Android 实现Activity后台运行

第一种方法

 

 Intent intent = new Intent(Intent.ACTION_MAIN);
 intent.addCategory(Intent.CATEGORY_HOME);
 intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
 startActivity(intent);

 

 

第二种方法

 

此方法其实不是主要是屏蔽Keycode_Back，让它不结束（finish()）Activity，直接显示HOME界面。

 

 PackageManager pm = getPackageManager();
                               ResolveInfo homeInfo = pm.resolveActivity(new Intent(Intent.ACTION_MAIN)
 .addCategory(Intent.CATEGORY_HOME), 0);

 

 

 public boolean onKeyDown(int keyCode, KeyEvent event) {
     if (keyCode == KeyEvent.KEYCODE_BACK) {
         ActivityInfo ai = homeInfo.activityInfo;
         Intent startIntent = new Intent(Intent.ACTION_MAIN);
         startIntent.addCategory(Intent.CATEGORY_LAUNCHER);
         startIntent.setComponent(new ComponentName(ai.packageName,
                 ai.name));
         startActivitySafely(startIntent);
         return true;
     } else
         return super.onKeyDown(keyCode, event);
 }

 

 

 void startActivitySafely(Intent intent) {
     intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
     try {
         startActivity(intent);
     } catch (ActivityNotFoundException e) {
         Toast.makeText(this, R.string.unabletoopensoftware,
                 Toast.LENGTH_SHORT).show();
     } catch (SecurityException e) {
         Toast.makeText(this, R.string.unabletoopensoftware,
                 Toast.LENGTH_SHORT).show();
         Log
                 .e(
                         TAG,
                         "Launcher does not have the permission to launch "
                                 + intent
                                 + ". Make sure to create a MAIN intent-filter for the corresponding activity "
                                 + "or use the exported attribute for this activity.",
                         e);
     }
 }