常用的工具（一 显示小红点）

显示圆点的：
复制下面这个类
public class BadgeView extends TextView {

public static final int POSITION_TOP_LEFT = 1;  
public static final int POSITION_TOP_RIGHT = 2;  
public static final int POSITION_BOTTOM_LEFT = 3;  
public static final int POSITION_BOTTOM_RIGHT = 4;  
public static final int POSITION_CENTER = 5;  

private static final int DEFAULT_MARGIN_DIP = 5;  
private static final int DEFAULT_LR_PADDING_DIP = 5;  
private static final int DEFAULT_CORNER_RADIUS_DIP = 8;  
private static final int DEFAULT_POSITION = POSITION_TOP_RIGHT;  
private static final int DEFAULT_BADGE_COLOR = Color.parseColor("#CCFF0000"); //Color.RED;  
private static final int DEFAULT_TEXT_COLOR = Color.WHITE;  

private static Animation fadeIn;  
private static Animation fadeOut;  

private Context context;  
private View target;  

private int badgePosition;  
private int badgeMarginH;  
private int badgeMarginV;  
private int badgeColor;  

private boolean isShown;  

private ShapeDrawable badgeBg;  

private int targetTabIndex;  

public BadgeView(Context context) {  
    this(context, (AttributeSet) null, android.R.attr.textViewStyle);  
}  

public BadgeView(Context context, AttributeSet attrs) {  
     this(context, attrs, android.R.attr.textViewStyle);  
}  

/**  
 * Constructor -  
 *   
 * create a new BadgeView instance attached to a target {@link View}.
 *  
 * @param context context for this view.  
 * @param target the View to attach the badge to.  
 */  
public BadgeView(Context context, View target) {  
     this(context, null, android.R.attr.textViewStyle, target, 0);  
}  

/**  
 * Constructor -  
 *   
 * create a new BadgeView instance attached to a target {@link TabWidget}
 * tab at a given index.  
 *  
 * @param context context for this view.  
 * @param target the TabWidget to attach the badge to.  
 * @param index the position of the tab within the target.  
 */  
public BadgeView(Context context, TabWidget target, int index) {  
    this(context, null, android.R.attr.textViewStyle, target, index);  
}  

public BadgeView(Context context, AttributeSet attrs, int defStyle) {  
    this(context, attrs, defStyle, null, 0);  
}  

public BadgeView(Context context, AttributeSet attrs, int defStyle, View target, int tabIndex) {
super(context, attrs, defStyle);
init(context, target, tabIndex);
}

private void init(Context context, View target, int tabIndex) {

   this.context = context;  
   this.target = target;  
   this.targetTabIndex = tabIndex;  

   // apply defaults  
   badgePosition = DEFAULT_POSITION;  
   badgeMarginH = dipToPixels(DEFAULT_MARGIN_DIP);  
   badgeMarginV = badgeMarginH;  
   badgeColor = DEFAULT_BADGE_COLOR;  

   setTypeface(Typeface.DEFAULT_BOLD);  
   int paddingPixels = dipToPixels(DEFAULT_LR_PADDING_DIP);  
   setPadding(paddingPixels, 0, paddingPixels, 0);  
   setTextColor(DEFAULT_TEXT_COLOR);  

   fadeIn = new AlphaAnimation(0, 1);  
   fadeIn.setInterpolator(new DecelerateInterpolator());  
   fadeIn.setDuration(200);  

   fadeOut = new AlphaAnimation(1, 0);  
   fadeOut.setInterpolator(new AccelerateInterpolator());  
   fadeOut.setDuration(200);  

   isShown = false;  

   if (this.target != null) {  
       applyTo(this.target);  
   } else {  
       show();  
   }  

}

private void applyTo(View target) {

   LayoutParams lp = target.getLayoutParams();  
   ViewParent parent = target.getParent();  
   FrameLayout container = new FrameLayout(context);  

   if (target instanceof TabWidget) {  

       // set target to the relevant tab child container  
       target = ((TabWidget) target).getChildTabViewAt(targetTabIndex);  
       this.target = target;  

