点缀-----未读信息小圆点的简洁实现
在微信，qq等聊天软件中经常可见未读消息，如下图：
通常的显示方式就是在某个控件的右上角出现一个小圆点，圆点中显示未读消息的条数，那么此功能怎么实现呢？最容易想到的大概是用布局实现，但是略显麻烦，现在有BadgeView类出现了，将更加简洁的实现这一功能。
好废话不多说，先上 BadgeView 代码：
package com.example.test;
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);
}
@SuppressWarnings("deprecation")
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);
}
/**将计数归零**/
public void clearCrement(){
CharSequence txt=getText();
int index=0;
if(txt!=null){
try {
index = Integer.parseInt(txt.toString());
} catch (NumberFormatException e) {
index = 0;
}
}
decrement(index);
}
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;
}
}
ok,对于 BadgeView的代码大家可以有时间再慢慢研究，下面主要给大家讲讲BadgeView的一些简单用法：下面以给 TextView 设置 小圆点 为例：
首先是 声明：
public class MainActivity extends Activity{
private TextView mTextView;
private BadgeView mBadgeView;
初始化TextView
mTextView=(TextView) findViewById(R.id.textView1);BadgeView 初始化，包括给 mTextView 设置小圆点
mBadgeView=new BadgeView(this, mTextView);//this 是 activity对应的上下文mBadgeView.setBadgeMargin(5);
mBadgeView.setBadgePosition(BadgeView.POSITION_TOP_RIGHT);setBadgeMargin是来调微间距的，若 setBadgePosition 设置的是 上左，则 setBadgeMargin 中的参数表示 BadgeView 在 mTextView中距 mTextView 上边和左边的距离，其他类似
设置 BadgeView 的显示和隐藏
mBadgeView.toggle();//当BadgeView不可见时，调用后BadgeView可见，当BadgeView可见时，调用后BadgeView不可见，调用时BadgeView的显隐不带动画效果
mBadgeView.toggle(true);//当BadgeView不可见时，调用后BadgeView可见，当BadgeView可见时，调用后BadgeView不可见,设置显示隐藏(含默认动画)
mBadgeView.isShown();//判断BadgeView是否可见
mBadgeView.show();//设置mBadgeView可见
mBadgeView.hide();//设置 mBadgeView不可见设置显示文本/字体颜色/字体大小
mBadgeView.setText("2");
mBadgeView.setTextSize(16);
mBadgeView.setTextColor(Color.BLUE);设置背景颜色
//mBadgeView.setBackgroundColor(Color.GREEN);//设置不含圆角的背景
mBadgeView.setBadgeBackgroundColor(Color.GREEN);//设置圆角背景用户自定义动画
// 设置进入的移动动画，设置了插值器，可以实现颤动的效果
TranslateAnimation anim = new TranslateAnimation(-100, 0, 0, 0);
anim.setInterpolator(new BounceInterpolator());
// 设置动画的持续时间
anim.setDuration(1000);
// 设置退出的移动动画
TranslateAnimation anim2 = new TranslateAnimation(0, -100, 0, 0);
anim2.setDuration(500);
mBadgeView.toggle(anim, anim2); 设置用户自定义的背景图片
mBadgeView.setBackgroundResource(R.drawable.badge_ifaux); if(!mBadgeView.isShown()){
mBadgeView.show();
}
mBadgeView.increment(1); 设置点击事件
mBadgeView.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
Toast.makeText(MainActivity.this, "pppp", 0).show();
if (mBadgeView.isShown()) {
//清除mBadgeView计数
mBadgeView.clearCrement();
//隐藏
mBadgeView.hide();
}
}
});//在tab上显示小圆点
TabWidget tabs = (TabWidget) findViewById(android.R.id.tabs);
mBadgeView = new BadgeView(this, tabs, 2); //this为上下文，2表示要显示小圆点的 标签的下标下面就是 一些 BadgeView 在布局中的使用了
看了 BadgeView 的代码应该知道
/**
* 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);
}
BadgeView 的初始化的第二个参数为 view ，所以当 布局中需要使用小圆点时，我们可以这样
BadgeView badge;
View target;
// *** test linear layout container ***
target = findViewById(R.id.linear_target);
badge = new BadgeView(this, target);
badge.setText("OK");
badge.show();
// *** test relative layout container ***
target = findViewById(R.id.relative_target);
badge = new BadgeView(this, target);
badge.setText("OK");
badge.show();
// *** test frame layout container ***
target = findViewById(R.id.frame_target);
badge = new BadgeView(this, target);
badge.setText("OK");
badge.show();
// *** test table layout container ***
target = findViewById(R.id.table_target);
badge = new BadgeView(this, target);
badge.setText("OK");
badge.show();
// *** test linear layout ***
target = findViewById(R.id.linear_group_target);
badge = new BadgeView(this, target);
badge.setText("OK");
badge.show();
// *** test relative layout ***
target = findViewById(R.id.relative_group_target);
badge = new BadgeView(this, target);
badge.setText("OK");
badge.show();
// *** test frame layout ***
target = findViewById(R.id.frame_group_target);
badge = new BadgeView(this, target);
badge.setText("OK");
badge.show();
// *** test table layout ***
target = findViewById(R.id.tablerow_group_target);
badge = new BadgeView(this, target);
badge.setText("OK");
badge.show();这样，布局中就可以显示小圆点了。
最后加点小提示：
1.由于我用到 BadgeView时要显示消息条目数，为了避免消息条数过多，如 100,1000或者更多导致 BadgeView变形压到其他信息，我们可以设置当 消息数目在100以下时显 示实际条数，超过99就显示“99+”
2.当我们要设置小圆点显示在TextView 的右上角时，当 BadgeView 中内容过多，势必会向左边拉长（因为我们设置的位置为setBadgePosition(BadgeView.POSITION_TOP_RIGHT)）那么，为了避免 BadgeView向左扩展压到 TextView中的内容，我们可以在 TextView的右边紧挨着它再放一个控件，然后将 TextView设置在新添加控件的 左上角处，适当调整此控件和 TextView 的边距，这样就可以让 BadgeView 中内容扩展时，向右延伸，不至于压到 TextView 中的内容。