content: /*
   * Copyright (C) 2016 The Android Open Source Project
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package com.example.hellojnicallback;
  
  import androidx.annotation.Keep;
  import androidx.appcompat.app.AppCompatActivity;
  import android.os.Bundle;
  import android.widget.TextView;
  
  public class MainActivity extends AppCompatActivity {
  
      int hour = 0;
      int minute = 0;
      int second = 0;
      TextView tickView;
      @Override
      protected void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);
          setContentView(R.layout.activity_main);
          tickView = (TextView) findViewById(R.id.tickView);
      }
      @Override
      public void onResume() {
          super.onResume();
          hour = minute = second = 0;
          ((TextView)findViewById(R.id.hellojniMsg)).setText(stringFromJNI());
          startTicks();
      }
  
      @Override
      public void onPause () {
          super.onPause();
          StopTicks();
      }
  
      /*
       * A function calling from JNI to update current timer
       */
      @Keep
      private void updateTimer() {
          ++second;
          if(second >= 60) {
              ++minute;
              second -= 60;
              if(minute >= 60) {
                  ++hour;
                  minute -= 60;
              }
          }
          runOnUiThread(new Runnable() {
              @Override
              public void run() {
                  String ticks = "" + MainActivity.this.hour + ":" +
                          MainActivity.this.minute + ":" +
                          MainActivity.this.second;
                  MainActivity.this.tickView.setText(ticks);
              }
          });
      }
      static {
          System.loadLibrary("hello-jnicallback");
      }
      public native  String stringFromJNI();
      public native void startTicks();
      public native void StopTicks();
  }
  