Android点击按钮拍照后如何在另一Activity显示？代码修改咨询

核心问题说明 #

你当前的代码仅获取了相机返回的缩略图并在当前Activity显示，要实现传递到下一个Activity，推荐采用「保存图片到本地文件，传递文件路径」的方式（避免直接传Bitmap导致的内存溢出问题），以下是具体修改步骤：

方案一：推荐（传递图片文件路径，支持高清图） #

步骤1：配置FileProvider（Android 7.0+ 必填） #

因为Android 7.0及以上禁止直接使用file://Uri，需要通过FileProvider共享文件：

1. 在AndroidManifest.xml的<application>标签内添加FileProvider配置：

<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>

2. 在res/xml目录下创建file_paths.xml文件（若xml目录不存在则新建）：

<?xml version="1.0" encoding="utf-8"?>
<paths xmlns:android="http://schemas.android.com/apk/res/android">
    <!-- 指定图片保存到应用私有Pictures目录 -->
    <external-files-path name="my_images" path="Pictures" />
</paths>

步骤2：修改MainActivity的拍照逻辑 #

添加变量存储图片Uri，并修改拍照Intent指定输出路径：

public class MainActivity extends AppCompatActivity {
    private static final int pic_id = 123;
    private Uri imageUri; // 新增：存储图片Uri

    Button camera_open_id;
    // 移除：不需要在当前Activity显示图片，可删除click_image_id变量

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        camera_open_id = findViewById(R.id.camera_button);

        camera_open_id.setOnClickListener(v -> {
            // 创建保存图片的临时文件
            File storageDir = getExternalFilesDir(Environment.DIRECTORY_PICTURES);
            try {
                File imageFile = File.createTempFile(
                        "JPEG_",  // 文件名前缀
                        ".jpg",    // 文件名后缀
                        storageDir // 存储目录
                );
                // 通过FileProvider获取合法Uri
                imageUri = FileProvider.getUriForFile(this,
                        getPackageName() + ".fileprovider",
                        imageFile);
                // 构建拍照Intent并指定输出Uri
                Intent camera_intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
                camera_intent.putExtra(MediaStore.EXTRA_OUTPUT, imageUri);
                startActivityForResult(camera_intent, pic_id);
            } catch (IOException e) {
                e.printStackTrace();
            }
        });

        verifyStoragePermissions(MainActivity.this);
    }

步骤3：修改onActivityResult，启动第二个Activity传递路径 #

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    if (requestCode == pic_id && resultCode == RESULT_OK) {
        // 获取图片文件的绝对路径
        String imagePath = new File(imageUri.getPath()).getAbsolutePath();
        // 启动第二个Activity并传递路径
        Intent intent = new Intent(this, ImageDisplayActivity.class);
        intent.putExtra("IMAGE_PATH", imagePath);
        startActivity(intent);
    }
}

// 保留原有的权限验证代码不变
private static final int REQUEST_EXTERNAL_STORAGE = 1;
private static String[] PERMISSIONS_STORAGE = {
        Manifest.permission.READ_EXTERNAL_STORAGE,
        Manifest.permission.WRITE_EXTERNAL_STORAGE
};
public static void verifyStoragePermissions(Activity activity) {
    int permission = ActivityCompat.checkSelfPermission(activity, Manifest.permission.WRITE_EXTERNAL_STORAGE);
    if (permission != PackageManager.PERMISSION_GRANTED) {
        ActivityCompat.requestPermissions(
                activity,
                PERMISSIONS_STORAGE,
                REQUEST_EXTERNAL_STORAGE
        );
    }
}
}

步骤4：创建第二个Activity（ImageDisplayActivity） #

1. 布局文件activity_image_display.xml：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:gravity="center">

    <ImageView
        android:id="@+id/display_image"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:scaleType="centerInside"/>
</LinearLayout>

2. Activity代码：

public class ImageDisplayActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_image_display);

        ImageView displayImage = findViewById(R.id.display_image);
        // 获取传递的图片路径
        String imagePath = getIntent().getStringExtra("IMAGE_PATH");
        
        if (imagePath != null) {
            // 优化：采样加载大图，避免OOM
            Bitmap bitmap = decodeSampledBitmapFromFile(imagePath, 1080, 1920);
            displayImage.setImageBitmap(bitmap);
        }
    }

    // 大图采样压缩工具方法
    private Bitmap decodeSampledBitmapFromFile(String path, int reqWidth, int reqHeight) {
        final BitmapFactory.Options options = new BitmapFactory.Options();
        options.inJustDecodeBounds = true;
        BitmapFactory.decodeFile(path, options);
        
        options.inSampleSize = calculateInSampleSize(options, reqWidth, reqHeight);
        options.inJustDecodeBounds = false;
        return BitmapFactory.decodeFile(path, options);
    }

    private int calculateInSampleSize(BitmapFactory.Options options, int reqWidth, int reqHeight) {
        final int height = options.outHeight;
        final int width = options.outWidth;
        int inSampleSize = 1;

        if (height > reqHeight || width > reqWidth) {
            final int halfHeight = height / 2;
            final int halfWidth = width / 2;
            while ((halfHeight / inSampleSize) >= reqHeight
                    && (halfWidth / inSampleSize) >= reqWidth) {
                inSampleSize *= 2;
            }
        }
        return inSampleSize;
    }
}

方案二：传递Bitmap（仅适合缩略图） #

如果只需要传递相机返回的缩略图，可直接通过Intent传递Parcelable类型的Bitmap，但注意大图会触发TransactionTooLargeException：

修改MainActivity的onActivityResult #

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    if (requestCode == pic_id && resultCode == RESULT_OK) {
        Bitmap photo = (Bitmap) data.getExtras().get("data");
        // 传递Bitmap到下一个Activity
        Intent intent = new Intent(this, ImageDisplayActivity.class);
        intent.putExtra("IMAGE_BITMAP", photo);
        startActivity(intent);
    }
}

在ImageDisplayActivity接收并显示 #

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_image_display);

    ImageView displayImage = findViewById(R.id.display_image);
    Bitmap bitmap = getIntent().getParcelableExtra("IMAGE_BITMAP");
    if (bitmap != null) {
        displayImage.setImageBitmap(bitmap);
    }
}

额外注意事项 #

1. 相机权限：在AndroidManifest.xml中添加相机权限声明：

<uses-permission android:name="android.permission.CAMERA" />
<uses-feature android:name="android.hardware.camera" />

2. Android 13+适配：使用应用私有目录（getExternalFilesDir）无需申请额外存储权限，若需访问公共目录需申请READ_MEDIA_IMAGES权限。

内容的提问来源于stack exchange，提问作者Abm