Android編程: 4月 2013

2013年4月22日星期一

通過讀取 android.os.Build.VERSION.SDK_INT 獲得操作系統版本

package com.example.androidbuildversion;


import java.util.Arrays;
import java.util.List;

import android.os.Bundle;
import android.app.Activity;
import android.widget.TextView;

public class MainActivity extends Activity {
 
 final static Integer[] VersionCode = {
  android.os.Build.VERSION_CODES.BASE,
  android.os.Build.VERSION_CODES.BASE_1_1,
  android.os.Build.VERSION_CODES.CUPCAKE,
  android.os.Build.VERSION_CODES.CUR_DEVELOPMENT,
  android.os.Build.VERSION_CODES.DONUT,
  android.os.Build.VERSION_CODES.ECLAIR,
  android.os.Build.VERSION_CODES.ECLAIR_0_1,
  android.os.Build.VERSION_CODES.ECLAIR_MR1,
  android.os.Build.VERSION_CODES.FROYO,
  android.os.Build.VERSION_CODES.GINGERBREAD,
  android.os.Build.VERSION_CODES.GINGERBREAD_MR1,
  android.os.Build.VERSION_CODES.HONEYCOMB,
  android.os.Build.VERSION_CODES.HONEYCOMB_MR1,
  android.os.Build.VERSION_CODES.HONEYCOMB_MR2,
  android.os.Build.VERSION_CODES.ICE_CREAM_SANDWICH,
  android.os.Build.VERSION_CODES.ICE_CREAM_SANDWICH_MR1,
  android.os.Build.VERSION_CODES.JELLY_BEAN,
  android.os.Build.VERSION_CODES.JELLY_BEAN_MR1 
 };
 
 final static String[] Version = {
  "BASE - October 2008: The original, first, version of Android",
  "BASE_1_1 - February 2009: First Android update, officially called 1.1",
  "CUPCAKE - May 2009: Android 1.5",
  "CUR_DEVELOPMENT - Magic version number for a current development build",
  "DONUT - September 2009: Android 1.6",
  "ECLAIR - November 2009: Android 2.0",
  "ECLAIR_0_1 - December 2009: Android 2.0.1",
  "ECLAIR_MR1 - January 2010: Android 2.1",
  "FROYO - June 2010: Android 2.2",
  "GINGERBREAD - November 2010: Android 2.3",
  "GINGERBREAD_MR1 - February 2011: Android 2.3.3",
  "HONEYCOMB - February 2011: Android 3.0",
  "HONEYCOMB_MR1 - May 2011: Android 3.1",
  "HONEYCOMB_MR2 - June 2011: Android 3.2",
  "ICE_CREAM_SANDWICH - October 2011: Android 4.0",
  "ICE_CREAM_SANDWICH_MR1 - December 2011: Android 4.0.3",
  "JELLY_BEAN - June 2012: Android 4.1",
  "JELLY_BEAN_MR1 - Android 4.2: Moar jelly beans!" 
 };

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  //setContentView(R.layout.activity_main);
  TextView textVersion = new TextView(this);
  setContentView(textVersion);
  
  int SDKversion = android.os.Build.VERSION.SDK_INT;
  int matched = Arrays.asList(VersionCode).indexOf((int)SDKversion);
  if(matched == -1){
   textVersion.setText(String.valueOf(SDKversion) 
     + " : " + "unknown!");
  }else{
   textVersion.setText(String.valueOf(SDKversion) 
     + " : " + Version[matched]);
  }
 }

}

2013年4月20日星期六

2013年4月12日星期五

runOnUiThread(), 在用戶界面線程上運行

在 Android 上, 應用程序不能在後台線程更新用戶界面. 如果你需要在後台線程更新用戶界面, 一個非常簡單的方法是呼叫 runOnUiThread(Runnable action) 方法. action Runnable 會在稍後的UI線程上運行.

 runOnUiThread(new Runnable(){

  @Override
  public void run() {
         //do something on UI here
  }

 });

2013年4月11日星期四

如何檢查目前是否運行在UI線程

可以使用下面的程序碼檢查目前是否運行在UI線程:

if(Looper.getMainLooper().getThread() == Thread.currentThread()){
 //目前運行在UI線程
}else{
 目前運行不是在UI線程
}

Android編程