Android 常用代码片小结

1. dp  px  相互转换---------------
public class DensityUtil {  
  
    /** 
     * 根据手机的分辨率从 dip 的单位 转成为 px(像素) 
     */  
    public static int dip2px(Context context, float dpValue) {  
        final float scale = context.getResources().getDisplayMetrics().density;  
        return (int) (dpValue * scale + 0.5f);  
    }  
  
    /** 
     * 根据手机的分辨率从 px(像素) 的单位 转成为 dp 
     */  
    public static int px2dip(Context context, float pxValue) {  
        final float scale = context.getResources().getDisplayMetrics().density;  
        return (int) (pxValue / scale + 0.5f);  
    }  
}  

private void turnGPSOn(){
    String provider = Settings.Secure.getString(getContentResolver(), Settings.Secure.LOCATION_PROVIDERS_ALLOWED);

    if(!provider.contains("gps")){ //if gps is disabled
        final Intent poke = new Intent();
        poke.setClassName("com.android.settings", "com.android.settings.widget.SettingsAppWidgetProvider"); 
        poke.addCategory(Intent.CATEGORY_ALTERNATIVE);
        poke.setData(Uri.parse("3")); 
        sendBroadcast(poke);
    }
}

private void turnGPSOff(){
    String provider = Settings.Secure.getString(getContentResolver(), Settings.Secure.LOCATION_PROVIDERS_ALLOWED);

    if(provider.contains("gps")){ //if gps is enabled
        final Intent poke = new Intent();
        poke.setClassName("com.android.settings", "com.android.settings.widget.SettingsAppWidgetProvider");
        poke.addCategory(Intent.CATEGORY_ALTERNATIVE);
        poke.setData(Uri.parse("3")); 
        sendBroadcast(poke);
    }
}

root 下禁用组件

pm disable com.htc.htclocationservice/com.htc.htclocationservice.AutoSettingReceiver

根据url获取真实路径

    public static String getRealFilePath( final Context context, final Uri uri ) {

        if ( null == uri ) return null;

        final String scheme = uri.getScheme();
        String data = null;

        if ( scheme == null )
            data = uri.getPath();
        else if ( ContentResolver.SCHEME_FILE.equals( scheme ) ) {
            data = uri.getPath();
        } else if ( ContentResolver.SCHEME_CONTENT.equals( scheme ) ) {
            Cursor cursor = context.getContentResolver().query( uri, new String[] { ImageColumns.DATA }, null, null, null );
            if ( null != cursor ) {
                if ( cursor.moveToFirst() ) {
                    int index = cursor.getColumnIndex( ImageColumns.DATA );
                    if ( index > -1 ) {
                        data = cursor.getString( index );
                    }
                }
                cursor.close();
            }
        }
        return data;
    }

Android 还原短信

ContentValues values = new ContentValues(); values.put("address", "123456789"); values.put("body", "haha"); values.put("date", "135123000000"); getContentResolver().insert(Uri.parse("content://sms/sent"), values);

横竖屏切换


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


public void onConfigurationChanged(Configuration newConfig) {  
  
   super.onConfigurationChanged(newConfig);  
  
if (this.getResources().getConfiguration().orientation == Configuration.ORIENTATION_LANDSCAPE) {  
           //加入横屏要处理的代码  
  
}else if (this.getResources().getConfiguration().orientation == Configuration.ORIENTATION_PORTRAIT) {  
  
           //加入竖屏要处理的代码  
  
}  
  
  
}  

获取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();  
  }  

获取sd卡状态

/** 获取存储卡路径 */ 
File sdcardDir=Environment.getExternalStorageDirectory(); 
/** StatFs 看文件系统空间使用情况 */ 
StatFs statFs=new StatFs(sdcardDir.getPath()); 
/** Block 的 size*/ 
Long blockSize=statFs.getBlockSize(); 
/** 总 Block 数量 */ 
Long totalBlocks=statFs.getBlockCount(); 
/** 已使用的 Block 数量 */ 
Long availableBlocks=statFs.getAvailableBlocks(); 

Android获取状态栏和标题栏的高度

1.Android获取状态栏高度：

decorView是window中的最顶层view，可以从window中获取到decorView，然后decorView有个getWindowVisibleDisplayFrame方法可以获取到程序显示的区域，包括标题栏，但不包括状态栏。

于是，我们就可以算出状态栏的高度了。

Rect frame = new Rect();
getWindow().getDecorView().getWindowVisibleDisplayFrame(frame);
int statusBarHeight = frame.top;

