详解Android中App的启动界面Splash的编写方法

  <TextView  android:id="@+id/tv_splash_version"  android:layout_width="wrap_content"  android:layout_height="wrap_content"  android:textColor="#000000"  android:textStyle="bold"  android:shadowDx="1"//阴影的偏移量  android:shadowDy="1"  android:shadowRadius="0.2"//阴影的半径  android:shadowColor="#ffff00"  android:text="版本：1.0"  android:textSize="16sp"  android:layout_centerInParent="true"/>

public String getAppVersion(){  PackageManager pm = getPackageManager();  try {    PackageInfo info = pm.getPackageInfo(getPackageName(), 0);    return info.versionName;  } catch (NameNotFoundException e) {    e.printStackTrace();    //不可能发生；    return "";  }}

protected void showUpdateDialog() { AlertDialog.Builder build = new Builder(this); build.setTitle("发现新版本"); build.setMessage(description); build.setNegativeButton("立刻升级", new OnClickListener() {   @Override   public void onClick(DialogInterface dialog, int which) {     //升级的代码；   }; }); build.setPositiveButton("下次再说", new OnClickListener() {   @Override   public void onClick(DialogInterface dialog, int which) {     dialog.dismiss(); enterHome();   } }); build.show();

private void checkup() { new Thread() {   public void run() {     Message msg = Message.obtain();     long startTime = System.currentTimeMillis();//启动该线程的系统时间     try {       //请求网络的代码       URL url = new URL(getString(R.string.serverurl));       HttpURLConnection conn = (HttpURLConnection) url           .openConnection();       conn.setRequestMethod("GET");//请求方法       conn.setConnectTimeout(4000);//超时时间       int code = conn.getResponseCode();//返回码200请求成功       if (code == 200) {         InputStream is = conn.getInputStream();         String result = StreamTools.readFromStream(is);         Log.i(TAG, "联网成功" + result);         JSONObject obj = new JSONObject(result);//解析json字符串         String version = (String) obj.get("version");//版本信息         description = (String) obj.get("description");//描述信息         apkurl = (String) obj.get("apkurl");         if (getAppVersion().equals(version)) {           msg.what = ENTER_HOME;         } else {           msg.what = SHOW_UPDATE_DIALOG;         }       }     } catch (MalformedURLException e) {       e.printStackTrace();       msg.what = URL_ERROR;     } catch (IOException e) {       e.printStackTrace();       msg.what = NETWORK_ERROR;     } catch (JSONException e) {       e.printStackTrace();       msg.what = JSON_ERROR;     } finally {       handler.sendMessage(msg);       long endTime = System.currentTimeMillis();//该线程执行完毕的时间       long dTime = endTime-startTime;//该线程的阻塞时间       if (dTime<3000) {         try {           Thread.sleep(3000-dTime);//若该线程的阻塞时间小于三秒继续睡眠到三秒         } catch (InterruptedException e) {                         e.printStackTrace();         }       }     }   } }.start(); }handler private Handler handler = new Handler() { @Override public void handleMessage(Message msg) {   // TODO Auto-generated method stub   super.handleMessage(msg);   switch (msg.what) {   case SHOW_UPDATE_DIALOG:     showUpdateDialog();     break;   case ENTER_HOME:     Toast.makeText(getApplicationContext(), "", 0).show();     enterhome();     break;   case URL_ERROR:     Toast.makeText(getApplicationContext(), "URL_ERROR", 0).show();     enterhome();     break;   case NETWORK_ERROR:     Toast.makeText(getApplicationContext(), "NETWORK_ERROR", 0).show();     enterhome();     break;   case JSON_ERROR:     Toast.makeText(getApplicationContext(), "JSON_ERROR", 0).show();     enterhome();     break;   } }};

  if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {      FinalHttp finalHttp = new FinalHttp();        finalHttp.download(apkurl,Environment.getExternalStorageDirectory().getAbsolutePath()+         "/mobilesafe2.0.apk" , new AjaxCallBack<File>() {          @Override          public void onLoading(long count, long current) {            super.onLoading(count, current);            tv_uapdate_info.setVisibility(View.VISIBLE);            int progress =(int) (current*100/count);                tv_uapdate_info.setText("下载进度："+progress+"%");          }          @Override          public void onFailure(Throwable t, int errorNo,              String strMsg) {            t.printStackTrace();            Toast.makeText(getApplicationContext(), "下载失败", 0).show();            enterhome();            super.onFailure(t, errorNo, strMsg);          }          @Override          public void onSuccess(File t) {            super.onSuccess(t);            installAPK(t);          }          private void installAPK(File t) {            Intent intent = new Intent();//自动安装程序可调用该段代码            intent.setAction("android.intent.action.VIEW");            intent.addCategory("android.intent.category.DEFAULT");            intent.setDataAndType(Uri.fromFile(t), "application/vnd.android.package-archive");            startActivity(intent);                      }        });      }else{        Toast.makeText(getApplicationContext(), "请插入内存卡再试",0).show();        return;      }

public class WelcomeActivity extends Activity  {   //定义一个handler,用来接收延迟发送的信息-启动activity   private Handler handler = new Handler()   {     @Override     <span style="color: #ff0000;">public void handleMessage(Message msg) </span>     {       // TODO Auto-generated method stub       super.handleMessage(msg);       switch(msg.what)       {       case 0x123:         Intent intent = new Intent(WelcomeActivity.this,              OnlineExamActivity.class);         startActivity(intent);         finish();       }     }   }; 

@Override   protected void onCreate(Bundle savedInstanceState)   {     // TODO Auto-generated method stub     super.onCreate(savedInstanceState);     setContentView(R.layout.welcome_activity);     start();   }    private void start()    {     <span style="color: #ff0000;">handler.sendEmptyMessageDelayed(0x123, 3000);</span>   }