一篇文章实现Android图片拼接并保存至相册

系列文章目录

一篇文章实现Android图片拼接并保存至相册

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前言

好久没有写Android系列的文章了，最近有小伙伴问到了Android图片拼接的问题，写一篇相关的博客。

在Android应用中实现图片拼接功能并保存到相册是一个常见的需求，比如制作全景图、拼图应用或照片编辑工具。本文将介绍如何实现一个完整的图片拼接应用，包括图片选择、拼接和保存功能。

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实现功能

1. 检查并请求必要的存储权限
2. 允许用户从相册选择一张或多张图片
3. 异步加载选中的图片
4. 使用ImageStitcher类拼接图片
5. 将拼接后的图片保存到相册
6. 在整个过程中显示适当的进度指示和操作反馈

类定义和成员变量

其中包括图片选择请求码，读取权限请求码， 写入权限请求码，保存目录名称，以及相关控件。

public class MainActivity extends AppCompatActivity {
    private static final int PICK_IMAGE_REQUEST = 1;  // 图片选择请求码
    private static final int REQUEST_PERMISSION = 2;  // 读取权限请求码
    private static final int REQUEST_WRITE_PERMISSION = 3;  // 写入权限请求码
    private static final String SAVE_DIRECTORY = "ImageStitcher";  // 保存目录名称
    
    private List<Bitmap> selectedImages = new ArrayList<>();  // 存储选择的图片
    private ImageView resultView;  // 显示拼接结果的ImageView
    private ProgressBar progressBar;  // 进度条
    private Button selectBtn, stitchBtn, saveBtn;  // 按钮控件

onCreate方法

初始化控件以及设置监听

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);  // 设置布局文件

    // 初始化视图控件
    resultView = findViewById(R.id.jm_result_image);
    progressBar = findViewById(R.id.jm_progress_bar);
    selectBtn = findViewById(R.id.jm_select_btn);
    stitchBtn = findViewById(R.id.jm_stitch_btn);
    saveBtn = findViewById(R.id.jm_save_btn);
    saveBtn.setVisibility(View.GONE);  // 初始时隐藏保存按钮

    // 设置按钮点击监听器
    selectBtn.setOnClickListener(v -> checkPermissionAndOpenChooser());
    stitchBtn.setOnClickListener(v -> stitchImagesAsync());
}

权限检查和图片选择

不动态申请权限小心报错：has no access to content 需在AndroidManifest.xml声明READ_EXTERNAL_STORAGE权限，Android Q及以上版本必须使用MediaStore API访问公共目录文件。

private void checkPermissionAndOpenChooser() {
    // 检查是否有读取外部存储权限
    if (ContextCompat.checkSelfPermission(this, Manifest.permission.READ_EXTERNAL_STORAGE)
            == PackageManager.PERMISSION_GRANTED) {
        openImageChooser();  // 有权限则直接打开图片选择器
    } else {
        // 没有权限则请求权限
        ActivityCompat.requestPermissions(this,
                new String[]{Manifest.permission.READ_EXTERNAL_STORAGE},
                REQUEST_PERMISSION);
    }
}

private void openImageChooser() {
    // 创建选择图片的Intent
    Intent intent = new Intent(Intent.ACTION_GET_CONTENT);
    intent.setType("image/*");  // 设置类型为图片
    intent.putExtra(Intent.EXTRA_ALLOW_MULTIPLE, true);  // 允许多选
    startActivityForResult(Intent.createChooser(intent, "选择图片"), PICK_IMAGE_REQUEST);
}

// 权限请求结果回调
@Override
public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {
    super.onRequestPermissionsResult(requestCode, permissions, grantResults);
    if (requestCode == REQUEST_PERMISSION && grantResults.length > 0
            && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
        openImageChooser();  // 权限被授予后打开图片选择器
    }
}

