[英]Reading Database File from External Storage
所以,这个程序从firebase存储中下载一个文件,我的下载代码是:
private void downloadFiles(Context context, String fileName, String destinationDirectory, String url) {
DownloadManager downloadManager = (DownloadManager) context.getSystemService(Context.DOWNLOAD_SERVICE);
Uri uri = Uri.parse(url);
DownloadManager.Request request = new DownloadManager.Request(uri);
request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);
request.setDestinationInExternalFilesDir(context, String.valueOf(destinationDirectory), fileName);
downloadManager.enqueue(request);
}
public void downloading(final String name) {
downloadRef = storage.getInstance().getReference().child(name);
downloadRef.getDownloadUrl().addOnSuccessListener(new OnSuccessListener<Uri>() {
@Override
public void onSuccess(Uri uri) {
String url = uri.toString();
downloadFiles(Main2Activity.this, name, getApplicationContext().getExternalFilesDir(Environment.DIRECTORY_DOWNLOADS), url);
}
}).addOnFailureListener(new OnFailureListener() {
@Override
public void onFailure(@NonNull Exception e) {
Toast.makeText(Main2Activity.this, "Failed!!!", Toast.LENGTH_LONG).show();
}
});
}
然后我想使用这个数据库,所以我尝试用以下方式打开它:
database = SQLiteDatabase.openDatabase(myPath, null, 0);
我该如何解决这个问题? 这将是非常有帮助的家伙。
我认为您的问题是可访问性。 这就是为什么我带回一个活动来获得用户的许可。 你测试这段代码
listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
if (ContextCompat.checkSelfPermission(MainActivity.this, Manifest.permission.READ_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED
&& ContextCompat.checkSelfPermission(MainActivity.this, Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {
ActivityCompat.requestPermissions(MainActivity.this, new String[] {Manifest.permission.READ_EXTERNAL_STORAGE,Manifest.permission.WRITE_EXTERNAL_STORAGE}, 1);
} else {
Intent intent = new Intent(MainActivity.this, Main2Activity.class);
intent.putExtra("name", arrayList.get(position));
startActivity(intent);
}
}
});
您正在使用Environment.getExternalStorageState()
返回主要共享/外部存储媒体的当前 state。 它不能用于获取路径作为任何文件的字符串。 使用context.getExternalFilesDir(Environment.DIRECTORY_DOWNLOADS)
获取Download
目录路径的字符串值。
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