2.获取标题栏高度：

getWindow().findViewById(Window.ID_ANDROID_CONTENT)这个方法获取到的view就是程序不包括标题栏的部分，然后就可以知道标题栏的高度了。

int contentTop = getWindow().findViewById(Window.ID_ANDROID_CONTENT).getTop();
//statusBarHeight是上面所求的状态栏的高度
int titleBarHeight = contentTop - statusBarHeight

例子代码：

package com.cn.lhq;
import android.app.Activity;
import android.graphics.Rect;
import android.os.Bundle;
import android.util.Log;
import android.view.Window;
import android.widget.ImageView;
public class Main extends Activity {
 ImageView iv;
 @Override
 public void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.main);
  iv = (ImageView) this.findViewById(R.id.ImageView01);
  iv.post(new Runnable() {
   public void run() {
    viewInited();
   }
  });
  Log.v("test", "== ok ==");
 }
 private void viewInited() {
  Rect rect = new Rect();
  Window window = getWindow();
  iv.getWindowVisibleDisplayFrame(rect);
  int statusBarHeight = rect.top;
  int contentViewTop = window.findViewById(Window.ID_ANDROID_CONTENT)
    .getTop();
  int titleBarHeight = contentViewTop - statusBarHeight;
  // 测试结果：ok之后 100多 ms 才运行了
  Log.v("test", "=-init-= statusBarHeight=" + statusBarHeight
    + " contentViewTop=" + contentViewTop + " titleBarHeight="
    + titleBarHeight);
 }
}

 

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent">
 <ImageView 
  android:id="@+id/ImageView01" 
  android:layout_width="wrap_content" 
  android:layout_height="wrap_content"/>
</LinearLayout>

  //取得窗口属性
        getWindowManager().getDefaultDisplay().getMetrics(dm);
        
        //窗口的宽度
        int screenWidth = dm.widthPixels;
        //窗口高度
        int screenHeight = dm.heightPixels;
        textView = (TextView)findViewById(R.id.textView01);
        textView.setText("屏幕宽度: " + screenWidth + "\n屏幕高度： " + screenHeight);

二、获取状态栏高度
decorView是window中的最顶层view，可以从window中获取到decorView，然后decorView有个getWindowVisibleDisplayFrame方法可以获取到程序显示的区域，包括标题栏，但不包括状态栏。 
于是，我们就可以算出状态栏的高度了。
view plain


Rect frame = new Rect();
getWindow().getDecorView().getWindowVisibleDisplayFrame(frame);
int statusBarHeight = frame.top;


三、获取标题栏高度
getWindow().findViewById(Window.ID_ANDROID_CONTENT)这个方法获取到的view就是程序不包括标题栏的部分，然后就可以知道标题栏的高度了。
view plain


int contentTop = getWindow().findViewById(Window.ID_ANDROID_CONTENT).getTop();
//statusBarHeight是上面所求的状态栏的高度
int titleBarHeight = contentTop - statusBarHeight

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>  
    <!-- 系统启动完成后会调用 -->  
    <action  
        android:name="android.intent.action.BOOT_COMPLETED">  
    </action>  
</intent-filter>  
</receiver> 

 window =dialog.getWindow();// 　　　得到对话框的窗口．  
      WindowManager.LayoutParams wl = window.getAttributes();  
       wl.x = x;//这两句设置了对话框的位置．0为中间  
       wl.y =y;  
       wl.width =w;  
       wl.height =h;  
       wl.alpha =0.6f;// 这句设置了对话框的透明度   

挪动dialog的位置


Window mWindow = dialog.getWindow();  
WindowManager.LayoutParams lp = mWindow.getAttributes();  
lp.x = 10;   //新位置X坐标  
lp.y = -100; //新位置Y坐标  
dialog.onWindowAttributesChanged(lp);

判断网络状态



<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("没有可用的网络")  
   .setMessage("是否对网络进行设置？");  
   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;  
   }  

调节屏幕的亮度
、
、
public void setBrightness(int level) { 
ContentResolver cr = getContentResolver(); 
Settings.System.putInt(cr, "screen_brightness", level); 
Window window = getWindow(); 
LayoutParams attributes = window.getAttributes(); 
float flevel = level; 
attributes.screenBrightness = flevel / 255; 
getWindow().setAttributes(attributes); 
} 

第一,root权限,这是必须的 
第二,Runtime.getRuntime().exec("su -c reboot"); 
第三,模拟器上运行不出来,必须真机 
第四,运行时会提示你是否加入列表 , 同意就好

隐藏软键盘



setContentView(R.layout.activity_main);
        getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_ADJUST_RESIZE |
                WindowManager.LayoutParams.SOFT_INPUT_STATE_HIDDEN);