<?xml version="1.0" encoding="utf-8"?><RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"  xmlns:tools="http://schemas.android.com/tools"  android:id="@+id/activity_takephoto"  android:layout_width="match_parent"  android:layout_height="match_parent"  android:paddingBottom="@dimen/activity_vertical_margin"  android:paddingLeft="@dimen/activity_horizontal_margin"  android:paddingRight="@dimen/activity_horizontal_margin"  android:paddingTop="@dimen/activity_vertical_margin"  tools:context="com.example.android_27.TakephotoActivity">      <SurfaceView        android:layout_width="match_parent"        android:layout_height="match_parent"        android:id="@+id/sv_takephoto"        />  <LinearLayout    android:layout_width="wrap_content"    android:layout_height="wrap_content">    <Button      android:layout_width="wrap_content"      android:layout_height="wrap_content"      android:text="拍照"      android:id="@+id/b_OK"      />    <Button      android:layout_width="wrap_content"      android:layout_height="wrap_content"      android:text="切換"      android:id="@+id/b_qh"      />  </LinearLayout></RelativeLayout>

public class TakephotoActivity extends AppCompatActivity {  private SurfaceView sv_takephoto;  private Button b_OK;  private Button b_qh;  private Camera camera;  @Override  protected void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentView(R.layout.activity_takephoto);    //獲得SurfaceView的ID    sv_takephoto =(SurfaceView) findViewById(R.id.sv_takephoto);    //獲得拍照的ID    b_OK =(Button)findViewById(R.id.b_OK);    //獲得切換鏡頭的ID    b_qh =(Button)findViewById(R.id.b_qh);    sv_takephoto.getHolder().addCallback(new SurfaceHolder.Callback() {      @Override      public void surfaceCreated(SurfaceHolder surfaceHolder) {      //打開相機        camera = Camera.open();        //給相機設置參數        Camera.Parameters parameters= camera.getParameters();        //設置保存的格式        parameters.setPictureFormat(PixelFormat.JPEG);        parameters.set("jpeg-quality",85);        camera.setParameters(parameters);        //將畫面展示到SurfaceView中        try {          camera.setPreviewDisplay(sv_takephoto.getHolder());          //開啟預覽          camera.startPreview();        } catch (IOException e) {          e.printStackTrace();        }      }      @Override      public void surfaceChanged(SurfaceHolder surfaceHolder, int i, int i1, int i2) {      }      @Override      public void surfaceDestroyed(SurfaceHolder surfaceHolder) {      }    });    //拍照的點擊事件    b_OK.setOnClickListener(new View.OnClickListener() {      @Override      public void onClick(View view) {        //拍照        camera.takePicture(null, null, new Camera.PictureCallback() {          @Override          public void onPictureTaken(byte[] bytes, Camera camera) {            //將字節數組轉成圖片            Bitmap bitmap= BitmapFactory.decodeByteArray(bytes,0,bytes.length);            try {              FileOutputStream fos=new FileOutputStream("/mnt/sdcard/DCIM/"+System.currentTimeMillis()+".jpg");              bitmap.compress(Bitmap.CompressFormat.PNG,85,fos);              camera.stopPreview();              camera.startPreview();            } catch (FileNotFoundException e) {              e.printStackTrace();            }          }        });    }    });  }}

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