android - 无法使用存储访问框架 (SAF) 设置文档导航器的初始位置

Question

文档说“调用者可以通过 EXTRA_INITIAL_URI 设置文档 URI 来指示文档导航器的初始位置。”

但它不会解决EXTRA_INITIAL_URI这里。我尝试设置为此给定的常量，如注释(EXTRA_INITIAL_URI = "android.provider.extra.INITIAL_URI")中所示，但这不起作用。我该如何解决？

package com.ship.saftwo;
import android.content.Intent;
import android.net.Uri;
import android.os.Environment;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import java.io.File;

public class MainActivity extends AppCompatActivity{
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Button button = (Button) findViewById(R.id.button1);
        button.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {navigateToAppDirectory();}});}

    private static final int READ_REQUEST_CODE = 42;
    // adding this does not help: public static final String EXTRA_INITIAL_URI = "android.provider.extra.INITIAL_URI";

    public void navigateToAppDirectory() {
        Intent intent = new Intent(Intent.ACTION_OPEN_DOCUMENT);
        Uri uri = Uri.parse(Environment.getExternalStorageDirectory().getPath() + File.separator + getResources().getString(R.string.app_name) + File.separator);
        intent.addCategory(Intent.CATEGORY_OPENABLE);
        intent.setType("*/*");
        intent.putExtra(Intent.EXTRA_INITIAL_URI, uri);
        //error message: Cannot resolve symbol 'EXTRA_INITIAL_URI'
        startActivityForResult(intent, READ_REQUEST_CODE);
    }
}

Answer 1

来自 DocumentsContract.EXTRA_INITIAL_URI :

Location should specify a document URI or a tree URI with document ID. If this URI identifies a non-directory, document navigator will attempt to use the parent of the document as the initial location.

据我所知

您不能使用任意 URI 指定起始位置，例如Uri.fromFile ，它需要来自 DocumentsProvider

您不能在 API 25 及以下

上指定起始位置

假设 uri检索自 Intent.ACTION_OPEN_DOCUMENT_TREE :

DocumentFile file = DocumentFile.fromTreeUri(context, uri);
intent.putExtra(EXTRA_INITIAL_URI, file.getUri());