【代码】android 遮罩层效果

本文主要是介绍【代码】android 遮罩层效果，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

看到一本电子杂志上有遮罩层的效果，感觉很漂亮，以为很麻烦，搜索了很多关于android遮罩层的，也没有得出一点思路，原来就是一个透明的效果，然后上面弹出的控件是透明或者半透明之类的，可以选择颜色，还是#ARBG，其中A就是传说中的透明色的值（可以根据需要设置透明的效果），废话不多说了，发一个简单的Demo吧，是我山寨的那本杂志的效果：（由于杂志内容主要是图片，弹出层才是给出的文字信息，所以我猜测是用Gallery显示的杂志内容）

xml布局文件：

<?xml version="1.0" encoding="utf-8"?>   
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"   android:id="@+id/layout"   android:layout_width="fill_parent"   android:layout_height="fill_parent"   >   <Gallery   android:id="@+id/showGallery"   android:layout_width="fill_parent"   android:layout_height="fill_parent"   android:spacing="0dip"   />   <RelativeLayout   android:orientation="horizontal"   android:layout_width="fill_parent"   android:layout_height="wrap_content"   android:layout_gravity="bottom"   android:background="#86222222"   >   <TextView   android:id="@+id/titleTextView"   android:layout_width="wrap_content"   android:layout_height="wrap_content"   android:layout_toRightOf="@id/secondKillButton"  android:text="00000000" android:textColor="#ff0000"   />   <Button   android:id="@+id/unfoldButton"   android:layout_width="wrap_content"   android:layout_height="wrap_content"   android:layout_alignParentRight="true"   android:text="展开"   />   </RelativeLayout>   
</FrameLayout>

主要的代码也很简单，还有一个简单的Adapter，有不理解的朋友可以看我之前的blog

[java]

view plaincopy 
package oneRain.UpMagazine;  
import java.io.File;  
import java.util.ArrayList;  
import java.util.List;  
import android.app.Activity;  
import android.graphics.Bitmap;  
import android.graphics.BitmapFactory;  
import android.graphics.Color;  
import android.os.Bundle;  
import android.view.Gravity;  
import android.view.View;  
import android.view.View.OnClickListener;  
import android.view.ViewGroup;  
import android.view.Window;  
import android.widget.AdapterView;  
import android.widget.AdapterView.OnItemSelectedListener;  
import android.widget.BaseAdapter;  
import android.widget.Button;  
import android.widget.FrameLayout;  
import android.widget.Gallery;  
import android.widget.ImageView;  
import android.widget.TextView;  
public class ShowActivity extends Activity  
{  private int i = 1;  private int pos = 0;  private List<String> contents = null;  private static final String DIR = "/mnt/sdcard/UpMagazine/2010/content/";  //设置是否展开  private boolean isFolded = true;  //设置控件  private FrameLayout layout = null;  private Gallery showGallery = null;  private Button unfoldButton = null;  private TextView textView = null;  private TextView titleTextView = null;  public void onCreate(Bundle savedInstanceState)  {  super.onCreate(savedInstanceState);  requestWindowFeature(Window.FEATURE_NO_TITLE);  setContentView(R.layout.show);  initView();  }  @Override  protected void onResume()   {  // TODO Auto-generated method stu  super.onResume();  isFolded = true;  }  //初始化  private void initView()  {     contents = new ArrayList<String>();  File dir = new File(DIR);  File[] files = dir.listFiles();  for(int i=0; i<files.length; i++)  {  contents.add(DIR + files[i].getName());  }  layout = (FrameLayout)findViewById(R.id.layout);  unfoldButton = (Button)findViewById(R.id.unfoldButton);  unfoldButton.setOnClickListener(new UnfoldClickListener());  showGallery = (Gallery)findViewById(R.id.showGallery);  showGallery.setOnItemSelectedListener(new GalleryOnItemSelectedListener());  showGallery.setAdapter(new ShowAdapter());  titleTextView = (TextView)findViewById(R.id.titleTextView);  }  //滑动监听  private class GalleryOnItemSelectedListener implements OnItemSelectedListener  {  public void onItemSelected(AdapterView<?> arg0, View arg1, int arg2,  long arg3)   {  // TODO Auto-generated method stub  pos = arg2 + 1;  titleTextView.setText("第" + pos +"个主题");  }  public void onNothingSelected(AdapterView<?> arg0)  {  // TODO Auto-generated method stub  }  }  //按钮监听，展开一个透明的显示文本的遮挡层  private class UnfoldClickListener implements OnClickListener  {  public void onClick(View v)   {         if(isFolded)  {  textView = new TextView(ShowActivity.this);  textView.setTextColor(Color.BLUE);  textView.setTextSize(20);  textView.setText("滚滚长江东逝水，浪花淘尽英雄。/n" +  "是非成败转头空，/n" +  "青山依旧在，几度夕阳红。/n" +  "白发渔樵江渚上，惯看秋月春风。 /n" +  "一壶浊酒喜相逢，/n" +  "古今多少事，都付笑谈中。");  textView.setGravity(Gravity.CENTER);  textView.setLayoutParams(new ViewGroup.LayoutParams(ViewGroup.LayoutParams.FILL_PARENT,   ViewGroup.LayoutParams.FILL_PARENT));  textView.setBackgroundColor(Color.parseColor("#86222222"));  unfoldButton.setText("收回");  isFolded = false;  layout.addView(textView);  }  else  {  unfoldButton.setText("展开");  isFolded = true;  layout.removeView(textView);  }  }  }  private class ShowAdapter extends BaseAdapter  {  public int getCount()   {  // TODO Auto-generated method stub  return contents.size();  }  public Object getItem(int position)   {  // TODO Auto-generated method stub  return position;  }  public long getItemId(int position)   {  // TODO Auto-generated method stub  return 0;  }  public View getView(int position, View convertView, ViewGroup parent)   {  // TODO Auto-generated method stub  ImageView i = new ImageView(ShowActivity.this);  Bitmap bm = BitmapFactory.decodeFile(contents.get(position));  
//          i.setLayoutParams(new Gallery.LayoutParams(Gallery.LayoutParams.FILL_PARENT,  
//                  Gallery.LayoutParams.FILL_PARENT));  i.setScaleType(ImageView.ScaleType.FIT_XY);  i.setImageBitmap(bm);  return i;  }  }  
}

效果如下：