當手機應用程序安裝后初始化時，為了提高用戶體驗，通常會以倒計時的形式給用戶一定的提示，本文是武林技術頻道小編介紹的Android自定義Chronometer實現短信驗證碼秒表倒計時功能，一起來看看吧！
一、自定義ChronometerView 繼續自TextView
主要原理：先設置一個基準倒計時時間mBaseSeconds，內置handler 每隔1s發送一個空消息，mRemainSeconds--，同時刷新界面視圖，回調給外部調用者，只到為零。外部調用者可通過start()/pause()/stop()來控制計時器的工作狀態。
可以app中發送短信驗證碼的場景為例，做了一個很粗糙的界面，但功能都實現了。
/** * @name 倒計時器（類似妙表倒數計時，支持暫停、停止、重新開始） * @author Fanjb * @date 2015年11月6日 */ public class ChronometerView extends TextView { /** * A callback that notifies when the chronometer has decremented on its own. * * @author Fanjb */ public interface OnTickChangeListener { /** * remain seconds changed * * @param view * @param remainSeconds */ public void onTickChanged(ChronometerView view, long remainSeconds); } private long mBase; private long mRemainSeconds; private boolean mStarted; private boolean mReStart; private boolean mVisible; private boolean mIsEnable; private OnTickChangeListener mTickListener; public ChronometerView(Context context) { this(context, null); } public ChronometerView(Context context, AttributeSet attrs) { super(context, attrs, 0); } public ChronometerView(Context context, AttributeSet attrs, int defStyleAttr) { super(context, attrs, defStyleAttr); updateText(mRemainSeconds); } @Override protected void onWindowVisibilityChanged(int visibility) { super.onWindowVisibilityChanged(visibility); mVisible = visibility == VISIBLE; updateStatus(); } @Override protected void onDetachedFromWindow() { super.onDetachedFromWindow(); mVisible = false; updateStatus(); } /** * 啟動計時器 */ public void start() { if (mReStart && !mStarted) { mRemainSeconds = mBase; } mStarted = true; updateStatus(); } /** * 暫停計時器 */ public void pause() { if (mStarted) { mStarted = mReStart = false; updateStatus(); } } /** * 停止計時器，再次調用 start()重新啟動 */ public void stop() { mStarted = false; mReStart = true; updateStatus(); updateText(mRemainSeconds = 0); dispatchTickListener(); } /** * 刷新內部狀態 */ private void updateStatus() { boolean isEnable = mVisible && mStarted; if (mIsEnable != isEnable) { if (isEnable) { mHandler.sendMessage(Message.obtain(mHandler, TICK_WHAT)); } else { mHandler.removeMessages(TICK_WHAT); } mIsEnable = isEnable; } } private static final int TICK_WHAT = 1; private Handler mHandler = new Handler() { public void handleMessage(android.os.Message msg) { if (mRemainSeconds > 0) { updateText(--mRemainSeconds); dispatchTickListener(); sendMessageDelayed(Message.obtain(this, TICK_WHAT), 1000); } } }; private void updateText(long now) { String text = DateUtils.formatElapsedTime(now); setText(text); } /** * 在未啟動狀態下設置開始倒計時時間 * * @param baseSeconds */ public void setBaseSeconds(long baseSeconds) { if (baseSeconds > 0 && baseSeconds != mBase && !mStarted) { mBase = mRemainSeconds = baseSeconds; updateText(mRemainSeconds); } } /** * 剩余時間 * * @return */ public long getRemainSeconds() { return mRemainSeconds; } public void setOnTickChangeListener(OnTickChangeListener listener) { mTickListener = listener; } public OnTickChangeListener getTickListener() { return mTickListener; } private void dispatchTickListener() { if (mTickListener != null) { mTickListener.onTickChanged(this, getRemainSeconds()); } } @Override public void onInitializeAccessibilityEvent(AccessibilityEvent event) { super.onInitializeAccessibilityEvent(event); event.setClassName(ChronometerView.class.getName()); } @Override public void onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo info) { super.onInitializeAccessibilityNodeInfo(info); info.setClassName(Chronometer.class.getName()); } }?二、xml 中沒有加入自定義的控件屬性，同TextView
<LinearLayout android:layout_width="wrap_content" android:layout_height="wrap_content" android:orientation="horizontal" > <com.freedoman.widgets.calendar.ChronometerView android:id="@+id/chronometer_view" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginLeft="5dp" android:background="@drawable/chronometer_view_bg" android:enabled="true" android:text="00:00" /> <Button android:id="@+id/start_chronometer_view_btn" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginLeft="5dp" android:text="Start" /> <Button android:id="@+id/pause_chronometer_view_btn" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginLeft="5dp" android:text="Pause" /> <Button android:id="@+id/stop_chronometer_view_btn" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginLeft="5dp" android:text="Stop" /> </LinearLayout>
三、在Activity中做一個簡單的測試（可以發送短信驗證碼的實際應用場景為例）
public class ChronometerActivity extends Activity { private ChronometerView mChronometerView; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_clock); // 自定義計時器 if (mChronometerView == null) { mChronometerView = (ChronometerView) findViewById(R.id.chronometer_view); mChronometerView.setBaseSeconds(60); mChronometerView.setOnTickChangeListener(new OnTickChangeListener() { @Override public void onTickChanged(ChronometerView view, long curTimeMills) { System.out.println(curTimeMills); view.setEnabled(curTimeMills == 0 || curTimeMills == 60); if (curTimeMills == 0) { mChronometerView.setText("重新發送"); } } }); mChronometerView.setText("點擊發送驗證碼"); } findViewById(R.id.start_chronometer_view_btn).setOnClickListener(mClickListener); findViewById(R.id.pause_chronometer_view_btn).setOnClickListener(mClickListener); findViewById(R.id.stop_chronometer_view_btn).setOnClickListener(mClickListener); } private View.OnClickListener mClickListener = new OnClickListener() { @Override public void onClick(View v) { switch (v.getId()) { case R.id.start_chronometer_view_btn: if (mChronometerView != null) { mChronometerView.start(); } break; case R.id.pause_chronometer_view_btn: if (mChronometerView != null) { mChronometerView.pause(); } break; case R.id.stop_chronometer_view_btn: if (mChronometerView != null) { mChronometerView.stop(); } break; } } }; } 上文是武林技術頻道小編介紹的Android自定義Chronometer實現短信驗證碼秒表倒計時功能的全部內容，大家學習到了多少呢？武林技術頻道小編每天都會為大家推薦值得大家學習的知識，繼續關注我們吧！
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