Question

我正在尝试将元素添加到已经在片段的onCreateView（）方法中成功膨胀的LinearLayout UI中。

下面是onActivityCreated（）方法，我正在尝试向UI添加更多元素。

UI为卷计算提供输入，但我不知道在运行时计算卷需要多少维度。维度数量由我的VolumeCalculation类提供，具体取决于 calcId 。

在调试时，只要我尝试在 dimHLayouts [dimNumber] 上设置任何内容，应用就会在 for 循环中崩溃（例如 dimHLayouts [dimNumber] .setId（100 + dimNumber）; ）。我已经尝试过交换我先设置的属性。一旦我尝试设置属性，无论我首先尝试设置哪个属性，都会发生此崩溃。

我还使用了 android.util.Log 工具并插入了一吨日志来试着看看发生了什么，但我仍然在因为到目前为止的一切似乎都按预期工作。任何帮助将不胜感激。

@Override
public void onActivityCreated(Bundle savedInstanceState) {

    // Get the volume Calculation Type from the bundle passed to this fragment
    Bundle bundle = this.getArguments();
    int calcId = bundle.getInt("CalcType");

    // Create a calculation object
    VolumeCalculation calc = new VolumeCalculation(ApplicationContextProvider.getContext());
    int calcDimensionCount = calc.getCalcDimensionCount(calcId);

    // Get the root LinearLayout of the inflated UI
    LinearLayout inputUILayout = (LinearLayout)view.findViewById(R.id.layout_input);

    // Create array of new LinearLayout objects
    LinearLayout[] dimHLayouts = new LinearLayout[calc.getCalcDimensionCount(calcId)];
    LinearLayout.LayoutParams lpDimHLayouts = new LinearLayout.LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT);

    // Create array of new TextView objects
    TextView[] dimTextViews = new TextView[calc.getCalcDimensionCount(calcId)];
    LayoutParams lpDimTextViews = new LinearLayout.LayoutParams(0, LayoutParams.WRAP_CONTENT, 1f);

    for(int dimNumber=0; dimNumber<calcDimensionCount; dimNumber++) {

        // Setup the horizontal linear layout for the dimension
        dimHLayouts[dimNumber].setId(100 + dimNumber);
        dimHLayouts[dimNumber].setOrientation(android.widget.LinearLayout.HORIZONTAL);
        dimHLayouts[dimNumber].setLayoutParams(lpDimHLayouts);

        // Setup the dimension label TextView
        dimTextViews[dimNumber].setId(150 + dimNumber);
        dimTextViews[dimNumber].setLayoutParams(lpDimTextViews);
        dimTextViews[dimNumber].setGravity(Gravity.RIGHT);
        dimTextViews[dimNumber].setText(calc.getDimLabel(calcId, dimNumber));

        // Add TextView to LinearLayout
        dimHLayouts[dimNumber].addView(dimTextViews[dimNumber]);

        // To Do: Setup an EditText and add it to the dimension LinearLayout

        // Add dimension LinearLayout to the UI  
        inputUILayout.addView(dimHLayouts[dimNumber]);
    }

    super.onActivityCreated(savedInstanceState);
}

Answer 1

我有解决问题的方法（感谢Boris Mocialov的帮助）。

新的UI组件数组已实例化，但数组的各个元素未初始化。

我已经更改 for 循环，如下所示，初始化每个元素，例如dimHLayouts[dimNumber] = new LinearLayout(getActivity());它现在可以正常工作。

    for(int dimNumber=0; dimNumber<calcDimensionCount; dimNumber++) {

        // Setup the horizontal linear layout for the dimension
        dimHLayouts[dimNumber] = new LinearLayout(getActivity());
        dimHLayouts[dimNumber].setOrientation(android.widget.LinearLayout.HORIZONTAL);
        dimHLayouts[dimNumber].setLayoutParams(lpDimHLayouts);

        // Setup the dimension label TextView
        dimTextViews[dimNumber] = new TextView(getActivity());
        textViewIds[dimNumber] = generateViewId();
        dimTextViews[dimNumber].setId(textViewIds[dimNumber]);
        dimTextViews[dimNumber].setLayoutParams(lpDimTextViews);
        dimTextViews[dimNumber].setGravity(Gravity.RIGHT);
        dimTextViews[dimNumber].setTextAppearance(getActivity(), android.R.attr.textAppearanceMedium);
        dimTextViews[dimNumber].setText(calc.getDimLabel(calcId, dimNumber));

        // Setup the dimension label EditText
        dimEditTexts[dimNumber] = new EditText(getActivity());
        editTextIds[dimNumber] = generateViewId();
        dimEditTexts[dimNumber].setId(editTextIds[dimNumber]);
        dimEditTexts[dimNumber].setLayoutParams(lpDimEditTexts);
        dimEditTexts[dimNumber].setInputType(InputType.TYPE_NUMBER_FLAG_DECIMAL | InputType.TYPE_CLASS_NUMBER);
        dimEditTexts[dimNumber].setTextAppearance(getActivity(), android.R.attr.textAppearanceMediumInverse);


        // Add TextView and EditText to LinearLayout
        dimHLayouts[dimNumber].addView(dimTextViews[dimNumber]);
        dimHLayouts[dimNumber].addView(dimEditTexts[dimNumber]);


        // Add dimension LinearLayout to the UI  
        inputUILayout.addView(dimHLayouts[dimNumber]);
    }

有没有人知道，是否有更有效和优雅的方法来动态添加一些在运行时未知的元素？

动态地向UI添加元素数组

1 个答案: