Android第一次app總結
阿新 • • 發佈:2018-12-14
- 點選按鈕彈出提示對話方塊:
在按鈕監聽器中的過載onClick方法裡面直接
new AlertDialog.Builder(QuizActivity.this) .setMessage("You Got A Score Of : "+s) .setPositiveButton(R.string.sure, new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { ; } }).show();
注意:這裡不能用
AlertDialog.Builder builder=new AlertDialog.Builder(this,1);
會報錯說不能在監聽器中 這樣用,我也不知道為啥( ⊙o⊙?)
- 儲存狀態saveInstanceState.xxx.(KEY,OBJECT),KEY是關鍵字,OBJECT是儲存的物件,KEY是用於恢復OBJECT的,如 :
private short answers[]=new short[LENGTH]; private static final String KEY_ANSWER="answer"; saveInstanceState.putShortArray(KEY_ANSWER,answers); //儲存answers陣列 if(savedInstanceState!=null) { answers=savedInstanceState.getShortArray(KEY_ANSWER); } //恢復answers陣列,用於onCreate中或者onRestoreInstanceState()
- 保留小數
double d = 123.456
NumberFormat nf = NumberFormat.getNumberInstance();
// 保留1位小數
nf.setMaximumFractionDigits(1);
// 四捨五入RoundingMode.UP
nf.setRoundingMode(RoundingMode.UP);
System.out.println(nf.format(d));
- 設定app圖示
Android→app →manifests→AndroidManifest.xml中修改Application中的icon為 自己的圖片資源即可