android 学习笔记有用代码片段(2)
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.*{ *;}
Java 中.class文件保护
http://blog.sina.com.cn/s/blog_6dc41baf01010khy.html
判断指定的服务是否运行：
public static boolean isServiceRunning(Context ctx, String serviceName, String processName) {
ActivityManager manager = (ActivityManager) ctx.getSystemService(Context.ACTIVITY_SERVICE);
for (RunningServiceInfo service : manager.getRunningServices(Integer.MAX_VALUE)) {
if (serviceName.equals(service.service.getClassName()) && processName.equals(service.process))
return true;
}
return false;
}
判断指定进程是否正在运行：
public static boolean isProcessRunning(Context ctx, String name) {
ActivityManager am = (ActivityManager) ctx.getSystemService(Context.ACTIVITY_SERVICE);
List<RunningAppProcessInfo> apps = am.getRunningAppProcesses();
for (RunningAppProcessInfo app : apps) {
if (app.processName.equals(name)) {
return true;
}
}
return false;
}
汉字转拼音：
百度搜素pinyin4j.jar 获取官网下载。添加至lib中
/**
* 汉字转换为拼音
* @author Administrator
*
*/
public class HanZiToPinYinUtil {
public static String toPinYin(String str) {
String py = "";
String[] t = new String[str.length()];
char [] hanzi=new char[str.length()];
for(int i=0;i<str.length();i++){
hanzi[i]=str.charAt(i);
}
net.sourceforge.pinyin4j.format.HanyuPinyinOutputFormat t1 = new HanyuPinyinOutputFormat();
t1.setCaseType(HanyuPinyinCaseType.LOWERCASE);
t1.setToneType(HanyuPinyinToneType.WITHOUT_TONE);
t1.setVCharType(HanyuPinyinVCharType.WITH_V);
try {
for (int i = 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 (BadHanyuPinyinOutputFormatCombination e) {
e.printStackTrace();
}
return py.trim().toString();
}
public static void main(String args[]){
System.out.println(HanZiToPinYinUtil.toPinYin("我屮艸芔茻"));
}
开启飞行模式：
boolean isEnabled = 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);
// Post an intent to reload
Intent intent = new Intent(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);
// Post an intent to reload
Intent intent = new Intent(Intent.ACTION_AIRPLANE_MODE_CHANGED);
intent.putExtra("state", !isEnabled);
paramContext.sendBroadcast(intent);
}
<uses-permission android:name="android.permission.WRITE_SETTINGS"/>
<uses-permission android: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）
<receiver android:name="com.pioneersoft.aoc.ui.BootBroadcastReceiver" android:enabled="true" android:exported="true">
<intent-filter >
<action android:name="android.intent.action.BOOT_COMPLETED" />
<category android:name="android.intent.category.HOME" />
</intent-filter>
</receiver>
public class BootBroadcastReceiver extends BroadcastReceiver {
// static final String action_boot="android.intent.action.BOOT_COMPLETED";
@Override
public void onReceive(Context context, Intent intent) {
// if (intent.getAction().equals(action_boot)){
Intent bootStartIntent=new Intent(context,MainActivity.class);
bootStartIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
context.startActivity(bootStartIntent);
// }
}
}
获取未安装apk信息：
/** 获取未安装的APK信息
* @param context
* @param archiveFilePath APK文件的路径。如：/sdcard /download/XX.apk
*/
public void getUninatllApkInfo(Context context, String archiveFilePath){
PackageManager pm = context.getPackageManager();
PackageInfo info = pm.getPackageArchiveInfo(archiveFilePath, PackageManager.GET_ACTIVITIES);
if(info != null){
ApplicationInfo appInfo = info.applicationInfo;
String appName = pm.getApplicationLabel(appInfo).toString();
String packageName = appInfo.packageName;
Drawable icon = pm.getApplicationIcon(appInfo);
}
}
监听apk安装，卸载，替换行为：
private void registerIntentReceivers() {
IntentFilter filter = new IntentFilter(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);
}
/**
* Receives notifications when applications are added/removed.
