主要逻辑：
public class UseCameraActivity extends Activity {
private Activity get() {
return this;
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_asome);
setTitle(getClass().getSimpleName());
final FrameLayout frameLayout = findViewById(R.id.prev_content_layout);
Button btn = findViewById(R.id.start_camera_preview);
btn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
AndPermission.with(get())
.permission(Manifest.permission.CAMERA,
Manifest.permission.WRITE_EXTERNAL_STORAGE
)
.onDenied(new Action() {
@Override
public void onAction(List<String> permissions) {
LogUtils.e("error....." + permissions);
}
})
.onGranted(new Action() {
@Override
public void onAction(List<String> permissions) {
LogUtils.w("you can do..");
ScanView scanView = new ScanView(get());
frameLayout.removeAllViews();
frameLayout.addView(scanView);
}
}).start();
}
});
}
static class ScanView extends SurfaceView implements SurfaceHolder.Callback,
Camera.AutoFocusCallback {
private Camera mCamera;
private final File fileImg;
private ScanView self;
public ScanView(Context context) {
super(context);
fileImg = new File(context.getCacheDir(), "prev_view.jpg");
SurfaceHolder mHolder = getHolder();
self = this;
mHolder.addCallback(this);
// deprecated setting, but required on Android versions prior to 3.0
mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
}
@Override
public void onAutoFocus(boolean success, Camera camera) {
LogUtils.w("auto focus..." + success);
if (mCamera != null) {
mCamera.takePicture(null, null, null, new Camera.PictureCallback() {
@Override
public void onPictureTaken(byte[] data, Camera camera) {
mCamera.cancelAutoFocus();
mCamera.stopPreview(); // 拿到数据就停止！！！
LogUtils.w("========data========");
LogUtils.w("----------data-----------------");
// camera.startPreview();
File pictureFile = fileImg;
if (pictureFile == null) {
LogUtils.e("Error creating media file, check storage permissions: " +
null);
return;
}
if (data == null) {
return;
}
try {
LogUtils.d(data);
FileOutputStream fos = new FileOutputStream(pictureFile);
fos.write(data);
fos.close();
LogUtils.e("save preview complete###!!!");
LogUtils.e("save preview complete###!!!" + pictureFile);
BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeFile(pictureFile.getAbsolutePath(), options);
options.inJustDecodeBounds = false;
int outWidth = options.outWidth;
int outHeight = options.outHeight;
if (outWidth >= getWidth() * 2) {
options.inSampleSize = outWidth / getWidth();
}
if (outHeight >= getHeight() * 2) {
options.inSampleSize = outHeight / getHeight();
}
Bitmap bmp = BitmapFactory.decodeFile(pictureFile.getAbsolutePath(), options);
Result result = parseInfoFromBitmap(bmp);
if (result != null) {
Toast.makeText(getContext(), "INFO:" + result.getText(), Toast.LENGTH_SHORT).show();
LogUtils.w("解析成功：" + result);
} else {
LogUtils.e("再次尝试中....");
mCamera.startPreview();
mCamera.autoFocus(self);
// todo:这里也可以做最大重试次数的限制...
}
} catch (Exception e) {
LogUtils.e("Error accessing file: " + e.getMessage());
}
}
});
}
}
public Result parseInfoFromBitmap(Bitmap bitmap) {
int[] pixels = new int[bitmap.getWidth() * bitmap.getHeight()];
bitmap.getPixels(pixels, 0, bitmap.getWidth(), 0, 0, bitmap.getWidth(), bitmap.getHeight());
LogUtils.w("### pixels dest==" + Arrays.toString(pixels));
RGBLuminanceSource source = new RGBLuminanceSource(bitmap.getWidth(),
bitmap.getHeight(), pixels);
GlobalHistogramBinarizer binarizer = new GlobalHistogramBinarizer(source);
BinaryBitmap image = new BinaryBitmap(binarizer);
Result result = null;
try {
result = new QRCodeReader().decode(image);
return result;
} catch (NotFoundException e) {
e.printStackTrace();
Toast.makeText(getContext(), "非二维码图片，不能解析", Toast.LENGTH_SHORT).show();
} catch (ChecksumException e) {
e.printStackTrace();
} catch (FormatException e) {
e.printStackTrace();
}
return null;
}
@Override
public void surfaceCreated(SurfaceHolder holder) {
LogUtils.e("x surfaceCreated.. #####");
try {
mCamera = Camera.open();
mCamera.setPreviewDisplay(holder);
mCamera.setDisplayOrientation(90);
Camera.Parameters parameters = mCamera.getParameters();
// parameters.setPictureSize(1600, 1200);
// parameters.setPreviewSize(640, 480);
mCamera.setParameters(parameters);
mCamera.startPreview();
mCamera.autoFocus(this);
LogUtils.e("surfaceCreated.. #####");
} catch (IOException e) {
LogUtils.e("Error setting camera preview: " + e.getMessage());
}
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
LogUtils.w("--change-");
}
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
LogUtils.w("destroy--");
if (mCamera != null) {
mCamera.cancelAutoFocus();
mCamera.stopPreview();
mCamera.release();
}
}
}
}
看起来有一点长，但是实际内容并不多。
注意：
- 实现相机预览，必须去实现一个
SurfaceView，一个普通的View貌似做不到这点。 - 要想获取相机预览数据，必须去对焦，不然不返回数据。
没有了。另外，代码里用的api是Camera的api，已经过时了，虽然可以继续使用。但是官方不建议了，后续有时间会去尝试Camera2。
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更详细的介绍：戳一下试试...