处理选择的图片

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    if (requestCode == PICK_IMAGE_REQUEST && resultCode == RESULT_OK && data != null) {
        handleSelectedImages(data);  // 处理选择的图片
    }
}

private void handleSelectedImages(Intent data) {
    progressBar.setVisibility(View.VISIBLE);  // 显示进度条
    ExecutorService executor = Executors.newSingleThreadExecutor();
    executor.execute(() -> {
        try {
            if (data.getClipData() != null) {
                processMultipleImages(data.getClipData());  // 处理多张图片
            } else if (data.getData() != null) {
                processSingleImage(data.getData());  // 处理单张图片
            }
        } finally {
            runOnUiThread(() -> progressBar.setVisibility(View.GONE));  // 隐藏进度条
        }
    });
}

private void processMultipleImages(ClipData clipData) {
    for (int i = 0; i < clipData.getItemCount(); i++) {
        loadAndAddImage(clipData.getItemAt(i).getUri());  // 加载并添加每张图片
    }
}

private void processSingleImage(Uri uri) {
    loadAndAddImage(uri);  // 加载并添加单张图片
}

private void loadAndAddImage(Uri uri) {
    try (InputStream is = getContentResolver().openInputStream(uri)) {
        Bitmap bitmap = BitmapFactory.decodeStream(is);  // 从URI加载图片
        runOnUiThread(() -> {
            selectedImages.add(bitmap);  // 添加到图片列表
            Toast.makeText(this, "成功加载图片", Toast.LENGTH_SHORT).show();
        });
    } catch (Exception e) {
        runOnUiThread(() ->
                Toast.makeText(this, "加载失败: " + e.getMessage(), Toast.LENGTH_SHORT).show());
    }
}

图片拼接功能

private void stitchImagesAsync() {
    if (selectedImages.isEmpty()) return;  // 如果没有选择图片则返回
    
    saveBtn.setVisibility(View.VISIBLE);  // 显示保存按钮
    progressBar.setVisibility(View.VISIBLE);  // 显示进度条
    
    ExecutorService executor = Executors.newSingleThreadExecutor();
    executor.execute(() -> {
        // 调用ImageStitcher类拼接图片
        Bitmap stitched = ImageStitcher.stitchImages(
                selectedImages.toArray(new Bitmap[0]), 0);
        
        runOnUiThread(() -> {
            resultView.setImageBitmap(stitched);  // 显示拼接结果
            progressBar.setVisibility(View.GONE);  // 隐藏进度条
            saveBtn.setVisibility(View.VISIBLE);  // 确保保存按钮可见
            // 设置保存按钮点击监听器
            saveBtn.setOnClickListener(v -> saveImageToGallery(stitched));
        });
    });
}

图片保存功能

private void saveImageToGallery(Bitmap bitmap) {
    // 检查是否有写入外部存储权限
    if (ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE)
            != PackageManager.PERMISSION_GRANTED) {
        // 没有权限则请求权限
        ActivityCompat.requestPermissions(this,
                new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE},
                REQUEST_WRITE_PERMISSION);
        return;
    }

    // 在新线程中执行保存操作
    new Thread(() -> {
        String fileName = "stitched_" + System.currentTimeMillis() + ".jpg";
        ContentValues values = new ContentValues();
        values.put(MediaStore.Images.Media.DISPLAY_NAME, fileName);
        values.put(MediaStore.Images.Media.MIME_TYPE, "image/jpeg");

        // 对于Android Q及以上版本
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {
            values.put(MediaStore.Images.Media.RELATIVE_PATH, 
                     Environment.DIRECTORY_PICTURES + File.separator + SAVE_DIRECTORY);
            values.put(MediaStore.Images.Media.IS_PENDING, 1);
        }

        try {
            // 插入媒体库记录
            Uri uri = getContentResolver().insert(
                    MediaStore.Images.Media.EXTERNAL_CONTENT_URI, values);

            try (OutputStream os = getContentResolver().openOutputStream(uri)) {
                // 压缩并写入图片数据
                bitmap.compress(Bitmap.CompressFormat.JPEG, 90, os);
                
