android实现程序的后台运行

改写返回键事件监听，使得back键功能类似home键，让Acitivty退至后台时不被系统销毁，代码如下： public boolean onKeyDown(int keyCode, KeyEvent event) { PackageManager pm = getPackageManager(); ResolveInfo homeInfo = pm.resolveActivity(new Intent(Intent.ACTION_MAIN).addCategory(Intent.CATEGORY_HOME), 0); 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); } private void startActivitySafely(Intent intent) { intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK); try { startActivity(intent); } catch (ActivityNotFoundException e) { Toast.makeText(this, "null", Toast.LENGTH_SHORT).show(); } catch (SecurityException e) { Toast.makeText(this, "null", Toast.LENGTH_SHORT).show(); } } 文章转载自互联网，感谢原作者的无私分享。