Android Java, 每0.25秒通过 setOnTouchListener 从字符串中删除最后1个字符。

huangapple
go评论106阅读模式
英文:

Android Java, setOnTouchListener delete 1 last character from string every 0.25s

问题

清除按钮：

  1. clear.setOnClickListener(new View.OnClickListener() {
  2.     @Override
  3.     public void onClick(View v) {
  4.         if (operation.length() != 0) {
  5.             String s = operation.getText().toString();
  6.             s = s.substring(0, operation.length() - 1);
  7.             operation.setText(s);
  8.         }
  9.     }
  10. });

长按触发想法：

  1. clear.setOnTouchListener(new View.OnTouchListener() {
  2.     @Override
  3.     public boolean onTouch(View v, MotionEvent event) {
  4.         return false;
  5.     }
  6. });
英文:

I am making calculator on java. I want to make a button, which corresponds to delete the last character.<br>
If you press on it for 1 second, it starts to delete 1 character every 0.25s form EditText string.<br>

Clear button:

  1. clear.setOnClickListener(new View.OnClickListener() {
  2.         @Override
  3.         public void onClick(View v) {
  4.             if(operation.length() != 0){
  5.                 String s=operation.getText().toString();
  6.                 s = s.substring(0,operation.length()-1);
  7.                 operation.setText(s);}
  8.         }
  9.     });

Long touch idea:

  1. clear.setOnTouchListener(new View.OnTouchListener() {
  2.             @Override
  3.             public boolean onTouch(View v, MotionEvent event) {
  4.                 return false;
  5.             }
  6.         });

答案1

得分: 1

你可以使用ScheduledExecutorService按照设定的速率和初始延迟来调度Runnable。以下是我如何实现的：

  1. // 为ExecutorService和ScheduledFuture创建成员变量
  2. private ScheduledExecutorService mExecutor;
  3. private ScheduledFuture<?> mFuture;
  5. @Override
  6. protected void onCreate(Bundle savedInstanceState) {
  7.     super.onCreate(savedInstanceState);
  8.     setContentView(R.layout.activity_test);
  10.     final EditText editText = findViewById(R.id.textView);
  11.     final Button button = findViewById(R.id.button2);
  13.     // 设置ExecutorService
  14.     mExecutor = Executors.newSingleThreadScheduledExecutor();
  16.     final Runnable deleteRunnable = new Runnable() {
  17.         @Override
  18.         public void run() {
  19.             // 我们将使用视图的post()方法
  20.             // 以确保我们从正确的线程更新它
  21.             editText.post(new Runnable() {
  22.                 @Override
  23.                 public void run() {
  24.                     String textValue = editText.getText().toString();
  26.                     if (textValue.length() > 0) {
  27.                         // 删除最后一个字符
  28.                         textValue = textValue.substring(0, textValue.length() - 1);
  30.                         Log.d("MY_LOG_TAG", textValue);
  31.                         editText.setText(textValue);
  32.                     }
  34.                     // （可选）
  35.                     // 保持光标在文本末尾
  36.                     editText.setSelection(textValue.length());
  37.                 }
  38.             });
  39.         }
  40.     };
  42.     button.setOnTouchListener(new View.OnTouchListener() {
  43.         @Override
  44.         public boolean onTouch(View v, MotionEvent event) {
  45.             int action = event.getAction();
  47.             switch (action) {
  48.                 case MotionEvent.ACTION_DOWN:
  49.                     Log.d("MY_LOG_TAG", "按下动作");
  51.                     // 使用初始延迟1000毫秒和速率250毫秒调度可运行项
  52.                     mFuture = mExecutor.scheduleAtFixedRate(deleteRunnable, 1000, 250, TimeUnit.MILLISECONDS);
  53.                     break;
  55.                 case MotionEvent.ACTION_UP:
  56.                     Log.d("MY_LOG_TAG", "抬起动作");
  58.                     // 当触发Up事件时取消已调度的可运行项
  59.                     if (mFuture != null) {
  60.                         mFuture.cancel(false);
  61.                     }
  62.                     break;
  63.             }
  64.             return false;
  65.         }
  66.     });
  67. }
  69. @Override
  70. protected void onDestroy() {
  71.     // 关闭Executor Service
  72.     mExecutor.shutdown();
  74.     super.onDestroy();
  75. }
英文:

You can use ScheduledExecutorService to schedule Runnables at a set rate and with an initial delay. Here's how I would do it:

  1. // Create member variables for your ExecutorService and ScheduledFuture
  2. private ScheduledExecutorService mExecutor;
  3. private ScheduledFuture&lt;?&gt; mFuture;
  4. @Override
  5. protected void onCreate(Bundle savedInstanceState) {
  6. super.onCreate(savedInstanceState);
  7. setContentView(R.layout.activity_test);
  8. final EditText editText = findViewById(R.id.textView);
  9. final Button button = findViewById(R.id.button2);
  10. // Set up the ExecutorService
  11. mExecutor = Executors.newSingleThreadScheduledExecutor();
  12. final Runnable deleteRunnable = new Runnable() {
  13. @Override
  14. public void run() {
  15. // We&#39;ll use the view&#39;s post() method
  16. // to make sure we&#39;re updating it from the correct thread
  17. editText.post(new Runnable() {
  18. @Override
  19. public void run() {
  20. String textValue = editText.getText().toString();
  21. if(textValue.length() &gt; 0){
  22. // Delete the last character
  23. textValue = textValue.substring(0, textValue.length() - 1);
  24. Log.d(&quot;MY_LOG_TAG&quot;, textValue);
  25. editText.setText(textValue);
  26. }
  27. // (Optionally)
  28. // Keep the cursor at the end of the text
  29. editText.setSelection(textValue.length());
  30. }
  31. });
  32. }
  33. };
  34. button.setOnTouchListener(new View.OnTouchListener() {
  35. @Override
  36. public boolean onTouch(View v, MotionEvent event) {
  37. int action = event.getAction();
  38. switch(action){
  39. case MotionEvent.ACTION_DOWN:
  40. Log.d(&quot;MY_LOG_TAG&quot;, &quot;Action down&quot;);
  41. // Schedule the runnable with an initial delay of 1000 milliseconds
  42. // and at a rate of 250 milliseconds
  43. mFuture = mExecutor.scheduleAtFixedRate(deleteRunnable, 1000, 250, TimeUnit.MILLISECONDS);
  44. break;
  45. case MotionEvent.ACTION_UP:
  46. Log.d(&quot;MY_LOG_TAG&quot;, &quot;Action up&quot;);
  47. // Cancel the scheduled runnable when the Up event is triggered
  48. if(mFuture != null){
  49. mFuture.cancel(false);
  50. }
  51. break;
  52. }
  53. return false;
  54. }
  55. });
  56. }
  57. @Override
  58. protected void onDestroy() {
  59. // Shutdown the Executor Service
  60. mExecutor.shutdown();
  61. super.onDestroy();
  62. }

huangapple
  • 本文由 发表于 2020年10月17日 04:34:58
  • 转载请务必保留本文链接：https://go.coder-hub.com/64396068.html
  • android
  • android-studio
  • java
匿名

发表评论

匿名网友

:?: :razz: :sad: :evil: :!: :smile: :oops: :grin: :eek: :shock: :???: :cool: :lol: :mad: :twisted: :roll: :wink: :idea: :arrow: :neutral: :cry: :mrgreen:

确定