安卓开发常用工具类utils

2019-11-08 00:03:44

字体：大中小

来源：转载

供稿：网友

Android开发中一些小功能收藏起来，可以提高开发效率，平时的积累也是很重要的，这些功能其实不需要记住，收藏好，拿来就用，拿完即走。不多说了，抓紧保存备忘吧。

1.android dp和px之间转换

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(Contextcontext,floatdpValue){ 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(Contextcontext,floatpxValue){ final float scale=context.getResources().getDisplayMetrics().density; return(int)(pxValue/scale+0.5f); }}

2.android 对话框样式

<stylename="MyDialog"parent="@android:Theme.Dialog"> <itemname="android:windowNoTitle">true</item> <itemname="android:windowBackground">@color/ha</item></style>

3.android 根据uri获取路径

Uri uri=data.getData();String[] PRoj={MediaStore.Images.Media.DATA};Cursor actualimagecursor=managedQuery(uri,proj,null,null,null);intactual_image_column_index=actualimagecursor.getColumnIndexOrThrow(MediaStore.Images.Media.DATA);actualimagecursor.moveToFirst();String img_path=actualimagecursor.getString(actual_image_column_index);File file=new File(img_path);

4.android 根据uri获取真实路径

public static String getRealFilePath(finalContextcontext,finalUriuri){ 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)){ Cursorcursor=context.getContentResolver().query(uri,newString[]{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;}

5.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);

6.android 横竖屏切换

<activity android:name="MyActivity"android:configChanges="orientation|keyboardHidden">public void onConfigurationChanged(ConfigurationnewConfig){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}}

7.android 获取mac地址

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

8.android 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;@Overridepublic void onCreate(Bundle savedInstanceState){super.onCreate(savedInstanceState);setContentView(R.layout.main);iv=(ImageView)this.findViewById(R.id.ImageView01);iv.post(newRunnable(){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);}}<?xmlversion="1.0"encoding="utf-8"?><LinearLayoutxmlns:android="http://schemas.android.com/apk/res/android"android:orientation="vertical"android:layout_width="fill_parent"android:layout_height="fill_parent"><ImageViewandroid:id="@+id/ImageView01"android:layout_width="wrap_content"android:layout_height="wrap_content"/></LinearLayout>

10.android 获取各种窗体高度

//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。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。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

11.android 禁用home键盘

问题的提出AndroidHome键系统负责监听，捕获后系统自动处理。有时候，系统的处理往往不随我们意，想自己处理点击Home后的事件，那怎么办？问题的解决先禁止Home键，再在onKeyDown里处理按键值，点击Home键的时候就把程序关闭，或者随你XXOO。@Overridepublic boolean onKeyDown(int keyCode,KeyEvent event){if(KeyEvent.KEYCODE_HOME==keyCode) android.os.Process.killProcess(android.os.Process.myPid()); returnsuper.onKeyDown(keyCode,event);}@Overridepublic void onAttachedToWindow() {//TODOAuto-generatedmethodstub this.getWindow().setType(WindowManager.LayoutParams.TYPE_KEYGUARD); super.onAttachedToWindow();}加权限禁止Home键<uses-permissionandroid:name="android.permission.DISABLE_KEYGUARD"></uses-permission>

12.android 控制对话框位置

window=dialog.getWindow();//　　　得到对话框的窗口．WindowManager.LayoutParamswl=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

13.android 挪动dialog的位置

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

14.android 判断网络状态

<uses-permissionandroid: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",newDialogInterface.OnClickListener(){public void onClick(DialogInterfacedialog,intwhichButton){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",newDialogInterface.OnClickListener(){public void onClick(DialogInterface dialog,int whichButton){dialog.cancel();}}).show();}return netSataus;}android 设置apnContentValues values=new ContentValues();values.put(NAME,"CMCCcmwap");values.put(APN,"cmwap");values.put(PROXY,"10.0.0.172");values.put(PORT,"80");values.put(MMSPROXY,"");values.put(MMSPORT,"");values.put(USER,"");values.put(SERVER,"");values.put(PASSWord,"");values.put(MMSC,"");values.put(TYPE,"");values.put(MCC,"460");values.put(MNC,"00");values.put(NUMERIC,"46000");reURI=getContentResolver().insert(Uri.parse("content://telephony/carriers"),values);//首选接入点"content://telephony/carriers/preferapn"

16.android 调节屏幕亮度

public void setBrightness(intlevel){ ContentResolver cr=getContentResolver(); Settings.System.putInt(cr,"screen_brightness",level); Windowwindow=getWindow(); LayoutParams attributes=window.getAttributes(); float flevel=level; attributes.screenBrightness=flevel/255; getWindow().setAttributes(attributes);}

17.android 重启

第一,root权限,这是必须的第二,Runtime.getRuntime().exec("su-creboot");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

