使用相机闪光灯开启

package com.home.light;

import android.app.Activity;
import android.hardware.Camera;
import android.hardware.Camera.Parameters;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

import com.home.cameralight.R;

public class TestActivity extends Activity implements OnClickListener {
  Camera camera;
  Parameters params;
  private Button onBtn;
  private Button offBtn;

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    camera = Camera.open();
    params = camera.getParameters();
    findView();
  }

  private void findView() {
    onBtn = (Button) findViewById(R.id.main_btn_on);
    onBtn.setOnClickListener(this);
    offBtn = (Button) findViewById(R.id.main_btn_off);
    offBtn.setOnClickListener(this);
  }


  @Override
  public void onClick(View v) {
    if (v == onBtn) {
//      open1();
      open2();
    } else if (v == offBtn) {
//      off1();
      off2();
    }
  }


  private void open1() {
    if (camera == null) {
      camera = Camera.open();
      params = camera.getParameters();
    }
    params.setFlashMode(Parameters.FLASH_MODE_TORCH);
    camera.setParameters(params);
  }

  private void off1() {
    if (camera == null) {
      return;
    }
    params.setFlashMode(Parameters.FLASH_MODE_OFF);
    camera.setParameters(params);
    camera.release();
    camera = null;
  }

  private void open2() {
    if (camera == null) {
      camera = Camera.open();
      params = camera.getParameters();
    }

    params.setFlashMode(Camera.Parameters.FLASH_MODE_TORCH);
    camera.setParameters(params);
    camera.autoFocus(new Camera.AutoFocusCallback() {
      public void onAutoFocus(boolean success, Camera camera) {
      }
    });
    camera.startPreview();
  }

  private void off2() {
    if (camera == null) {
      return;
    }
    camera.stopPreview();
    camera.release();
    camera = null;
  }

}

权限：

<uses-permission android:name="android.permission.FLASHLIGHT" />
    <uses-permission android:name="android.permission.CAMERA" />
    <uses-feature android:name="android.hardware.camera" />
    <uses-feature android:name="android.hardware.autofocus"/>