要调用的方法

public static boolean isExternalStorageDocument(Uri uri) {
return "com.android.externalstorage.documents".equals(uri.getAuthority());
}

public static boolean isDownloadsDocument(Uri uri) {
return "com.android.providers.downloads.documents".equals(uri.getAuthority());
}

public static boolean isMediaDocument(Uri uri) {
return "com.android.providers.media.documents".equals(uri.getAuthority());
}

public static boolean isGooglePhotosUri(Uri uri) {
return "com.google.android.apps.photos.content".equals(uri.getAuthority());
}

public static String getDataColumn(Context context, Uri uri, String selection,
String[] selectionArgs) {

Cursor cursor = null;
final String column = "_data";
final String[] projection = {column};

try {
cursor = context.getContentResolver().query(uri, projection, selection, selectionArgs,
null);
if (cursor != null && cursor.moveToFirst()) {
final int index = cursor.getColumnIndexOrThrow(column);
return cursor.getString(index);
}
} finally {
if (cursor != null)
cursor.close();
}
return null;
}

/*得到传入文件的大小*/
public static long getFileSizes(File f) throws Exception {

long s = 0;
if (f.exists()) {
FileInputStream fis = null;
fis = new FileInputStream(f);
s = fis.available();
fis.close();
} else {
f.createNewFile();
System.out.println("文件夹不存在");
}

return s;
}

/**
* 转换文件大小成KB  M等
*/
public static String FormentFileSize(long fileS) {
DecimalFormat df = new DecimalFormat("#.00");
String fileSizeString = "";
if (fileS < 1024) {
fileSizeString = df.format((double) fileS) + "B";
} else if (fileS < 1048576) {
fileSizeString = df.format((double) fileS / 1024) + "K";
} else if (fileS < 1073741824) {
fileSizeString = df.format((double) fileS / 1048576) + "M";
} else {
fileSizeString = df.format((double) fileS / 1073741824) + "G";
}
return fileSizeString;
}