在android中進行EditText驗證？

Question

我有一個場景像下面的圖片：

如果用戶不寫用戶名或電子郵件字段任何東西，它會顯示問號。另一方面它會顯示十字標記。如何實現它？

Answer 1

etUsername.addTextChangedListener(mTextWatcher); 

etUsername.setOnTouchListener(new MyOnTouchListener(etUsername)); 

TextWatcher：顯示或由用戶輸入隱藏清除按鈕

private TextWatcher mTextWatcher = new TextWatcher() { 

    boolean isnull = true; 

    @Override 
    public void onTextChanged(CharSequence s, int start, int before, int count) { 
    } 

    @Override 
    public void beforeTextChanged(CharSequence s, int start, int count, 
      int after) { 
    } 

    @Override 
    public void afterTextChanged(Editable s) { 
     if(TextUtils.isEmpty(s)){ 
      if(!isnull){ 
       etUsername.setCompoundDrawablesWithIntrinsicBounds(null, null, null, null); 
       isnull = true; 
      } 
     }else{ 
      if(isnull){ 
       etUsername.setCompoundDrawablesWithIntrinsicBounds(null, null, mClearIcon, null); 
       isnull = false; 
      } 
     } 
    } 

MyOnTouchListener：Clear按鈕點擊收聽

class MyOnTouchListener implements OnTouchListener{ 

    EditText mEditText; 

    public MyOnTouchListener(EditText editText){ 
     this.mEditText = editText; 
    } 

    @Override 
    public boolean onTouch(View v, MotionEvent event) { 
     switch(event.getAction()){ 
     case MotionEvent.ACTION_UP: 
      int curX = (int)event.getX(); 
      if(curX > v.getWidth() - 60 
        && !TextUtils.isEmpty(mEditText.getText())){ 
    // the clear button was clicked，do something you need 
    // for example, show the hint msg,etc 
       return true; 
      } 
      break; 
     } 
     return false; 
    } 

您可以使用代碼上面做一個自定義視圖