*/
private class ApplicationsIntentReceiver extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {
// PackageManager manager = context.getPackageManager();
if (intent.getAction().equals(Intent.ACTION_PACKAGE_ADDED)) {
String packageName = intent.getData().getSchemeSpecificPart();
Toast.makeText(context, "安装成功"+packageName, Toast.LENGTH_LONG).show();
}
if (intent.getAction().equals(Intent.ACTION_PACKAGE_REMOVED)) {
String packageName = intent.getData().getSchemeSpecificPart();
Toast.makeText(context, "卸载成功"+packageName, Toast.LENGTH_LONG).show();
}
if (intent.getAction().equals(Intent.ACTION_PACKAGE_REPLACED)) {
String packageName = 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：
public static void main(String[] args) {
byte[] bt=new byte[1024];
String msg="helo! you are very nice! have a good time! happy every day!";
byte[] t=msg.getBytes();
for(int i=0;i<t.length;i++){
bt[i]=t[i];
}
String message=new String(bt).trim();
System.out.println(" msg= "+message+" len= "+message.length());
}
获取现在正调用的方法名
String methodName = Thread.currentThread().getStackTrace()[1].getMethodName(); String methodName = Thread.currentThread().getStackTrace()[1].getMethodName();
/**
* 安装app
*/
public static void openAPK(File f, Context context) {
context.startActivity(getInstallApp(f, context));
}
public static Intent getInstallApp(File f, Context context) {
Intent intent = new Intent();
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");
return intent;
}
/**
* 卸载APP
* @param context
* @param packageName
*/
public static void uninstallApp(Context context,String packageName) {
Uri packageURI = Uri.parse("package:" + packageName);
Intent uninstallIntent = new Intent(Intent.ACTION_DELETE, packageURI);
uninstallIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
context.startActivity(uninstallIntent);
}
Android屏幕解锁和锁定
//屏幕解锁
KeyguardManager keyguardManager = (KeyguardManager)getSystemService(KEYGUARD_SERVICE);
KeyguardLock keyguardLock = 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
PowerManager pm = (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
*
* @param cx
* @param titleName
* 快捷方式名称
* @return
*/
public static boolean hasShortcut(Context cx) {
boolean result = false;
// 获取当前应用名称
String title = null;
try {
final PackageManager pm = cx.getPackageManager();
title = pm.getApplicationLabel(
pm.getApplicationInfo(cx.getPackageName(),
PackageManager.GET_META_DATA)).toString();
} catch (Exception e) {
}
final String uriStr;
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";
}
final Uri CONTENT_URI = Uri.parse(uriStr);
final Cursor c = cx.getContentResolver().query(CONTENT_URI, null,
"title=?", new String[] { title }, null);
if (c != null && c.getCount() > 0) {
result = true;
}
return result;
}
/** *
* 为当前应用添加桌面快捷方式
*
* @param cx
* @param appName
* 快捷方式名称
*/
public static void addShortcut(Context cx) {
Intent shortcut = new Intent("com.android.launcher.action.INSTALL_SHORTCUT");
Intent shortcutIntent = cx.getPackageManager()
.getLaunchIntentForPackage(cx.getPackageName());
shortcut.putExtra(Intent.EXTRA_SHORTCUT_INTENT, shortcutIntent);
// 获取当前应用名称
String title = null;
try {
final PackageManager pm = cx.getPackageManager();
title = pm.getApplicationLabel(
pm.getApplicationInfo(cx.getPackageName(),
PackageManager.GET_META_DATA)).toString();
} catch (Exception e) {
}
// 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
Parcelable iconResource = 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
*
* @param cx
*/
public static void delShortcut(Context cx) {
