安卓 - 使用意图从手机内存中打开文件

Question

我正在开发一个应用程序，该应用程序将手机中的.txt文件作为输入并将其打印在TextView上，

public class MainActivity extends AppCompatActivity {
Button button;
Intent intent;private StringBuilder text = new StringBuilder();

private InputStream getResources(String s) {
return null;
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
button = (Button) findViewById(R.id.btn);
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
intent = new Intent(Intent.ACTION_GET_CONTENT);
intent.setType("text/plain");
startActivityForResult(intent, 7);
Log.v("###", "parent "  + getParent());
}
});
} @Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
String Fpath = data.getDataString();
//  final String fileName = ""+Fpath;
Log.v("###", "yo " +Fpath);
super.onActivityResult(requestCode, resultCode, data);
switch (requestCode) {
case 7:
if (resultCode == RESULT_OK) {
setContentView(R.layout.activity_main);

Log.v("###", "hellow");
setContentView(R.layout.activity_main);
BufferedReader reader = null;
try {
reader = new BufferedReader(
new InputStreamReader(getAssets().open("filename.txt")));
//change code
// do reading
String mLine;
while ((mLine = reader.readLine()) != null) {
text.append(mLine);
text.append('n');
}
} catch (IOException e) {
String PathHolder = data.getData().getPath();
Toast.makeText(MainActivity.this, PathHolder, Toast.LENGTH_LONG).show();
e.printStackTrace();
} finally {

if (reader != null) {
try {
reader.close();
} catch (IOException e) {
//log the exception
}
}
TextView output = (TextView) findViewById(R.id.Txt);
output.setText((CharSequence) text);
}
}
}
}
}

一切都很好，但这条线

new InputStreamReader(getAssets((.open("filename.txt"(((;

从资产文件夹中获取文件， 帮我从我的手机获取文件，

资产文件夹中的文件正确打开，但我希望从手机中选择它

Answer 1

您可以在从文件管理器中选择的onActivityResult中获取文件路径。

Uri PathHolder = data.getData();

更新

上行为您提供了从存储中选择的文件的 uri。然后，您可以轻松地从该URI获取文件。

只是忘记了getAssets使用以下方法从文件中读取。

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
Uri PathHolder = data.getData();
FileInputStream fileInputStream = null;
StringBuilder text = new StringBuilder();
try {
InputStream inputStream = getContentResolver().openInputStream(PathHolder);
BufferedReader r = new BufferedReader(new InputStreamReader(inputStream));
String mLine;
while ((mLine = r.readLine()) != null) {
text.append(mLine);
text.append('n');
}
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}

Answer 2

您可以尝试此方法：

public static String getMimeType(String url) {
String type = null;
String extension = MimeTypeMap.getFileExtensionFromUrl(url);
if (extension != null) {
type = MimeTypeMap.getSingleton().getMimeTypeFromExtension(extension);
}
return type;
}
public static Uri getFileUri(String filePath) {
Uri fileUri = null;
File file = new File(filePath);
try {
if (Build.VERSION.SDK_INT >= 24) {
Method m = StrictMode.class.getMethod("disableDeathOnFileUriExposure");
m.invoke(null);
}
fileUri = Uri.fromFile(file);
} catch (Exception e) {
e.printStackTrace();
}
return fileUri;
}

对于意图：

if (path.endsWith(".txt") || path.endsWith(".TXT")) {
Intent intent = new Intent(Intent.ACTION_VIEW);
intent.setDataAndType(getFileUri(path.trim()), getMimeType(path.trim()));
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK);
if (intent.resolveActivity(context.getPackageManager()) != null) {
context.startActivity(intent);
} else
Toast.makeText(context, "There is no application available to handle your request!!", Toast.LENGTH_SHORT).show();
} 

Answer 3

您的 onActivityResult 略有变化 首先将此代码粘贴到您的活动中。

public static String getPath(final Context context, final Uri uri) {
final boolean isKitKat = true;
// DocumentProvider
if (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
}
// DownloadsProvider
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 getDataColumn(context, uri, null, null);
}
// File
else if ("file".equalsIgnoreCase(uri.getScheme())) {
return uri.getPath();
}
return null;
}
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 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 column_index = cursor.getColumnIndexOrThrow(column);
return cursor.getString(column_index);
}
} finally {
if (cursor != null) {
cursor.close();
}
}
return null;
}
public static boolean isMediaDocument(Uri uri) {
return "com.android.providers.media.documents".equals(uri.getAuthority());
}

现在将您的活动结果更改为此内容。

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
// TODO Auto-generated method stub
if (requestCode == 1) {
if (resultCode == RESULT_OK) {
//                String pickedImage = data.getData().getPath();
String dataString = getPath(this, Uri.parse(data.getDataString()));
Log.i(TAG, "onActivityResult: pathholder " + dataString);
File file = new File(dataString);//
FileInputStream fis = null;
Log.i(TAG, "onActivityResult: file " + file.getName());
/**if you get the uri(path) then add this following code that i given below*/
try {
fis = new FileInputStream(file.getAbsolutePath());
InputStreamReader isr = new InputStreamReader(fis);
BufferedReader bufferedReader = new BufferedReader(isr);
StringBuilder sb = new StringBuilder();
String line;
while ((line = bufferedReader.readLine()) != null) {
sb.append(line).append("n");
}
Log.i(TAG, "onActivityResult: pathholder " + sb.toString());
} catch (IOException e) {
e.printStackTrace();
}

}
}
}