android控件上面实现提醒信息

android开发中，经常会用到显示一个提醒信息，比如个人中心，有新信息，购买商品后，在购物车控件，显示购物数量等。我们可以用，2个控件来实现，或者用层叠图。

还有一种简单方便的办法，使用别人的开源代码来实现，使用很简单方便，通用。

效果图：

主类：不需要任何改动，直接可以用的。代码比较多，但是就一个java类，不需要知道它具体怎么实现，知道怎么用就行了。直接拷贝该java类到你的项目，就行了

package com.hck.badgeview;

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;
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 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;
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;
}

}

具体使用代码如下，有注释：

package com.hck.badgeview;

import android.os.Bundle;

import android.view.View;

import android.view.animation.BounceInterpolator;

import android.view.animation.TranslateAnimation;

import android.app.Activity;

import android.graphics.Color;

public class MainActivityextends Activity {

@Override

protectedvoid onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

}

public
void button1(View view) {

BadgeView
badge1 = new BadgeView(this, view);//创建一个BadgeView对象，view为你需要显示提醒信息的控件

//BadgeViewbadge1
= new BadgeView(this,
view,0); 在使用tabhost使用这个，view为

//TabWidget，0表示tabhost里面的第几个TabWidget

badge1.setText("12");
//显示类容

badge1.setBadgePosition(BadgeView.POSITION_CENTER);//显示的位置.中间，还有其他位置属性

badge1.setTextColor(Color.WHITE);
//文本颜色

badge1.setBadgeBackgroundColor(Color.RED); //背景颜色

badge1.setTextSize(12); //文本大小

badge1.setBadgeMargin(0, 0); //水平和竖直方向的间距

//badge1.setBadgeMargin(0);各边间距

/**

* 可以设置一个动画

// TranslateAnimation anim = new TranslateAnimation(-100, 0, 0, 0);

// anim.setInterpolator(new BounceInterpolator());

// anim.setDuration(1000);

// badge1.toggle(anim,null);

badge1.toggle(); //设置，还要加这句,已经显示则影藏，否则显示

//单纯的显示badge1.show();

//badge1.hiden();影藏

}

public
void button2(View view) {

BadgeView
badge1 = new BadgeView(this, view);

badge1.setText("你有新消息");

badge1.setBadgePosition(BadgeView.POSITION_TOP_RIGHT);

badge1.setTextColor(Color.RED);

badge1.setBadgeBackgroundColor(Color.YELLOW);

badge1.setTextSize(12);

badge1.toggle();

}

public
void button3(View view) {

BadgeView
badge1 = new BadgeView(this, view);

badge1.setText("呵呵呵");

badge1.setBadgePosition(BadgeView.POSITION_TOP_LEFT);

badge1.setTextColor(Color.DKGRAY);

badge1.setBadgeBackgroundColor(Color.YELLOW);

badge1.setTextSize(12);

TranslateAnimation anim = new TranslateAnimation(-100, 0, 0, 0);

anim.setInterpolator(new BounceInterpolator());

anim.setDuration(1000);

badge1.toggle(anim,null);

}

public
void button4(View view) {

BadgeView
badge1 = new BadgeView(this, view);

badge1.setText("你有新消息");

badge1.setBadgeMargin(30, 30);

badge1.setBadgePosition(BadgeView.POSITION_TOP_RIGHT);

badge1.setTextColor(Color.WHITE);

badge1.setBadgeBackgroundColor(Color.RED);

badge1.setTextSize(14);

badge1.toggle();

}

public
void button5(View view) {

}

xml：

<LinearLayoutxmlns:android="http://schemas.android.com/apk/res/android"

xmlns:tools="http://schemas.android.com/tools"

android:layout_width="match_parent"

android:layout_height="match_parent"

android:orientation="vertical">

<Button