Android实现手电筒demo

需求：

做一个手电筒APK,要求如下：

      1：手电筒应用打开后需要有具体的界面打开和关闭按钮。按Home,Recent键保持长亮，按  Back键关闭

      2：手电筒的状态必须和下拉栏的手电筒状态一致

      3：手电筒打开和关闭，需要有一个弹框提醒用户确认或者取消，弹框风格请自定义view来写

      4：APK要经过测试通过且代码规范方可视作完成

最终效果：

FlashlightActivity.java

package com.example.flashlight;

import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;

import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.hardware.camera2.CameraAccessException;
import android.hardware.camera2.CameraManager;
import android.os.Bundle;
import android.os.Handler;
import android.view.View;
import android.widget.ImageView;

import com.example.flashlight.view.CustomDialog;


public class FlashlightActivity extends AppCompatActivity implements View.OnClickListener {


    private static ImageView iv;
    private CameraManager mCameraManager;

    public static boolean isOpen = false;

    private static final CameraManager.TorchCallback torchCallback = new CameraManager.TorchCallback() {
        @Override
        public void onTorchModeUnavailable(@NonNull String cameraId) {
            super.onTorchModeUnavailable(cameraId);
        }

        @Override
        public void onTorchModeChanged(@NonNull String cameraId, boolean enabled) {
            super.onTorchModeChanged(cameraId, enabled);
            if (isOpen != enabled) {
                if (isOpen) {
                    iv.setImageResource(R.drawable.off_img);
                } else {
                    iv.setImageResource(R.drawable.on_img);
                }
            }
            isOpen = enabled;

        }

        @Override
        public void onTorchStrengthLevelChanged(@NonNull String cameraId, int newStrengthLevel) {
            super.onTorchStrengthLevelChanged(cameraId, newStrengthLevel);
        }
    };

    @Override
    public void onBackPressed() {
        super.onBackPressed();
        close();
    }


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

        iv = findViewById(R.id.iv_led);

        findViewById(R.id.on_btn).setOnClickListener(this);
        findViewById(R.id.off_btn).setOnClickListener(this);


        mCameraManager = (CameraManager) getApplicationContext().getSystemService(Context.CAMERA_SERVICE);
        mCameraManager.registerTorchCallback(torchCallback, new Handler());
        mCameraManager.registerTorchCallback(new CameraManager.To