關於

好久沒有更新文章了，感覺該寫點什麼了。就簡單點的啦，這次分享一個Activity管理工具，輕鬆關閉想關閉的頁面。寫這個的原因也是因為，在當前頁面需要關閉上一個頁面或其他之前開啟的頁面。其實網上也有很多的辦法，比如static修飾，比如Application、佇列管理等等，感比較麻煩，不注意容易記憶體洩漏。所以自己搞了一個管理類，只需要在Application中的onCreate方法中初始化一次，就OK了，剩下的就是你要關哪個頁面了。

演示

還是先來個GIF圖演示一下吧

操作

• 初始化

自定義Application，在onCreate中新增XActivityManager.addActivityListener(this);

public class App extends Application {
    @Override
    public void onCreate() {
        super.onCreate();
        XActivityManager.addActivityListener(this);
    }
}
複製程式碼

• 怎麼用？ 假如說當前有Activity：MainActivity、OneActivity、TwoActivity、ThreeActivity、FourActivity、FiveActivity

1. 當你在ThreeActivity關閉TwoActivity：

XActivityManager.getInstance().finishActivityByName(TwoActivity.class);
複製程式碼

2. 當你在FourActivity想關閉所有Activity排除MainActivity

XActivityManager.getInstance().finishAllExceptThisActivity(MainActivity.class);
複製程式碼

實現思路

程式碼在下面大家可以先看一看

1. 程式碼的主要思路在於新增了關於Application對Activity的監聽，當監聽到有Activity執行是則新增到Map中，如果Activity銷燬則從Map中刪除。
2. 用Map管理，是方便與通過名字就可以finish掉Activity。
3. 由於可能造成記憶體洩漏，Map新增的是含有Activity的WeakReference。
4. 通過方法傳入Activity的class，然後獲取Activity名字，通過Map的key得到Activity。

程式碼

import android.app.Activity;
import android.app.Application;
import android.os.Build;
import android.os.Bundle;
import android.util.Log;
import java.lang.ref.WeakReference;
import java.util.HashMap;
import java.util.Map;

public class XActivityManager {
    private static XActivityManager sInstance = new XActivityManager();
    private WeakReference<Activity> sCurrentActivityWeakRef;
    private Map<String, WeakReference<Activity>> mAllActivity;


    private XActivityManager() {
        mAllActivity = new HashMap<>();
    }

    public static XActivityManager getInstance() {
        return sInstance;
    }

    /**
     * 獲取當前Activity
     * @return
     */
    public Activity getCurrentActivity() {
        Activity currentActivity = null;
        if (sCurrentActivityWeakRef != null) {
            currentActivity = sCurrentActivityWeakRef.get();
        }
        return currentActivity;
    }

    private void setCurrentActivity(Activity activity) {
        sCurrentActivityWeakRef = new WeakReference<>(activity);
        mAllActivity.put(activity.getClass().getSimpleName(), sCurrentActivityWeakRef);
        for (Map.Entry<String, WeakReference<Activity>> entry :
                mAllActivity.entrySet()) {
            WeakReference<Activity> wr = entry.getValue();
            if (wr.get() == null) continue;
            Log.i("XActivityManager", "當前活動Activity:" + wr.get().getClass().getSimpleName());
        }

        Log.i("XActivityManager", "---------------------------------------");
    }

    private void removeThisActivity(Activity activity) {
        mAllActivity.remove(activity.getClass().getSimpleName());
    }

    /**
     * 通過Activity 名字幹掉這個Activity
     *
     * @param activityClass
     */
    public void finishActivityByName(Class<? extends Activity> activityClass) {
        WeakReference<Activity> wr = mAllActivity.get(activityClass.getSimpleName());
        if (wr == null) return;
        Activity activity = wr.get();
        if (
                activity == null
                || activity.isFinishing()
                || (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1 && activity.isDestroyed())
                )
            return;
        activity.finish();
    }

    /**
     * 幹掉所有的activity排除這個Activity
     */
    public void finishAllExceptThisActivity(Class<? extends Activity> activityClass) {
        for (Map.Entry<String, WeakReference<Activity>> entry :
                mAllActivity.entrySet()) {
            WeakReference<Activity> wr = entry.getValue();
            if (
                    wr.get() == null
                    || wr.get().isFinishing()
                    || (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1 && wr.get().isDestroyed())
                    || entry.getKey().equals(activityClass.getSimpleName())
                    )
                continue;
            wr.get().finish();
        }
    }

    /**
     * 新增對Activity的監聽
     */
    public static void addActivityListener(Application app) {

        app.registerActivityLifecycleCallbacks(new Application.ActivityLifecycleCallbacks() {
            @Override
            public void onActivityCreated(Activity activity, Bundle savedInstanceState) {
            }

            @Override
            public void onActivityStarted(Activity activity) {

            }

            @Override
            public void onActivityResumed(Activity activity) {
                XActivityManager.getInstance().setCurrentActivity(activity);
            }

            @Override
            public void onActivityPaused(Activity activity) {

            }

            @Override
            public void onActivityStopped(Activity activity) {

            }

            @Override
            public void onActivitySaveInstanceState(Activity activity, Bundle outState) {

            }

            @Override
            public void onActivityDestroyed(Activity activity) {
                XActivityManager.getInstance().removeThisActivity(activity);
            }
        });
    }

}
複製程式碼

---

END