android 学习笔记

原文地址：http://blog.csdn.net/yudajun/article/details/9119747

apk代码混淆保护4.0

# To enable ProGuard to shrink and obfuscate your code, uncomment this (available properties: sdk.dir, user.home):
#proguard.config=${sdk.dir}/tools/proguard/proguard-android.txt:proguard-project.txt
proguard.config=${sdk.dir}/tools/proguard/proguard-android-optimize.txt:proguard-project.txt
# Project target.
target=android-17

如果有报异常，例如这样，
java.io.IOException: Please correct the above warnings first.
at proguard.Initializer.execute(Initializer.java:308)
at proguard.ProGuard.initialize(ProGuard.java:210)
at proguard.ProGuard.execute(ProGuard.java:85)
at proguard.ProGuard.main(ProGuard.java:499)

这是由于第三方jar包的原因哦，

你可以这样，
${sdk.dir}\tools\proguard\proguard-android.txt中加入
-dontwarn com.aa.bb.*

-keep class com.aa.bb.*{ *;}

判断指定的服务是否运行：

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publicstaticbooleanisServiceRunning(Contextctx,StringserviceName,StringprocessName){
ActivityManagermanager=(ActivityManager)ctx.getSystemService(Context.ACTIVITY_SERVICE);
for(RunningServiceInfoservice:manager.getRunningServices(Integer.MAX_VALUE)){
if(serviceName.equals(service.service.getClassName())&&processName.equals(service.process))
returntrue;
}
returnfalse;
}

判断指定进程是否正在运行：

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publicstaticbooleanisProcessRunning(Contextctx,Stringname){
ActivityManageram=(ActivityManager)ctx.getSystemService(Context.ACTIVITY_SERVICE);
List<RunningAppProcessInfo>apps=am.getRunningAppProcesses();
for(RunningAppProcessInfoapp:apps){
if(app.processName.equals(name)){
returntrue;
}
}
returnfalse;
}

汉字转拼音：
百度搜素pinyin4j.jar 获取官网下载。添加至lib中

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/**
*汉字转换为拼音
*@authorAdministrator
*
*/
publicclassHanZiToPinYinUtil{
publicstaticStringtoPinYin(Stringstr){
Stringpy="";
String[]t=newString[str.length()];
char[]hanzi=newchar[str.length()];
for(inti=0;i<str.length();i++){
hanzi[i]=str.charAt(i);
}
net.sourceforge.pinyin4j.format.HanyuPinyinOutputFormatt1=newHanyuPinyinOutputFormat();
t1.setCaseType(HanyuPinyinCaseType.LOWERCASE);
t1.setToneType(HanyuPinyinToneType.WITHOUT_TONE);
t1.setVCharType(HanyuPinyinVCharType.WITH_V);
try{
for(inti=0;i<str.length();i++){
if((str.charAt(i)>='a'&&str.charAt(i)<'z')
||(str.charAt(i)>='A'&&str.charAt(i)<='Z')
||(str.charAt(i)>='0'&&str.charAt(i)<='9')){
py+=str.charAt(i);
}else{
t=PinyinHelper.toHanyuPinyinStringArray(hanzi[i],t1);
py=py+t[0];
}
}
}catch(BadHanyuPinyinOutputFormatCombinatione){
e.printStackTrace();
}
returnpy.trim().toString();
}
publicstaticvoidmain(Stringargs[]){
System.out.println(HanZiToPinYinUtil.toPinYin("我屮艸芔茻"));
}

开启飞行模式：

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booleanisEnabled=Settings.System.getInt(
paramContext.getContentResolver(),
Settings.System.AIRPLANE_MODE_ON,0)==1;
if(isEnabled==true)
{
Settings.System.putInt(
paramContext.getContentResolver(),
Settings.System.AIRPLANE_MODE_ON,isEnabled?0:1);
//Postanintenttoreload
Intentintent=newIntent(Intent.ACTION_AIRPLANE_MODE_CHANGED);
intent.putExtra("state",!isEnabled);
paramContext.sendBroadcast(intent);
}
else
{
Settings.System.putInt(
paramContext.getContentResolver(),
Settings.System.AIRPLANE_MODE_ON,isEnabled?0:1);
//Postanintenttoreload
Intentintent=newIntent(Intent.ACTION_AIRPLANE_MODE_CHANGED);
intent.putExtra("state",!isEnabled);
paramContext.sendBroadcast(intent);
}
<uses-permissionandroid:name="android.permission.WRITE_SETTINGS"/>
<uses-permissionandroid:name="android.permission.WRITE_SECURE_SETTINGS"/>

