ShareCompat.IntentBuilder.from(activity)
    .setType(mimeType)
    .setStream(uri)
    .setChooserTitle("分享文件")
    .startChooser();

<!-- ==================== File: AndroidManifest.xml ==================== -->
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.fileshare">
 
    <!-- Android 9 及以下若操作外部存儲(chǔ)需聲明此權(quán)限，但示例僅在私有目錄，無(wú)需存儲(chǔ)權(quán)限 -->
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"
                     android:maxSdkVersion="28"/>
 
    <application
        android:allowBackup="true"
        android:label="文件分享示例"
        android:theme="@style/Theme.AppCompat.Light.NoActionBar">
        
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN"/>
                <category android:name="android.intent.category.LAUNCHER"/>
            </intent-filter>
        </activity>
 
        <!-- FileProvider 注冊(cè) -->
        <provider
            android:name="androidx.core.content.FileProvider"
            android:authorities="${applicationId}.fileprovider"
            android:exported="false"
            android:grantUriPermissions="true">
            <meta-data
                android:name="android.support.FILE_PROVIDER_PATHS"
                android:resource="@xml/file_paths"/>
        </provider>
    </application>
</manifest>

<!-- ==================== File: res/xml/file_paths.xml ==================== -->
<?xml version="1.0" encoding="utf-8"?>
<paths xmlns:android="http://schemas.android.com/apk/res/android">
    <!-- 允許分享 app 私有外部目錄：.../Android/data/.../files/shared/ -->
    <external-files-path
        name="shared"
        path="shared/"/>
    <!-- 若需分享私有內(nèi)部存儲(chǔ)，可加：
    <files-path
        name="internal"
        path="shared/"/>
    -->
</paths>

<!-- ==================== File: res/layout/activity_main.xml ==================== -->
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:padding="24dp"
    android:gravity="center_horizontal"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
 
    <Button
        android:id="@+id/btn_share_single"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="分享單個(gè)文件"/>
 
    <Button
        android:id="@+id/btn_share_multiple"
        android:layout_width="match_parent"
        android:layout_marginTop="16dp"
        android:layout_height="wrap_content"
        android:text="分享多個(gè)文件"/>
 
    <TextView
        android:id="@+id/tv_status"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="32dp"
        android:text="分享狀態(tài)：未操作"
        android:textSize="16sp"/>
</LinearLayout>

// ==================== File: MainActivity.java ====================
package com.example.fileshare;
 
import android.content.Intent;
import android.net.Uri;
import android.os.Build;
import android.os.Bundle;
import android.widget.*;
import androidx.annotation.Nullable;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.content.FileProvider;
import java.io.*;
import java.util.ArrayList;
import java.util.List;
 
/**
 * MainActivity：演示 Android 文件分享功能
 */
public class MainActivity extends AppCompatActivity {
 
    private Button btnShareSingle, btnShareMultiple;
    private TextView tvStatus;
    private File sharedDir;
 
    @Override
    protected void onCreate(@Nullable Bundle saved) {
        super.onCreate(saved);
        setContentView(R.layout.activity_main);
 
        // 1. 綁定控件
        btnShareSingle   = findViewById(R.id.btn_share_single);
        btnShareMultiple = findViewById(R.id.btn_share_multiple);
        tvStatus         = findViewById(R.id.tv_status);
 
        // 2. 創(chuàng)建示例文件目錄
        sharedDir = new File(getExternalFilesDir("shared"), "");
        if (!sharedDir.exists()) sharedDir.mkdirs();
 
        // 3. 在目錄中創(chuàng)建示例文件
        createExampleFile("example1.txt", "這是示例文件 1 的內(nèi)容。");
        createExampleFile("example2.txt", "這是示例文件 2 的內(nèi)容。");
        createExampleFile("example3.txt", "這是示例文件 3 的內(nèi)容。");
 
        // 4. 單文件分享
        btnShareSingle.setOnClickListener(v -> {
            File file = new File(sharedDir, "example1.txt");
            if (file.exists()) shareSingleFile(file, "text/plain");
            else tvStatus.setText("文件不存在: example1.txt");
        });
 
        // 5. 多文件分享
        btnShareMultiple.setOnClickListener(v -> {
            List<File> files = new ArrayList<>();
            files.add(new File(sharedDir, "example1.txt"));
            files.add(new File(sharedDir, "example2.txt"));
            files.add(new File(sharedDir, "example3.txt"));
            shareMultipleFiles(files, "text/plain");
        });
    }
 
    /**
     * 創(chuàng)建示例文本文件
     */
    private void createExampleFile(String name, String content) {
        File out = new File(sharedDir, name);
        try (FileWriter fw = new FileWriter(out)) {
            fw.write(content);
        } catch (IOException e) {
            e.printStackTrace();
            tvStatus.setText("創(chuàng)建文件失?。? + name);
        }
    }
 
    /**
     * 分享單個(gè)文件
     */
    private void shareSingleFile(File file, String mimeType) {
        Uri uri = getUriForFile(file);
        if (uri == null) return;
        Intent intent = new Intent(Intent.ACTION_SEND);
        intent.setType(mimeType);
        intent.putExtra(Intent.EXTRA_STREAM, uri);
        intent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
        startActivity(Intent.createChooser(intent, "分享文件"));
    }
 
    /**
     * 分享多個(gè)文件
     */
    private void shareMultipleFiles(List<File> files, String mimeType) {
        ArrayList<Uri> uris = new ArrayList<>();
        for (File f : files) {
            Uri uri = getUriForFile(f);
            if (uri != null) uris.add(uri);
        }
        if (uris.isEmpty()) {
            tvStatus.setText("無(wú)可分享文件");
            return;
        }
        Intent intent = new Intent(Intent.ACTION_SEND_MULTIPLE);
        intent.setType(mimeType);
        intent.putParcelableArrayListExtra(Intent.EXTRA_STREAM, uris);
        intent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
        startActivity(Intent.createChooser(intent, "分享多個(gè)文件"));
    }
 
    /**
     * 獲取 content:// URI，兼容各版本
     */
    private Uri getUriForFile(File file) {
        try {
            // 使用 FileProvider 生成 URI
            String authority = getPackageName() + ".fileprovider";
            return FileProvider.getUriForFile(this, authority, file);
        } catch (IllegalArgumentException e) {
            e.printStackTrace();
            tvStatus.setText("無(wú)法獲取 URI：" + file.getName());
            return null;
        }
    }
}