An example tutorial for writing simple flashlight small applications in Android _android

The main implementation of two steps:

1, the realization turns on and closes the flash lamp, but realizes the operation Flash mainly through camera class

Camera Camera = Camera.open (); 
Parameters mparameters = Camera.getparameters (); 
Mparameters.setflashmode (Camera.Parameters.FLASH_MODE_TORCH);/Open Camera.Parameters.FLASH_MODE_OFF

is closed

Amera.setparameters (Mparameters) 

2, custom flash button; A custom control is primarily set to the size of the set view

onmeasure (int widthmeasurespec, int heightmeasurespec)  

The effect is as follows:

The source code is as follows:

 <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 Andro Id: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); 
    Define Click event 
    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 (); 
  Define the Painted mask Paint Paint = new Paint (); 
  Paint paint1 = new Paint (); 
  int x = 0; 
  int y = 0; 
 
  Open Flash Boolean islight; 
  Public Lightbkview (context, AttributeSet set) {Super (context, set); 
    @Override protected void OnDraw (Canvas Canvas) {//Get the width and height of the control int width = This.getwidth (); 
    int heigth = This.getheight (); 
    The coordinates of the dot x = WIDTH/2; 
    y = HEIGTH/2; 
    Replace the switch background if (!islight) {paint.setcolor (Color.Blue); 
    Canvas.drawcircle (x, y, n, paint); PainT1.setcolor (color.red); 
    Paint1.settextsize (20); 
    Canvas.drawtext ("Open flash", x-50, Y, paint1); 
    Invalidate (); 
      }else{Paint.setcolor (Color.White); 
      Canvas.drawcircle (x, y, n, paint); 
      Paint1.setcolor (color.red); 
      Paint1.settextsize (20); 
      Canvas.drawtext ("Turn off Flash", x-50, Y, paint1); 
    Invalidate (); }//define view size @Override protected void onmeasure (int widthmeasurespec, int heightmeasurespec) {Setm 
 
  Easureddimension (GetWidth (Widthmeasurespec), GetHeight (Heightmeasurespec)); 
    }//Defines the width of view 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; }//Define view's height 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; //implementation of the Flash switch @Override public void OnClick (View v) {if (!islight) {Parameters mparameters = Cam 
      Era.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; 
 } 
  } 
 
}