开机自启动：（注意：app一定要安装到内存中，在sd卡上无法自启动）

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<receiverandroid:name="com.pioneersoft.aoc.ui.BootBroadcastReceiver"android:enabled="true"android:exported="true">
<intent-filter>
<actionandroid:name="android.intent.action.BOOT_COMPLETED"/>
<categoryandroid:name="android.intent.category.HOME"/>
</intent-filter>
</receiver>

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publicclassBootBroadcastReceiverextendsBroadcastReceiver{
//staticfinalStringaction_boot="android.intent.action.BOOT_COMPLETED";
@Override
publicvoidonReceive(Contextcontext,Intentintent){
//if(intent.getAction().equals(action_boot)){
IntentbootStartIntent=newIntent(context,MainActivity.class);
bootStartIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
context.startActivity(bootStartIntent);
//}
}
}

获取未安装apk信息：

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/**获取未安装的APK信息
*@paramcontext
*@paramarchiveFilePathAPK文件的路径。如：/sdcard/download/XX.apk
*/
publicvoidgetUninatllApkInfo(Contextcontext,StringarchiveFilePath){
PackageManagerpm=context.getPackageManager();
PackageInfoinfo=pm.getPackageArchiveInfo(archiveFilePath,PackageManager.GET_ACTIVITIES);
if(info!=null){
ApplicationInfoappInfo=info.applicationInfo;
StringappName=pm.getApplicationLabel(appInfo).toString();
StringpackageName=appInfo.packageName;
Drawableicon=pm.getApplicationIcon(appInfo);
}
}

监听apk安装，卸载，替换行为：

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privatevoidregisterIntentReceivers(){
IntentFilterfilter=newIntentFilter(Intent.ACTION_PACKAGE_ADDED);
filter.addAction(Intent.ACTION_PACKAGE_REMOVED);
filter.addAction(Intent.ACTION_PACKAGE_CHANGED);
filter.addAction(Intent.ACTION_PACKAGE_REPLACED);
filter.addDataScheme("package");
registerReceiver(mApplicationsReceiver,filter);
}
/**
*Receivesnotificationswhenapplicationsareadded/removed.
*/
privateclassApplicationsIntentReceiverextendsBroadcastReceiver{
@Override
publicvoidonReceive(Contextcontext,Intentintent){
//PackageManagermanager=context.getPackageManager();
if(intent.getAction().equals(Intent.ACTION_PACKAGE_ADDED)){
StringpackageName=intent.getData().getSchemeSpecificPart();
Toast.makeText(context,"安装成功"+packageName,Toast.LENGTH_LONG).show();
}
if(intent.getAction().equals(Intent.ACTION_PACKAGE_REMOVED)){
StringpackageName=intent.getData().getSchemeSpecificPart();
Toast.makeText(context,"卸载成功"+packageName,Toast.LENGTH_LONG).show();
}
if(intent.getAction().equals(Intent.ACTION_PACKAGE_REPLACED)){
StringpackageName=intent.getData().getSchemeSpecificPart();
Toast.makeText(context,"替换成功"+packageName,Toast.LENGTH_LONG).show();
}
}
}

loadData()中的html data中不能包含'#', '%', '\', '?'四中特殊字符，出现这种字符就会出现解析错误，显示找不到网页还有部分html代码。需要如何处理呢？我们需要用UrlEncoder编码为%23, %25, %27, %3f 。
可以使用以下两种代码，data为string类型的html代码
1 webView.loadData(URLEncoder.encode(data, "utf-8"), "text/html", "utf-8");
这样一些背景效果什么的都不怎么好看了。不推荐。
2 webView.loadDataWithBaseURL(null,data, "text/html", "utf-8", null);

