http://blog.csdn.net/shaojie519/article/details/7026916

我们在使用如短信类的软件是时会有未看短信数字的提醒，本人在论坛看到这个效果，就给大家分享一下：

最重要的是BadgeView这个重写TextView的类：

import android.content.Context;
import android.content.res.Resources;
import android.graphics.Color;
import android.graphics.Typeface;
import android.graphics.drawable.ShapeDrawable;
import android.graphics.drawable.shapes.RoundRectShape;
import android.util.AttributeSet;
import android.util.TypedValue;
import android.view.Gravity;
import android.view.View;
import android.view.ViewGroup;
import android.view.ViewGroup.LayoutParams;
import android.view.ViewParent;
import android.view.animation.AccelerateInterpolator;
import android.view.animation.AlphaAnimation;
import android.view.animation.Animation;
import android.view.animation.DecelerateInterpolator;
import android.widget.FrameLayout;
import android.widget.TabWidget;
import android.widget.TextView;

/**
* A simple text label view that can be applied as a "badge" to any given {@link android.view.View}.
* This class is intended to be instantiated at runtime rather than included in XML layouts.
*
* @author Jeff Gilfelt
*/
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;

    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.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 badgeMargin;
    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 android.view.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 android.widget.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;
        badgeMargin = dipToPixels(DEFAULT_MARGIN_DIP);
        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(badgeMargin, badgeMargin,  0, 0);
            break;
        case POSITION_TOP_RIGHT:
            lp.gravity = Gravity.RIGHT | Gravity.TOP;
            lp.setMargins(0, badgeMargin, badgeMargin, 0);
            break;
        case POSITION_BOTTOM_LEFT:
            lp.gravity = Gravity.LEFT | Gravity.BOTTOM;
            lp.setMargins(badgeMargin,  0, 0, badgeMargin);
            break;
        case POSITION_BOTTOM_RIGHT:
            lp.gravity = Gravity.RIGHT | Gravity.BOTTOM;
            lp.setMargins(0, 0, badgeMargin, badgeMargin);
            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.
     *
     */
    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.
     *
     */
    public void setBadgePosition(int layoutPosition) {
        this.badgePosition = layoutPosition;
    }

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

    /**
     * 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.badgeMargin = badgeMargin;
    }

    /**
     * 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;
    }

}

import android.content.Context; import android.content.res.Resources; import android.graphics.Color; import android.graphics.Typeface; import android.graphics.drawable.ShapeDrawable; import android.graphics.drawable.shapes.RoundRectShape; import android.util.AttributeSet; import android.util.TypedValue; import android.view.Gravity; import android.view.View; import android.view.ViewGroup; import android.view.ViewGroup.LayoutParams; import android.view.ViewParent; import android.view.animation.AccelerateInterpolator; import android.view.animation.AlphaAnimation; import android.view.animation.Animation; import android.view.animation.DecelerateInterpolator; import android.widget.FrameLayout; import android.widget.TabWidget; import android.widget.TextView; /** * A simple text label view that can be applied as a "badge" to any given {@link android.view.View}. * This class is intended to be instantiated at runtime rather than included in XML layouts. * * @author Jeff Gilfelt */ 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; 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.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 badgeMargin; 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 android.view.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 android.widget.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; badgeMargin = dipToPixels(DEFAULT_MARGIN_DIP); 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(badgeMargin, badgeMargin, 0, 0); break; case POSITION_TOP_RIGHT: lp.gravity = Gravity.RIGHT | Gravity.TOP; lp.setMargins(0, badgeMargin, badgeMargin, 0); break; case POSITION_BOTTOM_LEFT: lp.gravity = Gravity.LEFT | Gravity.BOTTOM; lp.setMargins(badgeMargin, 0, 0, badgeMargin); break; case POSITION_BOTTOM_RIGHT: lp.gravity = Gravity.RIGHT | Gravity.BOTTOM; lp.setMargins(0, 0, badgeMargin, badgeMargin); 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. * */ 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. * */ public void setBadgePosition(int layoutPosition) { this.badgePosition = layoutPosition; } /** * Returns the horizontal/vertical margin from the target View that is applied to this badge. * */ public int getBadgeMargin() { return badgeMargin; } /** * 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.badgeMargin = badgeMargin; } /** * 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; } }
现在我们来使用它;

import android.app.Activity;
import android.graphics.Color;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.animation.BounceInterpolator;
import android.view.animation.TranslateAnimation;
import android.widget.Button;

public class BadgerActivity extends Activity {
    /** Called when the activity is first created. */
    Button  btn ;
    Button  btn1 ;
    BadgeView badge;
    BadgeView badge1;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        btn =(Button) findViewById(R.id.btn);
        btn1 =(Button) findViewById(R.id.btn1);

        badge = new BadgeView(this,btn);
        badge.setText("0");
        btn.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
              if(badge.isShown()){
                  badge.increment(1);
              }else{
                  badge.show();
              }
            }
        });
        badge1 = new BadgeView(this, btn1);
        badge1.setText("123");
        badge1.setBadgePosition(BadgeView.POSITION_TOP_LEFT);
        badge1.setBadgeMargin(15);
        badge1.setBadgeBackgroundColor(Color.parseColor("#A4C639"));
        btn1.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                TranslateAnimation anim =  new TranslateAnimation(-100, 0, 0, 0);
                anim.setInterpolator(new BounceInterpolator());
                anim.setDuration(1000);
                badge1.toggle(anim, null);
            }
        });

    }
}

import android.app.Activity; import android.graphics.Color; import android.os.Bundle; import android.view.View; import android.view.View.OnClickListener; import android.view.animation.BounceInterpolator; import android.view.animation.TranslateAnimation; import android.widget.Button; public class BadgerActivity extends Activity { /** Called when the activity is first created. */ Button btn ; Button btn1 ; BadgeView badge; BadgeView badge1; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); btn =(Button) findViewById(R.id.btn); btn1 =(Button) findViewById(R.id.btn1); badge = new BadgeView(this,btn); badge.setText("0"); btn.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { // TODO Auto-generated method stub if(badge.isShown()){ badge.increment(1); }else{ badge.show(); } } }); badge1 = new BadgeView(this, btn1); badge1.setText("123"); badge1.setBadgePosition(BadgeView.POSITION_TOP_LEFT); badge1.setBadgeMargin(15); badge1.setBadgeBackgroundColor(Color.parseColor("#A4C639")); btn1.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { TranslateAnimation anim = new TranslateAnimation(-100, 0, 0, 0); anim.setInterpolator(new BounceInterpolator()); anim.setDuration(1000); badge1.toggle(anim, null); } }); } }
BadgeView原始项目上传csdn,http://download.csdn.net/detail/shaojie519/3861841