参考文章：
https://blog.csdn.net/u011418943/article/details/107256406
https://blog.csdn.net/xiaodongvtion/article/details/110951754
Camera1的类android.hardware.Camera。Camera类常用的方法：
| 方法 |
描述 |
| getParameters() |
获取摄像头参数 |
| setParameters() |
设置摄像头参数 |
| setPreviewDisplay() |
为摄像头指定一个显示预览画面的SurfaceView |
| open() |
打开摄像头 |
| startPreview() |
开始预览 |
| stopPreview() |
停止预览 |
| release() |
释放摄像头资源 |
| takePicture() |
进行拍照 |
1 代码
MainActivity.java
public class MainActivity extends Activity {
public final static String TAG = "CameraPreview";
private Camera camera;
private boolean isPreview = false;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
if(ContextCompat.checkSelfPermission(MainActivity.this, Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED){
ActivityCompat.requestPermissions(MainActivity.this, new String[]{ Manifest.permission.CAMERA}, 1);
}
if(ContextCompat.checkSelfPermission(MainActivity.this, Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED){
ActivityCompat.requestPermissions(MainActivity.this, new String[]{ Manifest.permission.WRITE_EXTERNAL_STORAGE}, 1);
}
// 设置全屏显示
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
// 判断手机是否安装SD卡
if (!android.os.Environment.getExternalStorageState().equals(android.os.Environment.MEDIA_MOUNTED)) {
Toast.makeText(this, "请安装SD卡！", Toast.LENGTH_SHORT).show();
}
SurfaceView surfaceView = (SurfaceView) findViewById(R.id.surfaceView);
final SurfaceHolder surfaceHolder = surfaceView.getHolder();
// 设置该SurfaceHolder自己不维护缓冲
surfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
ImageButton preview = (ImageButton) findViewById(R.id.preview);
preview.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// 如果相机为非预览模式，则打开相机
if (!isPreview) {
camera = Camera.open();
isPreview = true;
}
try {
// 设置用于显示预览的SurfaceView
camera.setPreviewDisplay(surfaceHolder);
Camera.Parameters parameters = camera.getParameters();
// 测试Camera.Parameters
// (1)setPictureFormat======================================
// PixelFormat.JPEG:jpeg
// parameters.setPictureFormat(PixelFormat.JPEG); // 指定图片为JPEG图片
// parameters.set("jpeg-quality", 80); // 设置图片的质量
// PixelFormat.YCbCr_420_SP:NV21,等价于ImageFormat.NV21
parameters.setPictureFormat(PixelFormat.YCbCr_420_SP);
// (2)setWhiteBalance======================================
// auto
String whiteBalance = parameters.getWhiteBalance();
Log.d(TAG, "whiteBalance:" + whiteBalance);
// WHITE_BALANCE_INCANDESCENT:偏蓝
// WHITE_BALANCE_FLUORESCENT:偏淡蓝
// WHITE_BALANCE_WARM_FLUORESCENT:偏淡蓝
// WHITE_BALANCE_DAYLIGHT:日光，正常
// WHITE_BALANCE_CLOUDY_DAYLIGHT:阴天，偏黄
// WHITE_BALANCE_TWILIGHT:暮光，偏黄
// WHITE_BALANCE_SHADE:偏黄
parameters.setWhiteBalance(Camera.Parameters.WHITE_BALANCE_DAYLIGHT);
whiteBalance = parameters.getWhiteBalance();
Log.d(TAG, "whiteBalance:" + whiteBalance);
// (3)setExposureCompensation======================================曝光补偿
int minEx = parameters.getMinExposureCompensation();
int maxEx = parameters.getMaxExposureCompensation();
float stepEx = parameters.getExposureCompensationStep();
Log.d(TAG, "minEx:" + minEx + " maxEx:" + maxEx + " stepEx:" + stepEx);
parameters.setExposureCompensation(6);
// (4)setAutoExposureLock======================================
boolean isAELS = parameters.isAutoExposureLockSupported();
Log.d(TAG, "isAES:" + isAELS);
boolean getAELS = parameters.getAutoExposureLock();
Log.d(TAG, "getAES:" + getAELS);
parameters.setAutoExposureLock(false);
getAELS = parameters.getAutoExposureLock();
Log.d(TAG, "getAES:" + getAELS);
// (5)setAutoWhiteBalanceLock======================================
boolean isAWBLS = parameters.isAutoWhiteBalanceLockSupported();
Log.d(TAG, "isAWBLS:" + isAWBLS);
boolean getAWBL = parameters.getAutoWhiteBalanceLock();
Log.d(TAG, "getAWBL:" + getAWBL);
parameters.setAutoWhiteBalanceLock(false);
getAWBL = parameters.getAutoWhiteBalanceLock();
Log.d(TAG, "getAWBL:" + getAWBL);
// (5)setFocusMode======================================
String fm = parameters.getFocusMode();
Log.d(TAG, "fm:" + fm);
// FOCUS_MODE_AUTO:聚焦
// FOCUS_MODE_INFINITY:不聚焦
// FOCUS_MODE_MACRO:聚焦
// FOCUS_MODE_CONTINUOUS_VIDEO:跟随预览的物体远近自动聚焦，afcb返回fail
