Android 给scrollView添加毛玻璃效果的标题栏

淡淡的烟草味﹌ 2022-08-18 15:15 222阅读 0赞

效果如下

![Center][]

首先是布局文件，头部的标题栏是个压在scrollview上面的自定义控件

下面是自定义的scrollVIew，其实就是把里面探测scrollView滚动的方法给暴露到监听器上去

package com.npi.blureffect;
    
    import android.content.Context;
    import android.util.AttributeSet;
    import android.util.Log;
    import android.widget.ScrollView;
    
    public class CustomScrollView extends ScrollView {
    	private ScrollViewListener scrollViewListener;
    	public CustomScrollView(Context context) {
    		super(context);
    		// TODO Auto-generated constructor stub
    	}
    
    	public interface ScrollViewListener {  
    		  
    	    void onScrollChanged(CustomScrollView scrollView, int x, int y, int oldx, int oldy);  
    	  
    	}  
    	 public CustomScrollView(Context context, AttributeSet attrs,  
    	            int defStyle) {  
    	        super(context, attrs, defStyle);  
    	    }  
    	  
    	    public CustomScrollView(Context context, AttributeSet attrs) {  
    	        super(context, attrs);  
    	    }  
    	  
    	  
    	 public void setScrollViewListener(ScrollViewListener scrollViewListener) {  
    	        this.scrollViewListener = scrollViewListener;  
    	    }  
    	  
    	    @Override  
    	    protected void onScrollChanged(int x, int y, int oldx, int oldy) {  
    	        super.onScrollChanged(x, y, oldx, oldy);  
    	        if (scrollViewListener != null) {  
    	            scrollViewListener.onScrollChanged(this, x, y, oldx, oldy);  
    	        }  
    //	        Log.i("Alex", "$$$x是:"+x+" oldx是:"+oldx+"  Y是"+y+"oldY是"+oldy);
    	    }  
    	    
    	    
    }

然后是最主要的activity

package com.npi.blureffect;
 
 
 import java.io.FileNotFoundException;
 import java.io.FileOutputStream;
 import java.io.IOException;
 
 
 import com.npi.blureffect.CustomScrollView.ScrollViewListener;
 
 
 import android.app.Activity;
 import android.graphics.Bitmap;
 import android.graphics.Canvas;
 import android.graphics.Matrix;
 import android.os.Bundle;
 import android.util.Log;
 import android.view.Menu;
 import android.view.MenuItem;
 import android.view.MotionEvent;
 import android.view.View;
 import android.view.View.OnTouchListener;
 import android.widget.ScrollView;
 
 
 public class ScrollViewActivity extends Activity {
 
 ScrollableImageView header;
 CustomScrollView scrollView ;
 Bitmap screen;
 	@Override
 	protected void onCreate(Bundle savedInstanceState) {
 	super.onCreate(savedInstanceState);
 	setContentView(R.layout.activity_scroll_view);
 	header = (ScrollableImageView) findViewById(R.id.blurred_image_header);
 	scrollView = (CustomScrollView) findViewById(R.id.scrollView1);
 	initScrollView(header, scrollView);
 
 }
 	public void  initScrollView(final ScrollableImageView header,final CustomScrollView scrollView){
 	scrollView.setScrollViewListener(new ScrollViewListener() {
 	
 	@Override
 	public void onScrollChanged(CustomScrollView scrollView, int x, int y,
 	int oldx, int oldy) {
 	// TODO Auto-generated method stub
 	Log.i("Alex", "x是:"+x+" oldx是:"+oldx+"  Y是"+y+"oldY是"+oldy);
 	header.handleScroll(y, 0);
 	}
 	});
 
 	scrollView.post(new Runnable() {
 	@Override
 	public void run() {
 	// TODO Auto-generated method stub
 	screen = getBitmapByView(scrollView);
 	header.setoriginalImage(screen);
 	}
 	});
 }
 
 
 	/**
    * 截取scrollview的屏幕
    * **/
   public static Bitmap getBitmapByView(ScrollView scrollView) {
       int h = 0;
       Bitmap bitmap = null;
       // 获取listView实际高度
       for (int i = 0; i < scrollView.getChildCount(); i++) {
           h += scrollView.getChildAt(i).getHeight();
       }
       Log.d("Alex", "实际高度:" + h);
       Log.d("Alex", " 高度:" + scrollView.getHeight());
       // 创建对应大小的bitmap
       bitmap = Bitmap.createBitmap(scrollView.getWidth(), h,
               Bitmap.Config.ARGB_8888);
       final Canvas canvas = new Canvas(bitmap);
       scrollView.draw(canvas);
      
       return bitmap;
   }
  
 
 
 }

这里用到的自定义图片控件和模糊工具类请到我之前的博客去查看

[Center]: /images/20220731/f3406634694d43f68a0b3ad1a0a1bcac.png