使用ActivityResultLauncher拍照后未返回调用页面，直接回到主页面

在Activity中调用相机拍照，图片拍摄成功，但点击确认后未回到启动相机的页面，直接跳转至主页面。

代码实现 #

public void captureImage(){
    ContentValues values = new ContentValues();
    values.put(MediaStore.Images.Media.TITLE, "Cust-" + customerName+ newCustomerID);
    values.put(MediaStore.Images.Media.DESCRIPTION, "From the Camera");
    image_uri = getContentResolver().insert(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, values);

    cameraActivityResultLauncher.launch(image_uri);
}

ActivityResultLauncher<Uri> cameraActivityResultLauncher = registerForActivityResult(
        new ActivityResultContracts.TakePicture(),
        new ActivityResultCallback<Boolean>() {
            @Override
            public void onActivityResult(Boolean result) {
                if(result) {
                    Bitmap inputImage = uriToBitmap(image_uri);
                    Bitmap rotated = rotateBitmap(inputImage);
                    imageView.setImageBitmap(rotated);
                }

            }
        });



//TODO takes URI of the image and returns bitmap
private Bitmap uriToBitmap(Uri selectedFileUri) {
    try {
        ParcelFileDescriptor parcelFileDescriptor =
                getContentResolver().openFileDescriptor(selectedFileUri, "r");
        FileDescriptor fileDescriptor = parcelFileDescriptor.getFileDescriptor();
        Bitmap image = BitmapFactory.decodeFileDescriptor(fileDescriptor);
        parcelFileDescriptor.close();
        return image;
    } catch (IOException e) {
        e.printStackTrace();
    }
    return  null;
}

//TODO rotate image if image captured on samsung devices
//TODO Most phone cameras are landscape, meaning if you take the photo in portrait, the resulting photos will be rotated 90 degrees.
@SuppressLint("Range")
public Bitmap rotateBitmap(Bitmap input){
    String[] orientationColumn = {MediaStore.Images.Media.ORIENTATION};
    Cursor cur = getContentResolver().query(image_uri, orientationColumn, null, null, null);
    int orientation = -1;
    if (cur != null && cur.moveToFirst()) {
        orientation = cur.getInt(cur.getColumnIndex(orientationColumn[0]));
    }
    Log.d("tryOrientation",orientation+"");
    Matrix rotationMatrix = new Matrix();
    rotationMatrix.setRotate(orientation);
    Bitmap cropped = Bitmap.createBitmap(input,0,0, input.getWidth(), input.getHeight(), rotationMatrix, true);
    return cropped;
}

Logcat日志 #

Handler (com.samsung.android.camera.core2.device.CamDeviceHandlerManager$ExecTimeLoggingHandler) {8f36486} 向已销毁线程的Handler发送消息
java.lang.IllegalStateException: Handler (com.samsung.android.camera.core2.device.CamDeviceHandlerManager$ExecTimeLoggingHandler) {8f36486} 向已销毁线程的Handler发送消息
at android.os.MessageQueue.enqueueMessage(MessageQueue.java:560)
at android.os.Handler.enqueueMessage(Handler.java:778)
at android.os.Handler.sendMessageAtTime(Handler.java:727)
at android.os.Handler.sendMessageDelayed(Handler.java:697)
at android.os.Handler.post(Handler.java:427)
at com.samsung.android.camera.core2.device.CamDeviceImpl.lambda$createCaptureSessionInternal$2(CamDeviceImpl.java:634)
at com.samsung.android.camera.core2.device.-$$Lambda$CamDeviceImpl$5X5wiAbd03qI4TTgkJV3Zs0XzuA.accept(Unknown Source:4)
at java.util.Optional.ifPresent(Optional.java:179)
at com.samsung.android.camera.core2.device.CamDeviceImpl.lambda$createCaptureSessionInternal$3$CamDeviceImpl(CamDeviceImpl.java:634)
at com.samsung.android.camera.core2.device.-$$Lambda$CamDeviceImpl$ckQoqhLVTrOTDJwKo66Y0V6AUsk.execute(Unknown Source:2)
at android.hardware.camera2.impl.CallbackProxies$SessionStateCallbackProxy.onReady(CallbackProxies.java:74)
at android.hardware.camera2.impl.CameraCaptureSessionImpl$2.onIdle(CameraCaptureSessionImpl.java:843)
at android.hardware.camera2.impl.CameraDeviceImpl$6.run(CameraDeviceImpl.java:244)
at android.os.Handler.handleCallback(Handler.java:938)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loopOnce(Looper.java:226)
at android.os.Looper.loop(Looper.java:313)
at android.os.HandlerThread.run(HandlerThread.java:67)