这样就会完美解析了。

计算网络接收byte[] 字节数组的实际接受内容大小：

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publicstaticvoidmain(String[]args){
byte[]bt=newbyte[1024];
Stringmsg="helo!youareverynice!haveagoodtime!happyeveryday!";
byte[]t=msg.getBytes();
for(inti=0;i<t.length;i++){
bt[i]=t[i];
}
Stringmessage=newString(bt).trim();
System.out.println("msg="+message+"len="+message.length());
}

获取现在正调用的方法名

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StringmethodName=
Thread.currentThread().getStackTrace()[1].getMethodName();
StringmethodName=Thread.currentThread().getStackTrace()[1].getMethodName();

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/**
*安装app
*/
publicstaticvoidopenAPK(Filef,Contextcontext){
context.startActivity(getInstallApp(f,context));
}
publicstaticIntentgetInstallApp(Filef,Contextcontext){
Intentintent=newIntent();
intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
//设置应用的安装来源，例如谷歌市场
intent.putExtra("android.intent.extra.INSTALLER_PACKAGE_NAME",context.getPackageName());
intent.setAction(android.content.Intent.ACTION_VIEW);
/*设置intent的file*/
intent.setDataAndType(Uri.fromFile(f),"application/vnd.android.package-archive");
returnintent;
}
/**
*卸载APP
*@paramcontext
*@parampackageName
*/
publicstaticvoiduninstallApp(Contextcontext,StringpackageName){
UripackageURI=Uri.parse("package:"+packageName);
IntentuninstallIntent=newIntent(Intent.ACTION_DELETE,packageURI);
uninstallIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
context.startActivity(uninstallIntent);
}

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Android屏幕解锁和锁定
//屏幕解锁
KeyguardManagerkeyguardManager=(KeyguardManager)getSystemService(KEYGUARD_SERVICE);
KeyguardLockkeyguardLock=keyguardManager.newKeyguardLock(LOCK_TAG);
keyguardLock.disableKeyguard();
//屏幕锁定
keyguardLock.reenableKeyguard();
Android屏幕常亮/点亮
//保持屏幕常亮
PowerManagerpm=(PowerManager)getSystemService(Context.POWER_SERVICE);
mWakeLock=pm.newWakeLock(PowerManager.FULL_WAKE_LOCK|PowerManager.ACQUIRE_CAUSES_WAKEUP,LOCK_TAG);
mWakeLock.acquire();
//释放屏幕常亮锁
if(null!=mWakeLock){
mWakeLock.release();
}
/**
*判断桌面是否已添加快捷方式
*
*@paramcx
*@paramtitleName
*快捷方式名称
*@return
*/
publicstaticbooleanhasShortcut(Contextcx){
booleanresult=false;
//获取当前应用名称
Stringtitle=null;
try{
finalPackageManagerpm=cx.getPackageManager();
title=pm.getApplicationLabel(
pm.getApplicationInfo(cx.getPackageName(),
PackageManager.GET_META_DATA)).toString();
}catch(Exceptione){
}
finalStringuriStr;
if(android.os.Build.VERSION.SDK_INT<8){
uriStr="content://com.android.launcher.settings/favorites?notify=true";
}else{
uriStr="content://com.android.launcher2.settings/favorites?notify=true";
}
finalUriCONTENT_URI=Uri.parse(uriStr);
finalCursorc=cx.getContentResolver().query(CONTENT_URI,null,
"title=?",newString[]{title},null);
if(c!=null&&c.getCount()>0){
result=true;
}
returnresult;
}
/***
*为当前应用添加桌面快捷方式
*
*@paramcx
*@paramappName
*快捷方式名称
*/
publicstaticvoidaddShortcut(Contextcx){
Intentshortcut=newIntent("com.android.launcher.action.INSTALL_SHORTCUT");
IntentshortcutIntent=cx.getPackageManager()
.getLaunchIntentForPackage(cx.getPackageName());
shortcut.putExtra(Intent.EXTRA_SHORTCUT_INTENT,shortcutIntent);
//获取当前应用名称
Stringtitle=null;
try{
finalPackageManagerpm=cx.getPackageManager();
title=pm.getApplicationLabel(
pm.getApplicationInfo(cx.getPackageName(),
PackageManager.GET_META_DATA)).toString();
}catch(Exceptione){
}
//快捷方式名称
shortcut.putExtra(Intent.EXTRA_SHORTCUT_NAME,title);
//不允许重复创建（不一定有效）
shortcut.putExtra("duplicate",false);
//快捷方式的图标
ParcelableiconResource=Intent.ShortcutIconResource.fromContext(cx,
R.drawable.ic_launcher);
shortcut.putExtra(Intent.EXTRA_SHORTCUT_ICON_RESOURCE,iconResource);
cx.sendBroadcast(shortcut);
}
/***
*删除当前应用的桌面快捷方式
*
*@paramcx
*/
publicstaticvoiddelShortcut(Contextcx){
Intentshortcut=newIntent(
"com.android.launcher.action.UNINSTALL_SHORTCUT");
//获取当前应用名称
Stringtitle=null;
try{
finalPackageManagerpm=cx.getPackageManager();
title=pm.getApplicationLabel(
pm.getApplicationInfo(cx.getPackageName(),
PackageManager.GET_META_DATA)).toString();
}catch(Exceptione){
}
//快捷方式名称
shortcut.putExtra(Intent.EXTRA_SHORTCUT_NAME,title);
IntentshortcutIntent=cx.getPackageManager()
.getLaunchIntentForPackage(cx.getPackageName());
shortcut.putExtra(Intent.EXTRA_SHORTCUT_INTENT,shortcutIntent);
cx.sendBroadcast(shortcut);
}
相关权限配置
<uses-permissionandroid:name="com.android.launcher.permission.INSTALL_SHORTCUT"/>
<uses-permissionandroid:name="com.android.launcher.permission.UNINSTALL_SHORTCUT"/>
<uses-permissionandroid:name="com.android.launcher.permission.READ_SETTINGS"/>

