Android ThreadUtil 线程公共类，判断是否在主线程/ 子线程执行 相关操作

 /** * 加载网络图片 */ private void loadImage() { try { //用延时3秒操作来模拟网络操作 Thread.sleep( 3000 ); } catch (InterruptedException e) { e.printStackTrace(); } } 

package com.app; import android.os.Looper; /** * Created by ${zyj} on 2016/6/7. */ public class ThreadUtil { /** * Throws an {@link java.lang.IllegalArgumentException} if called on a thread other than the main thread. */ public static void assertMainThread() { if (!isOnMainThread()) { throw new IllegalArgumentException("You must call this method on the main thread"); } } /** * Throws an {@link java.lang.IllegalArgumentException} if called on the main thread. */ public static void assertBackgroundThread() { if (!isOnBackgroundThread()) { throw new IllegalArgumentException("YOu must call this method on a background thread"); } } /** * Returns {@code true} if called on the main thread, {@code false} otherwise. */ public static boolean isOnMainThread() { return Looper.myLooper() == Looper.getMainLooper(); } /** * Returns {@code true} if called on the main thread, {@code false} otherwise. */ public static boolean isOnBackgroundThread() { return !isOnMainThread(); } } 

 /** * 加载网络图片 */ private void loadImage() { //判断是否在子线程。 子线程：继续执行 主线程：抛出异常 ThreadUtil.assertBackgroundThread(); try { //用延时3秒操作来模拟网络操作 Thread.sleep( 3000 ); } catch (InterruptedException e) { e.printStackTrace(); } } 

 new Thread(new Runnable() { @Override public void run() { loadImage(); } }).start();