Android中编写简单的手电筒小应用的实例教程

主要实现两个步骤：

1、实现打开和关闭闪光灯；而实现操作闪光灯主要通过camera类

camera camera = camera.open(); 
parameters mparameters = camera.getparameters(); 
mparameters.setflashmode(camera.parameters.flash_mode_torch);//打开camera.parameters.flash_mode_off

则为关闭 

amera.setparameters(mparameters) 

2、自定义闪光灯的按钮；自定义控件主要是设置设置view的大小

onmeasure(int widthmeasurespec, int heightmeasurespec)  

效果如下：

源码如下：

<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:gravity="center" 
  android:background="@drawable/light" 
  tools:context=".mainactivity" > 
 
 
  <com.android.xiong.xionglight.lightbkview  
    android:id="@+id/light1" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content"/> 
 
</relativelayout> 

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

package com.android.xiong.xionglight; 
 
import android.app.activity; 
import android.os.bundle; 
import android.view.keyevent; 
import android.view.menu; 
 
public class mainactivity extends activity { 
 
  private lightbkview light1; 
 
  @override 
  protected void oncreate(bundle savedinstancestate) { 
    super.oncreate(savedinstancestate); 
    setcontentview(r.layout.activity_main); 
    light1 = (lightbkview) findviewbyid(r.id.light1); 
    //定义单击事件 
    light1.setonclicklistener(light1); 
     
  } 
 
  @override 
  public boolean oncreateoptionsmenu(menu menu) { 
    getmenuinflater().inflate(r.menu.main, menu); 
    return true; 
  } 
 
 
} 

package com.android.xiong.xionglight; 
 
import android.content.context; 
import android.graphics.canvas; 
import android.graphics.color; 
import android.graphics.paint; 
import android.hardware.camera; 
import android.hardware.camera.parameters; 
import android.util.attributeset; 
import android.view.view; 
import android.view.view.onclicklistener; 
 
public class lightbkview extends view implements onclicklistener { 
 
  camera camera = camera.open(); 
  // 定义画皮 
  paint paint = new paint(); 
  paint paint1 = new paint(); 
  int x = 0; 
  int y = 0; 
  // 打开闪光灯 
  boolean islight; 
 
  public lightbkview(context context, attributeset set) { 
    super(context, set); 
  } 
 
  @override 
  protected void ondraw(canvas canvas) { 
    // 获取控件的宽度和高度 
    int width = this.getwidth(); 
    int heigth = this.getheight(); 
    // 圆点的坐标 
    x = width / 2; 
    y = heigth / 2; 
    //更换开关背景 
    if(!islight){ 
    paint.setcolor(color.blue); 
    canvas.drawcircle(x, y, 60, paint); 
    paint1.setcolor(color.red); 
    paint1.settextsize(20); 
    canvas.drawtext("打开闪光灯", x-50, y, paint1); 
    invalidate(); 
    }else{ 
      paint.setcolor(color.white); 
      canvas.drawcircle(x, y, 60, paint); 
      paint1.setcolor(color.red); 
      paint1.settextsize(20); 
      canvas.drawtext("关闭闪光灯", x-50, y, paint1); 
      invalidate(); 
    } 
  } 
 
  // 定义view的大小 
  @override 
  protected void onmeasure(int widthmeasurespec, int heightmeasurespec) { 
    setmeasureddimension(getwidth(widthmeasurespec), 
        getheight(heightmeasurespec)); 
 
  } 
  //定义view的宽度 
  public int getwidth(int widthmeasurespec) { 
    int reslut = 0; 
    int widthmode = measurespec.getmode(widthmeasurespec); 
    if (widthmode == measurespec.at_most) { 
      reslut = 120; 
    } 
    if (widthmode == measurespec.exactly) { 
      reslut = measurespec.getsize(widthmeasurespec); 
    } 
    return reslut; 
  } 
  //定义view的高度 
  public int getheight(int heightmeasurespec) { 
    int reslut = 0; 
    int heightmode = measurespec.getmode(heightmeasurespec); 
    if (heightmode == measurespec.at_most) { 
      reslut = 120; 
    } 
    if (heightmode == measurespec.exactly) { 
      reslut = measurespec.getsize(heightmeasurespec); 
    } 
    return reslut; 
  } 
 
  // 实现闪光灯的的开关 
  @override 
  public void onclick(view v) { 
    if (!islight) { 
      parameters mparameters = camera.getparameters(); 
      mparameters.setflashmode(camera.parameters.flash_mode_torch); 
      camera.setparameters(mparameters); 
      islight = true; 
    } else { 
      parameters mparameters = camera.getparameters(); 
      mparameters.setflashmode(camera.parameters.flash_mode_off); 
      camera.setparameters(mparameters); 
      islight = false; 
    } 
  } 
 
}