Question

我正在制作一个使用相机的应用程序，我希望在应用程序打开后立即打开默认相机。我目前在主要活动的onCreate方法中启动我的图像捕获意图。这有时非常精细，但有时相机意图连续3次启动。

public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        mImageView = (ImageView) findViewById(R.id.imageView1);
        mImageBitmap = null;

        Button picBtn = (Button) findViewById(R.id.pictureButton);
        setBtnListenerOrDisable(
                picBtn,
                mTakePicOnClickListener,
                MediaStore.ACTION_IMAGE_CAPTURE
        );

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.FROYO) {
            mAlbumStorageDirFactory = new FroyoAlbumDirFactory();
        } else {
            mAlbumStorageDirFactory = new BaseAlbumDirFactory();
        }
        dispatchTakePictureIntent(ACTION_TAKE_PHOTO_B);
    }

private void dispatchTakePictureIntent(int actionCode) {

        Intent takePictureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
        File f;
        try {
            f = setUpPhotoFile();
            mCurrentPhotoPath = f.getAbsolutePath();
            takePictureIntent.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(f));
        } catch (IOException e) {
            e.printStackTrace();
            mCurrentPhotoPath = null;
        }

        startActivityForResult(takePictureIntent, actionCode);
    }

 protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        if (resultCode == RESULT_OK) {
            handleBigCameraPhoto();
        }
    }

private void handleBigCameraPhoto() {

        if (mCurrentPhotoPath != null) {
            setPic();
            galleryAddPic();
            lastPhotoPath = mCurrentPhotoPath;
            mCurrentPhotoPath = null;
        }

    }

 private void setPic() {

        /* There isn't enough memory to open up more than a couple camera photos */
        /* So pre-scale the target bitmap into which the file is decoded */

        /* Get the size of the ImageView */
        int targetW = mImageView.getWidth();
        int targetH = mImageView.getHeight();

        /* Get the size of the image */
        BitmapFactory.Options bmOptions = new BitmapFactory.Options();
        bmOptions.inJustDecodeBounds = true;
        BitmapFactory.decodeFile(mCurrentPhotoPath, bmOptions);
        int photoW = bmOptions.outWidth;
        int photoH = bmOptions.outHeight;

        /* Figure out which way needs to be reduced less */
        int scaleFactor = 1;
        if ((targetW > 0) || (targetH > 0)) {
            scaleFactor = Math.min(photoW / targetW, photoH / targetH);
        }

        /* Set bitmap options to scale the image decode target */
        bmOptions.inJustDecodeBounds = false;
        bmOptions.inSampleSize = scaleFactor;
        bmOptions.inPurgeable = true;

        /* Decode the JPEG file into a Bitmap */
        Bitmap bitmap = BitmapFactory.decodeFile(mCurrentPhotoPath, bmOptions);

        /* Associate the Bitmap to the ImageView */
        mImageView.setImageBitmap(bitmap);
        mImageView.setVisibility(View.VISIBLE);
    }

Answer 1

看这里：

Android: onCreate() getting called multiple times (and not by me)

我可以提供的一条指导是尝试将该呼叫转移到

public void onResume(){

}

您将获得自动进入摄像机的所需行为，但这可能会减少一些额外的呼叫，因为它只会在活动实际显示给用户时发生（包括从其他人返回）应用程序等..）。

Answer 2

我认为纳撒尼尔正在给你很好的建议，将你的相机意图推向onResume。

但是，您需要区分一个onResume，它是您第一次启动的活动，因为您的活动在相机意图完成后恢复活动。如果你不这样做，你就会得到你看到的循环。

为此，您可以更改onActivityResult()以在Activity中设置一个名为isResumingFromCaptureIntent的成员变量。当resultCode与用于启动摄像头意图的内容匹配时，在onActivityResult中将其设置为true。然后，在你的onResume中，检查isResumingFromCaptureIntent，如果为true，你知道你不需要启动相机意图并且可以设置为false并继续你的活动需要做的任何事情。

Answer 3

在onCreate方法中，我添加了逻辑来检查之前是否已调用onCreate。我通过检查传入的包是否为空来完成此操作

public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        mImageView = (ImageView) findViewById(R.id.imageView1);
        mImageBitmap = null;

        Button picBtn = (Button) findViewById(R.id.pictureButton);
        setBtnListenerOrDisable(
                picBtn,
                mTakePicOnClickListener,
                MediaStore.ACTION_IMAGE_CAPTURE
        );

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.FROYO) {
            mAlbumStorageDirFactory = new FroyoAlbumDirFactory();
        } else {
            mAlbumStorageDirFactory = new BaseAlbumDirFactory();
        }

        if(savedInstanceState == null)
            dispatchTakePictureIntent(ACTION_TAKE_PHOTO_B);
    }

Intent在onCreate中开始多次调用

3 个答案: