1.说明
1.camera2要求Android版本21及以上
2.Android版本23及以上需要动态申请权限
先看效果图：
2.权限及xml布局
权限：
<uses-permission android:name="android.permission.CAMERA"/>布局：
<?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:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<TextureView
android:id="@+id/ttv_camera"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
</RelativeLayout>3.Activity
package com.example.camerademo01;
import android.Manifest;
import android.content.Context;
import android.content.pm.PackageManager;
import android.graphics.SurfaceTexture;
import android.hardware.camera2.CameraAccessException;
import android.hardware.camera2.CameraCaptureSession;
import android.hardware.camera2.CameraCharacteristics;
import android.hardware.camera2.CameraDevice;
import android.hardware.camera2.CameraManager;
import android.hardware.camera2.CaptureRequest;
import android.hardware.camera2.CaptureResult;
import android.hardware.camera2.TotalCaptureResult;
import android.hardware.camera2.params.StreamConfigurationMap;
import android.os.Build;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.annotation.RequiresApi;
import android.support.v4.content.ContextCompat;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.util.Size;
import android.view.Surface;
import android.view.TextureView;
import android.widget.Toast;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
public class MainActivity extends AppCompatActivity {
private static final int REQUEST_CAMERA_PERMISSION = 1;
private static final String TAG = MainActivity.class.getSimpleName();
private TextureView textureView;
private CameraManager cameraManager;
private Size previewSize;
private String mCameraId;
private CameraDevice cameraDevice;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initView();
initData();
}
private void initData() {
cameraManager = (CameraManager) getSystemService(Context.CAMERA_SERVICE);
}
private void initView() {
textureView = (TextureView) findViewById(R.id.ttv_camera);
}
@Override
protected void onResume() {
super.onResume();
textureView.setSurfaceTextureListener(new TextureView.SurfaceTextureListener() {
@RequiresApi(api = Build.VERSION_CODES.M)
@Override
public void onSurfaceTextureAvailable(@NonNull SurfaceTexture surface, int width, int height) {
// 1.TextureView可用的时候配置相机
initCamera();
}
@Override
public void onSurfaceTextureSizeChanged(@NonNull SurfaceTexture surface, int width, int height) {
}
@Override
public boolean onSurfaceTextureDestroyed(@NonNull SurfaceTexture surface) {
return false;
}
@Override
public void onSurfaceTextureUpdated(@NonNull SurfaceTexture surface) {
}
});
}
@RequiresApi(api = Build.VERSION_CODES.M)
private void initCamera() {
// 2.配置前置相机，获取尺寸及id
getCameraIdAndPreviewSizeByFacing(CameraCharacteristics.LENS_FACING_FRONT);
// 3.打开相机
openCamera();
}
@RequiresApi(api = Build.VERSION_CODES.M)
private void openCamera() {
try {
// 4.权限检查
if (ContextCompat.checkSelfPermission(MainActivity.this, Manifest.permission.CAMERA)
!= PackageManager.PERMISSION_GRANTED) {
requestCameraPermission();
return;
}
// 5.真正打开相机
cameraManager.openCamera(mCameraId, new CameraDevice.StateCallback() {
@Override
public void onOpened(@NonNull CameraDevice camera) {
cameraDevice = camera;// 打开成功，保存代表相机的CameraDevice实例
SurfaceTexture surfaceTexture = textureView.getSurfaceTexture();
surfaceTexture.setDefaultBufferSize(textureView.getWidth(), textureView.getHeight());
Surface surface = new Surface(surfaceTexture);
ArrayList<Surface> previewList = new ArrayList<>();
previewList.add(surface);
try {
// 6.将TextureView的surface传递给CameraDevice
cameraDevice.createCaptureSession(previewList, new CameraCaptureSession.StateCallback() {
@Override
public void onConfigured(@NonNull CameraCaptureSession session) {
try {
CaptureRequest.Builder builder = cameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_PREVIEW);
