虽说Android程序是用JAVA写的,并且在Dalvik VM中实现了JAVA的内存自动回收机制,但还是不可避免的会发生内存泄露,而且JAVA的内存泄露看起来更是诡异,如果是C写的发生内存泄露后,只要去仔细地去找分配内存的地方,再找到释放的地方是否一一对应,而且也有很多工具可以帮助你找到内存泄露.但一旦用到JAVA,就会自然觉得内存回收是虚拟机的事情,与我何干?也许正是由于JAVA的内存回收机制在我们的心目中过于强大,所以往往也就不会太在意内存的使用和回收了,写Android应用程序亦如此,至少我到现在都没怎么注意内存的回收问题.

当然一般情况下不会出现很严重的内存泄露,Android允许每个进程分配最多40M的内存,不太会因为内存使用过多而FC,但当一个进程中需要存在多个全屏的Widget,而且每个Widget都是ListView/GridView组成,并且要显示很多图片,这40M内存就显得有点太少了,如果再发生一些内存泄露,那会随便切下屏幕就有可能产生Out of memory的Exception,然后也就是经常的FC了,所以在这样的情况下管理好内存是一件很重要的事情.

转载一些文章到我的wiki.

1. Android内存泄露测试

1. Android内存管理

1. 避免内存泄露, 有效利用内存

1. Avoiding memory leaks

1. Track memory allocations

1. Memory Analyzer (MAT) For Eclipse

1. What Android tools and methods work best to find memory/resource leaks?

    private void printMemInfo(String TAG) {
        TAG += ":meminfo";
        logI(TAG, "printMemInfo:");
 
        logI(TAG, "Max heap size = " + Runtime.getRuntime().maxMemory() / 1024 / 1024 + "M");
        logI(TAG, "Allocate heap size = " + android.os.Debug.getNativeHeapAllocatedSize() / 1024 + "K");
 
        Method _readProclines = null;
        try {
            Class procClass;
            procClass = Class.forName("android.os.Process");
            Class parameterTypes[] = new Class[]{String.class, String[].class, long[].class};
            _readProclines = procClass.getMethod("readProcLines", parameterTypes);
            Object arglist[] = new Object[3];
            final String[] mMemInfoFields = new String[]{"MemTotal:", "MemFree:", "Buffers:", "Cached:"};
            long[] mMemInfoSizes = new long[mMemInfoFields.length];
            mMemInfoSizes[0] = 30;
            mMemInfoSizes[1] = -30;
            arglist[0] = new String("/proc/meminfo");
            arglist[1] = mMemInfoFields;
            arglist[2] = mMemInfoSizes;
            if (_readProclines != null) {
                _readProclines.invoke(null, arglist);
                for (int i = 0; i < mMemInfoSizes.length; i++) {
                    logI(TAG, mMemInfoFields[i] + " = " + mMemInfoSizes[i] / 1024 + "M");
                }
            }
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (SecurityException e) {
            e.printStackTrace();
        } catch (IllegalArgumentException e) {
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (InvocationTargetException e) {
            e.printStackTrace();
        } catch (NoSuchMethodException e) {
            e.printStackTrace();
        }
    }

unbindDrawables(activity.findViewById(R.id.root_view));
System.gc();

    /**
     * Unbind all the drawables.
     * @param view
     */
    private void unbindDrawables(View view) {
        if (view != null) {
            if (view.getBackground() != null) {
                view.getBackground().setCallback(null);
            }

            if (view instanceof ViewGroup && !(view instanceof AdapterView)) {
                for (int i = 0; i < ((ViewGroup) view).getChildCount(); i++) {
                    unbindDrawables(((ViewGroup) view).getChildAt(i));
                }
                ((ViewGroup) view).removeAllViews();
            }
        }
    }