Intent shortcut = new Intent(
"com.android.launcher.action.UNINSTALL_SHORTCUT");
// 获取当前应用名称
String title = null;
try {
final PackageManager pm = cx.getPackageManager();
title = pm.getApplicationLabel(
pm.getApplicationInfo(cx.getPackageName(),
PackageManager.GET_META_DATA)).toString();
} catch (Exception e) {
}
// 快捷方式名称
shortcut.putExtra(Intent.EXTRA_SHORTCUT_NAME, title);
Intent shortcutIntent = cx.getPackageManager()
.getLaunchIntentForPackage(cx.getPackageName());
shortcut.putExtra(Intent.EXTRA_SHORTCUT_INTENT, shortcutIntent);
cx.sendBroadcast(shortcut);
}
相关权限配置
<uses-permission android:name="com.android.launcher.permission.INSTALL_SHORTCUT" />
<uses-permission android:name="com.android.launcher.permission.UNINSTALL_SHORTCUT" />
<uses-permission android:name="com.android.launcher.permission.READ_SETTINGS" />
/**
* 添加快捷方式到桌面 要点：
* 1.给Intent指定action="com.android.launcher.INSTALL_SHORTCUT"
* 2.给定义为Intent.EXTRA_SHORTCUT_INENT的Intent设置与安装时一致的action(必须要有)
* 3.添加权限:com.android.launcher.permission.INSTALL_SHORTCUT
*/
private void addShortcutToDesktop() {
Intent shortcut = new Intent("com.android.launcher.action.INSTALL_SHORTCUT");
// 不允许重建
shortcut.putExtra("duplicate", false);
// 设置名字
shortcut.putExtra(Intent.EXTRA_SHORTCUT_NAME,this.getString(R.string.app_name));
// 设置图标
shortcut.putExtra(Intent.EXTRA_SHORTCUT_ICON_RESOURCE,Intent.ShortcutIconResource.fromContext(this,
R.drawable.ic_launcher));
// 设置意图和快捷方式关联程序
shortcut.putExtra(Intent.EXTRA_SHORTCUT_INTENT,new Intent(this, this.getClass()).setAction(Intent.ACTION_MAIN));
// 发送广播
sendBroadcast(shortcut);
}
方法二：
首先在xml中设置IntentFilter
<intent-filter>
<action android:name="android.intent.action.CREATE_SHORTCUT" />
</intent-filter>
if (Intent.ACTION_CREATE_SHORTCUT.equals(action)) {
Intent shortcut = new Intent(Intent.ACTION_CREATE_SHORTCUT);
// 不允许重建
shortcut.putExtra("duplicate", false);
// 设置名字
shortcut.putExtra(Intent.EXTRA_SHORTCUT_NAME,
this.getString(R.string.app_name));
// 设置图标
shortcut.putExtra(Intent.EXTRA_SHORTCUT_ICON_RESOURCE,
Intent.ShortcutIconResource.fromContext(this,
R.drawable.ic_launcher));
// 设置意图和快捷方式关联的程序
shortcut.putExtra(Intent.EXTRA_SHORTCUT_INTENT,
new Intent(this, this.getClass()));
//将结果返回到launcher
setResult(RESULT_OK, intent);
}
在launcher中我们运行程序就可以将快捷方式创建在桌面上。
由于快捷方式launcher管理的，我们可以通过查看launcher中是否已经有此快捷方式数据，如果有就不在创建
添加权限：<uses-permission android:name="com.android.launcher.permission.READ_SETTINGS"/>
private boolean hasInstallShortcut() {
boolean hasInstall = false;
final String AUTHORITY = "com.android.launcher.settings";
Uri CONTENT_URI = Uri.parse("content://" + AUTHORITY
+ "/favorites?notify=true");
Cursor cursor = this.getContentResolver().query(CONTENT_URI,
new String[] { "title", "iconResource" }, "title=?",
new String[] { this.getString(R.string.app_name) }, null);
if (cursor != null && cursor.getCount() > 0) {
hasInstall = true;
}
return hasInstall;
}
上传文件到服务器：
HttpURLConnection connection = null;
DataOutputStream outputStream = null;
DataInputStream inputStream = null;
String pathToOurFile = "/data/file_to_send.mp3";
String urlServer = "http://192.168.1.1/handle_upload.php";
String lineEnd = "\r\n";
String twoHyphens = "--";
String boundary = "*****";
int bytesRead, bytesAvailable, bufferSize;
byte[] buffer;
int maxBufferSize = 1*1024*1024;
try
{
FileInputStream fileInputStream = new FileInputStream(new File(pathToOurFile) );
URL url = new URL(urlServer);
connection = (HttpURLConnection) url.openConnection();
// Allow Inputs & Outputs.
