在Android中实现九宫格布局

Android中可以使用GridLayout或者自定义布局实现九宫格布局。

1. 使用GridLayout

GridLayout是Android提供的布局，可以实现网格布局。以下是一个九宫格布局的例子：

<GridLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:rowCount="3"
    android:columnCount="3"
    android:orientation="horizontal">

    <Button
        android:text="Button 1"
        android:layout_row="0"
        android:layout_column="0"/>

    <Button
        android:text="Button 2"
        android:layout_row="0"
        android:layout_column="1"/>

    <Button
        android:text="Button 3"
        android:layout_row="0"
        android:layout_column="2"/>

    <Button
        android:text="Button 4"
        android:layout_row="1"
        android:layout_column="0"/>

    <Button
        android:text="Button 5"
        android:layout_row="1"
        android:layout_column="1"/>

    <Button
        android:text="Button 6"
        android:layout_row="1"
        android:layout_column="2"/>

    <Button
        android:text="Button 7"
        android:layout_row="2"
        android:layout_column="0"/>

    <Button
        android:text="Button 8"
        android:layout_row="2"
        android:layout_column="1"/>

    <Button
        android:text="Button 9"
        android:layout_row="2"
        android:layout_column="2"/>

</GridLayout>

2. 自定义布局

也可以使用自定义布局实现九宫格布局。以下是一个自定义九宫格布局的例子：

public class NineGridLayout extends LinearLayout {

    private static final int DEFAULT_COLUMN_COUNT = 3;

    private int mColumnCount;
    private List<View> mViewList;

    public NineGridLayout(Context context) {
        super(context);
        init();
    }

    public NineGridLayout(Context context, AttributeSet attrs) {
        super(context, attrs);
        init();
    }

    public NineGridLayout(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        init();
    }

    private void init() {
        setOrientation(VERTICAL);
        mViewList = new ArrayList<>();
        mColumnCount = DEFAULT_COLUMN_COUNT;
    }

    public void setColumnCount(int columnCount) {
        mColumnCount = columnCount;
    }

    public void setViews(List<View> viewList) {
        mViewList.clear();
        mViewList.addAll(viewList);
        notifyDataSetChanged();
    }

    public void notifyDataSetChanged() {
        removeAllViews();
        int rowCount = (int) Math.ceil(mViewList.size() * 1.0 / mColumnCount);
        for (int i = 0; i < rowCount; i++) {
            LinearLayout rowLayout = new LinearLayout(getContext());
            rowLayout.setLayoutParams(new LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT));
            rowLayout.setOrientation(HORIZONTAL);
            for (int j = 0; j < mColumnCount; j++) {
                int index = i * mColumnCount + j;
                if (index < mViewList.size()) {
                    View view = mViewList.get(index);
                    view.setLayoutParams(new LayoutParams(0, ViewGroup.LayoutParams.WRAP_CONTENT, 1));
                    rowLayout.addView(view);
                } else {
                    View emptyView = new View(getContext());
                    emptyView.setLayoutParams(new LayoutParams(0, ViewGroup.LayoutParams.WRAP_CONTENT, 1));
                    rowLayout.addView(emptyView);
                }
            }
            addView(rowLayout);
        }
    }
}

使用时可以在XML中定义布局：

<com.example.customview.NineGridLayout
    android:id="@+id/nine_grid_layout"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    app:columnCount="3"/>

然后在代码中设置View：

List<View> viewList = new ArrayList<>();
for (int i = 0; i < 9; i++) {
    Button button = new Button(this);
    button.setText("Button " + (i + 1));
    viewList.add(button);
}
NineGridLayout nineGridLayout = findViewById(R.id.nine_grid_layout);
nineGridLayout.setViews(viewList);