                // 对于Android Q及以上版本，更新IS_PENDING标志
                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {
                    values.put(MediaStore.Images.Media.IS_PENDING, 0);
                    getContentResolver().update(uri, values, null, null);
                }
                
                // 显示保存成功提示
                runOnUiThread(() ->
                        Toast.makeText(this, "图片已保存至相册", Toast.LENGTH_SHORT).show());
            }
        } catch (Exception e) {
            // 显示保存失败提示
            runOnUiThread(() ->
                    Toast.makeText(this, "保存失败: " + e.getMessage(), Toast.LENGTH_SHORT).show());
        }
    }).start();
}

使用ImageStitcher类拼接图片

代码解释：ImageStitcher.java

这是一个用于拼接多张图片的工具类，提供了将多张图片横向或纵向拼接成一张大图的功能。下面是对代码的详细解释：

类定义和方法

public class ImageStitcher {
    public static Bitmap stitchImages(Bitmap[] images, int direction) {
        // 检查输入参数是否有效
        if (images == null || images.length == 0) return null;

计算拼接后图片的尺寸

        int width = images[0].getWidth();
        int height = images[0].getHeight();

        // 计算拼接后图片的总尺寸
        if (direction == 0) { // 横向拼接
            for (int i = 1; i < images.length; i++) {
                width += images[i].getWidth();  // 累加宽度
                height = Math.max(height, images[i].getHeight());  // 取最大高度
            }
        } else { // 纵向拼接
            for (int i = 1; i < images.length; i++) {
                height += images[i].getHeight();  // 累加高度
                width = Math.max(width, images[i].getWidth());  // 取最大宽度
            }
        }

计算逻辑

• 横向拼接：总宽度为所有图片宽度之和，高度为所有图片中的最大高度
• 纵向拼接：总高度为所有图片高度之和，宽度为所有图片中的最大宽度

创建并绘制拼接后的图片

        // 创建拼接后的Bitmap
        Bitmap result = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(result);

        // 绘制图片
        int currentPos = 0;
        for (Bitmap image : images) {
            if (direction == 0) { // 横向拼接
                canvas.drawBitmap(image, currentPos, 0, null);  // 在当前位置绘制图片
                currentPos += image.getWidth();  // 更新横向位置
            } else { // 纵向拼接
                canvas.drawBitmap(image, 0, currentPos, null);  // 在当前位置绘制图片
                currentPos += image.getHeight();  // 更新纵向位置
            }
        }

        return result;  // 返回拼接后的图片
    }
}

绘制过程

1. 创建一个新的空白Bitmap，大小为之前计算的总尺寸
2. 使用Canvas在这个Bitmap上绘制所有输入图片
3. 根据拼接方向，依次将每张图片绘制到正确的位置
4. 更新当前位置指针(currentPos)，以便下一张图片绘制在正确的位置

注意事项

• 所有输入图片应为非空且尺寸相同（代码中未做严格检查）
• 拼接方向通过简单的int值判断（0为横向，非0为纵向）
• 使用了ARGB_8888配置创建Bitmap，保证图片质量
• 这是一个基础实现，没有处理图片尺寸不一致时的缩放或裁剪

效果图

源码

MainActivity.java

import androidx.appcompat.app.AppCompatActivity;
import androidx.core.app.ActivityCompat;
import androidx.core.content.ContextCompat;

import android.Manifest;
import android.content.ClipData;
import android.content.ContentValues;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.net.Uri;
import android.os.Build;
import android.os.Bundle;
import android.os.Environment;
import android.provider.MediaStore;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.ProgressBar;
import android.widget.Toast;

import java.io.File;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;


public class MainActivity extends AppCompatActivity {
    private static final int PICK_IMAGE_REQUEST = 1;
    private static final int REQUEST_PERMISSION = 2;
    private List<Bitmap> selectedImages = new ArrayList<>();
    private ImageView resultView;
    private ProgressBar progressBar;
    private static final int REQUEST_WRITE_PERMISSION = 3;
    private static final String SAVE_DIRECTORY = "JmImgStitcher";
    private Button selectBtn,stitchBtn,saveBtn;

