闪关灯的开启和关闭

1、activity_main.xml 两个按钮，一个open一个close

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" >

    <TextView
        android:id="@+id/textView1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="@string/hello_world" />

    <Button
        android:id="@+id/button_open"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/textView1"
        android:layout_below="@+id/textView1"
        android:layout_marginTop="38dp"
        android:text="open" />

    <Button
        android:id="@+id/button_close"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/button_open"
        android:layout_below="@+id/button_open"
        android:layout_marginTop="50dp"
        android:text="close" />

</RelativeLayout>

2、MainActivity 核心代码

package com.qiantu.flashlight;

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

public class MainActivity extends Activity {
	private Camera camera;
	private Button openBtn;
	private Button closeBtn;

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

		openBtn = (Button) findViewById(R.id.button_open);
		openBtn.setOnClickListener(new OnClickListener() {
			@Override
			public void onClick(View v) {
				if (null != camera) {
					Parameters parameters = camera.getParameters();
					parameters.setFlashMode(Parameters.FLASH_MODE_TORCH);
					camera.setParameters(parameters);
				}
			}
		});

		closeBtn = (Button) findViewById(R.id.button_close);
		closeBtn.setOnClickListener(new OnClickListener() {
			@Override
			public void onClick(View v) {
				if (null != camera) {
					Parameters parameters = camera.getParameters();
					parameters.setFlashMode(Parameters.FLASH_MODE_OFF);
					camera.setParameters(parameters);
				}
			}
		});
	}

	@Override
	protected void onStart() {
		super.onStart();
		camera = Camera.open();
	}

	@Override
	protected void onDestroy() {
		super.onDestroy();
		if (null != camera) {
			camera.release();
		}
	}

	@Override
	public boolean onCreateOptionsMenu(Menu menu) {
		getMenuInflater().inflate(R.menu.main, menu);
		return true;
	}

}

3、AndroidManifest.xml 加入摄像头和闪关灯的权限

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.qiantu.flashlight"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="18" />
    
    <!-- 添加的部分 -->
    <uses-feature android:name="android.hardware.camera" />
	<uses-feature android:name="android.hardware.autofocus" />
    <uses-permission android:name="android.permission.CAMERA" />
	<uses-permission android:name="android.permission.FLASHLIGHT" />
	<uses-permission android:name="android.permission.DISABLE_KEYGUARD" />
	<!-- end -->

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="com.qiantu.flashlight.MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

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

</manifest>

参考： http://my.eoe.cn/618785/archive/23033.html?f_section=new