Android中编写简单的手电筒小应用的实例教程

Camera camera = Camera.open(); Parameters mParameters = camera.getParameters(); mParameters.setFlashMode(Camera.Parameters.FLASH_MODE_TORCH);//打开Camera.Parameters.FLASH_MODE_OFF

amera.setParameters(mParameters) 

onMeasure(int widthMeasureSpec, int heightMeasureSpec)  

<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;     }   }  }