Android实现未读消息小红点显示实例
目录
- 代码实现
- 小红点实现
- 总结
使用 fragmentlayout 实现,可以把小红点添加到任意 view 上。
效果 添加小红点到 textview 上

添加小红点到 imageview 上

代码实现
首先定义一个圆形 drawable
import android.graphics.canvas;
import android.graphics.colorfilter;
import android.graphics.paint;
import android.graphics.pixelformat;
import android.graphics.drawable.drawable;
import android.graphics.drawable.shapedrawable;
import androidx.annotation.intrange;
import androidx.annotation.nonnull;
import androidx.annotation.nullable;
public class circledrawable extends shapedrawable {
private paint mpaint;
private int mradio;
public circledrawable(int radio, int paincolor) {
mpaint = new paint();
mpaint.setantialias(true);
mpaint.setcolor(paincolor);
mradio = radio;
}
@override
public void draw(@nonnull canvas canvas) {
canvas.drawcircle(mradio, mradio, mradio, mpaint);
}
@override
public void setalpha(@intrange(from = 0, to = 255) int i) {
mpaint.setalpha(i);
}
@override
public void setcolorfilter(@nullable colorfilter colorfilter) {
mpaint.setcolorfilter(colorfilter);
}
@override
public int getopacity() {
return pixelformat.translucent;
}
/***
* drawable实际宽高,圆形关键
*
* @return
*/
@override
public int getintrinsicwidth() {
return mradio * 2;
}
@override
public int getintrinsicheight() {
return mradio * 2;
}
}
小红点实现
思路:
一个容器 fragmentlayout 包含两个 view (小红点view + 文本view 「当然也可以是其他的view」),通过 fragmentlayout 添加 view 重叠的特征实现
当前有待优化点:
1、通过 margin 实现小红点可以添加到任意位置「可以是有 layoutparams margin 实现」
2、其他
import android.content.context;
import android.graphics.canvas;
import android.graphics.color;
import android.graphics.rect;
import android.graphics.drawable.colordrawable;
import android.graphics.drawable.shapedrawable;
import android.graphics.drawable.shapes.ovalshape;
import android.graphics.drawable.shapes.roundrectshape;
import android.util.attributeset;
import android.util.printer;
import android.view.gravity;
import android.view.view;
import android.view.viewgroup;
import android.widget.framelayout;
import android.widget.textview;
import androidx.annotation.nullable;
import com.primer.common.constant.gravitydirection;
import com.primer.common.mvp.logininterface;
import com.primer.common.util.loghelper;
import com.primer.common.util.uihelper;
import com.primer.common.view.drawable.circledrawable;
public class badgeview extends textview {
private final int default_badge_radio = 5;
private final int default_text_size = 5;
private final int default_text_color = color.white;
private final int default_badge_color = color.red;
private final int default_badge_gravity = gravitydirection.direct_top_left;
private string mtext;
private int mbadgecolor = default_badge_color;
private int mtextcolor = default_text_color;
private int mtextsize = default_text_size;
private int mbadgeradio = default_badge_radio;
private int mbadgegravity = default_badge_gravity;
private framelayout mfragmentlayout;
private viewgroup mtargetviewgroup;
private view mtarget;
private context mcontext;
public badgeview(context context) {
super(context);
init(context);
}
public badgeview(context context, @nullable attributeset attrs) {
super(context, attrs);
init(context);
}
public badgeview(context context, @nullable attributeset attrs, int defstyleattr) {
super(context, attrs, defstyleattr);
init(context);
}
public badgeview(context context, @nullable attributeset attrs, int defstyleattr, int defstyleres) {
super(context, attrs, defstyleattr, defstyleres);
init(context);
}
private void init(context context) {
mfragmentlayout = new framelayout(context);
mfragmentlayout.setlayoutparams(new framelayout.layoutparams(
viewgroup.layoutparams.match_parent, viewgroup.layoutparams.match_parent));
mcontext = context;
}
/***
*
* @param content
* @param target
* @param textcolor
* @param textsize
* @param badgecolor
* @param badgeradio
*/
public void showbadgeview(string content, view target, int textcolor, int textsize, int badgecolor, int badgeradio) {
if (target == null) {
throw new illegalargumentexception("target view must not be null");
}
mtarget = target;
mtargetviewgroup = (viewgroup) target.getparent();
mtargetviewgroup.removeview(target);
mtargetviewgroup.addview(mfragmentlayout, target.getlayoutparams());
settextcolor(mtextcolor);
settextsize(mtextsize);
setgravity(gravity.center);
if (content != null && content.length() <= 3) {
settext(content);
}
//文字和半径之间的适配
if (content != null) {
rect rect = new rect();
this.getpaint().gettextbounds(content, 0, content.length(), rect);
if (content.length() <= 3 && rect.width() >= mbadgeradio) {
mbadgeradio = (uihelper.px2dip(mcontext, rect.width()) / 2) + 1;
}
}
setbackgrounddrawable(getshapedrawable());
mfragmentlayout.addview(target);
mfragmentlayout.addview(this);
mtargetviewgroup.invalidate();
}
private shapedrawable getshapedrawable() {
int radio = uihelper.dip2px(mcontext, mbadgeradio);
circledrawable drawable = new circledrawable(radio, mbadgecolor);
return drawable;
}
/***
*
* @param content
* @param target
*/
public void showbadgeview(string content, view target) {
showbadgeview(content, target,
default_text_color,
default_text_size,
default_badge_color,
default_badge_radio);
}
public void showbadgeview(view target) {
showbadgeview(null, target,
default_text_color,
default_text_size,
default_badge_color,
default_badge_radio);
}
@override
protected void onmeasure(int widthmeasurespec, int heightmeasurespec) {
super.onmeasure(widthmeasurespec, heightmeasurespec);
}
@override
protected void ondraw(canvas canvas) {
super.ondraw(canvas);
}
@override
protected void onlayout(boolean changed, int left, int top, int right, int bottom) {
super.onlayout(changed, left, top, right, bottom);
}
}
使用
private badgeview mreadbadgeview;
private textview mread;
mreadbadgeview = new badgeview(getactivity());
mreadbadgeview.showbadgeview("+99", mread);
总结
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