connection.setDoInput(true);
connection.setDoOutput(true);
connection.setUseCaches(false);
// Set HTTP method to POST.
connection.setRequestMethod("POST");
connection.setRequestProperty("Connection", "Keep-Alive");
connection.setRequestProperty("Content-Type", "multipart/form-data;boundary="+boundary);
outputStream = new DataOutputStream( connection.getOutputStream() );
outputStream.writeBytes(twoHyphens + boundary + lineEnd);
outputStream.writeBytes("Content-Disposition: form-data; name=\"uploadedfile\";filename=\"" + pathToOurFile +"\"" + lineEnd);
outputStream.writeBytes(lineEnd);
bytesAvailable = fileInputStream.available();
bufferSize = Math.min(bytesAvailable, maxBufferSize);
buffer = new byte[bufferSize];
// Read file
bytesRead = fileInputStream.read(buffer, 0, bufferSize);
while (bytesRead > 0)
{
outputStream.write(buffer, 0, bufferSize);
bytesAvailable = fileInputStream.available();
bufferSize = Math.min(bytesAvailable, maxBufferSize);
bytesRead = fileInputStream.read(buffer, 0, bufferSize);
}
outputStream.writeBytes(lineEnd);
outputStream.writeBytes(twoHyphens + boundary + twoHyphens + lineEnd);
// Responses from the server (code and message)
serverResponseCode = connection.getResponseCode();
serverResponseMessage = connection.getResponseMessage();
fileInputStream.close();
outputStream.flush();
outputStream.close();
}
catch (Exception ex)
{
//Exception handling
}
需要授权用户：
tring usernamePassword = yourUsername + “:” + yourPassword; String encodedUsernamePassword = Base64.encodeToString(usernamePassword.getBytes(), Base64.DEFAULT); connection.setRequestProperty (“Authorization”, “Basic ” + encodedUsernamePassword);
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
public class MyListView extends ListView{
public MyListView(Context context, AttributeSet attrs) {
super(context, attrs);
}
public MyListView(Context context) {
super(context);
}
public MyListView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
}
@Override
public void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
int expandSpec = MeasureSpec.makeMeasureSpec(
Integer.MAX_VALUE >> 2, MeasureSpec.AT_MOST);
super.onMeasure(widthMeasureSpec, expandSpec);
}
}
设置texview 垂直滚动条
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
public class MyTextView extends TextView {
public MyTextView(Context context) {
super(context);
}
public MyTextView(Context context, AttributeSet attrs) {
super(context, attrs);
}
public MyTextView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
}
@Override
public boolean isFocused() {
return true;
}
}
setContentView(R.layout.scrollview1);
MyTextView tv=(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。
public void insertAll(String databaseName,
ArrayList<ContentValues> valuesArr) {
SQLiteDatabase db = getWritableDatabase();
db.beginTransaction();
for (ContentValues val : valuesArr) {
db.insert(databaseName, null, val);
}
db.setTransactionSuccessful();
db.endTransaction();
db.close();
}
计算日期之间相隔几天：
public long compareDataToNow(String date){
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
Date passDate,nowDate;
long diff=-100l,days=-100l;
try {
passDate = sdf.parse(date);
String nowStr=sdf.format(new Date());
nowDate=sdf.parse(nowStr);
diff = passDate.getTime() - nowDate.getTime();
days = diff / (1000 * 60 * 60 * 24);
System.out.println( "相隔："+days+"天");
} catch (ParseException e) {
e.printStackTrace();
}
return diff;
}