Start a command to request a file from the system

Using the Storage Access Framework through something like

	termux-storage-get output-file

will allow one to get files from e.g. usb memory sticks.

app/src/main/AndroidManifest.xml

@@ -45,6 +45,10 @@
                   android:noHistory="true"
                   android:excludeFromRecents="true"
                   android:exported="false"/>
+        <activity android:name="com.termux.api.StorageGetAPI$StorageActivity"
+                  android:theme="@android:style/Theme.Translucent.NoTitleBar"
+                  android:excludeFromRecents="true"
+                  android:exported="false"/>
         <service android:name="com.termux.api.SpeechToTextAPI$SpeechToTextService"/>
         <service android:name="com.termux.api.TextToSpeechAPI$TextToSpeechService" />
         <provider android:authorities="com.termux.sharedfiles"

app/src/main/java/com/termux/api/StorageGetAPI.java

@@ -0,0 +1,89 @@
+package com.termux.api;
+
+import android.app.Activity;
+import android.content.Context;
+import android.content.Intent;
+import android.net.Uri;
+import android.util.Log;
+
+import com.termux.api.util.ResultReturner;
+
+import java.io.File;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.io.PrintWriter;
+
+public class StorageGetAPI {
+
+    private static final String FILE_EXTRA = "com.termux.api.storage.file";
+
+    static void onReceive(TermuxApiReceiver apiReceiver, final Context context, final Intent intent) {
+        ResultReturner.returnData(apiReceiver, intent, new ResultReturner.ResultWriter() {
+            @Override
+            public void writeResult(PrintWriter out) throws Exception {
+                final String fileExtra = intent.getStringExtra("file");
+                if (fileExtra == null || !new File(fileExtra).getParentFile().canWrite()) {
+                    out.println("ERROR: Not a writable folder: " + fileExtra);
+                    return;
+                }
+
+                Intent intent = new Intent(context, StorageActivity.class);
+                intent.putExtra(FILE_EXTRA, fileExtra);
+                context.startActivity(intent);
+            }
+        });
+    }
+
+    public static class StorageActivity extends Activity {
+
+        private String outputFile;
+
+        @Override
+        public void onResume() {
+            super.onResume();
+            outputFile = getIntent().getStringExtra(FILE_EXTRA);
+            Log.e("termux-api", "output file: " + outputFile);
+
+            // ACTION_OPEN_DOCUMENT is the intent to choose a file via the system's file browser.
+            Intent intent = new Intent(Intent.ACTION_OPEN_DOCUMENT);
+
+            // Filter to only show results that can be "opened", such as a
+            // file (as opposed to a list of contacts or timezones)
+            intent.addCategory(Intent.CATEGORY_OPENABLE);
+
+            intent.setType("*/*");
+
+            startActivityForResult(intent, 42);
+        }
+
+        @Override
+        protected void onActivityResult(int requestCode, int resultCode, Intent resultData) {
+            super.onActivityResult(requestCode, resultCode, resultData);
+            if (resultCode == RESULT_OK) {
+                Uri data = resultData.getData();
+                try {
+                    try (InputStream in = getContentResolver().openInputStream(data)) {
+                        try (OutputStream out = new FileOutputStream(outputFile)) {
+                            byte[] buffer = new byte[8192];
+                            while (true) {
+                                int read = in.read(buffer);
+                                if (read <= 0) {
+                                    break;
+                                } else {
+                                    out.write(buffer, 0, read);
+                                }
+                            }
+                        }
+                    }
+                } catch (IOException e) {
+                    Log.e("termux-api", "Error copying " + data + " to " + outputFile);
+                }
+            }
+            finish();
+        }
+
+    }
+
+}

app/src/main/java/com/termux/api/TermuxApiReceiver.java

@@ -77,6 +77,11 @@ public class TermuxApiReceiver extends BroadcastReceiver {
                     SmsSendAPI.onReceive(this, intent);
                 }
                 break;
+
+            case "StorageGet":
+                StorageGetAPI.onReceive(this, context, intent);
+                break;
+
             case "SpeechToText":
                 if (TermuxApiPermissionActivity.checkAndRequestPermissions(context, intent, Manifest.permission.RECORD_AUDIO)) {
                     SpeechToTextAPI.onReceive(context, intent);