本文主要是介绍自定义气泡背景View，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！
今天来实现一个自定义气泡背景：先来张图（那些泡泡会跑的。。。
）
看起来很高端？你要是这么想那你就输了
，接下来就看看是怎么实现的。
这个就是一个自定义View，其实自定义View也就是重写那么几个方法，onDraw（），onMeasure（）。还是直接来看代码吧，注视里面都有的
package com.tianzhao.myapplication;import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.view.View;
import java.util.Random;/*** Created by tianzhao on 2015/10/25.* Date 21:38*/
public class CircleView extends View {private int circleSum;//圆的数量private int circleRadio;//圆的半径private int circleColor;//圆的颜色private int backColor;//背景颜色private Paint backPaint;//背景画笔private Paint circlePaint;//圆的画笔private Circle[] circles;private int[] direction = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10};private Random random;private float width;private float height;private int[] location = new int[2];private MyThread mMyThread;private boolean running = true;public CircleView(Context context) {super(context);backPaint = new Paint();init();}public CircleView(Context context, AttributeSet attrs) {super(context, attrs);TypedArray ta = context.obtainStyledAttributes(attrs, R.styleable.CircleView);circleSum = ta.getInteger(R.styleable.CircleView_circleSum, 10);circleColor = ta.getColor(R.styleable.CircleView_circleColor, Color.parseColor("#7756ffff"));backColor = ta.getColor(R.styleable.CircleView_backColor, Color.parseColor("#21efef"));circleRadio = ta.getInteger(R.styleable.CircleView_circleRadio, 60);ta.recycle();init();}/*** 初始化画笔*/private void init() {backPaint = new Paint();backPaint.setColor(backColor);circlePaint = new Paint();circlePaint.setColor(circleColor);}/*** 比onDraw先执行* <p/>* 一个MeasureSpec封装了父布局传递给子布局的布局要求，每个MeasureSpec代表了一组宽度和高度的要求。* 一个MeasureSpec由大小和模式组成* 它有三种模式：UNSPECIFIED(未指定),父元素部队自元素施加任何束缚，子元素可以得到任意想要的大小;* EXACTLY(完全)，父元素决定自元素的确切大小，子元素将被限定在给定的边界里而忽略它本身大小；* AT_MOST(至多)，子元素至多达到指定大小的值。* <p/>* 它常用的三个函数：* 1.static int getMode(int measureSpec):根据提供的测量值(格式)提取模式(上述三个模式之一)* 2.static int getSize(int measureSpec):根据提供的测量值(格式)提取大小值(这个大小也就是我们通常所说的大小)* 3.static int makeMeasureSpec(int size,int mode):根据提供的大小值和模式创建一个测量值(格式)*/@Overrideprotected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {super.onMeasure(widthMeasureSpec, heightMeasureSpec);//获取控件宽度width = getMeasuredWidth();//获取控件高度height = getMeasuredHeight();//获取控件相对于父控件的位置坐标this.getLocationInWindow(location);//初始化圆initCircle();}/*** 初始化圆*/private void initCircle() {circles = new Circle[circleSum];random = new Random();for (int i = 0; i < circleSum; i++) {int d = random.nextInt(direction.length);int x = random.nextInt((int) width);int y = random.nextInt((int) height);circles[i] = new Circle(x, y, d);}}@Overrideprotected void onDraw(Canvas canvas) {//绘制背景canvas.drawRect(0, 0, location[0] + width, location[1] + height, backPaint);//遍历绘制每一个圆for (Circle c : circles) {canvas.drawCircle(c.getX(), c.getY(), circleRadio, circlePaint);}if (mMyThread == null) {mMyThread = new MyThread();mMyThread.start();}}/*** 不在窗口显示的时候停止线程*/@Overrideprotected void onDetachedFromWindow() {running = false;super.onDetachedFromWindow();}class MyThread extends Thread {@Overridepublic void run() {while (running) {for (int i = 0; i < circleSum; i++) {Circle c = circles[i];changeDirection(c);//超出边界后重置方向if (c.getX() > width || c.getX() < 0 || c.getY() > height || c.getY() < 0) {int d;while (true) {d = random.nextInt(direction.length);int lastD = c.getDirection();if ((lastD == 0 || lastD == 4 || lastD == 6 || lastD == 8 || lastD == 10) && (d == 0 || d == 4 || d == 6 || d == 8 || d == 10)) {//上continue;} else if ((lastD == 1 || lastD == 5 || lastD == 7 || lastD == 9) && (d == 1 || d == 5 || d == 7 || d == 9)) {//下continue;} else if ((lastD == 2 || lastD == 4 || lastD == 5 || lastD == 8 || lastD == 9) && (d == 2 || d == 4 || d == 5 || d == 8 || d == 9)) {//左continue;} else if ((lastD == 3 || lastD == 6 || lastD == 7 || lastD == 10) && (d == 3 || d == 6 || d == 7 || d == 10)) {//右continue;}break;}circles[i].setDirection(d);}}try {Thread.sleep(30);} catch (InterruptedException e) {e.printStackTrace();}postInvalidate();}}private void changeDirection(Circle c) {float dx = 0.3f;switch (c.getDirection()) {case 0://上c.setY(c.getY() - dx);break;case 1://下c.setY(c.getY() + dx);break;case 2://左c.setX(c.getX() - dx);break;case 3://右c.setX(c.getX() + dx);break;case 4://左上c.setX(c.getX() - dx);c.setY(c.getY() - dx);break;case 5://左下c.setX(c.getX() - dx);c.setY(c.getY() + dx);break;case 6://右上c.setX(c.getX() + dx);c.setY(c.getY() - dx);break;case 7://右下c.setX(c.getX() + dx);c.setY(c.getY() + dx);break;case 8://左上c.setX(c.getX() - dx);c.setY(c.getY() - dx * 2);break;case 9://左下c.setX(c.getX() - dx * 2);c.setY(c.getY() + dx);break;case 10://右上c.setX(c.getX() + dx);c.setY(c.getY() - dx * 2);break;}}}class Circle {private float x;private float y;private int direction;public Circle(float x, float y, int d) {this.x = x;this.y = y;this.direction = d;}public float getX() {return x;}public void setX(float x) {this.x = x;}public void setY(float y) {this.y = y;}public float getY() {return y;}public void setDirection(int direction) {this.direction = direction;}public int getDirection() {return direction;}}}
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"android:layout_width="match_parent"android:layout_height="match_parent"><com.tianzhao.myapplication.CircleViewxmlns:cv="http://schemas.android.com/apk/res/com.tianzhao.myapplication" //自己的命名空间android:layout_width="fill_parent"android:layout_height="200dp"cv:circleSum="10" //圆的数量cv:circleColor="#7756ffff" //圆的颜色cv:backColor="#21efef"/> //背景颜色<RelativeLayoutandroid:layout_width="fill_parent"android:layout_height="200dp"><ImageViewandroid:id="@+id/iv"android:layout_width="80dp"android:layout_height="80dp"android:layout_centerInParent="true"android:background="@drawable/user" /><TextViewandroid:layout_width="wrap_content"android:layout_height="wrap_content"android:layout_below="@id/iv"android:layout_centerHorizontal="true"android:layout_marginTop="5dp"android:text="登录"android:textSize="20dp" /></RelativeLayout><LinearLayoutandroid:layout_width="wrap_content"android:layout_height="40dp"android:layout_centerHorizontal="true"android:layout_marginTop="230dp"><TextViewandroid:layout_width="wrap_content"android:layout_height="wrap_content"android:gravity="center_vertical"android:text="用户名:"android:textSize="20dp" /><EditTextandroid:layout_width="200dp"android:layout_height="wrap_content"android:layout_marginLeft="5dp"android:gravity="center_vertical" /></LinearLayout><LinearLayoutandroid:layout_width="wrap_content"android:layout_height="40dp"android:layout_centerHorizontal="true"android:layout_marginTop="280dp"><TextViewandroid:layout_width="wrap_content"android:layout_height="wrap_content"android:gravity="center_vertical"android:text="密 码:"android:textSize="20dp" /><EditTextandroid:layout_width="200dp"android:layout_height="wrap_content"android:layout_marginLeft="5dp"android:gravity="center_vertical" /></LinearLayout>
</RelativeLayout>
<?xml version="1.0" encoding="utf-8"?>
<resources><declare-styleable name="CircleView"><attr name="circleSum" format="integer"></attr><attr name="circleColor" format="color"></attr><attr name="backColor" format="color"></attr><attr name="circleRadio" format="integer"></attr></declare-styleable>
</resources>
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