18.android隐藏软键盘

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

19.android隐藏以及显示软键盘以及不自动弹出键盘的方法

1、//隐藏软键盘((InputMethodManager)getSystemService(INPUT_METHOD_SERVICE)).hideSoftInputFromWindow(WidgetSearchActivity.this.getCurrentFocus().getWindowToken(),InputMethodManager.HIDE_NOT_ALWAYS);2、//显示软键盘,控件ID可以是EditText,TextView((InputMethodManager)getSystemService(INPUT_METHOD_SERVICE)).showSoftInput(控件ID,0);22.BitMap、Drawable、inputStream及byte[] 互转（1）BitMaptoinputStream：ByteArrayOutputStreambaos=newByteArrayOutputStream();bm.compress(Bitmap.CompressFormat.PNG,100,baos);InputStreamisBm=newByteArrayInputStream(baos.toByteArray());（2）BitMaptobyte[]：BitmapdefaultIcon=BitmapFactory.decodeStream(in);ByteArrayOutputStreamstream=newByteArrayOutputStream();defaultIcon.compress(Bitmap.CompressFormat.JPEG,100,stream);byte[]bitmapdata=stream.toByteArray();（3）Drawabletobyte[]：Drawabled;//thedrawable(CaptainObvious,totherescue!!!)Bitmapbitmap=((BitmapDrawable)d).getBitmap();ByteArrayOutputStreamstream=newByteArrayOutputStream();defaultIcon.compress(Bitmap.CompressFormat.JPEG,100,bitmap);byte[]bitmapdata=stream.toByteArray();（4）byte[]toBitmap：Bitmapbitmap=BitmapFactory.decodeByteArray(byte[],0,byte[].length);23.发送指令out=process.getOutputStream();out.write(("amstart-aandroid.intent.action.VIEW-ncom.android.browser/com.android.browser.BrowserActivityn").getBytes());out.flush();InputStream in=process.getInputStream();BufferedReader re=new BufferedReader(new InputStreamReader(in));String line=null;while((line=re.readLine())!=null){Log.d("conio","[result]"+line);}

20.通过URI得到文件路径

// 通用的从uri中获取路径的方法 public static String getPath(final Context context, final Uri uri) { final boolean isKitKat = Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT; // DocumentProvider if (isKitKat && DocumentsContract.isDocumentUri(context, uri)) { // ExternalStorageProvider if (isExternalStorageDocument(uri)) { final String docId = DocumentsContract.getDocumentId(uri); final String[] split = docId.split(":"); final String type = split[0]; if ("primary".equalsIgnoreCase(type)) { return Environment.getExternalStorageDirectory() + "/" + split[1]; } } // DownloadsProvider else if (isDownloadsDocument(uri)) { final String id = DocumentsContract.getDocumentId(uri); final Uri contentUri = ContentUris.withAppendedId(Uri.parse("content://downloads/public_downloads"), Long.valueOf(id)); return getDataColumn(context, contentUri, null, null); } // MediaProvider else if (isMediaDocument(uri)) { final String docId = DocumentsContract.getDocumentId(uri); final String[] split = docId.split(":"); final String type = split[0]; Uri contentUri = null; if ("image".equals(type)) { contentUri = MediaStore.Images.Media.EXTERNAL_CONTENT_URI; } else if ("video".equals(type)) { contentUri = MediaStore.Video.Media.EXTERNAL_CONTENT_URI; } else if ("audio".equals(type)) { contentUri = MediaStore.Audio.Media.EXTERNAL_CONTENT_URI; } final String selection = "_id=?"; final String[] selectionArgs = new String[] { split[1] }; return getDataColumn(context, contentUri, selection, selectionArgs); } } // MediaStore (and general) else if ("content".equalsIgnoreCase(uri.getScheme())) { // Return the remote address if (isGooglePhotosUri(uri)) return uri.getLastPathSegment(); return getDataColumn(context, uri, null, null); } // File else if ("file".equalsIgnoreCase(uri.getScheme())) { return uri.getPath(); } return ""; } public static String getDataColumn(Context context, Uri uri, String selection, String[] selectionArgs) { Cursor cursor = null; final String column = "_data"; final String[] projection = { column }; try { cursor = context.getContentResolver().query(uri, projection, selection, selectionArgs, null); if (cursor != null && cursor.moveToFirst()) { final int index = cursor.getColumnIndexOrThrow(column); return cursor.getString(index); } } finally { if (cursor != null) cursor.close(); } return ""; } public static boolean isExternalStorageDocument(Uri uri) { return "com.android.externalstorage.documents".equals(uri.getAuthority()); } public static boolean isDownloadsDocument(Uri uri) { return "com.android.providers.downloads.documents".equals(uri.getAuthority()); } public static boolean isMediaDocument(Uri uri) { return "com.android.providers.media.documents".equals(uri.getAuthority()); } public static boolean isGooglePhotosUri(Uri uri) { return "com.google.android.apps.photos.content".equals(uri.getAuthority()); }

上一篇：有关前端代码的一些总结

下一篇：理解快速傅里叶变换（FFT）算法