       ((ViewGroup) target).addView(container,   
               new LayoutParams(LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT));  

       this.setVisibility(View.GONE);  
       container.addView(this);  

   } else {  

       // TODO verify that parent is indeed a ViewGroup  
       ViewGroup group = (ViewGroup) parent;   
       int index = group.indexOfChild(target);  

       group.removeView(target);  
       group.addView(container, index, lp);  

       container.addView(target);  

       this.setVisibility(View.GONE);  
       container.addView(this);  

       group.invalidate();  

   }  

}

/**
* Make the badge visible in the UI.
*
*/
public void show() {
show(false, null);
}

/**
* Make the badge visible in the UI.
*
* @param animate flag to apply the default fade-in animation.
*/
public void show(boolean animate) {
show(animate, fadeIn);
}

/**
* Make the badge visible in the UI.
*
* @param anim Animation to apply to the view when made visible.
*/
public void show(Animation anim) {
show(true, anim);
}

/**
* Make the badge non-visible in the UI.
*
*/
public void hide() {
hide(false, null);
}

/**
* Make the badge non-visible in the UI.
*
* @param animate flag to apply the default fade-out animation.
*/
public void hide(boolean animate) {
hide(animate, fadeOut);
}

/**
* Make the badge non-visible in the UI.
*
* @param anim Animation to apply to the view when made non-visible.
*/
public void hide(Animation anim) {
hide(true, anim);
}

/**
* Toggle the badge visibility in the UI.
*
*/
public void toggle() {
toggle(false, null, null);
}

/**
* Toggle the badge visibility in the UI.
*
* @param animate flag to apply the default fade-in/out animation.
*/
public void toggle(boolean animate) {
toggle(animate, fadeIn, fadeOut);
}

/**
* Toggle the badge visibility in the UI.
*
* @param animIn Animation to apply to the view when made visible.
* @param animOut Animation to apply to the view when made non-visible.
*/
public void toggle(Animation animIn, Animation animOut) {
toggle(true, animIn, animOut);
}

private void show(boolean animate, Animation anim) {
if (getBackground() == null) {
if (badgeBg == null) {
badgeBg = getDefaultBackground();
}
setBackgroundDrawable(badgeBg);
}
applyLayoutParams();

   if (animate) {  
       this.startAnimation(anim);  
   }  
   this.setVisibility(View.VISIBLE);  
   isShown = true;  

}

private void hide(boolean animate, Animation anim) {
this.setVisibility(View.GONE);
if (animate) {
this.startAnimation(anim);
}
isShown = false;
}

private void toggle(boolean animate, Animation animIn, Animation animOut) {
if (isShown) {
hide(animate && (animOut != null), animOut);
} else {
show(animate && (animIn != null), animIn);
}
}

/**
* Increment the numeric badge label. If the current badge label cannot be converted to
* an integer value, its label will be set to “0”.
*
* @param offset the increment offset.
*/
public int increment(int offset) {
CharSequence txt = getText();
int i;
if (txt != null) {
try {
i = Integer.parseInt(txt.toString());
} catch (NumberFormatException e) {
i = 0;
}
} else {
i = 0;
}
i = i + offset;
setText(String.valueOf(i));
return i;
}

/**
* Decrement the numeric badge label. If the current badge label cannot be converted to
* an integer value, its label will be set to “0”.
*
* @param offset the decrement offset.
*/
public int decrement(int offset) {
return increment(-offset);
}

private ShapeDrawable getDefaultBackground() {

   int r = dipToPixels(DEFAULT_CORNER_RADIUS_DIP);  
   float[] outerR = new float[] {r, r, r, r, r, r, r, r};  

   RoundRectShape rr = new RoundRectShape(outerR, null, null);  
   ShapeDrawable drawable = new ShapeDrawable(rr);  
   drawable.getPaint().setColor(badgeColor);  

   return drawable;  

