package com.example.mediacamera;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.app.Activity;
import android.graphics.ImageFormat;
import android.hardware.Camera;
import android.hardware.Camera.Parameters;
import android.hardware.Camera.PreviewCallback;
import android.os.Bundle;
import android.view.SurfaceHolder;
import android.view.SurfaceView;

import java.io.IOException;
import java.util.concurrent.ArrayBlockingQueue;


import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.appcompat.app.AppCompatActivity;
import androidx.camera.core.CameraX;
import androidx.camera.core.ImageAnalysis;
import androidx.camera.core.ImageAnalysisConfig;
import androidx.camera.core.ImageCapture;
import androidx.camera.core.ImageCaptureConfig;
import androidx.camera.core.ImageProxy;
import androidx.camera.core.Preview;
import androidx.camera.core.PreviewConfig;
import androidx.core.app.ActivityCompat;
import androidx.core.content.ContextCompat;
import androidx.lifecycle.LifecycleOwner;

import android.content.pm.PackageManager;
import android.graphics.Matrix;
import android.os.Bundle;
import android.os.Environment;
import android.util.Rational;
import android.util.Size;
import android.view.Surface;
import android.view.TextureView;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Toast;

import java.io.File;

public class MainActivity extends AppCompatActivity {
    private int REQUEST_CODE_PERMISSIONS = 10;
    private final String[] REQUIRED_PERMISSIONS = new String[]{
            "android.permission.CAMERA",
            "android.permission.WRITE_EXTERNAL_STORAGE",
            "android.permission.READ_EXTERNAL_STORAGE",

    };
    TextureView txView;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        txView = findViewById(R.id.view_finder);

        if(allPermissionsGranted()){
            startCamera(); //start camera if permission has been granted by user
        } else{
            ActivityCompat.requestPermissions(this, REQUIRED_PERMISSIONS, REQUEST_CODE_PERMISSIONS);
        }
    }

    private void startCamera() {
        //make sure there isn't another camera instance running before starting
        CameraX.unbindAll();

        /* start preview */
        int aspRatioW = txView.getWidth(); //get width of screen
        int aspRatioH = txView.getHeight(); //get height
        Rational asp = new Rational (aspRatioW, aspRatioH); //aspect ratio
        Size screen = new Size(aspRatioW, aspRatioH); //size of the screen

        //config obj for preview/viewfinder thingy.
        PreviewConfig pConfig = new PreviewConfig.Builder().setTargetAspectRatio(asp).setTargetResolution(screen).build();
        Preview preview = new Preview(pConfig); //lets build it

        preview.setOnPreviewOutputUpdateListener(
                new Preview.OnPreviewOutputUpdateListener() {
                    //to update the surface texture we have to destroy it first, then re-add it
                    @Override
                    public void onUpdated(Preview.PreviewOutput output){
                        ViewGroup parent = (ViewGroup) txView.getParent();
                        parent.removeView(txView);
                        parent.addView(txView, 0);

                        txView.setSurfaceTexture(output.getSurfaceTexture());
                        updateTransform();
                    }
                });

        /* image capture */

        //config obj, selected capture mode
        ImageCaptureConfig imgCapConfig = new ImageCaptureConfig.Builder().setCaptureMode(ImageCapture.CaptureMode.MIN_LATENCY)
                .setTargetRotation(getWindowManager().getDefaultDisplay().getRotation()).build();
        final ImageCapture imgCap = new ImageCapture(imgCapConfig);

        findViewById(R.id.capture_button).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                File file = new File( /*Environment.getExternalStorageDirectory()*/
                       Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES)+ "/" + System.currentTimeMillis() + ".jpg");
                imgCap.takePicture(file, new ImageCapture.OnImageSavedListener() {
                    @Override
                    public void onImageSaved(@NonNull File file) {
                        String msg = "Photo capture succeeded: " + file.getAbsolutePath();
                        Toast.makeText(getBaseContext(), msg,Toast.LENGTH_LONG).show();
                    }

