按两次back键返回
Java代码
private long exitTime = 0;???
?
@Override???
public boolean onKeyDown(int keyCode, KeyEvent event) {???
?? if(keyCode == KeyEvent.KEYCODE_BACK && event.getAction() == KeyEvent.ACTION_DOWN){???
?????????????????
?? if((System.currentTimeMillis()-exitTime) > 2000){???
??????? Toast.makeText(getApplicationContext(), "再按一次退出程序", Toast.LENGTH_SHORT).show();??????????????????????????????? exitTime = System.currentTimeMillis();???
??? }???
??? else{???
??????? finish();???
????? System.exit(0);???
?????? }???
?????????????????
?? return true;???
?? }???
? return super.onKeyDown(keyCode, event);???
}????
