Camera2_API_Sample

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="horizontal"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >

    <TextureView
        android:id="@+id/texture"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:layout_weight="1"
        >
    </TextureView>

    <Button
        android:id="@+id/button_capture"
        android:text="Capture"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        />
</LinearLayout>

MainActivity.java

package com.example.woshidan.cameratest;

import android.annotation.TargetApi;
import android.app.Activity;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.SurfaceTexture;
import android.hardware.camera2.CameraAccessException;
import android.hardware.camera2.CameraCaptureSession;
import android.hardware.camera2.CameraDevice;
import android.hardware.camera2.CameraManager;
import android.hardware.camera2.CaptureRequest;
import android.os.Build;
import android.os.Bundle;
import android.os.Handler;
import android.view.Surface;
import android.view.TextureView;
import android.view.View;
import android.widget.Button;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Arrays;


@TargetApi(Build.VERSION_CODES.LOLLIPOP)
public class MainActivity extends Activity {

    private CameraDevice mCameraDevice;
    private TextureView mTextureView;
    private Handler mBackgroundHandler = new Handler();
    private CameraCaptureSession mCaptureSession = null;

    private CaptureRequest.Builder mPreviewRequestBuilder;
    private CaptureRequest mPreviewRequest;

    @TargetApi(Build.VERSION_CODES.M)
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        mTextureView = (TextureView) findViewById(R.id.texture);
        mTextureView.setSurfaceTextureListener(new TextureView.SurfaceTextureListener() {
            @Override
            public void onSurfaceTextureAvailable(SurfaceTexture surface, int width, int height) {
                // 先ほどのカメラを開く部分をメソッド化した
                openCamera();
            }

            @Override
            public void onSurfaceTextureSizeChanged(SurfaceTexture surface, int width, int height) {

            }

            @Override
            public boolean onSurfaceTextureDestroyed(SurfaceTexture surface) {
                return true;
            }

            @Override
            public void onSurfaceTextureUpdated(SurfaceTexture surface) {

            }
        });

        Button capture = (Button) findViewById(R.id.button_capture);
        capture.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                try {
                    mCaptureSession.stopRepeating(); // プレビューの更新を止める
                    if(mTextureView.isAvailable()) {
                        File file = new File(getFilesDir(), "surface_text.jpg");
                        FileOutputStream fos = new FileOutputStream(file);
                        Bitmap bitmap = mTextureView.getBitmap();
                        bitmap.compress(Bitmap.CompressFormat.JPEG, 50, fos);
                        fos.close();
                    }
                } catch (CameraAccessException e) {
                    e.printStackTrace();
                } catch (FileNotFoundException e) {
                    e.printStackTrace();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        });
    }

    private void openCamera() {
        CameraManager manager = (CameraManager) getSystemService(Context.CAMERA_SERVICE);
        String selectedCameraId = "";
        try {
            selectedCameraId = manager.getCameraIdList()[0];

            // https://github.com/googlesamples/android-Camera2Basic/blob/5dad16c103715b5e7e3c001cc5f6067f8d23f29e/Application/src/main/java/com/example/android/camera2basic/Camera2BasicFragment.java#L499
            // あたりにあるのですが、顔用カメラを使いたくないなどがあれば、CameraCharacteristicsを経由して確認可能
            //            CameraCharacteristics characteristics
            //                    = manager.getCameraCharacteristics(selectedCameraId);
        } catch (CameraAccessException e) {
            e.printStackTrace();
        }

        try {
            manager.openCamera(selectedCameraId, mStateCallback, mBackgroundHandler);
        } catch (CameraAccessException e) {
            e.printStackTrace();
        }
    }

    private final CameraDevice.StateCallback mStateCallback = new CameraDevice.StateCallback() {
        @Override
        public void onOpened(CameraDevice cameraDevice) {
            mCameraDevice = cameraDevice;
            createCameraPreviewSession();
        }

        @Override
        public void onDisconnected(CameraDevice cameraDevice) {
            cameraDevice.close();
            mCameraDevice = null;
        }

        @Override
        public void onError(CameraDevice cameraDevice, int error) {
            cameraDevice.close();
            mCameraDevice = null;
        }

    };

    private void createCameraPreviewSession() {
        SurfaceTexture texture = mTextureView.getSurfaceTexture();
        texture.setDefaultBufferSize(320, 240); // 自分の手元のデバイスで決めうちしてます
        Surface surface = new Surface(texture);

        try {
            mPreviewRequestBuilder = mCameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_PREVIEW);
            mPreviewRequestBuilder.addTarget(surface);
            mPreviewRequest = mPreviewRequestBuilder.build();
        } catch (CameraAccessException e) {
            e.printStackTrace();
        }

        try {
            mCameraDevice.createCaptureSession(Arrays.asList(surface), new CameraCaptureSession.StateCallback() {
                @Override
                public void onConfigured(CameraCaptureSession session) {
                    // カメラがcloseされている場合
                    if (null == mCameraDevice) {
                        return;
                    }

                    mCaptureSession = session;

                    try {
                        session.setRepeatingRequest(mPreviewRequest, null, null);
                    } catch (CameraAccessException e) {
                        e.printStackTrace();
                    }
                }

                @Override
                public void onConfigureFailed(CameraCaptureSession session) {

                }
            }, null);
        } catch (CameraAccessException e) {
            e.printStackTrace();
        }
    }
}

Manifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.woshidan.cameratest">
    <uses-permission android:name="android.permission.CAMERA" />
    <uses-feature android:name="android.hardware.camera" /><!-- カメラが使えない端末でプレイストアで検索したときこのアプリを表示させない -->
    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@android:style/Theme.Holo">
        <activity
            android:name=".MainActivity"
            android:label="@string/app_name"
            android:screenOrientation="landscape"
            android:theme="@android:style/Theme.Holo.NoActionBar">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>