                    @Override
                    public void one rror(@NonNull ImageCapture.UseCaseError useCaseError, @NonNull String message, @Nullable Throwable cause) {
                        String msg = "Photo capture failed: " + message;
                        Toast.makeText(getBaseContext(), msg,Toast.LENGTH_LONG).show();
                        if(cause != null){
                            cause.printStackTrace();
                        }
                    }
                });
            }
        });

        /* image analyser */

        ImageAnalysisConfig imgAConfig = new ImageAnalysisConfig.Builder().setImageReaderMode(ImageAnalysis.ImageReaderMode.ACQUIRE_LATEST_IMAGE).build();
        ImageAnalysis analysis = new ImageAnalysis(imgAConfig);

        analysis.setAnalyzer(
                new ImageAnalysis.Analyzer(){
                    @Override
                    public void analyze(ImageProxy image, int rotationDegrees){
                        //y'all can add code to analyse stuff here idek go wild.
                    }
                });

        //bind to lifecycle:
        CameraX.bindToLifecycle((LifecycleOwner)this, analysis, imgCap, preview);
    }

    private void updateTransform(){
        /*
         * compensates the changes in orientation for the viewfinder, bc the rest of the layout stays in portrait mode.
         * methinks :thonk:
         * imgCap does this already, this class can be commented out or be used to optimise the preview
         */
        Matrix mx = new Matrix();
        float w = txView.getMeasuredWidth();
        float h = txView.getMeasuredHeight();

        float centreX = w / 2f; //calc centre of the viewfinder
        float centreY = h / 2f;

        int rotationDgr;
        int rotation = (int)txView.getRotation(); //cast to int bc switches don't like floats

        switch(rotation){ //correct output to account for display rotation
            case Surface.ROTATION_0:
                rotationDgr = 0;
                break;
            case Surface.ROTATION_90:
                rotationDgr = 90;
                break;
            case Surface.ROTATION_180:
                rotationDgr = 180;
                break;
            case Surface.ROTATION_270:
                rotationDgr = 270;
                break;
            default:
                return;
        }

        mx.postRotate((float)rotationDgr, centreX, centreY);
        txView.setTransform(mx); //apply transformations to textureview
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        //start camera when permissions have been granted otherwise exit app
        if(requestCode == REQUEST_CODE_PERMISSIONS){
            if(allPermissionsGranted()){
                startCamera();
            } else{
                Toast.makeText(this, "Permissions not granted by the user.", Toast.LENGTH_SHORT).show();
                finish();
            }
        }
    }

    private boolean allPermissionsGranted(){
        //check if req permissions have been granted
        for(String permission : REQUIRED_PERMISSIONS){
            if(ContextCompat.checkSelfPermission(this, permission) != PackageManager.PERMISSION_GRANTED){
                return false;
            }
        }
        return true;
    }
}

布局里

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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">


    <TextureView
        android:id="@+id/view_finder"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintEnd_toEndOf="parent" />

    <ImageButton
        android:id="@+id/capture_button"
        android:layout_width="72dp"
        android:layout_height="72dp"
        android:layout_margin="24dp"
        app:srcCompat="@android:drawable/ic_menu_camera"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.mediacamera">
    <uses-permission android:name="android.permission.CAMERA"></uses-permission>
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"></uses-permission>
    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
    <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.MediaCamera"
        android:requestLegacyExternalStorage="true"
        >
        <activity
            android:name=".MainActivity"
            android:exported="true">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

一开始要么报 

open failed: EPERM (Operation not permitted)

把文件放到 dcim 和picture目录下时又报 .jpg.tmp         at androidx.exifinterface.media.ExifInterface.saveAttribut

  android:requestLegacyExternalStorage="true" 加上这个就好了
参考 https://blog.csdn.net/o279642707/article/details/105790720

另外 各个目录
https://www.wangt.cc/2021/05/android%E4%BF%9D%E5%AD%98%E8%87%AA%E5%AE%9A%E4%B9%89%E8%B7%AF%E5%BE%84%E7%9A%84%E5%9B%BE%E7%89%87%E7%9A%84%E4%B8%80%E4%BA%9B%E9%97%AE%E9%A2%98/