以编程方式管理 LinearLayout

Question

我有一个正在以编程方式构建的 class，我需要调整 2 按钮布局，使其看起来像我拥有的其他 class。

在这个 class AttributeWizard 中，我通过代码进行操作，因为我进行数据库操作并且需要像这样构建 GUI。

我想调整按钮 (layoutButtons) 的布局以适应屏幕的整个宽度。目前他们没有填满整个 space.

public class AttributeWizard extends Activity {

private LinearLayout linearLayoutAttribute;
private LinearLayout layoutBotoes;
private Button bNext;
private Button bPrev;

@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    setContentView(R.layout.activity_uisarde_attributes);
    linearLayoutAttribute = findViewById(R.id.linearLayoutAttribute);

    createLayoutForButtons();

    linearLayoutAttribute.addView(layoutBotoes);

    layoutBotoes.getLayoutParams().height = LinearLayout.LayoutParams.FILL_PARENT;
    layoutBotoes.getLayoutParams().width = LinearLayout.LayoutParams.MATCH_PARENT;
}


public void createLayoutForButtons() {
    layoutBotoes = new LinearLayout(AttributeWizard.this);
    bNext = new Button(AttributeWizard.this);
    bNext.setText("Próximo");
    bPrev = new Button(AttributeWizard.this);
    bPrev.setText("Anterior");

    layoutBotoes.setOrientation(LinearLayout.HORIZONTAL);
    layoutBotoes.addView(bPrev);
    layoutBotoes.addView(bNext);
}

}

以activity_uisarde_percurso.xml布局文件为例，看看我希望按钮如何位于底部（如果有人知道如何删除它们之间的制表符，谢谢）

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="fill_parent"
    android:layout_alignParentBottom="true"
    android:layout_marginStart="10dp"
    android:layout_marginTop="10dp"
    android:layout_marginEnd="10dp"
    android:layout_marginBottom="10dp"
    android:orientation="vertical">


    <TextView
        android:id="@+id/textView"
        style="?android:textAppearanceLarge"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginBottom="10dp"
        android:text="Seleção de percurso"
        android:textStyle="bold" />

    <TextView
        android:id="@+id/tvInfoProperty"
        style="?android:textAppearanceSmall"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="@string/inst_percurso" />

    <RadioGroup
        android:id="@+id/rgPercurso"
        style="?android:textAppearanceSmall"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="10dp"
        android:layout_marginBottom="10dp" >

        <RadioButton
            android:id="@+id/rbPadrao"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="Padrão" />

        <RadioButton
            android:id="@+id/rbPersonalizado"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="Personalizado" />
    </RadioGroup>

    <LinearLayout
        style="?android:attr/buttonBarStyle"
        android:layout_width="match_parent"
        android:layout_height="fill_parent"
        android:layout_gravity="bottom"
        android:gravity="bottom"
        android:orientation="horizontal">

        <Button
            android:id="@+id/prev_button_percurso"
            style="?android:attr/buttonBarButtonStyle"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:background="@drawable/selectable_item_background"
            android:text="@string/prev" />

        <Button
            android:id="@+id/next_button_percurso"
            style="?android:attr/buttonBarButtonStyle"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:background="@drawable/selectable_item_background"
            android:text="@string/next" />

    </LinearLayout>

</LinearLayout>

我什么时候应该更改属性？添加到主布局后？前？我设置对了吗属性?

Answer 1

这是我的解决方案：

public class AttributeWizard extends Activity {

    private LinearLayout linearLayoutAttribute;
    private LinearLayout layoutBotoes;
    private Button bNext;
    private Button bPrev;

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_uisarde_attributes);

        createLayoutForButtons();

        linearLayoutAttribute = findViewById(R.id.linearLayoutAttribute);
        linearLayoutAttribute.addView(layoutBotoes);
    }


    public void createLayoutForButtons() {
        layoutBotoes = new LinearLayout(this);
        bNext = createButton();
        bNext.setText("Próximo");
        bPrev = createButton();
        bPrev.setText("Anterior");

        layoutBotoes.setOrientation(LinearLayout.HORIZONTAL);
        layoutBotoes.addView(bPrev);
        layoutBotoes.addView(bNext);

        LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(MATCH_PARENT, 0);
        params.weight = 1;
        layoutBotoes.setLayoutParams(params);
    }

    private Button createButton() {
        Button button = new Button(this);
        LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(0, WRAP_CONTENT);
        params.weight = 1;
        params.gravity = Gravity.BOTTOM;
        button.setLayoutParams(params);
        return button;
    }
}

创建新的 Views/ViewGroups 时，您通常会创建新的 LayoutParams，设置布局属性，然后调用 setLayoutParams()。

更改已添加的Views/ViewGroups的布局属性时，您可以获取其LayoutParams，设置属性，然后调用setLayoutParams()。例如：

LinearLayout.LayoutParams params = layoutBotoes.getLayoutParams();
params.weight = 0;
layoutBotoes.setLayoutParams(params);

When should I change properties? After adding to the main layout? Before?

没关系，只要你打电话setLayoutParams()。您需要始终调用 setLayoutParams() 以使布局属性的更改生效。

I want to adjust the layout of the buttons (layoutButtons) to fit the full width of the screen. Currently they do not fill the entire space.

您需要将每个按钮的权重设置为 1。根据其 javadoc 描述，权重：

Indicates how much of the extra space in the LinearLayout will be allocated to the view associated with these LayoutParams. Specify 0 if the view should not be stretched. Otherwise the extra pixels will be pro-rated among all views whose weight is greater than 0.

为每个按钮赋予 1 的权重，允许它们以相等的比例填充额外的 space。

I want the buttons to be at the bottom

首先给layoutBotoes一个权重1来填充额外的space。然后，将每个按钮的 layout_gravity 设置为 BOTTOM。要以编程方式执行此操作：

params.gravity = Gravity.BOTTOM;

if anyone knows how to remove the tab between them, thank you

用于按钮背景的图像有额外的填充。您可以将其背景更改为另一个没有的可绘制对象。您需要使用 StateList Drawable 为每个状态手动设置可绘制对象，例如按下按钮、悬停等。

以编程方式管理 LinearLayout

Manage LinearLayout programmatically

java

xml

android

android-linearlayout