android小知識

 .獲取mac地址

1、<uses-permission android:name="android.permission.ACCESS_WIFI_STATE"/>
2、private String getLocalMacAddress() {
    WifiManager wifi = (WifiManager) getSystemService(Context.WIFI_SERVICE);
    WifiInfo info = wifi.getConnectionInfo();
    return info.getMacAddress();
  }

1、<uses-permission android:name="android.permission.ACCESS_WIFI_STATE"/>  
2、private String getLocalMacAddress() {
    WifiManager wifi = (WifiManager) getSystemService(Context.WIFI_SERVICE);
    WifiInfo info = wifi.getConnectionInfo();
    return info.getMacAddress();
  }

 

 2.全屏
一是在代碼中設置，另一種方法是在配置文件裏改！

一、在代碼中設置:

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    //無title
    requestWindowFeature(Window.FEATURE_NO_TITLE);
    //全屏
    getWindow().setFlags(WindowManager.LayoutParams. FLAG_FULLSCREEN ,
        WindowManager.LayoutParams. FLAG_FULLSCREEN);
    setContentView(R.layout.main);
    }
}

public void onCreate(Bundle savedInstanceState) { 
	super.onCreate(savedInstanceState); 
	//無title   
	requestWindowFeature(Window.FEATURE_NO_TITLE);   
	//全屏   
	getWindow().setFlags(WindowManager.LayoutParams. FLAG_FULLSCREEN ,     
		WindowManager.LayoutParams. FLAG_FULLSCREEN);          
	setContentView(R.layout.main); 
	} 
} 

 設置全屏的倆段代碼必須在setContentView(R.layout.main) 之前，不然會報錯。

二、在配置文件裏修改(android:theme="@android:style/Theme.NoTitleBar.Fullscreen"):

 

3、網絡狀態

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

 private boolean getNetWorkStatus() {

   boolean netSataus = false;
   ConnectivityManager cwjManager = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);

   cwjManager.getActiveNetworkInfo();

   if (cwjManager.getActiveNetworkInfo() != null) {
   netSataus = cwjManager.getActiveNetworkInfo().isAvailable();
   }

   if (!netSataus) {
   Builder b = new AlertDialog.Builder(this).setTitle("沒有可用的網絡")
   .setMessage("是否對網絡進行設置？");
   b.setPositiveButton("是", new DialogInterface.OnClickListener() {
   public void onClick(DialogInterface dialog, int whichButton) {
   Intent mIntent = new Intent("/");
   ComponentName comp = new ComponentName(
   "com.android.settings",
   "com.android.settings.WirelessSettings");
   mIntent.setComponent(comp);
   mIntent.setAction("android.intent.action.VIEW");
   startActivityForResult(mIntent,0);
   }
   }).setNeutralButton("否", new DialogInterface.OnClickListener() {
   public void onClick(DialogInterface dialog, int whichButton) {
   dialog.cancel();
   }
   }).show();
   }

   return netSataus;
   }

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

  private boolean getNetWorkStatus() {

    boolean netSataus = false;
    ConnectivityManager cwjManager = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);

    cwjManager.getActiveNetworkInfo();

    if (cwjManager.getActiveNetworkInfo() != null) {
    netSataus = cwjManager.getActiveNetworkInfo().isAvailable();
    }

    if (!netSataus) {
    Builder b = new AlertDialog.Builder(this).setTitle("沒有可用的網絡")
    .setMessage("是否對網絡進行設置？");
    b.setPositiveButton("是", new DialogInterface.OnClickListener() {
    public void onClick(DialogInterface dialog, int whichButton) {
    Intent mIntent = new Intent("/");
    ComponentName comp = new ComponentName(
    "com.android.settings",
    "com.android.settings.WirelessSettings");
    mIntent.setComponent(comp);
    mIntent.setAction("android.intent.action.VIEW");
    startActivityForResult(mIntent,0); 
    }
    }).setNeutralButton("否", new DialogInterface.OnClickListener() {
    public void onClick(DialogInterface dialog, int whichButton) {
    dialog.cancel();
    }
    }).show();
    }

    return netSataus;
    }

 

4 .判斷GPS狀態

public boolean isGpsEnabled(Context context)
{
    LocationManager locationManager =((LocationManager)context.getSystemService(Context.LOCATION_SERVICE));
    List<String> accessibleProviders = locationManager.getProviders(true);
    return accessibleProviders != null && accessibleProviders.size() > 0;
}

    public boolean isGpsEnabled(Context context)
    {
        LocationManager locationManager =((LocationManager)context.getSystemService(Context.LOCATION_SERVICE));
        List<String> accessibleProviders = locationManager.getProviders(true);
        return accessibleProviders != null && accessibleProviders.size() > 0;
    } 

 

 

5.禁止橫屏幕 setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_NOSENSOR);

 

6.禁用重複加載
    1. 修改AndroidManifest.xml文件，在activity標籤下面增加參數：

< activity android:name="MyActivity"
android:configChanges="orientation|keyboardHidden">

< activity android:name="MyActivity"
android:configChanges="orientation|keyboardHidden">

    2.在MyActivity 中重載onConfigurationChanged（每次切屏的時候會自動調用）方法，初始化橫豎屏方向不同的顯示界面，以及其他數據的初始化操作：

@Override

public void onConfigurationChanged(Configuration newConfig) {

   super.onConfigurationChanged(newConfig);

if (this.getResources().getConfiguration().orientation == Configuration.ORIENTATION_LANDSCAPE) {
           //加入橫屏要處理的代碼

}else if (this.getResources().getConfiguration().orientation == Configuration.ORIENTATION_PORTRAIT) {

           //加入豎屏要處理的代碼

}


}

@Override

public void onConfigurationChanged(Configuration newConfig) {

   super.onConfigurationChanged(newConfig);

if (this.getResources().getConfiguration().orientation == Configuration.ORIENTATION_LANDSCAPE) {
           //加入橫屏要處理的代碼

}else if (this.getResources().getConfiguration().orientation == Configuration.ORIENTATION_PORTRAIT) {

           //加入豎屏要處理的代碼

}


}

 

 

7、開機啓動程序

Java代碼  

1)public class StartupReceiver extends BroadcastReceiver {

  @Override
  public void onReceive(Context context, Intent intent) {
    Intent startupintent = new Intent(context,StrongTracks.class);
    startupintent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
    context.startActivity(startupintent);
  }

}
2)<receiver
android:name=".StartupReceiver">
<intent-filter>
    <!-- 系統啓動完成後會調用 -->
    <action
        android:name="android.intent.action.BOOT_COMPLETED">
    </action>
</intent-filter>
</receiver>

在Activity的onCreate函數中，加入如下代碼：

requestWindowFeature(Window.FEATURE_NO_TITLE);
getWindow().setFlags(WindowManager.LayoutParams. FLAG_FULLSCREEN ,
              WindowManager.LayoutParams. FLAG_FULLSCREEN);

 

 

ImageView imageView = new ImageView(context);

URL url = new URL("圖片路徑");
URLConnection conn = url.openConnection();
        conn.connect();
        InputStream is = conn.getInputStream();
        BitmapFactory.Options options=new BitmapFactory.Options();
            options.inSampleSize = 10;
originalImage = BitmapFactory.decodeStream(is,null,options);
imageView.setImageBitmap(bitmapWithReflection);