builder.addTarget(surface); // 必须设置才能正常预览
CaptureRequest captureRequest = builder.build();
// 7.CameraCaptureSession与CaptureRequest绑定（这是最后一步，已可显示相机预览）
session.setRepeatingRequest(captureRequest, new CameraCaptureSession.CaptureCallback() {
@Override
public void onCaptureProgressed(@NonNull CameraCaptureSession session, @NonNull CaptureRequest request, @NonNull CaptureResult partialResult) {
super.onCaptureProgressed(session, request, partialResult);
}
@Override
public void onCaptureCompleted(@NonNull CameraCaptureSession session, @NonNull CaptureRequest request, @NonNull TotalCaptureResult result) {
super.onCaptureCompleted(session, request, result);
}
},null);
} catch (CameraAccessException e) {
e.printStackTrace();
}
}
@Override
public void onConfigureFailed(@NonNull CameraCaptureSession session) {
}
},null);
} catch (CameraAccessException e) {
e.printStackTrace();
}
}
@Override
public void onDisconnected(@NonNull CameraDevice camera) {
releaseCamera();
}
@Override
public void onError(@NonNull CameraDevice camera, int error) {
releaseCamera();
}
}, null);
} catch (CameraAccessException e) {
e.printStackTrace();
}
}
private void releaseCamera() {
if (cameraDevice != null) {
cameraDevice.close();
cameraDevice = null;
}
}
/*获取cameraId及相机预览的最佳尺寸*/
private void getCameraIdAndPreviewSizeByFacing(int lensFacingFront) {
try {
String[] cameraIdList = cameraManager.getCameraIdList();
for (String cameraId : cameraIdList) {
CameraCharacteristics cameraCharacteristics = cameraManager.getCameraCharacteristics(cameraId);
int facing = cameraCharacteristics.get(CameraCharacteristics.LENS_FACING);
if(facing != lensFacingFront){
continue;
}
StreamConfigurationMap streamConfigurationMap = cameraCharacteristics.get(CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP);
Size[] outputSizes = streamConfigurationMap.getOutputSizes(SurfaceTexture.class);
mCameraId = cameraId;
previewSize = setOptimalPreviewSize(outputSizes, textureView.getMeasuredWidth(), textureView.getMeasuredHeight());
Log.d(TAG,"最佳预览尺寸（w-h）：" + previewSize.getWidth() + "-" + previewSize.getHeight()+",相机id："+mCameraId);
}
} catch (CameraAccessException e) {
e.printStackTrace();
}
}
/*根据相机可用的预览尺寸和用户给定的TextureView的显示尺寸选择最接近的预览尺寸*/
private Size setOptimalPreviewSize(Size[] sizes, int previewViewWidth, int previewViewHeight) {
List<Size> bigEnoughSizes = new ArrayList<>();
List<Size> notBigEnoughSizes = new ArrayList<>();
for (Size size : sizes) {
if (size.getWidth() >= previewViewWidth && size.getHeight() >= previewViewHeight) {
bigEnoughSizes.add(size);
} else {
notBigEnoughSizes.add(size);
}
}
if (bigEnoughSizes.size() > 0) {
return Collections.min(bigEnoughSizes, new Comparator<Size>() {
@Override
public int compare(Size lhs, Size rhs) {
return Long.signum((long) lhs.getWidth() * lhs.getHeight() -
(long) rhs.getWidth() * rhs.getHeight());
}
});
} else if (notBigEnoughSizes.size() > 0) {
return Collections.max(notBigEnoughSizes, new Comparator<Size>() {
@Override
public int compare(Size lhs, Size rhs) {
return Long.signum((long) lhs.getWidth() * lhs.getHeight() -
(long) rhs.getWidth() * rhs.getHeight());
}
});
} else {
Log.d(TAG, "未找到合适的预览尺寸");
return sizes[0];
}
}
@RequiresApi(api = Build.VERSION_CODES.M)
private void requestCameraPermission() {
requestPermissions(new String[]{Manifest.permission.CAMERA}, REQUEST_CAMERA_PERMISSION);
}
@RequiresApi(api = Build.VERSION_CODES.M)
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions,
@NonNull int[] grantResults) {
if (requestCode == REQUEST_CAMERA_PERMISSION) {
if (grantResults.length != 1 || grantResults[0] != PackageManager.PERMISSION_GRANTED) {
Toast.makeText(this, "请授予相机权限！", Toast.LENGTH_SHORT).show();
}else {
openCamera();
}
} else {
super.onRequestPermissionsResult(requestCode, permissions, grantResults);
}
}
}