我如何在創建視圖時測量視圖的寬度？

Question

我試圖連接單個單詞的TextViews並創建它們的多排行。爲了確定何時創建一個新行，我需要檢查單詞「TextViews」的寬度。

這裏是一個事先知情同意，類似於什麼即時試圖完成

我得到一個奇怪的錯誤，當我嘗試使用getWidth：

Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'int android.widget.RelativeLayout.getWidth()' on a null object reference 

然而，當我調試代碼rL2不是null並且有一個值。

我猜我的視圖尚未創建？但是我怎樣才能動態地改變它呢？我如何製作我的排？

這裏是我的代碼：

@Override 
public View onCreateView(LayoutInflater inflater, ViewGroup container, 
         Bundle savedInstanceState) { 
    // Inflate the layout for this fragment 
    View v = inflater.inflate(R.layout.fragment_call_response, container, false); 
    v.measure(widthMeasureSpec, heightMeasureSpec); 
    int lineWidth = 0; 

    RelativeLayout rL2 = (RelativeLayout) v.findViewById(R.id.row1); 
    int lineCount = 0; 
    int rowWidth = rL2.getWidth(); 

    int wordCountRow = 0; 


    TextView question = (TextView) v.findViewById(R.id.Question); 
    TextView choice1 = (TextView) v.findViewById(R.id.choice1); 
    TextView choice2 = (TextView) v.findViewById(R.id.choice2); 
    TextView choice3 = (TextView) v.findViewById(R.id.choice3); 
    TextView choice4 = (TextView) v.findViewById(R.id.choice4); 
    TextView speaker = (TextView) v.findViewById(R.id.Speaker); 
    TextView progress = (TextView) v.findViewById(R.id.progress); 


    ArrayList<String> answers = new ArrayList<>(); 
    answers.addAll(quote.getAnswerChoice()); 
    answers.add(quote.getWordSplitTypeA().get(quote.getAnswerIndex().get(0))); 
    Collections.shuffle(answers); 

    speaker.setText("How would " + quote.getSpeaker().get(0) + " Marx answer the above question?"); 
    choice1.setText(answers.get(0)); 
    choice2.setText(answers.get(1)); 
    choice3.setText(answers.get(2)); 
    choice4.setText(answers.get(3)); 

    progress.setText(String.format("%.1f%% Complete", (SingletonFactory.getPlayer().getLessonProgress()[0]/12.0) * 100)); 

    //addTextViews(v); 


    for(int i = 0;i<quote.getWordSplitTypeA().size(); i++) { 

     if (lineWidth + 10 > rowWidth) { 
      lineCount++; 
      wordCountRow = 0; 
     } 

     int padding = getResources().getDimensionPixelOffset(R.dimen.wordBoxPadding); 
     TextView tv = new TextView(getActivity()); 
     tv.setId(i); 
     tv.setText(quote.getWordSplitTypeA().get(i)); 
     tv.setBackgroundColor(Color.parseColor(bGColor)); 
     tv.setTextColor(Color.WHITE); 
     tv.setGravity(Gravity.CENTER); 
     tv.setPadding(padding, padding, padding, padding); 
     ViewGroup.LayoutParams LP = new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT); 
     tv.setLayoutParams(LP); 

     RelativeLayout.LayoutParams params = (RelativeLayout.LayoutParams) tv.getLayoutParams(); 

     if (wordCountRow == 0) { 
      params.addRule(RelativeLayout.CENTER_VERTICAL); 
      params.addRule(RelativeLayout.ALIGN_PARENT_LEFT); 
      params.addRule(RelativeLayout.ALIGN_PARENT_START); 
     } else { 
      params.addRule(RelativeLayout.CENTER_VERTICAL); 
      params.addRule(RelativeLayout.RIGHT_OF, (i - 1)); 
     } 

     tv.setLayoutParams(params); 

     if (quote.getAnswerIndex().contains(i)) { 
      tv.setBackgroundColor(Color.RED); 
      tv.setText("....."); 
     } 
     int width = tv.getWidth(); 
     lineWidth += width; 
     if (lineCount == 0) { 
      RelativeLayout rL = (RelativeLayout) v.findViewById(R.id.row1); 
      rL.addView(tv); 
     } else if (lineCount == 1) { 
      RelativeLayout rL = (RelativeLayout) v.findViewById(R.id.row2); 
      rL.addView(tv); 
     } else if (lineCount == 2) { 
      RelativeLayout rL = (RelativeLayout) v.findViewById(R.id.row3); 
      rL.addView(tv); 
     } else if (lineCount == 3) { 
      RelativeLayout rL = (RelativeLayout) v.findViewById(R.id.row4); 
      rL.addView(tv); 
     } 


     choice1.setOnClickListener(mClickListener); 
     choice2.setOnClickListener(mClickListener); 
     choice3.setOnClickListener(mClickListener); 
     choice4.setOnClickListener(mClickListener); 

     question.setText(quote.getSpeaker().get(0) + ": " + quote.getQuote().get(0)); 
    } 
    return v; 
} 

Answer 1

如何衡量自己的看法寬度爲我創造呢？

你不能。這是在度量和佈局過程中處理的，在創建小部件後會發生這種情況。

我想連接單個單詞的TextViews並創建它們的多行。

它看起來像你應該使用a FlowLayout，或類似的東西，作爲TextViews的容器，它會自動包裝它們。

如果該FlowLayout不符合您的需求，here is another one。

而且，如果這些都不是你想要的，你可以用它們來寫作自己的靈感。您試圖實現的UI規則應該在容器中實現，因爲容器處理大小和定位其子級。