嵌套的线性布局不起作用

Question

我已经尝试了 2 天来创建嵌套线性布局（线性布局内的线性布局），但收效甚微。我的主布局有 3 个部分，权重分别为 45、45 和 10。当我运行它时，它似乎工作得很好。我在屏幕上得到 3 个不同颜色的矩形。

一旦我创建了“子”线性布局并将其添加到主布局，子布局就会在屏幕上占主导地位。次线性布局的权重为 35,35 和 30。所以我希望在屏幕上看到顶部矩形分成 3 个更薄的矩形。相反，我得到了属于子布局的 3 个矩形。

有什么想法吗？

public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState);

    // Ensure there is a full screen blank window to work with
    requestWindowFeature(Window.FEATURE_NO_TITLE);
    getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
                         WindowManager.LayoutParams.FLAG_FULLSCREEN);

      testViewA = new TestView(this);
      testViewB = new TestView(this);
      testViewC = new TestView(this);

      testViewD = new TestView(this);
      testViewE = new TestView(this);
      testViewF = new TestView(this);

      testViewA.color = 0;
      testViewB.color = 1;
      testViewC.color = 2;
      testViewD.color = 3;
      testViewE.color = 4;
      testViewF.color = 5;

    LinearLayout.LayoutParams paramsA = new LinearLayout.LayoutParams(LayoutParams.FILL_PARENT, 0, .45f);
    LinearLayout.LayoutParams paramsB = new LinearLayout.LayoutParams(LayoutParams.FILL_PARENT, 0, .45f);
    LinearLayout.LayoutParams paramsC = new LinearLayout.LayoutParams(LayoutParams.FILL_PARENT, 0, .10f);

    LinearLayout.LayoutParams paramsX = new LinearLayout.LayoutParams(LayoutParams.FILL_PARENT, 0, .35f);
    LinearLayout.LayoutParams paramsY = new LinearLayout.LayoutParams(LayoutParams.FILL_PARENT, 0, .35f);
    LinearLayout.LayoutParams paramsZ = new LinearLayout.LayoutParams(LayoutParams.FILL_PARENT, 0, .30f);

    paramsA.setMargins(10, 10, 10, 10);
    paramsB.setMargins(10, 10, 10, 10);

    testViewA.setLayoutParams(paramsA);
    testViewB.setLayoutParams(paramsB);
    testViewC.setLayoutParams(paramsC);
    testViewD.setLayoutParams(paramsX);
    testViewE.setLayoutParams(paramsY);
    testViewF.setLayoutParams(paramsZ);

    LinearLayout sub1 = new LinearLayout(this);
    sub1.setOrientation(LinearLayout.VERTICAL);
    sub1.setLayoutParams(new LayoutParams(LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT));
    sub1.addView(testViewD);
    sub1.addView(testViewE);
    sub1.addView(testViewF);

    LinearLayout masterL = new LinearLayout(this);
    masterL.setOrientation(LinearLayout.VERTICAL);
    masterL.setLayoutParams(new LayoutParams(LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT));
    masterL.addView(sub1);
    masterL.addView(testViewB);
    masterL.addView(testViewC);

    setContentView(masterL);

}

Answer 1

您的布局可以正常工作，但不是为您实际添加到masterL LinearLayout 的新子布局（sub1）添加LayoutParams paramsA，而是设置了一组新的@ 987654326@（width 和height 设置为FILL_PARENT?!!?）使您的sub1 填充整个主布局。您所要做的就是将正确的LayoutParams 设置为sub1：

    sub1.setLayoutParams(paramsA);

注意： 正如其他人所说的嵌套权重对性能不太好，也许您可​​以使用其他类型的布局来改进您的布局。

Answer 2

layout weight 属性仅在子布局参数设置为wrap_content 并且他们确实有额外的空白空间时才有用。

Answer 3

首先是在 xml 中执行此操作，当它用 Java 编写时，它非常难以阅读/维护布局代码（特别是当它如此简单时）。在 Java 中编写此类属性很少有充分的理由。

第二，不要嵌套权重，这对性能不利：http://developer.android.com/resources/articles/layout-tricks-efficiency.html 您应该能够提出不需要嵌套布局的替代布局。

第三，如果你绝对必须使用嵌套权重（同样你几乎肯定不会），你需要设置 sub1 的权重。通过将其高度设置为填充父级，而不是使用权重设置为 0，您是在告诉它填充屏幕，因此它完全按照您的指示进行操作也就不足为奇了。

Answer 4

你需要：

1) 将要为其设置体重的孩子的身高设置为 0。

2)设置父布局的setweightSum（子布局的权重之和）。

检查此代码作为我从您的代码示例中制作的示例：

 requestWindowFeature(Window.FEATURE_NO_TITLE);
        getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
                             WindowManager.LayoutParams.FLAG_FULLSCREEN);

          TextView TextViewA = new TextView(this);
          TextView   TextViewB = new TextView(this);
          TextView      TextViewC = new TextView(this);

          TextView      TextViewD = new TextView(this);
          TextView      TextViewE = new TextView(this);
          TextView      TextViewF = new TextView(this);

         TextViewA.setBackgroundColor( Color.RED);
          TextViewB.setBackgroundColor( Color.BLACK);
          TextViewC.setBackgroundColor( Color.BLUE);
          TextViewD.setBackgroundColor( Color.CYAN);
          TextViewE.setBackgroundColor( Color.GRAY);
          TextViewF.setBackgroundColor( Color.GREEN);



       LinearLayout.LayoutParams paramsA = new LinearLayout.LayoutParams(LayoutParams.FILL_PARENT, 0, .45f);
        LinearLayout.LayoutParams paramsB = new LinearLayout.LayoutParams( LayoutParams.FILL_PARENT,0, .45f);
        LinearLayout.LayoutParams paramsC = new LinearLayout.LayoutParams(LayoutParams.FILL_PARENT,0, .10f);

        LinearLayout.LayoutParams paramsX = new LinearLayout.LayoutParams( LayoutParams.FILL_PARENT, 0,.35f);
        LinearLayout.LayoutParams paramsY = new LinearLayout.LayoutParams( LayoutParams.FILL_PARENT,0, .35f);
        LinearLayout.LayoutParams paramsZ = new LinearLayout.LayoutParams( LayoutParams.FILL_PARENT,0, .30f);

        paramsA.setMargins(10, 10, 10, 10);
       paramsB.setMargins(10, 10, 10, 10);

      TextViewA.setLayoutParams(paramsA);
        TextViewB.setLayoutParams(paramsB);
        TextViewC.setLayoutParams(paramsC);
        TextViewD.setLayoutParams(paramsX);
        TextViewE.setLayoutParams(paramsY);
        TextViewF.setLayoutParams(paramsZ);

        LinearLayout sub1 = new LinearLayout(this);
        sub1.setOrientation(LinearLayout.VERTICAL);

        sub1.setLayoutParams(new LayoutParams( LayoutParams.FILL_PARENT,0,0.45f));
        sub1.setWeightSum(1f);
        sub1.addView(TextViewD);
        sub1.addView(TextViewE);
        sub1.addView(TextViewF);

        LinearLayout masterL = new LinearLayout(this);
        masterL.setOrientation(LinearLayout.VERTICAL);
        masterL.setLayoutParams(new LayoutParams(LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT));
       masterL.setWeightSum(1f);
        masterL.addView(sub1);
        masterL.addView(TextViewB);
        masterL.addView(TextViewC);

        setContentView(masterL);