每个月的第几号执行提醒功能：

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Calendarcal=Calendar.getInstance();
cal.set(Calendar.DAY_OF_MONTH,4);
cal.set(Calendar.HOUR_OF_DAY,10);
cal.set(Calendar.MINUTE,0);
cal.set(Calendar.SECOND,0);
Datenow=newDate(System.currentTimeMillis());
if(cal.getTime().before(now)){
cal.add(Calendar.MONTH,1);
}
longfirstTime=cal.getTime().getTime();
alarmManager.setRepeating(AlarmManager.RTC_WAKEUP,firstTime,1000*60
*60*24*30,pendingIntent);

上传应用到服务器：

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privateStringnewName="htys.mp3";
//要上传的本地文件路径
privateStringuploadFile="/data/data/com.xzq/htys.mp3";
//上传到服务器的指定位置
privateStringactionUrl="http://192.168.100.100:8080/upload/upload.jsp";

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privatevoiduploadFile()
{
Stringend="/r/n";
StringHyphens="--";
Stringboundary="*****";
try
{
URLurl=newURL(actionUrl);
HttpURLConnectioncon=(HttpURLConnection)url.openConnection();
con.setDoInput(true);
con.setDoOutput(true);
con.setUseCaches(false);
con.setRequestMethod("POST");
con.setRequestProperty("Connection","Keep-Alive");
con.setRequestProperty("Charset","UTF-8");
con.setRequestProperty("Content-Type",
"multipart/form-data;boundary="+boundary);
DataOutputStreamds=newDataOutputStream(con.getOutputStream());
ds.writeBytes(Hyphens+boundary+end);
ds.writeBytes("Content-Disposition:form-data;"
+"name=/"file1/";filename=/""+newName+"/""+end);
ds.writeBytes(end);
FileInputStreamfStream=newFileInputStream(uploadFile);
intbufferSize=1024;
byte[]buffer=newbyte[bufferSize];
intlength=-1;
while((length=fStream.read(buffer))!=-1)
{
ds.write(buffer,0,length);
}
ds.writeBytes(end);
ds.writeBytes(Hyphens+boundary+Hyphens+end);
fStream.close();
ds.flush();
InputStreamis=con.getInputStream();
intch;
StringBufferb=newStringBuffer();
while((ch=is.read())!=-1)
{
b.append((char)ch);
}
System.out.println("上传成功");
Toast.makeText(MainActivity.this,"上传成功",Toast.LENGTH_LONG)
.show();
ds.close();
}catch(Exceptione)
{
System.out.println("上传失败"+e.getMessage());
Toast.makeText(MainActivity.this,"上传失败"+e.getMessage(),
Toast.LENGTH_LONG).show();
}
}
}

