实现手机App实现拍照功能

<?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="切换"
android:id="@+id/b_qh"
/>
</LinearLayout>
</RelativeLayout>
第二步：TakephotoActivity类

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);
//获得SurfaceView的ID
sv_takephoto =(SurfaceView) findViewById(R.id.sv_takephoto);
//获得拍照的ID
b_OK =(Button)findViewById(R.id.b_OK);
//获得切换镜头的ID
b_qh =(Button)findViewById(R.id.b_qh);

sv_takephoto.getHolder().addCallback(new SurfaceHolder.Callback() {
@Override
public void surfaceCreated(SurfaceHolder surfaceHolder) {
//打开相机
camera = Camera.open();
//给相机设置参数
Camera.Parameters parameters= camera.getParameters();
//设置保存的格式
parameters.setPictureFormat(PixelFormat.JPEG);
parameters.set("jpeg-quality",85);
camera.setParameters(parameters);

//将画面展示到SurfaceView中
try {
camera.setPreviewDisplay(sv_takephoto.getHolder());
//开启预览
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) {

}
});

//拍照的点击事件
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) {
//将字节数组转成图片
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();
}
}
});

}
});

}
}

第三步：在AndroidManifest.xml中加权限

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