Github地址：https://github.com/google/cameraview

該控制元件為Google開源，非官方，只為了開發人員輕鬆整合Camera功能。

混淆：

釋出release版本時，請在主module中得proguard-rules.pro檔案中加入 -ignorewarnings，否則會出現waring警告導致構建失敗。

-ignorewarnings

許可權：

<uses-permission android:name="android.permission.CAMERA" />

XML：

?xml version="1.0" encoding="utf-8"?>
<
 
RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <Button
        android:id="@+id/btn_take_picture"
        android:layout_width="wrap_content"
 

        android:layout_height="wrap_content"
        android:background="@android:color/white"
        android:text="拍照" />

    <Button
        android:id="@+id/btn_start_camera"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below
 
="@+id/btn_take_picture"
        android:background="@android:color/white"
        android:text="開啟相機" />

    <Button
        android:id="@+id/btn_stop_camera"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/btn_start_camera"
        android:background="@android:color/white"
        android:text="關閉相機" />

    <com.google.android.cameraview.CameraView
        android:id="@+id/camera_view"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:adjustViewBounds="true"
        android:keepScreenOn="true"
        app:aspectRatio="4:3"
        app:autoFocus="true"
        app:facing="back"
        app:flash="auto" />
</RelativeLayout>

程式碼：

mCameraView = (CameraView) findViewById(R.id.camera_view);
//為控制元件設定回撥方法，相機開啟，停止預覽的時候會走該回調方法。
mCameraView.addCallback(new CameraView.Callback() {
    @Override
    public void onCameraOpened(CameraView cameraView) {
        //相機開啟呼叫
        Toast.makeText(MainActivity.this, "開啟相機回撥", Toast.LENGTH_SHORT).show();
    }
    @Override
    public void onCameraClosed(CameraView cameraView) {
        //相機關閉呼叫
        Toast.makeText(MainActivity.this, "關閉相機回撥", Toast.LENGTH_SHORT).show();
    }
    @Override
    public void onPictureTaken(CameraView cameraView, final byte[] data) {
        //data 相機拍攝得到得圖片，可以通過位元組流寫入檔案中儲存。
        //FileIOUtils.writeFileFromBytesByStream(filePath, data);
        Toast.makeText(MainActivity.this, "抓取圖片回撥   " + data.toString(), Toast.LENGTH_SHORT).show();
    }
});
//拍照
findViewById(R.id.btn_take_picture).setOnClickListener(v -> {
    new RxPermissions(this)
            .requestEach(Manifest.permission.CAMERA)
            .subscribe(permission -> {
                if (permission.granted) {
                    if (mCameraView.isCameraOpened()) {
                        mCameraView.takePicture();
                    }else {
                        Toast.makeText(MainActivity.this, "請開啟相機後再進行拍照 ", Toast.LENGTH_SHORT).show();
                    }
                } else {
                    Toast.makeText(MainActivity.this, "請開啟相機許可權", Toast.LENGTH_SHORT).show();
                }
            });
});
//啟動相機並預覽
findViewById(R.id.btn_start_camera).setOnClickListener(v -> {
    new RxPermissions(this)
            .requestEach(Manifest.permission.CAMERA)
            .subscribe(permission -> {
                if (permission.granted) {
                    if (!mCameraView.isCameraOpened()) {
                        mCameraView.start();
                    }
                } else {
                    Toast.makeText(MainActivity.this, "請開啟相機許可權", Toast.LENGTH_SHORT).show();
                }
            });
});
//關閉相機
findViewById(R.id.btn_stop_camera).setOnClickListener(v -> {
    new RxPermissions(this)
            .requestEach(Manifest.permission.CAMERA)
            .subscribe(permission -> {
                if (permission.granted) {
                    if (mCameraView.isCameraOpened()) {
                        mCameraView.stop();
                    }
                } else {
                    Toast.makeText(MainActivity.this, "請開啟相機許可權", Toast.LENGTH_SHORT).show();
                }
            });
});

實現效果：