自定义控件（1）---初探之不断闪烁的圆环

来源：互联网发布：张曼玉演技知乎编辑：程序博客网时间：2024/06/05 09:51

小案例的原理：

1、new Thread(mCustomView).start();

2、public class CustomView extends View implements Runnable

3、

<strong>public void run() {/*确保线程不断执行不断刷新界面*/while (true) {try {/*如果半径小于200则自加否则大于200后重置半径值以实现往复*/if (radiu <= 200) {radiu += 10;//刷新ViewpostInvalidate();} else {radiu = 0;}// 每执行一次暂停40毫秒Thread.sleep(40);} catch (InterruptedException e) {e.printStackTrace();}}}</strong>

activity_main.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:background="#FFFFFF"    android:orientation="vertical" >    <com.aigestudio.customviewdemo.views.CustomView        android:id="@+id/main_cv"        android:layout_width="match_parent"        android:layout_height="match_parent" /></LinearLayout>

MainActivity

package com.aigestudio.customviewdemo.activities;import android.app.Activity;import android.os.Bundle;import com.aigestudio.customviewdemo.R;import com.aigestudio.customviewdemo.views.CustomView;/** * 主界面 */public class MainActivity extends Activity {private CustomView mCustomView;// 我们的自定义View@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);// 获取控件mCustomView = (CustomView) findViewById(R.id.main_cv);/* * 开线程 */new Thread(mCustomView).start();}}

MeasureUtil

package com.aigestudio.customviewdemo.views;import android.app.Activity;import android.util.DisplayMetrics;/** * 测绘工具类 */public final class MeasureUtil {/** * 获取屏幕尺寸 *  * @param activity *            Activity * @return 屏幕尺寸像素值，下标为0的值为宽，下标为1的值为高 */public static int[] getScreenSize(Activity activity) {DisplayMetrics metrics = new DisplayMetrics();activity.getWindowManager().getDefaultDisplay().getMetrics(metrics);return new int[] { metrics.widthPixels, metrics.heightPixels };}}

package com.aigestudio.customviewdemo.views;import android.app.Activity;import android.content.Context;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Paint;import android.util.AttributeSet;import android.view.View;/** * 自定义View */public class CustomView extends View implements Runnable {private Paint mPaint;// 画笔private Context mContext;// 上下文环境引用private int radiu;// 圆环半径public CustomView(Context context) {this(context, null);}public CustomView(Context context, AttributeSet attrs) {super(context, attrs);mContext = context;// 初始化画笔initPaint();}/** * 初始化画笔 */private void initPaint() {// 实例化画笔并打开抗锯齿mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);/* * 设置画笔样式为描边，圆环嘛……当然不能填充不然就么意思了 *  * 画笔样式分三种： * 1.Paint.Style.STROKE：描边 * 2.Paint.Style.FILL_AND_STROKE：描边并填充 * 3.Paint.Style.FILL：填充 */mPaint.setStyle(Paint.Style.STROKE);// 设置画笔颜色为浅灰色mPaint.setColor(Color.LTGRAY);/* * 设置描边的粗细，单位：像素px * 注意：当setStrokeWidth(0)的时候描边宽度并不为0而是只占一个像素 */mPaint.setStrokeWidth(10);}@Overrideprotected void onDraw(Canvas canvas) {super.onDraw(canvas);// 绘制圆环canvas.drawCircle(MeasureUtil.getScreenSize((Activity) mContext)[0] / 2, MeasureUtil.getScreenSize((Activity) mContext)[1] / 2, radiu, mPaint);}@Overridepublic void run() {/* * 确保线程不断执行不断刷新界面 */while (true) {try {/* * 如果半径小于200则自加否则大于200后重置半径值以实现往复 */if (radiu <= 200) {radiu += 10;// 刷新ViewpostInvalidate();} else {radiu = 0;}// 每执行一次暂停40毫秒Thread.sleep(40);} catch (InterruptedException e) {e.printStackTrace();}}}}

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