java代码实现相对布局

用java代码实现相对布局

1：扫描指定文件夹下的所有图片，用一个ImageSwitcher显示出来。

2：在ImageSwitcher的底部，添加相应的按钮，可以在各图片之间切换。

package gto.ImageSwitchTest;

import java.io.File;
import java.io.FileReader;

import android.R.drawable;
import android.app.Activity;
import android.graphics.drawable.Drawable;
import android.os.Bundle;
import android.os.Environment;
import android.text.AlteredCharSequence;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.FrameLayout;
import android.widget.ImageSwitcher;
import android.widget.ImageView;
import android.widget.RelativeLayout;
import android.widget.RelativeLayout.LayoutParams;
import android.widget.ViewSwitcher.ViewFactory;

public class ImageSwitchTest extends Activity implements OnClickListener,ViewFactory{
    /** Called when the activity is first created. */
    
    private File[] m_imgList;
    private ImageSwitcher m_ImageSwitch;
    private static int    m_picIndex;    
    private static int IMAGESWITCHER_ID = 0x123456;
    private static int ButtonStartID = 0x2000000;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        
        //创建一个相对布局
        RelativeLayout main_View = new RelativeLayout(this);
        //创建一个ImageSwitcher
        m_ImageSwitch = new ImageSwitcher(this);
        
        //在相对布局中添加图片切换器
        RelativeLayout.LayoutParams param = new RelativeLayout.LayoutParams(LayoutParams.FILL_PARENT,LayoutParams.FILL_PARENT);
        main_View.addView(m_ImageSwitch,param);
        m_ImageSwitch.setId(IMAGESWITCHER_ID);
        m_ImageSwitch.setFactory(this);
        
        File file = Environment.getExternalStorageDirectory();
        String strPic = file + "\\mag\\mag01\\";
        File magdir = new File(strPic);
        m_imgList = magdir.listFiles();

        Drawable myDrawable = Drawable.createFromPath(m_imgList[m_picIndex].toString());
        m_ImageSwitch.setImageDrawable(myDrawable);
        
        setContentView(main_View);
        
        //创建按钮
        int count = m_imgList.length;
        for(int i = count - 1; i >= 0; --i)
        {
            Button btn = new Button(this);
            btn.setId(ButtonStartID + i);
            btn.setText(Integer.toString(i));
            btn.setOnClickListener(this);
            
            param = new RelativeLayout.LayoutParams(20,20);
            if( count - 1 == i ){
                param.addRule(RelativeLayout.ALIGN_PARENT_RIGHT);
            }
            else{
                param.addRule(RelativeLayout.LEFT_OF,ButtonStartID + i + 1);
            }
            param.addRule(RelativeLayout.ALIGN_PARENT_BOTTOM);
            btn.setLayoutParams(param);
             main_View.addView(btn,param);
        }
    }
    
    @Override
    public void onClick(View v) {
        // TODO Auto-generated method stub
        m_picIndex = v.getId() - ButtonStartID;
        Drawable myDrawable = Drawable.createFromPath(m_imgList[m_picIndex].toString());
        m_ImageSwitch.setImageDrawable(myDrawable);
    }
    
    @Override
    public View makeView() {
        // TODO Auto-generated method stub
        return new ImageView(this);
    }
}