CameraX is a Jetpack library designed to help you develop camera applications more easily. For new applications, we recommend starting with CameraX. It provides a consistent and easy-to-use API for the vast majority of Android devices and is backward compatible with Android 5.0 (API level 21).
CameraX supports most common camera use cases:
预览: View the picture on the screen.图片分析: Seamlessly access images in buffers for use in algorithms, such as passing them to machine learning suites.图片拍摄:save Picture.视频拍摄: Save video and audio.
This article is about –实现预览
When adding previews to your app, use PreviewView, a View that can be clipped, scaled, and rotated to ensure proper display.
When the camera is active, the image preview is streamed to the Surface in PreviewView.
renderings
Configuration:
注意：CameraX 支持的最小SDK版本是21
- 1. Add permissions
1. Add camera permissions to the manifest file
<uses-permission android:name="android.permission.CAMERA" />
2. Dynamically obtain camera permissions
if (ContextCompat.checkSelfPermission(this, Manifest.permission.CAMERA) == PackageManager.PERMISSION_DENIED) {
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
requestPermissions(new String[]{
Manifest.permission.CAMERA}, 11);
}
} else {
//启动相机
}
- 2. Add CameraX dependency in build.gradle
implementation "androidx.camera:camera-core:1.1.0-alpha10"
// CameraX Camera2 extensions[可选]拓展库可实现人像、HDR、夜间和美颜、滤镜但依赖于OEM
implementation "androidx.camera:camera-camera2:1.1.0-alpha10"
// CameraX Lifecycle library[可选]避免手动在生命周期释放和销毁数据
implementation "androidx.camera:camera-lifecycle:1.1.0-alpha10"
// CameraX View class[可选]最佳实践，最好用里面的PreviewView，它会自行判断用SurfaceView还是TextureView来实现
implementation 'androidx.camera:camera-view:1.0.0-alpha23'
Use PreviewView case steps:
1. (Optional) Configure CameraXConfig.Provider.
2. Add PreviewView to the layout.
3. Request ProcessCameraProvider.
4. When creating View, please check ProcessCameraProvider.
5. Select the camera and bind the life cycle and use case.
- Add PreviewView to layout
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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">
<FrameLayout
android:layout_centerInParent="true"
android:layout_width="500dp"
android:layout_height="500dp">
<androidx.camera.view.PreviewView
android:id="@+id/previewView"
android:layout_width="match_parent"
android:layout_height="match_parent"
/>
</FrameLayout>
</RelativeLayout>
- Steps 3, 4, 5, processing
package com.example.myapplication;
import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import androidx.camera.core.Camera;
import androidx.camera.core.CameraSelector;
import androidx.camera.core.Preview;
import androidx.camera.lifecycle.ProcessCameraProvider;
import androidx.camera.view.PreviewView;
import androidx.core.content.ContextCompat;
import androidx.lifecycle.LifecycleOwner;
import android.Manifest;
import android.content.pm.PackageManager;
import android.os.Build;
import android.os.Bundle;
import com.google.common.util.concurrent.ListenableFuture;
import java.util.concurrent.ExecutionException;
public class MainActivity extends AppCompatActivity {
private ListenableFuture<ProcessCameraProvider> cameraProviderFuture;
private PreviewView previewView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
previewView=findViewById(R.id.previewView);//初始化
if (ContextCompat.checkSelfPermission(this, Manifest.permission.CAMERA) == PackageManager.PERMISSION_DENIED) {
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
requestPermissions(new String[]{
Manifest.permission.CAMERA}, 11);
}
} else {
//启动相机
startCamera();
}
}
private void startCamera() {
// 请求 CameraProvider
cameraProviderFuture = ProcessCameraProvider.getInstance(this);
//检查 CameraProvider 可用性，验证它能否在视图创建后成功初始化
cameraProviderFuture.addListener(() -> {
try {
ProcessCameraProvider cameraProvider = cameraProviderFuture.get();
bindPreview(cameraProvider);
} catch (ExecutionException | InterruptedException e) {
// No errors need to be handled for this Future.
// This should never be reached.
}
}, ContextCompat.getMainExecutor(this));
}
//选择相机并绑定生命周期和用例
private void bindPreview(@NonNull ProcessCameraProvider cameraProvider) {
Preview preview = new Preview.Builder()
.build();
CameraSelector cameraSelector = new CameraSelector.Builder()
.requireLensFacing(CameraSelector.LENS_FACING_BACK)
.build();
preview.setSurfaceProvider(previewView.getSurfaceProvider());
Camera camera = cameraProvider.bindToLifecycle((LifecycleOwner)this, cameraSelector, preview);
}
}
- At the step of bindPreview, the camera preview has been displayed, please check