解决方案 #

1. 处理Activity被回收的情况 #

拍照过程中原Activity可能因系统内存不足被销毁，返回时会重新启动任务栈的主Activity。需保存和恢复关键状态：

• 保存状态：

@Override
protected void onSaveInstanceState(Bundle outState) {
    super.onSaveInstanceState(outState);
    if (image_uri != null) {
        outState.putParcelable("image_uri", image_uri);
    }
}

• 恢复状态：

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.your_activity_layout);
    if (savedInstanceState != null) {
        image_uri = savedInstanceState.getParcelable("image_uri");
    }
    // 初始化ActivityResultLauncher等组件
}

2. 检查Activity启动模式 #

确保当前Activity的launchMode为默认的standard，避免singleTask/singleInstance导致的任务栈异常：

<activity
    android:name=".YourCameraCallingActivity"
    android:launchMode="standard"/>

3. 优化图片存储方式（解决Samsung相机兼容性） #

Log中的报错是Samsung相机内部问题，但改用私有目录存储可避免媒体库写入的潜在异常：

• 配置FileProvider（在Manifest中）：

<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>

• 创建res/xml/file_paths.xml：

<?xml version="1.0" encoding="utf-8"?>
<paths xmlns:android="http://schemas.android.com/apk/res/android">
    <external-files-path name="camera_photos" path="Pictures"/>
</paths>

• 修改拍照方法：

public void captureImage(){
    try {
        File imageDir = getExternalFilesDir(Environment.DIRECTORY_PICTURES);
        File imageFile = new File(imageDir, "Cust-" + customerName + newCustomerID + ".jpg");
        image_uri = FileProvider.getUriForFile(this, getPackageName() + ".fileprovider", imageFile);
        cameraActivityResultLauncher.launch(image_uri);
    } catch (Exception e) {
        e.printStackTrace();
    }
}

4. 修复代码中的资源泄漏与异常 #

• 关闭Cursor避免内存泄漏：

@SuppressLint("Range")
public Bitmap rotateBitmap(Bitmap input){
    String[] orientationColumn = {MediaStore.Images.Media.ORIENTATION};
    Cursor cur = getContentResolver().query(image_uri, orientationColumn, null, null, null);
    int orientation = -1;
    if (cur != null) {
        if (cur.moveToFirst()) {
            orientation = cur.getInt(cur.getColumnIndex(orientationColumn[0]));
        }
        cur.close(); // 必须关闭Cursor
    }
    Log.d("tryOrientation", orientation + "");
    Matrix rotationMatrix = new Matrix();
    rotationMatrix.setRotate(orientation);
    return Bitmap.createBitmap(input, 0, 0, input.getWidth(), input.getHeight(), rotationMatrix, true);
}

• 增加空值判断防止崩溃：

@Override
public void onActivityResult(Boolean result) {
    if(result && image_uri != null) {
        Bitmap inputImage = uriToBitmap(image_uri);
        if (inputImage != null) {
            Bitmap rotated = rotateBitmap(inputImage);
            imageView.setImageBitmap(rotated);
        }
    }
}

内容的提问来源于stack exchange，提问作者youssef SULTAN