// FOCUS_MODE_CONTINUOUS_PICTURE:跟随预览的物体远近自动聚焦，afcb返回fail
parameters.setFocusMode(Camera.Parameters.FOCUS_MODE_CONTINUOUS_VIDEO);
fm = parameters.getFocusMode();
Log.d(TAG, "fm:" + fm);
camera.setParameters(parameters);
camera.startPreview();
// AF:自动对焦
camera.autoFocus(afcb);
camera.setDisplayOrientation(90);
} catch (IOException e) {
e.printStackTrace();
}
}
});
ImageButton takePicture = (ImageButton) findViewById(R.id.takephoto);
takePicture.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (camera != null) {
camera.takePicture(null, null, jpeg);
}
}
});
}
final Camera.AutoFocusCallback afcb = new Camera.AutoFocusCallback() {
@Override
public void onAutoFocus(boolean success, Camera camera) {
if(success) {
// success表示对焦成功
Log.d(TAG, "afcb: success");
//camera.setOneShotPreviewCallback(null);
}
else {
// 未对焦成功
Log.d(TAG, "afcb: fail");
}
}
};
// 照片回调函数，实现将照片保存到系统图库中
final Camera.PictureCallback jpeg = new Camera.PictureCallback() {
@Override
public void onPictureTaken(byte[] data, Camera camera) {
// 根据拍照所得的数据创建位图
final Bitmap bm = BitmapFactory.decodeByteArray(data, 0, data.length);
camera.stopPreview();
isPreview = false;
Log.d(TAG, "Environment.getExternalStorageDirectory():" + Environment.getExternalStorageDirectory());
//获取sd卡根目录
File appDir = new File(Environment.getExternalStorageDirectory(), "/DCIM/Camera/");
if (!appDir.exists()) { // 如果该目录不存在就创建该目录
appDir.mkdir();
}
String fileName = System.currentTimeMillis() + ".jpg";
File file = new File(appDir, fileName);
// 保存拍到的图片
try {
FileOutputStream fos = new FileOutputStream(file); // 创建一个文件输出流对象
boolean ret = bm.compress(Bitmap.CompressFormat.JPEG, 100, fos); // 将图片内容压缩为JPEG格式输出到输出流对象中
Log.d(TAG, "bm.compress ret:" + ret);
fos.flush();
fos.close();
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
//将照片插入到系统图库
try {
MediaStore.Images.Media.insertImage(MainActivity.this.getContentResolver(),
file.getAbsolutePath(), fileName, null);
} catch (FileNotFoundException e) {
e.printStackTrace();
}
// 最后通知图库更新
MainActivity.this.sendBroadcast(new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE,
Uri.parse("file://" + "")));
Toast.makeText(MainActivity.this, "照片保存至：" + file, Toast.LENGTH_LONG).show();
resetCamera();
}
};
// 创建resetCamera()方法，实现重新预览功能
private void resetCamera() {
if (!isPreview) {
camera.startPreview();
isPreview = true;
}
}
@Override
protected void onPause() {
if (camera != null) {
camera.stopPreview();
camera.release();
}
super.onPause();
}
}查看手机是否安装SD卡：
adb shell mount
adb shell df -h
手机内部存储相册路径：/storage/emulated/0/DCIM/Camera/
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<!--SurfaceView组件-->
<SurfaceView
android:id="@+id/surfaceView"
android:layout_width="match_parent"
android:layout_height="match_parent" />
<!--拍照按钮-->
<ImageButton
android:id="@+id/takephoto"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="right|top"
android:layout_marginTop="@dimen/margin_top"
android:background="@color/btn_background"
android:src="@drawable/camera" />
<!--预览按钮-->
<ImageButton
android:id="@+id/preview"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="right|bottom"
android:layout_marginBottom="@dimen/margin_bottom"
android:background="@color/btn_background"
android:src="@drawable/preview" />
</FrameLayout>AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
package="com.hyh.camerapreview">
<!-- 授予程序可以向SD卡中保存文件的权限 -->
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
<!-- 授予程序使用摄像头的权限 -->
<uses-permission android:name="android.permission.CAMERA"/>
<uses-feature android:name="android.hardware.camera.autofocus"/>
<uses-feature android:name="android.hardware.camera"/>
<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="@style/Theme.CameraPreview"
android:requestLegacyExternalStorage="true">
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>2 遇到的问题
2.1 预览时图片拉伸
需要设置预览方向
camera.setDisplayOrientation(90);2.2 拍照时不能保存相片
java.io.FileNotFoundException: /storage/emulated/0/DCIM/Camera/1638007179710.jpg: open failed: ENOENT (No such file or directory)
android:requestLegacyExternalStorage="true"原因是Android10弃用了管理分区外部储存