android實現程式的後台運行

標籤：android   後台   onkeydown   

</pre><pre name="code" class="java">/** * 改寫返回鍵事件監聽，使得back鍵功能類似home鍵，讓Acitivty退至後台時不被系統銷毀 */@Overridepublic 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;} elsereturn 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();}}

android實現程式的後台運行