Android 多图片情况下，发生内存溢出的解决办法

由于在项目中有用到多图片的处理，这里的图片在60张以上，本篇所采取的案例均通过测试，在模拟器上都可以很流畅的使用。

本篇关键节点如下：

1、图片显示采取GridView控件，图片源头由res下drawable资源文件；

2、获取资源图片的时候采取AsyncTask进行操作；

3、图片缓存采取LinkedHashMap<Integer, Bitmap>，需要注意的是：

static LinkedHashMap<Integer, Bitmap> hard = new LinkedHashMap<Integer, Bitmap>(6, 0.75f, true);

4、进行手动内存回收，方式为在adapter 的getView里面进行主动回收，具体查看下面实例代码；

5、图片压缩采取 BitmapFactory.Options ，opt.inSampleSize = 4;

示例代码：

package com.demo.image;

import java.lang.reflect.Field;
import java.util.ArrayList;

import android.app.Activity;
import android.os.Bundle;
import android.widget.GridView;

import com.demo.R;

/**
 * 目前在模拟器上都比较流畅，需要再加多图片试试 05-14
 * 
 * 
 * 
 * @author Michael ku
 * 
 *         2015-5-14 下午9:18:37
 */
public class DemoImage extends Activity {
	final static int CWJ_HEAP_SIZE = 6 * 1024 * 1024;

	public void onCreate(Bundle bun) {
		super.onCreate(bun);
		this.requestWindowFeature(1);

		// 设置最小heap内存为6MB大小。当然对于内存吃紧来说还可以通过手动干涉GC去处理
		// VMRuntime.getRuntime().setMinimumHeapSize(CWJ_HEAP_SIZE);

		this.setContentView(R.layout.activity_demo_image);

		grid = (GridView) this.findViewById(R.id.image_grid);

		adapter = new ImageAdapter(this, getDatas());
		grid.setAdapter(adapter);
	}

	ImageAdapter adapter;

	public void onDestroy() {
		super.onDestroy();

		if (adapter.data != null) {
			adapter.data.clear();
		}
		ImageAdapter.hard.clear();
	}

	private static ArrayList<Integer> getDatas() {

		ArrayList<Integer> result = new ArrayList<Integer>();
		Field[] fs = R.drawable.class.getDeclaredFields();
		for (Field fi : fs) {
			try {
				result.add(fi.getInt(R.drawable.class));

			} catch (IllegalArgumentException e) {
				e.printStackTrace();
			} catch (IllegalAccessException e) {
				e.printStackTrace();
			}
		}

		return result;
	}

	GridView grid;

}// end

package com.demo.image;

import java.util.ArrayList;
import java.util.LinkedHashMap;

import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.AsyncTask;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;

import com.demo.R;

/**
 * 
 * 
 * 
 * 
 * @author Michael ku
 * 
 *         2015-5-14 下午9:19:48
 */
public class ImageAdapter extends BaseAdapter {

	ArrayList<Integer> data;
	private Activity base;

	public ImageAdapter(Activity ac, ArrayList<Integer> srcs) {
		this.data = srcs;
		base = ac;
	}

	public int getCount() {

		return data.size();
	}

	public Object getItem(int position) {

		return data.get(position);
	}

	public long getItemId(int position) {

		return position;
	}

	public View getView(int position, View convertView, ViewGroup parent) {
		Holder holder = null;
		if (convertView == null) {
			convertView = base.getLayoutInflater().inflate(
					R.layout.image_demo_item, null);
			holder = new Holder(convertView);
			convertView.setTag(holder);
		} else {
			holder = (Holder) convertView.getTag();
			resetHolder(holder);
		}

		int resid = data.get(position);
		if (resid > 0) {

			if (hard.get(position) != null) {
				holder.img.setImageBitmap(hard.get(position));
			} else {

				new Task(holder.img, position).execute(resid);

			}
		}
		if (position % 7 == 6) {
			System.gc();
		}

		return convertView;
	}

	static LinkedHashMap<Integer, Bitmap> hard = new LinkedHashMap<Integer, Bitmap>(
			6, 0.75f, true);

	private class Task extends AsyncTask<Integer, Void, Bitmap> {
		int position;
		ImageView image;

		Task(ImageView img, int posi) {
			position = posi;
			image = img;
		}

		protected Bitmap doInBackground(Integer... params) {

			Bitmap bm = BitmapFactory.decodeResource(base.getResources(),
					params[0], getOpt());

			hard.put(position, bm);

			return bm;
		}

		protected void onPostExecute(Bitmap result) {
			super.onPostExecute(result);

			if (result != null) {
				image.setImageBitmap(result);
			}
		}
	}

	static BitmapFactory.Options getOpt() {

		BitmapFactory.Options opt = new BitmapFactory.Options();
		opt.inSampleSize = 4;

		return opt;
	}

	private void resetHolder(Holder ho) {
		ho.img.setImageResource(0);
	}

	private class Holder {
		ImageView img;

		Holder(View view) {
			img = (ImageView) view.findViewById(R.id.item_image);
		}
	}
}// end

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:gravity="center"
    android:orientation="vertical" >

    <ImageView
        android:id="@+id/item_image"
        android:layout_width="80dip"
        android:layout_height="80dip"
        android:contentDescription="@string/app_name" />

</LinearLayout>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <GridView
        android:id="@+id/image_grid"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:horizontalSpacing="10dip"
        android:numColumns="auto_fit"
        android:stretchMode="columnWidth"
        android:columnWidth="80dip"
        android:verticalSpacing="10dip" />

</LinearLayout>

资源文件，图片





测试虚拟机



以上就是全部的测试代码。



上面这个是在网上看到的，我在测试的时候没有通过，提示找不到这个类，如果有知道的朋友，提示下呗！