SurfaceView中的自动对焦

问题描述 投票:1回答:2

我正在使用SurfaceView在Android中编写QR码阅读器。我在互联网上的教程中编写了这段代码,我对SurfaceView不是很熟悉。

我有一个主要问题,我不知道如何在SurfaceView中设置自动对焦。

我搜索了这么多。我尝试了一些我在互联网上找到的方法,但我无法设置自动对焦。我该如何实现它?

我的代码:

public class page_qr extends AppCompatActivity   {

SurfaceView cameraView;
TextView barcodeInfo;

BarcodeDetector barcodeDetector;
CameraSource cameraSource;

static Context _C;

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

    _C = this;

    focusMode = (TextView) findViewById(R.id.focus_mode);
    cameraView = (SurfaceView) findViewById(R.id.camera_view);
    barcodeInfo = (TextView) findViewById(R.id.code_info);

    barcodeDetector =
            new BarcodeDetector.Builder(this)
                    .setBarcodeFormats(Barcode.QR_CODE)
                    .build();

    cameraSource = new CameraSource
            .Builder(this, barcodeDetector)
            .setRequestedPreviewSize(640, 480)
            .setFacing(CameraSource.CAMERA_FACING_BACK)
            .setRequestedFps(30.0f)
            .build();       

    cameraView.getHolder().addCallback(new SurfaceHolder.Callback() {
        @Override
        public void surfaceCreated(SurfaceHolder holder) {
            try {
                cameraSource.start(cameraView.getHolder());
            } catch (IOException ie) {
                Log.e("CAMERA SOURCE", ie.getMessage());
            }
        }

        @Override
        public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
        }

        @Override
        public void surfaceDestroyed(SurfaceHolder holder) {
            cameraSource.stop();
        }
    });

    barcodeDetector.setProcessor(new Detector.Processor<Barcode>() {
        @Override
        public void release() {
        }

        @Override
        public void receiveDetections(Detector.Detections<Barcode> detections) {
            final SparseArray<Barcode> barcodes = detections.getDetectedItems();

            if (barcodes.size() != 0) {
                barcodeInfo.post(new Runnable() {    // Use the post method of the TextView
                    public void run() {
                        barcodeInfo.setText(    // Update the TextView
                                barcodes.valueAt(0).displayValue
                        );
                    }
                });
            }
        }
    });

}

我的布局:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:padding="16dp">

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:weightSum="4">

        <TextView
            android:id="@+id/code_info"
            android:layout_width="match_parent"
            android:layout_height="0dp"
            android:layout_alignParentTop="true"
            android:layout_marginLeft="16dp"
            android:layout_weight="1"
            android:text="Nothing to read."
            android:textColor="#DE043B3F"
            android:textSize="20sp" />

    <SurfaceView
        android:id="@+id/camera_view"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_alignParentLeft="true"
        android:layout_centerVertical="true"
        android:layout_weight="3"
        android:focusable="true"
        android:focusableInTouchMode="true" />

</LinearLayout>

android surfaceview qr-code autofocus
2个回答
1
投票

用这个

cameraSource = new CameraSource.Builder(this, barcodeDetector)
                .setRequestedPreviewSize(640, 480)
                .setAutoFocusEnabled(true)
                .setFacing(CameraSource.CAMERA_FACING_BACK)
                .setRequestedFps(30.0f)
                .build();

0
投票

在下面的链接有一个很好的教程:http://technologysupportforall.blogspot.gr/2014/01/custom-camera-using-surfaceview-android.html

虽然教程没有提到它,但您应该在清单中添加以下行:

<uses-feature android:name="android.hardware.camera.autofocus" android:required="false"/>

如果你不这样做,你的代码将无效。

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