GridLayout 布局使用網(wǎng)格來布置其中的 UI 組件。每個網(wǎng)格提供行，列來定義。每個 UI 組件可以占據(jù)一個或多個網(wǎng)格。由網(wǎng)格的坐標(biāo)(x1,y1,x2,y2)來定義。 GridLayout 布局內(nèi)部使用一個游標(biāo)(cursor)來記錄當(dāng)前的網(wǎng)格位置，GridLayout 布局添加 UI 組件的順序為從左到右，從上到下。如果游標(biāo)越過當(dāng)前網(wǎng)格的右下角，GridLayout 布局自動添加一行。下例為 GridLayout 布局的基本用法，addComponent 第一個參數(shù)為所添加的 UI 組件對象，第二個參數(shù)可選，指定 UI 組件添加的網(wǎng)格坐標(biāo)?？梢允褂脝蝹€坐標(biāo)或是一個區(qū)域。網(wǎng)格坐標(biāo)從0開始。

// Create a 4 by 4 grid layout.
GridLayout grid = new GridLayout(4, 4);
grid.addStyleName("example-gridlayout");

// Fill out the first row using the cursor.
grid.addComponent(new Button("R/C 1"));
for (int i = 0; i < 3; i++) {
    grid.addComponent(new Button("Col " + (grid.getCursorX() + 1)));
}

// Fill out the first column using coordinates.
for (int i = 1; i < 4; i++) {
    grid.addComponent(new Button("Row " + i), 0, i);
}

// Add some components of various shapes.
grid.addComponent(new Button("3x1 button"), 1, 1, 3, 1);
grid.addComponent(new Label("1x2 cell"), 1, 2, 1, 3);
InlineDateField date = new InlineDateField("A 2x2 date field");
date.setResolution(DateField.RESOLUTION_DAY);
grid.addComponent(date, 2, 2, 3, 3);

http://wiki.jikexueyuan.com/project/vaadin-web-development-tutorial/images/79.png" alt="" />

GridLayout 布局缺省使用“未定義”寬度和高度，因此缺省自適應(yīng)其所包含的 UI 組件。如果使用指定大小或是比例，其可使用的選項類同Vaadin Web應(yīng)用開發(fā)教程(29):UI布局-VerticalLayout和HorizontalLayout布局

類似 VerticalLayout 和 HorizontalLayout 布局也可以為 UI 組件指定擴(kuò)展比例，讓某些 UI 組件占據(jù) GridLayout 布局剩余空間?？梢酝ㄟ^ setRowExpandRatio()和 setColumnExpandRatio()為行和列分別制定擴(kuò)展（權(quán)重）比例。第一個參數(shù)為行或列的坐標(biāo)，第二個參數(shù)為權(quán)重。如下例：

GridLayout grid = new GridLayout(3,2);

// Layout containing relatively sized components must have
// a defined size, here is fixed size.
grid.setWidth("600px");
grid.setHeight("200px");

// Add some content
String labels [] = {
        "Shrinking column<br/>Shrinking row",
        "Expanding column (1:)<br/>Shrinking row",
        "Expanding column (5:)<br/>Shrinking row",
        "Shrinking column<br/>Expanding row",
        "Expanding column (1:)<br/>Expanding row",
        "Expanding column (5:)<br/>Expanding row"
};
for (int i=0; i<labels.length; i++) {
    Label label = new Label(labels[i], Label.CONTENT_XHTML);
    label.setWidth(null); // Set width as undefined
    grid.addComponent(label);
}

// Set different expansion ratios for the two columns
grid.setColumnExpandRatio(1, 1);
grid.setColumnExpandRatio(2, 5);

// Set the bottom row to expand
grid.setRowExpandRatio(1, 1);

// Align and size the labels.
for (int col=0; col<grid.getColumns(); col++) {
    for (int row=0; row<grid.getRows(); row++) {
        Component c = grid.getComponent(col, row);
        grid.setComponentAlignment(c, Alignment.TOP_CENTER);

        // Make the labels high to illustrate the empty
        // horizontal space.
        if (col != 0 || row != 0)
            c.setHeight("100%");
    }
}

http://wiki.jikexueyuan.com/project/vaadin-web-development-tutorial/images/80.png" alt="" />

Tags: Java EE, Vaadin, Web

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