本文介紹了Android定時器Timer的停止和重啟實現代碼，分享給大家，具體如下：
7月份做了一個項目，利用自定義控件呈現一幅動畫，當時使用定時器來控制時間，但是當停止開啟時總是出現問題。一直在尋找合理的方法解決這個問題，一直沒有找到，最近終于找到了合理的方法來解決這個問題。
大家如何查詢有關資料，一定知道timer,timertask取消的方式是采用Timer.cancel()和mTimerTask.cancel()，可是大家發現這種發式取消后，再次開始timer時，會報錯
FATAL EXCEPTION: main Process: com.example.zhongzhi.gate_control_scheme, PID: 2472 java.lang.IllegalStateException: Timer already cancelled. at java.util.Timer.sched(Timer.java:397) at java.util.Timer.schedule(Timer.java:248) at com.example.zhongzhi.gate_control_scheme.MainActivity.onClick(MainActivity.java:401) at android.view.View.performClick(View.java:5637) at android.view.View$PerformClick.run(View.java:22429) at android.os.Handler.handleCallback(Handler.java:751) at android.os.Handler.dispatchMessage(Handler.java:95) at android.os.Looper.loop(Looper.java:154) at android.app.ActivityThread.main(ActivityThread.java:6119) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)
這個問題的解決采用cancle(),取消timer后，還需要清空timer。合理的代碼應該是這樣的：
mTimer.cancel();mTimer = null;mTimerTask.cancel();mTimerTask = null;
關鍵的問題解決完了，下面給出我的案例代碼Mainactivity.Java：
public class MainActivity extends AppCompatActivity { private static String TAG = "TimerDemo"; private TextView mTextView = null; private Button mButton_start = null; private Button mButton_pause = null; private Timer mTimer = null; private TimerTask mTimerTask = null; private Handler mHandler = null; private static int count = 0; private boolean isPause = false; private boolean isStop = true; private static int delay = 1000; //1s private static int period = 1000; //1s private static final int UPDATE_TEXTVIEW = 0; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); mTextView = (TextView)findViewById(R.id.mytextview); mButton_start = (Button)findViewById(R.id.mybutton_start); mButton_pause = (Button)findViewById(R.id.mybutton_pause); mButton_start.setOnClickListener(new Button.OnClickListener() { public void onClick(View v) { if (isStop) { Log.i(TAG, "Start"); } else { Log.i(TAG, "Stop"); } isStop = !isStop; if (!isStop) { startTimer(); }else { stopTimer(); } if (isStop) { mButton_start.setText(R.string.start); } else { mButton_start.setText(R.string.stop); } } }); mButton_pause.setOnClickListener(new Button.OnClickListener() { public void onClick(View v) { if (isPause) { Log.i(TAG, "Resume"); } else { Log.i(TAG, "Pause"); } isPause = !isPause; if (isPause) { mButton_pause.setText(R.string.resume); } else { mButton_pause.setText(R.string.pause); } } }); mHandler = new Handler(){ @Override public void handleMessage(Message msg) { switch (msg.what) { case UPDATE_TEXTVIEW: updateTextView(); break; default: break; } } }; } private void updateTextView(){ mTextView.setText(String.valueOf(count)); } private void startTimer(){ if (mTimer == null) { mTimer = new Timer(); } if (mTimerTask == null) { mTimerTask = new TimerTask() { @Override public void run() { Log.i(TAG, "count: "+String.valueOf(count)); sendMessage(UPDATE_TEXTVIEW); do { try { Log.i(TAG, "sleep(1000)..."); Thread.sleep(1000); } catch (InterruptedException e) { } } while (isPause); count ++; } }; } if(mTimer != null && mTimerTask != null ) mTimer.schedule(mTimerTask, delay, period); } private void stopTimer(){ if (mTimer != null) { mTimer.cancel(); mTimer = null; } if (mTimerTask != null) { mTimerTask.cancel(); mTimerTask = null; } count = 0; } public void sendMessage(int id){ if (mHandler != null) { Message message = Message.obtain(mHandler, id); mHandler.sendMessage(message); } }}xml部分代碼：
<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="fill_parent" android:orientation="vertical" > <TextView android:id="@+id/mytextview" android:layout_width="fill_parent" android:layout_height="wrap_content" android:gravity="center" android:text="@string/number" /> <LinearLayout android:layout_width="fill_parent" android:layout_height="wrap_content" android:gravity="center" android:orientation="horizontal" > <Button android:id="@+id/mybutton_start" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="@string/start" /> <Button android:id="@+id/mybutton_pause" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="@string/pause" /> </LinearLayout></LinearLayout>
string部分代碼：
<?xml version="1.0" encoding="utf-8"?><resources> <string name="app_name">TimerDemo</string> <string name="number">0</string> <string name="start">start</string> <string name="stop">stop</string> <string name="pause">pause</string> <string name="resume">resume</string></resources>
上面就是我的源代碼，如果大家有什么問題可以留言進行探討。
以上就是本文的全部內容，希望對大家的學習有所幫助，也希望大家多多支持VEVB武林網。
新聞熱點
疑難解答
