动态创建扩展 LinearLayout 并在内部包含 TextView 的类

Question

我正在开发一个为 DB 创建 UML 图的项目。问题是我很难实现实际的类对象（包含类名、pk、属性等的对象）。是否可以创建一个扩展 LinearLayout 的类，同时在内部包含 3 个 TextView 来显示数据？我需要它在按钮的单击上动态创建。谢谢！

Answer 1

当然可以。 Android 为您提供了很多创建自己的视图和视图组的能力。 Here training 你可以从那里开始。

下面是LinearLayout 的一些非常基本的示例，其中包含三个TextView：

MyActivity.java

public class MyActivity extends Activity implements View.OnClickListener {

    private static final String TAG = "MyActivity";
    private Button mCreateViewButton = null;

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

        setContentView(R.layout.main);

        mCreateViewButton = (Button) findViewById(R.id.createView);
        mCreateViewButton.setOnClickListener(this);
    }

    @Override
    public void onClick(final View view) {
        switch(view.getId()) {
            case R.id.createView:
                // Add new class view
                final ClassItemView item = new ClassItemView(this);
                final RelativeLayout.LayoutParams params = new RelativeLayout.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT);

                params.addRule(RelativeLayout.CENTER_IN_PARENT, 1);
                item.setClassName("MyClass").setMethods("myMethod()").setAttributes("int myAttribute");

                ((RelativeLayout)findViewById(R.id.mainContainer)).addView(item, params);
                break;
        }
    }
}

ma​​in.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:id="@+id/mainContainer"
    android:background="#fff3f2f2"
    android:orientation="horizontal" >

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/createView"
        android:text="Create text view"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:layout_margin="5dp"/>
</RelativeLayout>

ClassItemView.java

public class ClassItemView extends LinearLayout {
    private TextView mClassNameView;
    private TextView mMethodsView;
    private TextView mAttributesView;

    private Context mContext;

    /**
     * Default constructor
     *
     * @param context {@link android.content.Context}
     */
    public ClassItemView(@NotNull final Context context) {
        super(context);

        setOrientation(VERTICAL);

        mContext = context;

        initChild();
        setupBorder();
    }

    /**
     * Setups border for linear layout
     */
    private void setupBorder() {
        setBackground(mContext.getResources().getDrawable(R.drawable.border_bg));
        setDividerDrawable(mContext.getResources().getDrawable(android.R.drawable.divider_horizontal_bright));
        setShowDividers(SHOW_DIVIDER_MIDDLE);
    }

    /**
     * Inits child views
     */
    private void initChild() {
        final int padding = getResources().getDimensionPixelSize(R.dimen.padding);

        mClassNameView = new TextView(mContext);
        mClassNameView.setTypeface(null, Typeface.BOLD);
        // Set paddings for border, not needed if bg is 9png
        mClassNameView.setPadding(padding, padding, padding, padding);
        // Setup other properties like font size etc.

        mMethodsView = new TextView(mContext);
        // Set paddings for border, not needed if bg is 9png
        mMethodsView.setPadding(padding, padding, padding, padding);

        mAttributesView = new TextView(mContext);
        // Set paddings for border, not needed if bg is 9png
        mAttributesView.setPadding(padding, padding, padding, padding);

        final LinearLayout.LayoutParams classNameParams = new LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT);

        addView(mClassNameView, classNameParams);

        final LinearLayout.LayoutParams methodsParams = new LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT);

        addView(mMethodsView, methodsParams);

        final LinearLayout.LayoutParams attribParams = new LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT);

        addView(mAttributesView, attribParams);
    }

    /**
     * @param name class name
     */
    public ClassItemView setClassName(final CharSequence name) {
        mClassNameView.setText(name);
        return this;
    }

    /**
     * @param methods methods string
     */
    public ClassItemView setMethods(final CharSequence methods) {
        mMethodsView.setText(methods);
        return this;
    }

    /**
     * @param attrs methods string
     */
    public ClassItemView setAttributes(final CharSequence attrs) {
        mAttributesView.setText(attrs);
        return this;
    }
}

border_bg.xml

<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
    <item>
        <shape android:shape="rectangle">
            <stroke android:color="#0F0F0F" android:width="2dp"/>
        </shape>
    </item>
</layer-list>

结果将如下所示：