Android仿微信雷达辐射搜索好友(逻辑清晰实现简单)

<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="@drawable/photo" ><com.lgl.radarsearch.RadarViewandroid:layout_width="match_parent"android:layout_height="match_parent" /><ImageViewandroid:layout_width="wrap_content"android:layout_height="wrap_content"android:layout_centerInParent="true"android:src="@drawable/circle_photo" /></RelativeLayout>

RadarViewpackage com.lgl.radarsearch;import android.content.Context;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Matrix;import android.graphics.Paint;import android.graphics.Paint.Style;import android.graphics.Shader;import android.graphics.SweepGradient;import android.os.Handler;import android.util.AttributeSet;import android.view.View;/*** 雷达搜索* * @author LGL**/public class RadarView extends View {/*** 思路：我们首先初始化画笔，并且获取到控件的宽高，在onMeasure()中设置铺满，然后在onDraw()方法中绘制四个静态圆和一个渐变圆，* 我们通过Matrix矩阵来让他不停的旋转就达到我们想要的效果了*/private Paint mPaintLine, mPaintCircle;private int w, h;// 动画private Matrix matrix;// 旋转角度private int start;// Handler定时动画private Handler handler = new Handler();private Runnable run = new Runnable() {@Overridepublic void run() {start = start + 1;matrix = new Matrix();// 参数：旋转角度，围绕点坐标的x,y坐标点matrix.postRotate(start, w / 2, h / 2);// 刷新重绘RadarView.this.invalidate();// 继续循环handler.postDelayed(run, 60);}};public RadarView(Context context, AttributeSet attrs) {super(context, attrs);initView();// 获取高宽w = context.getResources().getDisplayMetrics().widthPixels;h = context.getResources().getDisplayMetrics().heightPixels;// 一致旋转handler.post(run);}private void initView() {mPaintLine = new Paint();mPaintLine.setColor(Color.WHITE);mPaintLine.setAntiAlias(true);mPaintLine.setStyle(Style.STROKE);mPaintCircle = new Paint();mPaintCircle.setColor(Color.RED);mPaintCircle.setAntiAlias(true);matrix = new Matrix();}/*** 测量* * @author LGL*/@Overrideprotected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {// 设置铺满setMeasuredDimension(w, h);}@Overrideprotected void onDraw(Canvas canvas) {super.onDraw(canvas);// 画四个圆形canvas.drawCircle(w / 2, h / 2, w / 2, mPaintLine);canvas.drawCircle(w / 2, h / 2, w / 3, mPaintLine);canvas.drawCircle(w / 2, h / 2, w * 7 / 10, mPaintLine);canvas.drawCircle(w / 2, h / 2, w / 4, mPaintLine);// 绘制渐变圆Shader mShader = new SweepGradient(w / 2, h / 2, Color.TRANSPARENT,Color.parseColor("#AAAAAAAA"));// 绘制时渐变mPaintCircle.setShader(mShader);// 增加旋转动画，使用矩阵实现canvas.concat(matrix); // 前置动画canvas.drawCircle(w / 2, h / 2, w * 7 / 10, mPaintCircle);}}