<uses-permission android:name="android.permission.CAMERA"/>
<uses-permission android:name="android.permission.FLASHLIGHT" />

package com.google.yang.myapplication;
 
import android.hardware.Camera;
import android.hardware.Camera.Parameters;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
 
/**
 * 閃光燈的控制
 *
 * @author yang
 */
public class MainActivity extends AppCompatActivity {
 
  private Button open;
  private Button close;
  private Button openFlicker;
  private Button closeFlicker;
  private Camera camera;
  private Boolean isShanshuo;
 
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
 
    open = (Button) this.findViewById(R.id.open);
    close = (Button) this.findViewById(R.id.close);
    openFlicker = (Button) findViewById(R.id.openFlicker);
    closeFlicker = (Button) findViewById(R.id.closeFlicker);
 
    open.setOnClickListener(openOnClickListener);
    close.setOnClickListener(closeOnClickListener);
    openFlicker.setOnClickListener(openFlickerOnClickListener);
    closeFlicker.setOnClickListener(closeFlickerOnClickListener);
  }
 
  /**
   * 打開手電筒
   */
  private OnClickListener openOnClickListener = new OnClickListener() {
    @Override
    public void onClick(View v) {
      open();
    }
  };
 
  /**
   * 關閉手電筒
   */
  private OnClickListener closeOnClickListener = new OnClickListener() {
    @Override
    public void onClick(View v) {
      close();
    }
  };
 
  /**
   * 開啟閃爍
   */
  private OnClickListener openFlickerOnClickListener = new OnClickListener() {
    @Override
    public void onClick(View v) {
      isShanshuo = true;
      openFlicker.setEnabled(false);
      new Thread(new Runnable() {
        @Override
        public void run() {
          while (isShanshuo) {
            open();
            try {
              Thread.sleep(300);
            } catch (InterruptedException e) {
              e.printStackTrace();
            }
            close();
            try {
              Thread.sleep(300);
            } catch (InterruptedException e) {
              e.printStackTrace();
            }
          }
        }
      }).start();
    }
  };
 
  /**
   * 關閉閃爍
   */
  private OnClickListener closeFlickerOnClickListener = new OnClickListener() {
    @Override
    public void onClick(View v) {
      isShanshuo = false;
      openFlicker.setEnabled(true);
    }
  };
  /**
   * 打開閃光燈
   *
   * @return
   */
  private void open() {
    try {
      camera = Camera.open();
      camera.startPreview();
      Parameters parameters = camera.getParameters();
      parameters.setFlashMode(Parameters.FLASH_MODE_TORCH);
      camera.setParameters(parameters);
    } catch (Exception e) {
      e.printStackTrace();
    }
  }
  /**
   * 關閉閃光燈
   *
   * @return
   */
  private void close() {
    try {
      Parameters parameters = camera.getParameters();
      parameters.setFlashMode(Camera.Parameters.FLASH_MODE_OFF);
      camera.setParameters(parameters);
      camera.release();
      camera = null;
    } catch (Exception e) {
      e.printStackTrace();
    }
  }
 
}