创建两个对话框模式进度样式：

ProgressDialog pdialog = new ProgressDialog(SettingActivity.this，0);

ScrollView 嵌套 ListView GridView问题

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publicclassMyListViewextendsListView{
publicMyListView(Contextcontext,AttributeSetattrs){
super(context,attrs);
}
publicMyListView(Contextcontext){
super(context);
}
publicMyListView(Contextcontext,AttributeSetattrs,intdefStyle){
super(context,attrs,defStyle);
}
@Override
publicvoidonMeasure(intwidthMeasureSpec,intheightMeasureSpec){
intexpandSpec=MeasureSpec.makeMeasureSpec(
Integer.MAX_VALUE>>2,MeasureSpec.AT_MOST);
super.onMeasure(widthMeasureSpec,expandSpec);
}
}

设置texview 垂直滚动条

<TextView      android:focusable="true"      android:focusableInTouchMode="true"      android:ellipsize="marquee"      android:marqueeRepeatLimit="marquee_forever"      android:scrollbars="vertical"              android:singleLine="false" />

设置textview 文字水平自动滚动（跑马灯效果）

<com.example.playpic.MyTextView        android:id="@+id/myTv"        android:layout_width="fill_parent"        android:layout_height="fill_parent"        android:textColor="#000000"        android:focusable="true"        android:focusableInTouchMode="true"        android:scrollHorizontally="true"        android:ellipsize="marquee"        android:marqueeRepeatLimit="marquee_forever"        android:singleLine="true"        />

布局文件需添加属性：android:addStatesFromChildren="true"
修改的textview

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publicclassMyTextViewextendsTextView{
publicMyTextView(Contextcontext){
super(context);
}
publicMyTextView(Contextcontext,AttributeSetattrs){
super(context,attrs);
}
publicMyTextView(Contextcontext,AttributeSetattrs,intdefStyle){
super(context,attrs,defStyle);
}
@Override
protectedvoidonDraw(Canvascanvas){
super.onDraw(canvas);
}
@Override
publicbooleanisFocused(){
returntrue;
}
}
setContentView(R.layout.scrollview1);
MyTextViewtv=(MyTextView)findViewById(R.id.myTv);
tv.setText(str);
tv.setMovementMethod(ScrollingMovementMethod.getInstance());

大数据量提高sqlite数据存储效率：
在开发过程中解析xml中的数据有上万条之多，发现在想sqlite中插入的时候非常耗时，原因是没有使用事务，默认是每插入一次使用
一次事务，这样如果插入1w条数据，就要开启1w次事务，非常耗时，所以我们可以通过手动开启和关闭的方式控制事务。

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publicvoidinsertAll(StringdatabaseName,
ArrayList<ContentValues>valuesArr){
SQLiteDatabasedb=getWritableDatabase();
db.beginTransaction();
for(ContentValuesval:valuesArr){
db.insert(databaseName,null,val);
}
db.setTransactionSuccessful();
db.endTransaction();
db.close();
}

计算日期之间相隔几天：

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publicvoidt(){
Stringbefore="2013-5-15";
Stringnow="2013-5-17";
SimpleDateFormatsdf=newSimpleDateFormat("yyyy-MM-dd");
try{
Dated1=sdf.parse(before);
Dated2=sdf.parse(now);
longdaysBetween=(d2.getTime()-d1.getTime()+1000000)
/(3600*24*1000);
System.out.println("相隔："+daysBetween+"天");
}catch(Exceptione){
System.out.println(e.getMessage());
}
}

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