Android 底部导航栏添加消息数目提示

效果图

写一篇短小精悍，好用的知识积累吧。开发中时常会出现信息提醒，新内容提示等等一堆问题。其实就是在各种控件或者是item上面加“小圆点”。网上一搜一大堆。。。但是感觉说的好多。我们只需要基本功能2333.
下面介绍三种方式吧，但是大体套路相同。

一、解需求思路

在 RadioGroup 的 RadioButton 上面直接加小圆点，对于我来说实现有点困难，因为我下面还有文字。搞不好，文字就挤没了。所有我现在在原有的 RadioGroup 上面加一层覆盖物，类似于 ui 常常接触的图层。

二、布局

就是在原有的 RadioGroup 上覆盖一层透明的 button 并且保证位置相同相同

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns: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:background="@color/colorGrayBg"tools:context="cn.ln80.happybirdcloud119.activity.MainActivity"><android.support.v4.view.ViewPagerandroid:id="@+id/vp_main_page"android:layout_width="match_parent"android:layout_height="match_parent"android:layout_marginBottom="61dp" /><!--底栏--><RadioGroupandroid:id="@+id/rg_main_bottom"android:layout_width="match_parent"android:layout_height="@dimen/iconsize_60"android:layout_alignParentBottom="true"android:background="@android:color/white"android:orientation="horizontal"><RadioButtonandroid:id="@+id/rb_main_task"style="@style/BottomRadio"android:drawableTop="@drawable/bg_bottom_task"android:text="可视化"android:textColor="@drawable/txt_bottom_notify" /><RadioButtonandroid:id="@+id/rb_main_notify"style="@style/BottomRadio"android:layout_height="match_parent"android:drawableTop="@drawable/bg_bottom_notify"android:text="通知"android:textColor="@drawable/txt_bottom_notify" /><RadioButtonandroid:id="@+id/rb_main_home"style="@style/BottomRadio"android:layout_marginTop="@dimen/widget_margin_5"android:checked="true"android:drawableTop="@drawable/bg_bottom_home"android:text="主页"android:textColor="@drawable/txt_bottom_notify" /><RadioButtonandroid:id="@+id/rb_main_inspect"style="@style/BottomRadio"android:drawableTop="@drawable/bg_bottom_inspect"android:text="巡检"android:textColor="@drawable/txt_bottom_notify" /><RadioButtonandroid:id="@+id/rb_main_mine"style="@style/BottomRadio"android:drawableTop="@drawable/bg_bottom_mine"android:text="我的"android:textColor="@drawable/txt_bottom_notify" /></RadioGroup><LinearLayoutandroid:layout_width="match_parent"android:layout_height="@dimen/iconsize_60"android:layout_alignParentBottom="true"android:orientation="horizontal"><Buttonandroid:id="@+id/btn_main_task"android:layout_width="0dp"android:layout_height="match_parent"android:layout_weight="1"android:background="@null" /><Buttonandroid:id="@+id/btn_main_notification"android:layout_width="0dp"android:layout_height="match_parent"android:layout_weight="1"android:background="@null" /><Buttonandroid:id="@+id/btn_main_home"android:layout_width="0dp"android:layout_height="match_parent"android:layout_weight="1"android:background="@null" /><Buttonandroid:id="@+id/btn_main_inspect"android:layout_width="0dp"android:layout_height="match_parent"android:layout_weight="1"android:background="@null" /><Buttonandroid:id="@+id/btn_main_my"android:layout_width="0dp"android:layout_height="match_parent"android:layout_weight="1"android:background="@null" /></LinearLayout>
</RelativeLayout>

