Android Shader应用开发之雷达扫描效果
本文实例为大家分享了Android雷达扫描效果的具体代码,供大家参考,具体内容如下
效果图
知识点提要
- Shader
- 矩阵matrix
- 属性动画
ShaderView3
package com.example.apple.shaderdemo; import android.content.Context; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.graphics.BitmapShader; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.Matrix; import android.graphics.Paint; import android.graphics.Shader; import android.graphics.SweepGradient; import android.support.annotation.Nullable; import android.util.AttributeSet; import android.view.View; /** * Created by apple on 2017/5/23. * 女神面部扫描 */ public class ShaderView3 extends View { /** * 绘制扫描圈的笔 */ private Paint mSweepPaint; /** * 绘制女神bitmap的笔 */ private Paint mBitmapPaint; /** * 这个自定义View的宽度,就是你在xml布局里面设置的宽度(目前不支持) */ private int mWidth; /** * 女神图片 */ private Bitmap mBitmap; /** * 雷达扫描旋转角度 */ private int degrees = 0; /** * 用于控制扫描圈的矩阵 */ Matrix mSweepMatrix = new Matrix(); /** * 用于控制女神Bitmap的矩阵 */ Matrix mBitmapMatrix = new Matrix(); /** * 着色器---生成扫描圈 */ private SweepGradient mSweepGradient; /** * 图片着色器 */ private BitmapShader mBitmapShader; private float mScale; public ShaderView3(Context context) { super(context); init(); } public ShaderView3(Context context, @Nullable AttributeSet attrs) { super(context, attrs); init(); } /** * 属性动画,必须有setXxx方法,才可以针对这个属性实现动画 * * @param degrees */ public void setDegrees(int degrees) { this.degrees = degrees; postInvalidate();//在主线程里执行OnDraw } private void init() { // 1.准备好画笔 mSweepPaint = new Paint(); mBitmapPaint = new Paint(); // 2.图片着色器 mBitmap = BitmapFactory.decodeResource(getResources(), R.drawable.ccc); mBitmapShader = new BitmapShader(mBitmap, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP); // 3.将图片着色器设置给画笔 mBitmapPaint.setShader(mBitmapShader); } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { super.onMeasure(widthMeasureSpec, heightMeasureSpec); // 获取这个自定义view的宽高,注意在onMeasure里获取,在构造函数里得到的是0 mWidth = getMeasuredWidth(); // 根据你所设置的view的尺寸和bitmap的尺寸计算一个缩放比例,否则的话,得到的图片是一个局部,而不是一整张图片 mScale = (float) mWidth / (float) mBitmap.getWidth(); // 4.梯度扫描着色器 mSweepGradient = new SweepGradient(mWidth / 2, mWidth / 2, new int[]{Color.argb(200, 200, 0, 0), Color.argb(10, 30, 0, 0)}, null); // 5.将梯度扫描着色器设置给另外一支画笔 mSweepPaint.setShader(mSweepGradient); } @Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); // 迫不得已的时候,才在onDraw方法写代码,能提前准备的要在之前去准备, // 不要写在onDraw里面,因为onDraw会不停地刷新绘制,写的代码越多,越影响效率 // 将图片缩放至你指定的自定义View的宽高 mBitmapMatrix.setScale(mScale, mScale); mBitmapShader.setLocalMatrix(mBitmapMatrix); // 设置扫描圈旋转角度 mSweepMatrix.setRotate(degrees, mWidth / 2, mWidth / 2); mSweepGradient.setLocalMatrix(mSweepMatrix); // 5. 使用设置好图片着色器的画笔,画圆,先画出下层的女神图片,在画出上层的扫描图片 canvas.drawCircle(mWidth / 2, mWidth / 2, mWidth / 2, mBitmapPaint); canvas.drawCircle(mWidth / 2, mWidth / 2, mWidth / 2, mSweepPaint); } }
外部调用
package com.example.apple.shaderdemo; import android.animation.ObjectAnimator; import android.animation.ValueAnimator; import android.os.Bundle; import android.support.v7.app.AppCompatActivity; import android.view.View; import android.view.animation.LinearInterpolator; public class MainActivity extends AppCompatActivity { private ShaderView3 mShaderView; int degrees = 0; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); mShaderView = (ShaderView3) findViewById(R.id.sv); mShaderView.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { ObjectAnimator degrees = ObjectAnimator.ofInt(mShaderView, "degrees", 0, 360); degrees.setInterpolator(new LinearInterpolator()); degrees.setDuration(10000); degrees.setRepeatCount(ValueAnimator.INFINITE); degrees.start(); /* new Thread(new Runnable() { @Override public void run() { while (degrees <= 360) { degrees += 1; mShaderView.setDegrees(degrees); try { Thread.sleep(30); } catch (InterruptedException e) { e.printStackTrace(); } } } }).start(); degrees = 0; mShaderView.setDegrees(degrees);*/ } }); } }
XML布局
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" tools:context="com.example.apple.shaderdemo.MainActivity"> <com.example.apple.shaderdemo.ShaderView3 android:id="@+id/sv" android:layout_width="300dp" android:layout_height="300dp" /> </LinearLayout>
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