在特定时间更改图像

Question

我正在试图让一个图像每半小时更换一次的Android工作室项目，我遵循一个示例但没有运气;它不引发错误，它只是doesen't工作，这里就是我有 什么，我已经试过：

public class MainActivity extends AppCompatActivity { 

long startTime = 0; 
Handler feed = new Handler(); 
Runnable runTimer = new Runnable() 
{ 
    @Override 
    public void run() { 
     Calendar now = Calendar.getInstance(); 
     TextView output = (TextView) findViewById(R.id.output); 
     ImageView roto = (ImageView) findViewById(R.id.earthView); 
     Globals g = (Globals) getApplication(); 
     int vision = 0; 
     int visionb = 0; 
     int hour = now.get(Calendar.HOUR); 
     int minute = now.get(Calendar.MINUTE); 
     String[] epos = g.getData56(); 

     if (minute >= 30) { 
      visionb = 1; 
     } 
     if (minute < 30) { 
      visionb = 0; 
     } 
     long millis = System.currentTimeMillis() - startTime; 
     int seconds = (int) (millis/1000); 
     int minutes = seconds/60; 
     seconds = seconds % 60; 
     output.setText(String.format("%d:%02d", minutes, seconds)); 
     vision = ((hour * 2) + visionb); 
     int resID = getResources().getIdentifier(epos[vision], "drawable", getPackageName()); 
     if (roto != null) { 
      roto.setImageResource(resID); 
      feed.postDelayed(this, 500); // tried moving this around and changing the value from 0 - 3000 
     } 
     startTime = System.currentTimeMillis(); 
     feed.postDelayed(runTimer, 500); // tried moving this around and changing the value from 0 - 3000 
    } 
}; 

为了测试我的代码，我把这个在onUserInteraction方法和它的作品完美的罚款：

@Override 
    public void onUserInteraction() { 
    super.onUserInteraction(); 
    final Globals g = (Globals) getApplication(); 
    Calendar now = Calendar.getInstance(); 
    ImageView roto = (ImageView) findViewById(R.id.earthView); 
    int vision = 0; 
    int visionb = 0; 
    int hour = now.get(Calendar.HOUR); 
    int minute = now.get(Calendar.MINUTE); 
    String[] epos = g.getData56(); 

    if (minute >= 30) { 
     visionb = 1; 
    } 
    if (minute < 30) { 
     visionb = 0; 
    } 
    vision = ((hour * 2) + visionb); 
    int resID = getResources().getIdentifier(epos[vision], "drawable", getPackageName()); 
    if (roto != null) { 
     roto.setImageResource(resID); 
    } 
} 

所以我假设我做错了什么，任何人都知道我做错了或失踪？

感谢您的帮助Landice这是工作成果，给我一个时钟和每一个小时 改变我的形象（其中有48个全部图像），再次感谢您的帮助！

long startTime = 0; 
{ 
final Handler feed = new Handler(); 
final Runnable runTimer = new Runnable() { 
    @Override 
    public void run() { 

     Calendar now = Calendar.getInstance(); 
     TextView output = (TextView) findViewById(R.id.output); 
     ImageView roto = (ImageView) findViewById(R.id.earthView); 
     Globals g = (Globals) getApplication(); 
     int vision = 0; 
     int visionb = 0; 
     int second = now.get(Calendar.SECOND); 
     int hour = now.get(Calendar.HOUR); 
     int minute = now.get(Calendar.MINUTE); 
     String[] epos = g.getData56(); 
     if (minute >= 30) {visionb = 1;}    
     if (minute < 30) {visionb = 0;} 
     output.setText(String.format(hour + ":" + minute + ":" + second)); 
     feed.postDelayed(this, 0); 
     if (minute == 30 || minute == 0) {vision = ((hour * 2) + visionb); 
      int resID = getResources().getIdentifier(epos[vision], "drawable", getPackageName()); 
      if (roto != null) { 
      roto.setImageResource(resID); 
      } 
     } 
     startTime = System.currentTimeMillis(); 
    } 
}; 
feed.postDelayed(runTimer,1000); 
} 

Answer 1

我想你忘了安排第一篇文章。 这是一个使用Handler和Runnable来安排定期事件的例子。 此行安排第一次运行。

handler.post(runTimer); 

而此行中的run（）时间表当时的事件后运行：

handler.postDelayed(this, 1000); 

是1000谨防指一秒钟。因此，30分钟将是60 * 1000 * 30，即1800000。

例子：

public class MainActivity extends AppCompatActivity { 

    TextView mTextView; 
    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_main); 

     mTextView = (TextView) findViewById(R.id.textview); 

     final Handler handler = new Handler(); 
     Runnable runTimer = new Runnable() 
     { 
      @Override 
      public void run() { 
       mTextView.setText("Current Time: " + (new Date()).toString()); 
       handler.postDelayed(this, 1000); 
      } 
     }; 

     handler.post(runTimer); 
    } 
} 

此外，你可能想通过除去预定延迟情况下，停止循环：

handler.removeCallbacks(runTimer); 

Answer 2

您可以试试这个回答：How to change images in imageview every n number of seconds。

int[] imageArray = { R.drawable.image1, R.drawable.image2, R.drawable.image3, R.drawable.image4, R.drawable.image5 }; 

int position=0; 

Timer mTimer = new Timer();