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：

 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" />

每个月的第几号执行提醒功能：

 Calendar cal = 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);
     Date now = new Date(System.currentTimeMillis());
     if (cal.getTime().before(now)) {
         cal.add(Calendar.MONTH, 1);
     }
     long firstTime = cal.getTime().getTime();
      alarmManager.setRepeating(AlarmManager.RTC_WAKEUP, firstTime, 1000 * 60
             * 60 * 24 * 30, pendingIntent);

上传应用到服务器：

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

 private void uploadFile()
   {
     String end = "/r/n";
     String Hyphens = "--";
     String boundary = "*****";
     try
     {
       URL url = new URL(actionUrl);
       HttpURLConnection con = (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);

       DataOutputStream ds = new DataOutputStream(con.getOutputStream());
       ds.writeBytes(Hyphens + boundary + end);
       ds.writeBytes("Content-Disposition: form-data; "
           + "name=/"file1/";filename=/"" + newName + "/"" + end);
       ds.writeBytes(end);

       FileInputStream fStream = new FileInputStream(uploadFile);

       int bufferSize = 1024;
       byte[] buffer = new byte[bufferSize];
       int length = -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();

       InputStream is = con.getInputStream();
       int ch;
       StringBuffer b = new StringBuffer();
       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 (Exception e)
     {
       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

 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

<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

 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 void t(){
   String before = "2013-5-15";
   String now = "2013-5-17";
   SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
   try {
    Date d1 = sdf.parse(before);
    Date d2 = sdf.parse(now);
    long daysBetween = (d2.getTime() - d1.getTime() + 1000000)
      / (3600 * 24 * 1000);
    System.out.println("相隔："+daysBetween+"天");
   } catch (Exception e) {
    System.out.println(e.getMessage());
   }
  }