Add a file picker to pick files from $HOME

This allows e.g. files from the $HOME folder to be attached to emails
or uploaded when in other apps.

Also bump version to 0.18.

app/src/main/java/com/termux/filepicker/TermuxFilePickerActivity.java

@@ -0,0 +1,111 @@
+package com.termux.filepicker;
+
+import android.annotation.SuppressLint;
+import android.app.Activity;
+import android.app.ListActivity;
+import android.content.Intent;
+import android.net.Uri;
+import android.os.Bundle;
+import android.view.MenuItem;
+import android.view.View;
+import android.widget.ArrayAdapter;
+import android.widget.ListView;
+
+import com.termux.R;
+
+import java.io.File;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.List;
+
+/** Activity allowing picking files from the $HOME folder. */
+public class TermuxFilePickerActivity extends ListActivity {
+
+    @SuppressLint("SdCardPath")
+    final String TERMUX_HOME = "/data/data/com.termux/files/home";
+
+    private File mCurrentDirectory;
+    private final List<File> mFiles = new ArrayList<>();
+    private final List<String> mFileNames = new ArrayList<>();
+    private ArrayAdapter mAdapter;
+
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        setContentView(R.layout.file_picker);
+
+        mAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, mFileNames);
+
+        enterDirectory(new File(TERMUX_HOME));
+        setListAdapter(mAdapter);
+    }
+
+    @Override
+    protected void onResume() {
+        super.onResume();
+    }
+
+    @Override
+    public boolean onOptionsItemSelected(MenuItem item) {
+        int id = item.getItemId();
+        if (id == android.R.id.home) {
+            enterDirectory(mCurrentDirectory.getParentFile());
+            return true;
+        } else {
+            return super.onOptionsItemSelected(item);
+        }
+    }
+
+    @Override
+    protected void onListItemClick(ListView l, View v, int position, long id) {
+        super.onListItemClick(l, v, position, id);
+        File requestFile = mFiles.get(position);
+        if (requestFile.isDirectory()) {
+            enterDirectory(requestFile);
+        } else {
+            Uri returnUri = Uri.withAppendedPath(Uri.parse("content://com.termux.filepicker.provider/"), requestFile.getAbsolutePath());
+            Intent returnIntent = new Intent().setData(returnUri);
+            returnIntent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
+            setResult(Activity.RESULT_OK, returnIntent);
+            finish();
+        }
+    }
+
+    void enterDirectory(File directory) {
+        getActionBar().setDisplayHomeAsUpEnabled(!directory.getAbsolutePath().equals(TERMUX_HOME));
+
+        String title = directory.getAbsolutePath() + "/";
+        if (title.startsWith(TERMUX_HOME)) {
+            title = "~" + title.substring(TERMUX_HOME.length(), title.length());
+        }
+        setTitle(title);
+
+        mCurrentDirectory = directory;
+        mFiles.clear();
+        mFileNames.clear();
+        mFiles.addAll(Arrays.asList(mCurrentDirectory.listFiles()));
+
+        Collections.sort(mFiles, new Comparator<File>() {
+            @Override
+            public int compare(File f1, File f2) {
+                final String n1 = f1.getName();
+                final String n2 = f2.getName();
+                // Display dot folders last:
+                if (n1.startsWith(".") && !n2.startsWith(".")) {
+                    return 1;
+                } else if (n2.startsWith(".") && !n1.startsWith(".")) {
+                    return -1;
+                }
+                return n1.compareToIgnoreCase(n2);
+            }
+        });
+
+        for (File file : mFiles) {
+            mFileNames.add(file.getName() + (file.isDirectory() ? "/" : ""));
+        }
+        mAdapter.notifyDataSetChanged();
+    }
+
+}

app/src/main/java/com/termux/filepicker/TermuxFilePickerProvider.java

@@ -0,0 +1,50 @@
+package com.termux.filepicker;
+
+
+import android.content.ContentProvider;
+import android.content.ContentValues;
+import android.database.Cursor;
+import android.net.Uri;
+import android.os.ParcelFileDescriptor;
+
+import java.io.File;
+import java.io.FileNotFoundException;
+
+/** Provider of files content uris picked from {@link com.termux.filepicker.TermuxFilePickerActivity}. */
+public class TermuxFilePickerProvider extends ContentProvider {
+    @Override
+    public boolean onCreate() {
+        return false;
+    }
+
+    @Override
+    public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder) {
+        return null;
+    }
+
+    @Override
+    public String getType(Uri uri) {
+        return null;
+    }
+
+    @Override
+    public Uri insert(Uri uri, ContentValues values) {
+        return null;
+    }
+
+    @Override
+    public int delete(Uri uri, String selection, String[] selectionArgs) {
+        return 0;
+    }
+
+    @Override
+    public int update(Uri uri, ContentValues values, String selection, String[] selectionArgs) {
+        return 0;
+    }
+
+    @Override
+    public ParcelFileDescriptor openFile(Uri uri, String mode) throws FileNotFoundException {
+        File file = new File(uri.getPath());
+        return ParcelFileDescriptor.open(file, ParcelFileDescriptor.MODE_READ_ONLY);
+    }
+}