Es kann Mängel geben, aber es kann Ergebnisse erzielen.
1. Wirkungsdiagramm
Die Haupterkenntnis besteht darin, dass Sie eine Datei im lokalen Speicher des Mobiltelefons auswählen und den lokalen Speicherpfad-String der Datei erhalten können.
2. AndriodStudio Dateien und Code
Es gibt drei weitere Codedateien – der rot eingekreiste Teil
1. Hauptaktivität
öffentliche Klasse MainActivity erweitert AppCompatActivity {
TextView filePathtextView;
Schaltfläche Schaltfläche;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
filePathtextView = findViewById(R.id.fileTextView);
button = findViewById(R.id.button);
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Intent intent = new Intent(Intent.ACTION_GET_CONTENT);
intent.setType("*/*");
intent.addCategory(Intent.CATEGORY_OPENABLE);
startActivityForResult(Intent.createChooser(intent,"需要选择文件"),1);
}
});
}
@Override
protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (resultCode == Activity.RESULT_OK) {
Uri uri = data.getData();
String pathString = UriUtil.getPath(this,uri);
filePathtextView.setText(pathString);
/*
//保存读取到的内容
StringBuilder result = new StringBuilder();
//获取输入流
InputStream is = this.getContentResolver().openInputStream(uri);
//创建用于字符输入流中读取文本的bufferReader对象
BufferedReader br = new BufferedReader(new InputStreamReader(is));
String line;
while ((line = br.readLine()) != null) {
//将读取到的内容放入结果字符串
result.append(line);
}
//文件中的内容
String content = result.toString();
*/
}
}
}
2. Um den Dateipfad über Uri zu erhalten, muss Uri in die FilePath-Klasse konvertiert werden
Klasse UriUtil {
/**
* 从Uri获取文件路径，存储路径需要获取
* android.permission.READ_EXTERNAL_STORAGE权限
* 适用于MediaStore和其他基于文件的内容提供
*
* @param context 上下文对象
* @param uri Uri
*/
@RequiresApi(api = Build.VERSION_CODES.KITKAT)
public static String getPath(Context context, Uri uri) {
final boolean isKitKat = Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT;
// 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];
}
}
// 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;
}
/**
* Get the value of the data column for this Uri. This is useful for
* MediaStore Uris, and other file-based ContentProviders.
*
* @param context The context.
* @param uri The Uri to query.
* @param selection (Optional) Filter used in the query.
* @param selectionArgs (Optional) Selection arguments used in the query.
* @return The value of the _data column, which is typically a file path.
*/
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;
}
/**
* @param uri The Uri to check.
* @return Whether the Uri authority is ExternalStorageProvider.
*/
public static boolean isExternalStorageDocument(Uri uri) {
return "com.android.externalstorage.documents".equals(uri.getAuthority());
}
/**
* @param uri The Uri to check.
* @return Whether the Uri authority is DownloadsProvider.
*/
public static boolean isDownloadsDocument(Uri uri) {
return "com.android.providers.downloads.documents".equals(uri.getAuthority());
}
/**
* @param uri The Uri to check.
* @return Whether the Uri authority is MediaProvider.
*/
public static boolean isMediaDocument(Uri uri) {
return "com.android.providers.media.documents".equals(uri.getAuthority());
}
}
3. activity_main.xml
<?xml version="1.0" encoding="utf-8"?><TextView
android:id="@+id/fileTextView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginLeft="75dp"
android:layout_marginRight="75dp"
android:text="显示路径"
android:textAlignment="center"
/>
<Button
android:id="@+id/button"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginLeft="75dp"
android:layout_marginRight="75dp"
android:layout_marginTop="50dp"
android:text="文件路径选择"
android:textColor="@color/white"
/>
3. Berechtigungseinstellung - aufgrund des Zugriffs auf den lokalen Speicher müssen Sie eine Berechtigung beantragen.
Fügen Sie drei Codezeilen hinzu - fügen Sie die Position gemäß dem Bild hinzu
android:requestLegacyExternalStorage="true"