}

private void applyLayoutParams() {

   FrameLayout.LayoutParams lp = new FrameLayout.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);  

   switch (badgePosition) {  
   case POSITION_TOP_LEFT:  
       lp.gravity = Gravity.LEFT | Gravity.TOP;  
       lp.setMargins(badgeMarginH, badgeMarginV, 0, 0);  
       break;  
   case POSITION_TOP_RIGHT:  
       lp.gravity = Gravity.RIGHT | Gravity.TOP;  
       lp.setMargins(0, badgeMarginV, badgeMarginH, 0);  
       break;  
   case POSITION_BOTTOM_LEFT:  
       lp.gravity = Gravity.LEFT | Gravity.BOTTOM;  
       lp.setMargins(badgeMarginH, 0, 0, badgeMarginV);  
       break;  
   case POSITION_BOTTOM_RIGHT:  
       lp.gravity = Gravity.RIGHT | Gravity.BOTTOM;  
       lp.setMargins(0, 0, badgeMarginH, badgeMarginV);  
       break;  
   case POSITION_CENTER:  
       lp.gravity = Gravity.CENTER;  
       lp.setMargins(0, 0, 0, 0);  
       break;  
   default:  
       break;  
   }  

   setLayoutParams(lp);  

}

/**
* Returns the target View this badge has been attached to.
*
*/
public View getTarget() {
return target;
}

/**
* Is this badge currently visible in the UI?
*
*/
@Override
public boolean isShown() {
return isShown;
}

/**
* Returns the positioning of this badge.
*
* one of POSITION_TOP_LEFT, POSITION_TOP_RIGHT, POSITION_BOTTOM_LEFT, POSITION_BOTTOM_RIGHT, POSTION_CENTER.
*
*/
public int getBadgePosition() {
return badgePosition;
}

/**
* Set the positioning of this badge.
*
* @param layoutPosition one of POSITION_TOP_LEFT, POSITION_TOP_RIGHT, POSITION_BOTTOM_LEFT, POSITION_BOTTOM_RIGHT, POSTION_CENTER.
*
*/
public void setBadgePosition(int layoutPosition) {
this.badgePosition = layoutPosition;
}

/**
* Returns the horizontal margin from the target View that is applied to this badge.
*
*/
public int getHorizontalBadgeMargin() {
return badgeMarginH;
}

/**
* Returns the vertical margin from the target View that is applied to this badge.
*
*/
public int getVerticalBadgeMargin() {
return badgeMarginV;
}

/**
* Set the horizontal/vertical margin from the target View that is applied to this badge.
*
* @param badgeMargin the margin in pixels.
*/
public void setBadgeMargin(int badgeMargin) {
this.badgeMarginH = badgeMargin;
this.badgeMarginV = badgeMargin;
}

/**
* Set the horizontal/vertical margin from the target View that is applied to this badge.
*
* @param horizontal margin in pixels.
* @param vertical margin in pixels.
*/
public void setBadgeMargin(int horizontal, int vertical) {
this.badgeMarginH = horizontal;
this.badgeMarginV = vertical;
}

/**
* Returns the color value of the badge background.
*
*/
public int getBadgeBackgroundColor() {
return badgeColor;
}

/**
* Set the color value of the badge background.
*
* @param badgeColor the badge background color.
*/
public void setBadgeBackgroundColor(int badgeColor) {
this.badgeColor = badgeColor;
badgeBg = getDefaultBackground();
}

private int dipToPixels(int dip) {
Resources r = getResources();
float px = TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, dip, r.getDisplayMetrics());
return (int) px;
}

}
在代码中使用下面的方法
BadgeView badgeView = new BadgeView(MessageFragment.this.mActivity, viewHolder.icon); // viewHolder.icon 是要显示的控件
badgeView.setText(mRepareTaskNum + “”);//显示的个数
badgeView.setTextColor(Color.WHITE);
badgeView.setBadgePosition(BadgeView.POSITION_TOP_RIGHT); // 判断显示的位置
badgeView.setAlpha(1f);
badgeView.setBadgeMargin(0, 0);
badgeView.show(); // 设置角标