package de.bvb.study.common; /** * 用于规范 Message.what此属性,避免出现魔法数字 */ public final class What { public static final int ZERO = 0; public static final int ONE = 1; /** 标记异步操作返回时目标界面已经消失时的处理状态 */ public static final int ACTIVITY_GONE = -1; }
package de.bvb.study.common; import android.app.Activity; import android.os.Handler; import android.os.Message; import android.support.v4.app.Fragment; import java.lang.ref.WeakReference; import de.bvb.study.util.LogUtil; /** * handler包装类 */ public abstract class BaseHandler extends Handler { protected WeakReference<Activity> activityWeakReference; protected WeakReference<Fragment> fragmentWeakReference; private BaseHandler() {}//构造私有化,让调用者必须传递一个Activity 或者 Fragment的实例 public BaseHandler(Activity activity) { this.activityWeakReference = new WeakReference<>(activity); } public BaseHandler(Fragment fragment) { this.fragmentWeakReference = new WeakReference<>(fragment); } @Override public void handleMessage(Message msg) { if (activityWeakReference == null || activityWeakReference.get() == null || activityWeakReference.get().isFinishing()) { // 确认Activity是否不可用 LogUtil.i("Activity is gone"); handleMessage(msg, What.ACTIVITY_GONE); } else if (fragmentWeakReference == null || fragmentWeakReference.get() == null || fragmentWeakReference.get().isRemoving()) { //确认判断Fragment不可用 LogUtil.i("Fragment is gone"); handleMessage(msg, What.ACTIVITY_GONE); } else { handleMessage(msg, msg.what); } } /** * 抽象方法用户实现,用来处理具体的业务逻辑 * * @param msg * @param what {@link What} */ public abstract void handleMessage(Message msg, int what); }
package de.bvb.study.ui.activity; import android.app.Activity; import android.os.Bundle; import android.os.Message; import de.bvb.study.common.BaseHandler; import de.bvb.study.common.What; public class LoginActivity extends BaseActivity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); new Thread(new Runnable() { @Override public void run() { handler.obtainMessage(What.ZERO, "data 0").sendToTarget(); } }).start(); new Thread(new Runnable() { @Override public void run() { handler.obtainMessage(What.ONE, "data 1").sendToTarget(); } }).start(); } MyHandler handler = new MyHandler(this); private static class MyHandler extends BaseHandler { public MyHandler(Activity activity) { super(activity); } @Override public void handleMessage(Message msg, int what) { switch (what) { case What.ZERO: break; case What.ONE: break; case What.ACTIVITY_GONE: break; } } } }
时间: 2024-10-25 02:22:50