今天一朋友问了我计类似下图的效果，很多人会说简单啊一个framelayout布局就解决了，没错是可以实现该功能需求。但是如果是以前的老项目，运用的RadioGroup就会有一个问题，导航栏根本就不存在布局!所以这里会谈到另一种解决方案。
该方法运用的是GitHub上一个开源的工具类BadgeView，在RadioGroup的布局之上覆盖一层透明的LinearLayout用于消息提示。废话不多说，让我们一起体验下。
首先你需要把BadgeView拷贝到你的项目中，这里我已经为你准备好了该工具类
**
* @author:程龙 date; On 2018/9/4
*/
public class BadgeView extends android.support.v7.widget.AppCompatTextView {
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 = 1;
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;
/**
* Color.RED;
*/
private static final int DEFAULT_BADGE_COLOR = Color.parseColor("#CCFF0000");
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 -
* <p>
* 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 -
* <p>
* 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) {
ViewGroup.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 ViewGroup.LayoutParams(ViewGroup.LayoutParams.FILL_PARENT, ViewGroup.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(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.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, 0, 0, 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.
* <p>
* 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;
}
}
接着在你的RadioGroup布局中覆盖一层透明的LinearLayout布局，如下
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:focusable="false">
<View
android:layout_width="match_parent"
android:layout_height="1.0px"
android:layout_above="@+id/main_radio_group"
android:background="@android:color/black" />
<RadioGroup
android:id="@+id/main_radio_group"
android:layout_width="match_parent"
android:layout_height="80dp"
android:layout_alignParentBottom="true"
android:gravity="center_vertical"
android:orientation="horizontal">
<RadioButton
android:id="@+id/radio_btn_home"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:checked="true"
android:drawableTop="@mipmap/ic_launcher"
android:gravity="center_horizontal"
android:text="one" />
<RadioButton
android:id="@+id/radio_btn_house"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:checked="false"
android:drawableTop="@mipmap/ic_launcher"
android:gravity="center_horizontal"
android:text="two" />
<RadioButton
android:id="@+id/radio_btn_forum"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:checked="false"
android:drawableTop="@mipmap/ic_launcher"
android:gravity="center_horizontal"
android:text="three" />
<RadioButton
android:id="@+id/radio_btn_group"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:checked="false"
android:drawableTop="@mipmap/ic_launcher"
android:gravity="center_horizontal"
android:text="four" />
<RadioButton
android:id="@+id/radio_btn_person"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:checked="false"
android:button="@null"
android:drawableTop="@mipmap/ic_launcher"
android:gravity="center_horizontal"
android:text="five" />
</RadioGroup>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="80dp"
android:layout_alignParentBottom="true"
android:background="#00000000"
android:orientation="horizontal">
<Button
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:background="#00000000"
android:visibility="invisible" />
<Button
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:visibility="invisible" />
<Button
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:background="#00000000"
android:visibility="invisible" />
<Button
android:id="@+id/btn_msg"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:visibility="invisible" />
<Button
android:id="@+id/btn_my"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:visibility="invisible" />
</LinearLayout>
</RelativeLayout>
最后在activity中设置BadgeView，如下
public class RedDotActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_red_dot);
//覆盖在RadioGroup之上LinearLayout的第五个占位子布局
Button button5 = (Button) findViewById(R.id.btn_my);
remind(button5);
}
private void remind(View view) { //BadgeView的具体使用
// 创建一个BadgeView对象，view为你需要显示提醒的控件
BadgeView badge1 = new BadgeView(this, view);
// 需要显示的提醒类容
badge1.setText("12");
// 显示的位置.右上角,BadgeView.POSITION_BOTTOM_LEFT,下左，还有其他几个属性
badge1.setBadgePosition(BadgeView.POSITION_TOP_RIGHT);
// 文本颜色
badge1.setTextColor(Color.WHITE);
// 提醒信息的背景颜色，自己设置
badge1.setBadgeBackgroundColor(Color.RED);
//还可以设置背景图片
//badge1.setBackgroundResource(R.mipmap.icon_message_png);
// 文本大小
badge1.setTextSize(12);
// 水平和竖直方向的间距
//badge1.setBadgeMargin(3, 3);
//各边间隔
badge1.setBadgeMargin(5);
//显示效果，如果已经显示，则隐藏，如果隐藏，则显示
// badge1.toggle();
// 显示
badge1.show();
//隐藏
// badge1.hide();
}
}
到此消息提醒功能就做好了，有什么问题欢迎留言交流。
