1 /* 2 * Copyright (C) 2009 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package com.android.contacts.util; 18 19 import android.os.AsyncTask; 20 21 import java.lang.ref.WeakReference; 22 23 public abstract class WeakAsyncTask<Params, Progress, Result, WeakTarget> extends 24 AsyncTask<Params, Progress, Result> { 25 protected WeakReference<WeakTarget> mTarget; 26 27 public WeakAsyncTask(WeakTarget target) { 28 mTarget = new WeakReference<WeakTarget>(target); 29 } 30 31 /** {@inheritDoc} */ 32 @Override 33 protected final void onPreExecute() { 34 final WeakTarget target = mTarget.get(); 35 if (target != null) { 36 this.onPreExecute(target); 37 } 38 } 39 40 /** {@inheritDoc} */ 41 @Override 42 protected final Result doInBackground(Params... params) { 43 final WeakTarget target = mTarget.get(); 44 if (target != null) { 45 return this.doInBackground(target, params); 46 } else { 47 return null; 48 } 49 } 50 51 /** {@inheritDoc} */ 52 @Override 53 protected final void onPostExecute(Result result) { 54 final WeakTarget target = mTarget.get(); 55 if (target != null) { 56 this.onPostExecute(target, result); 57 } 58 } 59 60 protected void onPreExecute(WeakTarget target) { 61 // No default action 62 } 63 64 protected abstract Result doInBackground(WeakTarget target, Params... params); 65 66 protected void onPostExecute(WeakTarget target, Result result) { 67 // No default action 68 } 69 } 70