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

        resultView = findViewById(R.id.jm_result_image);
        progressBar = findViewById(R.id.jm_progress_bar);
        selectBtn = findViewById(R.id.jm_select_btn);
        stitchBtn = findViewById(R.id.jm_stitch_btn);
        // 初始化保存按钮
        saveBtn = findViewById(R.id.jm_save_btn);
        saveBtn.setVisibility(View.GONE);

        selectBtn.setOnClickListener(v -> checkPermissionAndOpenChooser());
        stitchBtn.setOnClickListener(v -> stitchImagesAsync());
    }

    private void checkPermissionAndOpenChooser() {
        if (ContextCompat.checkSelfPermission(this, Manifest.permission.READ_EXTERNAL_STORAGE)
                == PackageManager.PERMISSION_GRANTED) {
            openImageChooser();
        } else {
            ActivityCompat.requestPermissions(this,
                    new String[]{Manifest.permission.READ_EXTERNAL_STORAGE},
                    REQUEST_PERMISSION);
        }
    }

    private void openImageChooser() {
        Intent intent = new Intent(Intent.ACTION_GET_CONTENT);
        intent.setType("image/*");
        intent.putExtra(Intent.EXTRA_ALLOW_MULTIPLE, true);
        startActivityForResult(Intent.createChooser(intent, "选择图片"), PICK_IMAGE_REQUEST);
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        if (requestCode == REQUEST_PERMISSION && grantResults.length > 0
                && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
            openImageChooser();
        }
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if (requestCode == PICK_IMAGE_REQUEST && resultCode == RESULT_OK && data != null) {
            handleSelectedImages(data);
        }
    }

    private void handleSelectedImages(Intent data) {
        progressBar.setVisibility(View.VISIBLE);
        ExecutorService executor = Executors.newSingleThreadExecutor();
        executor.execute(() -> {
            try {
                if (data.getClipData() != null) {
                    processMultipleImages(data.getClipData());
                } else if (data.getData() != null) {
                    processSingleImage(data.getData());
                }
            } finally {
                runOnUiThread(() -> progressBar.setVisibility(View.GONE));
            }
        });
    }

    private void processMultipleImages(ClipData clipData) {
        for (int i = 0; i < clipData.getItemCount(); i++) {
            loadAndAddImage(clipData.getItemAt(i).getUri());
        }
    }

    private void processSingleImage(Uri uri) {
        loadAndAddImage(uri);
    }

    private void loadAndAddImage(Uri uri) {
        try (InputStream is = getContentResolver().openInputStream(uri)) {
            Bitmap bitmap = BitmapFactory.decodeStream(is);
            runOnUiThread(() -> {
                selectedImages.add(bitmap);
                Toast.makeText(this, "成功加载图片", Toast.LENGTH_SHORT).show();
            });
        } catch (Exception e) {
            runOnUiThread(() ->
                    Toast.makeText(this, "加载失败: " + e.getMessage(), Toast.LENGTH_SHORT).show());
        }
    }

    // 修改stitchImagesAsync方法
    private void stitchImagesAsync() {
        if (selectedImages.isEmpty()) return;
        saveBtn.setVisibility(View.VISIBLE);
        progressBar.setVisibility(View.VISIBLE);
        ExecutorService executor = Executors.newSingleThreadExecutor();
        executor.execute(() -> {
            Bitmap stitched = ImageStitcher.stitchImages(
                    selectedImages.toArray(new Bitmap[0]), 0);
            runOnUiThread(() -> {
                resultView.setImageBitmap(stitched);
                progressBar.setVisibility(View.GONE);
                //设置出现
                saveBtn.setVisibility(View.VISIBLE);
                saveBtn.setOnClickListener(v -> saveImageToGallery(stitched));
            });
        });

