1、volley引发的NetworkDispatcher

加入！！！！那句话解决

 @Override
    public void run() {
        Process.setThreadPriority(Process.THREAD_PRIORITY_BACKGROUND);
        Request<?> request;

        while (true) {
            //注意！！！！这是防止内存泄露的重点！
            request = null;
            try {

                // Take a request from the queue.
                request = mQueue.take();
            } catch (InterruptedException e) {
                // We may have been interrupted because it was time to quit.
                if (mQuit) {
                    return;
                }
                continue;
            }

            try {
                request.addMarker("network-queue-take");

                // If the request was cancelled already, do not perform the
                // network request.
                if (request.isCanceled()) {
                    request.finish("network-discard-cancelled");
                    continue;
                }

                // Tag the request (if API >= 14)
                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.ICE_CREAM_SANDWICH) {
                    TrafficStats.setThreadStatsTag(request.getTrafficStatsTag());
                }

                // Perform the network request.
                NetworkResponse networkResponse = mNetwork.performRequest(request);
                request.addMarker("network-http-complete");

                // If the server returned 304 AND we delivered a response already,
                // we're done -- don't deliver a second identical response.
                if (networkResponse.notModified && request.hasHadResponseDelivered()) {
                    request.finish("not-modified");
                    continue;
                }

                // Parse the response here on the worker thread.
                Response<?> response = request.parseNetworkResponse(networkResponse);
                request.addMarker("network-parse-complete");

                // Write to cache if applicable.
                // TODO: Only update cache metadata instead of entire record for 304s.
                if (request.shouldCache() && response.cacheEntry != null) {
                    mCache.put(request.getCacheKey(), response.cacheEntry);
                    request.addMarker("network-cache-written");
                }

                // Post the response back.
                request.markDelivered();
                mDelivery.postResponse(request, response);
            } catch (VolleyError volleyError) {
                parseAndDeliverNetworkError(request, volleyError);
            } catch (Exception e) {
                VolleyLog.e(e, "Unhandled exception %s", e.toString());
                mDelivery.postError(request, new VolleyError(e));
            }
        }
    }

2、Volley StringRequest等引起的内存泄漏

（1）在引用StringRequest的地方给request添加tag
     request.setTag(REQUEST_TAG);
（2）在不用的时候
 @Override
 protected void onDestroy() {
     super.onDestroy();
     RequestManager.getRequestQueue().cancelAll(ShortUrlFactory.REQUEST_TAG);
 }

3、EventBus引发的内存泄漏

//取消注册 , 防止Activity内存泄漏
EventBus.getDefault().unregister( this );

4、Webview引发的内存泄漏

（1）//延长webview的生命周期，防止内存泄漏
    mContext = this.getContext().getApplicationContext();
（2）在onDestroy时取消webview的绑定，并销毁
 @Override
    protected void onDestroy() {
        super.onDestroy();
        if (webView != null) {
            // 如果先调用destroy()方法，则会命中if (isDestroyed()) return;
            // 这一行代码，需要先onDetachedFromWindow()，再
            // destory()
            ViewParent parent = webView.getParent();
            if (parent != null) {
                ((ViewGroup) parent).removeView(webView);
            }
            webView.stopLoading();
            // 退出时调用此方法，移除绑定的服务，否则某些特定系统会报错
            webView.getSettings().setJavaScriptEnabled(false);
            webView.clearHistory();
            webView.clearView();
            webView.removeAllViews();
            webView.destroy();
            webView = null;
        }
    }

5、Surface要release

 mSurface.release();