通過edittexts陣列循環和得到的每個

Question

我有來自用戶的輸入得到edittexts的自動生成的列表中的文本。我想要做的就是在單擊隨機播放按鈕時拖動edittext，或者獲取文本並將它們設置爲不同的edittext。我試着做的是讓每個edittext的文本添加到arraylist並洗牌，然後用混洗列表重新創建佈局。但是這本身就給了我錯誤。當單擊隨機按鈕時，它給了我這個錯誤 java.lang.NullPointerException：嘗試調用空對象上的虛擬方法'android.text.Editable android.widget.EditText.getText（）'參考 感謝有關幫助 `

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

    btnForCreate = (Button) findViewById(R.id.btnCreateTxt); 
    editTextForInputToCreate = (EditText) findViewById(R.id.textForInputToCreate); 
    listLayout = (LinearLayout) findViewById(R.id.listLayout); 
    btnDisplay = (Button) findViewById(R.id.btnDisplay); 
    btnShuffleTxt = (Button) findViewById(R.id.btnShuffleTxt); 


    editTextForInputToCreate.animate().translationX(-1000f); 



    btnForCreate.setOnClickListener(new View.OnClickListener() { 
     @Override 
     public void onClick(View view) { 

      bringTextInputBackOnScreen(); 


     } 
    }); 


    btnDisplay.setOnClickListener(new View.OnClickListener() { 
     @Override 
     public void onClick(View view) { 


      if (editTextForInputToCreate.getText().toString().length() >= 0) { 
       try { 
        listLayout.removeAllViews(); 

       } catch (Throwable throwable) { 
        throwable.printStackTrace(); 
       } 
      } 


      length = Integer.parseInt(editTextForInputToCreate.getText().toString()); 


      for (i = 0; i < length; i++) { 
       editTextCollection = new EditText[length]; 
       editText = new EditText(MainActivity.this); 
       editText.setId(i + 1); 
       editText.setLayoutParams(new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT)); 
       editText.setHint("Input" + " " + (i + 1)); 
       listLayout.addView(editText); 
       editTextCollection[i] = editText; 


      } 


     } 


    }); 


    btnShuffleTxt.setOnClickListener(new View.OnClickListener() { 
     @Override 
     public void onClick(View view) { 

      listLayout.removeAllViews(); 
      for (EditText gottenEditText:editTextCollection) 
      { 
       String gottenTexts = gottenEditText.getText().toString(); 
       list.add(gottenTexts); 
      } 

      Collections.shuffle(list); 


     } 


    }); 


} 


private void bringTextInputBackOnScreen() 
{ 
    editTextForInputToCreate.animate().translationXBy(1000f).setDuration(2000); 
} 

`

Answer 1

請您EditTextCollection作出一些修正。

 editTextCollection = new EditText[length];// initialization outside the loop 

for (i = 0; i < length; i++) { 
      editText = new EditText(MainActivity.this); 
      editText.setId(i + 1); 
      editText.setLayoutParams(new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT)); 
      editText.setHint("Input" + " " + (i + 1)); 
      listLayout.addView(editText); 
      editTextCollection[i] = editText; 
     } 


btnShuffleTxt.setOnClickListener(new View.OnClickListener() { 
     @Override 
     public void onClick(View view) { 

     listLayout.removeAllViews(); 
     for (EditText gottenEditText:editTextCollection) 
     { 
      String gottenTexts = gottenEditText.getText().toString(); 
      list.add(gottenTexts); 
     } 

    Collections.shuffle(list); 

    for (EditText gottenEditText:editTextCollection) 
    { 
     gottenEditText.setText(list.get(editTextCollection.indexOf(gottenEditText))); 
    } 

} 

}）;