在Android中動態(tài)添加Panel框架的實現(xiàn)代碼

更新時間：2013年05月09日 10:12:32 作者：

項目經(jīng)常會有這種需求，就是想動態(tài)的在某個界面上添加一個Panel。比如，有一個按鈕，點(diǎn)擊后會顯示下拉菜單式的界面。這種需求，就屬于動態(tài)添加一個Panel。需求多了，就要研究是否可以抽象出通用的框架代碼，以方便開發(fā)，所以就有了以下內(nèi)容

這里說是框架，說的大了點(diǎn)，其實沒有那么復(fù)雜，只是一個容易擴(kuò)展的基類而已。不過至少算是框架類的代碼。

復(fù)制代碼代碼如下:

package arui;  

import android.app.Activity;  
import android.os.Handler;  
import android.os.Looper;  
import android.os.Message;  
import android.view.Gravity;  
import android.view.LayoutInflater;  
import android.view.View;  
import android.view.ViewGroup.LayoutParams;  
import android.view.ViewManager;  
import android.widget.FrameLayout;  

/** 
 * Base class for panel. 
 *  
 */  
public abstract class BasePanel {  

    /** 
     * left up position 
     */  
    public static final int LEFT_UP = 1;  

    /** 
     * right up position 
     */  
    public static final int RIGHT_UP = 2;  

    /** 
     * left bottom position 
     */  
    public static final int LEFT_BOTTOM = 3;  

    /** 
     * right bottom position 
     */  
    public static final int RIGHT_BOTTOM = 4;  

    private static final int DEFAULT_MARGIN = 10;  

    private static final int SHOW_PANEL = 0;  

    private Activity activity;  

    private LayoutParams parameters;  

    private View view = null;  

    private int layoutId;  

    /** 
     * constructor. 
     *  
     * @param activity 
     *            this panel will be attached to the activity 
     * @param layoutId 
     *            the panel's layout id 
     */  
    public BasePanel(Activity activity, int layoutId) {  
        this.activity = activity;  
        this.layoutId = layoutId;  
    }  

    /** 
     * The developer can use this method to add the panel to the Activity. 
     *  
     * @param act 
     *            Activity 
     * @param params 
     *            LayoutParams 
     */  
    public void attach(LayoutParams params) {  
        parameters = params;  
        mHandler.sendMessage(mHandler.obtainMessage(SHOW_PANEL));  

    }  

    /** 
     * The developer can use this method to add the panel to the Activity. 
     *  
     * @param act 
     *            Activity 
     * @param position 
     *            int. You can use BasePanel.LEFT_UP,BasePanel.RIGHT_UP, 
     *            BasePanel.RIGHT_BOTTOM or BasePanel.LEFT_BOTTOM. 
     */  
    public void attach(int position) {  
        attach(position, DEFAULT_MARGIN, DEFAULT_MARGIN, DEFAULT_MARGIN,  
                DEFAULT_MARGIN);  
    }  

    /** 
     * The developer can use this method to add the panel to the Activity. 
     *  
     * @param act 
     *            Activity 
     * @param position 
     *            int. You can use BasePanel.LEFT_UP,BasePanel.RIGHT_UP, 
     *            BasePanel.RIGHT_BOTTOM or BasePanel.LEFT_BOTTOM. 
     * @param leftMargin 
     *            int, left margin. 
     * @param topMargin 
     *            int, top margin. 
     * @param rightMargin 
     *            int, right margin. 
     * @param bottomMargin 
     *            int, bottom margin. 
     *  
     */  
    public void attach(int position, int leftMargin, int topMargin,  
            int rightMargin, int bottomMargin) {  
        FrameLayout.LayoutParams params = null;  
        params = new FrameLayout.LayoutParams(LayoutParams.WRAP_CONTENT,  
                LayoutParams.WRAP_CONTENT);  
        params.setMargins(leftMargin, topMargin, rightMargin, bottomMargin);  
        switch (position) {  
        case LEFT_UP:  
            params.gravity = Gravity.LEFT;  
            break;  
        case RIGHT_UP:  
            params.gravity = Gravity.RIGHT;  
            break;  
        case LEFT_BOTTOM:  
            params.gravity = Gravity.LEFT | Gravity.BOTTOM;  
            break;  
        case RIGHT_BOTTOM:  
            params.gravity = Gravity.RIGHT | Gravity.BOTTOM;  
            break;  
        default:  
            break;  
        }  
        attach(params);  
    }  

    /** 
     * The developer can use this method to remove the panel from the Activity. 
     *  
     */  
    public void remove() {  
        if (view != null) {  
            ViewManager mViewManager = (ViewManager) view.getParent();  
            if (mViewManager != null) {  
                mViewManager.removeView(view);  
            }  
        }  
    }  

    private Handler mHandler = new Handler(Looper.getMainLooper()) {  

        @Override  
        public void handleMessage(Message msg) {  
            switch (msg.what) {  
            case SHOW_PANEL:  
                if (view == null) {  
                    LayoutInflater factory = LayoutInflater.from(activity);  
                    view = factory.inflate(layoutId, null);  
                }  
                dealwithPanel(view);  
                remove();  
                activity.addContentView(view, parameters);  
                break;  
            }  
        }  

    };  

    /** 
     * do something with this panel. 
     *  
     * @param view 
     *            View of the panel 
     */  
    public abstract void dealwithPanel(View view);  
}  