Android開發(fā)中一些小功能收藏起來，可以提高開發(fā)效率，平時的積累也是很重要的，這些功能其實不需要記住，收藏好，拿來就用，拿完即走。不多說了，抓緊保存?zhèn)渫伞?/p>
1.android dp和px之間轉(zhuǎn)換
public class DensityUtil{ /** *根據(jù)手機的分辨率從dip的單位轉(zhuǎn)成為px(像素) */ public static int dip2px(Contextcontext,floatdpValue){ final float scale=context.getResources().getDisplayMetrics().density; return(int)(dpValue*scale+0.5f); } /** *根據(jù)手機的分辨率從px(像素)的單位轉(zhuǎn)成為dp */ public static int px2dip(Contextcontext,floatpxValue){ final float scale=context.getResources().getDisplayMetrics().density; return(int)(pxValue/scale+0.5f); }}2.android 對話框樣式
<stylename="MyDialog"parent="@android:Theme.Dialog"> <itemname="android:windowNoTitle">true</item> <itemname="android:windowBackground">@color/ha</item></style>3.android 根據(jù)uri獲取路徑
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 根據(jù)uri獲取真實路徑
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 還原短信
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 橫豎屏切換
<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.android 獲取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 獲取sd卡狀態(tài)
/**獲取存儲卡路徑*/File sdcardDir=Environment.getExternalStorageDirectory();/**StatFs看文件系統(tǒng)空間使用情況*/StatFs statFs=new StatFs(sdcardDir.getPath());/**Block的size*/Long blockSize=statFs.getBlockSize();/**總Block數(shù)量*/Long totalBlocks=statFs.getBlockCount();/**已使用的Block數(shù)量*/Long availableBlocks=statFs.getAvailableBlocks();Android獲取狀態(tài)欄和標(biāo)題欄的高度1.Android獲取狀態(tài)欄高度：decorView是window中的最頂層view，可以從window中獲取到decorView，然后decorView有個getWindowVisibleDisplayFrame方法可以獲取到程序顯示的區(qū)域，包括標(biāo)題欄，但不包括狀態(tài)欄。 于是，我們就可以算出狀態(tài)欄的高度了。 Rect frame=new Rect();getWindow().getDecorView().getWindowVisibleDisplayFrame(frame);int statusBarHeight=frame.top;2.獲取標(biāo)題欄高度： getWindow().findViewById(Window.ID_ANDROID_CONTENT)這個方法獲取到的view就是程序不包括標(biāo)題欄的部分，然后就可以知道標(biāo)題欄的高度了。 int contentTop=getWindow().findViewById(Window.ID_ANDROID_CONTENT).getTop();//statusBarHeight是上面所求的狀態(tài)欄的高度int titleBarHeight=contentTop-statusBarHeight例子代碼：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;//測試結(jié)果：ok之后100多ms才運行了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 獲取各種窗體高度
//取得窗口屬性getWindowManager().getDefaultDisplay().getMetrics(dm);//窗口的寬度int screenWidth=dm.widthPixels;//窗口高度int screenHeight=dm.heightPixels;textView=(TextView)findViewById(R.id.textView01);textView.setText("屏幕寬度:"+screenWidth+"n屏幕高度："+screenHeight);二、獲取狀態(tài)欄高度decorView是window中的最頂層view，可以從window中獲取到decorView，然后decorView有個getWindowVisibleDisplayFrame方法可以獲取到程序顯示的區(qū)域，包括標(biāo)題欄，但不包括狀態(tài)欄。于是，我們就可以算出狀態(tài)欄的高度了。Rect frame=new Rect();getWindow().getDecorView().getWindowVisibleDisplayFrame(frame);int statusBarHeight=frame.top;三、獲取標(biāo)題欄高度getWindow().findViewById(Window.ID_ANDROID_CONTENT)這個方法獲取到的view就是程序不包括標(biāo)題欄的部分，然后就可以知道標(biāo)題欄的高度了。int contentTop=getWindow().findViewById(Window.ID_ANDROID_CONTENT).getTop();//statusBarHeight是上面所求的狀態(tài)欄的高度int titleBarHeight=contentTop-statusBarHeight11.android 禁用home鍵盤
問題的提出AndroidHome鍵系統(tǒng)負(fù)責(zé)監(jiān)聽，捕獲后系統(tǒng)自動處理。有時候，系統(tǒng)的處理往往不隨我們意，想自己處理點擊Home后的事件，那怎么辦？問題的解決先禁止Home鍵，再在onKeyDown里處理按鍵值，點擊Home鍵的時候就把程序關(guān)閉，或者隨你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();}加權(quán)限禁止Home鍵<uses-permissionandroid:name="android.permission.DISABLE_KEYGUARD"></uses-permission>12.android 控制對話框位置
window=dialog.getWindow();// 得到對話框的窗口．WindowManager.LayoutParamswl=window.getAttributes();wl.x=x;//這兩句設(shè)置了對話框的位置．0為中間wl.y=y;wl.width=w;wl.height=h;wl.alpha=0.6f;//這句設(shè)置了對話框的透明度13.android 挪動dialog的位置
Window mWindow=dialog.getWindow();WindowManager.LayoutParamslp=mWindow.getAttributes();lp.x=10;//新位置X坐標(biāo)lp.y=-100;//新位置Y坐標(biāo)dialog.onWindowAttributesChanged(lp);14.android 判斷網(wǎng)絡(luò)狀態(tài)
<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("沒有可用的網(wǎng)絡(luò)").setMessage("是否對網(wǎng)絡(luò)進(jìn)行設(shè)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 設(shè)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);//首選接入點"content://telephony/carriers/preferapn"16.android 調(diào)節(jié)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 重啟
第一,root權(quán)限,這是必須的第二,Runtime.getRuntime().exec("su-creboot");第三,模擬器上運行不出來,必須真機第四,運行時會提示你是否加入列表,同意就好18.android隱藏軟鍵盤
setContentView(R.layout.activity_main);getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_ADJUST_RESIZE|WindowManager.LayoutParams.SOFT_INPUT_STATE_HIDDEN);19.android隱藏以及顯示軟鍵盤以及不自動彈出鍵盤的方法
1、//隱藏軟鍵盤((InputMethodManager)getSystemService(INPUT_METHOD_SERVICE)).hideSoftInputFromWindow(WidgetSearchActivity.this.getCurrentFocus().getWindowToken(),InputMethodManager.HIDE_NOT_ALWAYS);2、//顯示軟鍵盤,控件ID可以是EditText,TextView((InputMethodManager)getSystemService(INPUT_METHOD_SERVICE)).showSoftInput(控件ID,0);22.BitMap、Drawable、inputStream及byte[] 互轉(zhuǎn)（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.發(fā)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.通過URI得到文件路徑
// 通用的從uri中獲取路徑的方法 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()); }新聞熱點
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