@Override 
public void drawableStateChanged() { 
    Drawable background = getBackground(); 
    if(background != null) { 
        if(!isEnabled()) { 
            background.setColorFilter(Color.GRAY, PorterDuff.Mode.MULTIPLY); 
        } else { 
            background.setColorFilter(null); 
        } 
    } 
} 

引用来的没有亲测 备用吧

FileOutputStream fos = openFileOutput("urls.txt", Context.MODE_PRIVATE); 
fos.write("Alex".getBytes()); 
fos.close(); 

FileInputStream fis = openFileInput("urls.txt"); 
int c; 
while((c=fis.read())!=-1) 
        { 
 
            k += (char)c; 
        } 
fis.close(); 
http://developer.android.com/guide/topics/data/data-storage.html#filesInternal

listView 有时候项目太少占用空间太大，如何能够自动控制

自适用大小

package com.customcontrols; 
public class NoScrollListView extends ListView 
{ 
    @Override 
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) 
    { 
        super.onMeasure(widthMeasureSpec, MeasureSpec.makeMeasureSpec(MeasureSpec.UNSPECIFIED, 0) ); 
 
        // here I assume that height's being calculated for one-child only, seen it in ListView's source which is actually a bad idea 
        int childHeight = getMeasuredHeight() - (getListPaddingTop() + getListPaddingBottom() +  getVerticalFadingEdgeLength() * 2); 
 
        int fullHeight = getListPaddingTop() + getListPaddingBottom() + childHeight*(getCount()); 
 
        setMeasuredDimension(getMeasuredWidth(), fullHeight); 
    } 
}