三、第一种方式

import android.content.Context;
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.Log;
import android.util.TypedValue;
import android.view.Gravity;
import android.view.View;
import android.view.ViewGroup;
import android.widget.FrameLayout;
import android.widget.LinearLayout;
import android.widget.TabWidget;/*** Content：* Actor：韩小呆 ヾ(ﾟ▽ﾟ)ノ* Time:  2018/8/6 17:47* Update:* Time:*/
public class BadgeView extends android.support.v7.widget.AppCompatTextView {private boolean mHideOnNull = true;public BadgeView(Context context) {this(context, null);}public BadgeView(Context context, AttributeSet attrs) {this(context, attrs, android.R.attr.textViewStyle);}public BadgeView(Context context, AttributeSet attrs, int defStyle) {super(context, attrs, defStyle);init();}private void init() {if (!(getLayoutParams() instanceof LinearLayout.LayoutParams)) {LinearLayout.LayoutParams layoutParams =new LinearLayout.LayoutParams(android.view.ViewGroup.LayoutParams.WRAP_CONTENT,android.view.ViewGroup.LayoutParams.WRAP_CONTENT,Gravity.END | Gravity.TOP);setLayoutParams(layoutParams);}// set default fontsetTextColor(Color.WHITE);setTypeface(Typeface.DEFAULT_BOLD);setTextSize(TypedValue.COMPLEX_UNIT_SP, 11);setPadding(dip2Px(5), dip2Px(1), dip2Px(5), dip2Px(1));// set default backgroundsetBackground(9, Color.parseColor("#d3321b"));setGravity(Gravity.CENTER);// default valuessetHideOnNull(true);setBadgeCount(0);}public void setBackground(int dipRadius, int badgeColor) {int radius = dip2Px(dipRadius);float[] radiusArray = new float[]{radius, radius, radius, radius, radius, radius, radius, radius};RoundRectShape roundRect = new RoundRectShape(radiusArray, null, null);ShapeDrawable bgDrawable = new ShapeDrawable(roundRect);bgDrawable.getPaint().setColor(badgeColor);setBackground(bgDrawable);}/*** @return Returns true if view is hidden on badge value 0 or null;*/public boolean isHideOnNull() {return mHideOnNull;}/*** @param hideOnNull the hideOnNull to set*/public void setHideOnNull(boolean hideOnNull) {mHideOnNull = hideOnNull;setText(getText());}/** (non-Javadoc)** @see android.widget.TextView#setText(java.lang.CharSequence, android.widget.TextView.BufferType)*/@Overridepublic void setText(CharSequence text, BufferType type) {if (isHideOnNull() && (text == null || text.toString().equalsIgnoreCase("0"))) {setVisibility(View.GONE);} else {setVisibility(View.VISIBLE);}super.setText(text, type);}public void setBadgeCount(int count) {setText(String.valueOf(count));}public Integer getBadgeCount() {if (getText() == null) {return null;}String text = getText().toString();try {return Integer.parseInt(text);} catch (NumberFormatException e) {return null;}}public void setBadgeGravity(int gravity) {FrameLayout.LayoutParams params = (FrameLayout.LayoutParams) getLayoutParams();params.gravity = gravity;setLayoutParams(params);}public int getBadgeGravity() {FrameLayout.LayoutParams params = (FrameLayout.LayoutParams) getLayoutParams();return params.gravity;}public void setBadgeMargin(int dipMargin) {setBadgeMargin(dipMargin, dipMargin, dipMargin, dipMargin);}public void setBadgeMargin(int leftDipMargin, int topDipMargin, int rightDipMargin, int bottomDipMargin) {FrameLayout.LayoutParams params = (FrameLayout.LayoutParams) getLayoutParams();params.leftMargin = dip2Px(leftDipMargin);params.topMargin = dip2Px(topDipMargin);params.rightMargin = dip2Px(rightDipMargin);params.bottomMargin = dip2Px(bottomDipMargin);setLayoutParams(params);}public int[] getBadgeMargin() {FrameLayout.LayoutParams params = (FrameLayout.LayoutParams) getLayoutParams();return new int[]{params.leftMargin, params.topMargin, params.rightMargin, params.bottomMargin};}public void incrementBadgeCount(int increment) {Integer count = getBadgeCount();if (count == null) {setBadgeCount(increment);} else {setBadgeCount(increment + count);}}public void decrementBadgeCount(int decrement) {incrementBadgeCount(-decrement);}/** Attach the BadgeView to the TabWidget** @param target the TabWidget to attach the BadgeView** @param tabIndex index of the tab*/public void setTargetView(TabWidget target, int tabIndex) {View tabView = target.getChildTabViewAt(tabIndex);setTargetView(tabView);}/** Attach the BadgeView to the target view** @param target the view to attach the BadgeView*/public void setTargetView(View target) {if (getParent() != null) {((ViewGroup) getParent()).removeView(this);}if (target == null) {return;}if (target.getParent() instanceof FrameLayout) {((FrameLayout) target.getParent()).addView(this);} else if (target.getParent() instanceof ViewGroup) {ViewGroup parentContainer = (ViewGroup) target.getParent();int groupIndex = parentContainer.indexOfChild(target);parentContainer.removeView(target);FrameLayout badgeContainer = new FrameLayout(getContext());ViewGroup.LayoutParams parentLayoutParams = target.getLayoutParams();badgeContainer.setLayoutParams(parentLayoutParams);target.setLayoutParams(new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT));parentContainer.addView(badgeContainer, groupIndex, parentLayoutParams);badgeContainer.addView(target);badgeContainer.addView(this);} else if (target.getParent() == null) {Log.e(getClass().getSimpleName(), "ParentView is needed");}}/** converts dip to px*/private int dip2Px(float dip) {return (int) (dip * getContext().getResources().getDisplayMetrics().density + 0.5f);}
}

将这个代码直接 C、V 到自己的类内，然后在使用的地方直接填写如下代码：

   BadgeView badgeView = new BadgeView(this);badgeView.setTargetView(btnMainNotification);badgeView.setBadgeCount(12);badgeView.setBackground(20, getResources().getColor(R.color.colorRed));

这个自定义的代码是一位外国大佬搞出来的，原版代码在这，欢迎查阅：BadgeView。

这里面的一些属性：

    //设置依附的控件setTargetView(View) //设置显示的数字setBadgeCount(int) //设置显示的位置setBadgeGravity(Gravity) //设置背景色setBackgroundColor() //设置背景图片setBackgroundResource() //设置显示字体  比如说加粗、倾斜、啥的setTypeface() //设置字体阴影setShadowLayer()

四、第二种方式

引用这位大佬的依赖：BadgeView ---> compile 'q.rorbin:badgeview:1.1.3'

代码代码中使用：

new QBadgeView(this).bindTarget(btnMainNotification).setBadgeText("99+").setBadgeBackgroundColor(getResources().getColor(R.color.colorRed));

可以返回一个 Badge 对象提高开发者操作。

一些常用属性

          //设置Badge数字setBadgeNumber(int i);//设置Badge文本setBadgeText(String text);  //设置文本字体大小setBadgeTextSize(int size); // 设置文本颜色setBadgeTextColor();//设置是否显示精确模式数值setExactMode();//设置Badge相对于TargetView的位置setBadgeGravity(); //设置外边距setGravityOffset();//设置内边距setBadgePadding();//设置背景色setBadgeBackgroundColor(); //设置背景图片setBadgeBackground();//设置是否显示阴影setShowShadow();//打开拖拽消除模式并设置监听setOnDragStateChangedListener();//描边stroke();//隐藏Badgehide();

官方的演示

五、最后一种实现方式

BGABadgeView-Android

六、总结

总体的实现思路就是，在底部导航栏覆盖一层透明的布局，然后在透明布局内的控件上面依赖（寄生）上小圆点。