    }

    private void saveImageToGallery(Bitmap bitmap) {
        if (ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE)
                != PackageManager.PERMISSION_GRANTED) {
            ActivityCompat.requestPermissions(this,
                    new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE},
                    REQUEST_WRITE_PERMISSION);
            return;
        }

        new Thread(() -> {
            String fileName = "stitched_" + System.currentTimeMillis() + ".jpg";
            ContentValues values = new ContentValues();
            values.put(MediaStore.Images.Media.DISPLAY_NAME, fileName);
            values.put(MediaStore.Images.Media.MIME_TYPE, "image/jpeg");

            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {
                values.put(MediaStore.Images.Media.RELATIVE_PATH, Environment.DIRECTORY_PICTURES + File.separator + SAVE_DIRECTORY);
                values.put(MediaStore.Images.Media.IS_PENDING, 1);
            }

            try {
                Uri uri = getContentResolver().insert(
                        MediaStore.Images.Media.EXTERNAL_CONTENT_URI, values);

                try (OutputStream os = getContentResolver().openOutputStream(uri)) {
                    bitmap.compress(Bitmap.CompressFormat.JPEG, 90, os);
                    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {
                        values.put(MediaStore.Images.Media.IS_PENDING, 0);
                        getContentResolver().update(uri, values, null, null);
                    }
                    runOnUiThread(() ->
                            Toast.makeText(this, "图片已保存至相册", Toast.LENGTH_SHORT).show());
                }
            } catch (Exception e) {
                runOnUiThread(() ->
                        Toast.makeText(this, "保存失败: " + e.getMessage(), Toast.LENGTH_SHORT).show());
            }
        }).start();
    }

}

ImageStitcher.java

import android.graphics.Bitmap;
import android.graphics.Canvas;

public class ImageStitcher {
    public static Bitmap stitchImages(Bitmap[] images, int direction) {
        if (images == null || images.length == 0) return null;

        int width = images[0].getWidth();
        int height = images[0].getHeight();

        // 计算拼接后图片的总尺寸
        if (direction == 0) { // 横向拼接
            for (int i = 1; i < images.length; i++) {
                width += images[i].getWidth();
                height = Math.max(height, images[i].getHeight());
            }
        } else { // 纵向拼接
            for (int i = 1; i < images.length; i++) {
                height += images[i].getHeight();
                width = Math.max(width, images[i].getWidth());
            }
        }

        // 创建拼接后的Bitmap
        Bitmap result = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(result);

        // 绘制图片
        int currentPos = 0;
        for (Bitmap image : images) {
            if (direction == 0) { // 横向拼接
                canvas.drawBitmap(image, currentPos, 0, null);
                currentPos += image.getWidth();
            } else { // 纵向拼接
                canvas.drawBitmap(image, 0, currentPos, null);
                currentPos += image.getHeight();
            }
        }

        return result;
    }
}

AndroidManifest权限申明

    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
    <!-- Android 10+ 需要添加 -->
    <uses-permission android:name="android.permission.ACCESS_MEDIA_LOCATION"
        android:maxSdkVersion="29" />

activity_main.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">
    <ProgressBar
        android:id="@+id/jm_progress_bar"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:visibility="gone"/>
    <Button
        android:id="@+id/jm_select_btn"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="选择要拼接的图片"/>

    <Button
        android:id="@+id/jm_stitch_btn"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="开始拼接图片"/>
    <Button
        android:id="@+id/jm_save_btn"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="保存图片"
        android:visibility="gone"/>
    <ImageView
        android:id="@+id/jm_result_image"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:scaleType="centerInside"/>
</LinearLayout>

总结

此文章可以作为基础，根据具体需求进行扩展和优化。欢迎留言，如有问题可以联系计蒙。